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THESIS

THE PHYSICAL OCEANOGRAPHY

OF THE

NORTHERN BAFFIN BAY-NARES STRAIT REGION

by

Victor G. Addison, Jr.

December 1987

Thesis Advisor

R.H. Bourke

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This thesis was prepared in conjunction with research sponsored by the
Arctic Submarine Laboratory, Naval Ocean Systems Center, San Diego, California
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TiTic. (inciuae iecunty Claudication)

THE PHYSICAL OCEANOGRAPHY OF THE NORTHERN BAFFIN BAY-NARES STRAIT REGION

PERSONAL AUTHOR(S)

Addision, Victor G., Jr.

la TYPE OF REPORT

Master's Thesis

13d TiME COVERED
FROM TO

14 DATE OF REPORT ( Year, Month, Day)

1987 December

15 PAGE COUNT

110

) SUPPLEMENTARY NOTATION

Prepared in conjunction with R.H. Bourke and R.G. Paquette

COSATi CODES

FIELD

GROUP I SUBGROUp

16 SUBJECT TERMS iContinue on reverse it neceuary ana taentiry Dy tuocx numoer)

Baffin Bay
Nares Strait

SIR JOHN FRANKLIN
North Water

) ABSTRACT (Continue on reverse it necessary arxj identity oy block numoer)

A dense network of conductivity-temperature-depth (CTD) measurements was conducted from
affin Bay northward to 82"09'N at the entrance to the Lincoln Sea, in most comprehensive
>hysical oceanographic survey ever performed in the northern Baffin Bay-Nares Strait (NBB-NS)
egion. These data indicate Nares Strait Atlantic Intermediate Water (NSAIW) and Arctic
asin Polar Water (ABPW) to be derived from Arctic Basin waters via the Canadian Archipelago,
'hereas the West Greenland (WGC) is the source of the comparatively dilute West Greenland
:urrent Atlantic Intermediate Water (WGCAIW) and West Greenland Current Polar Water (WGCPW)
Tactions. Baffin Bay Surface Water (BBSW) is found seasonally throughout northern Baffin
»ay. Recurvature of component branches of the WGC, which attains a maximum baroclinic
ransport of 0.7 Sv, occurs primarily in Melville Bay (0.2 Sv) , south of the Carey Islands
0.1 Sv) and ultimately in Smith Sound (0.2 Sv) . The Baffin Current originates as an
ce-edge Jet in Smith Sound and is augmented by net outflow from Smith, Jones, and Lancaster
ounds at rates of 0.3 Sv, 0.3 Sv and 1.1 Sv, respectively. Circulation in Sxr.ith, Jones and

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Block 18 (continued)

Geostrophic Estuarine Circulation
Lancaster Sound
Jones Sound

Smith Sound
Kane Basin
Melville Bay

niock 19 (continued)

Lancaster Sounds can be described in terms of the Geostrophic Estuarine
Circulation Model (GEO. The North Water is caused by the combined influences
of near-surface layer enthalpy and mechanical ice removal.

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The Physical Oceanography of the
Northern Baffin Bay-Nares Strait Region

by

Victor G. Addison, Jr.

Lieutenant, United States Navy

B.S., State University of New York, Stony Brook, 1979

Submitted in partial fulfillment of the
requirements for the degree of

MASTER OF SCIENCE IN METEOROLOGY AND OCEANOGRAPHY

from the

NAVAL POSTGRADUATE SCHOOL
December 1987

^ ■

ABSTRACT
A dense network of conductivity- temperature -depth (CTD) measurements
was conducted from Baffin Bay northward to 82'09'N at the entrance to
the Lincoln Sea, in the most comprehensive physical oceanographic survey
ever performed in the northern Baffin Bay-Nares Strait (NBB-NS) region.
These data indicate Nares Strait Atlantic Intermediate Water (NSAIW) and
Arctic Basin Polar Water (ABPW) to be derived from Arctic Basin waters
via the Canadian Archipelago, whereas the West Greenland Current (WCC)
is the source of the comparatively dilute West Greenland Current
Atlantic Intermediate Water (WGCAIW) and West Greenland Current Polar
Water (WGCPW) fractions. Baffin Bay Surface Water (BBSW) is found
seasonally throughout northern Baffin Bay. Recurvature of component
branches of the WGC , which attains a maximum baroclinic transport of
0.7 Sv, occurs primarily in Melville Bay (0.2 Sv) , south of the Carey
Islands (0.1 Sv) and ultimately in Smith Sound (0.2 Sv) . The Baffin
Current originates as an ice-edge jet in Smith Sound and is augmented by
net outflow from Smith, Jones, and Lancaster Sounds at rates of 0.3 Sv,
0.3 Sv and 1.1 Sv, respectively. Circulation in Smith, Jones and
Lancaster Sounds can be described in terms of the Geostrophic Estuarine
Circulation Model (GEC). The North Water is caused by the combined
influences of near-surface layer enthalpy and mechanical ice removal.

TABLE OF CONTENTS

I . INTRODUCTION 12

A. PURPOSE 12

B. BACKGROUND 13

1 . Bathymetry 15

2 . General Circulation 16

3 . Water Masses 19

4 . The North Water 20

II . METHODS AND MEASUREMENTS 23

A. CRUISE SUMMARY 23

B. INSTRUMENTATION 23

C. DATA REDUCTION AND ANALYSIS 2 5

III. THERMOHALINE STRUCTURE 28

A. INTRODUCTION 28

B. BAFFIN BAY SURFACE WATER 28

C . POLAR WATER 34

D. ATLANTIC INTERMEDIATE WATER 53

IV. CIRCULATION AND TRANSPORT 58

A . INTRODUCTION 58

B . DYNAMIC TOPOGRAPHY 58

C . THE WEST GREENLAND CURRENT 61

D. CIRCULATION IN NARES STRAIT 65

E . THE BAFFIN CURRENT 70

F . CIRCULATION IN THE SOUNDS 71

1 . Introduction 71

2 . Smi th Sound 71

3 . Jones Sound 73

4 . Lancaster Sound 75

5. Geostrophic Estuarine Circulation 75

G . BAROCLINIC TRANSPORTS 82

V . THE NORTH WATER PROCESS 88

VI. DISCUSSION 92

VII . CONCLUSIONS 94

APPENDIX: COMPUTATIONS ASSOCIATED WITH THE GEC MODEL 96

LIST OF REFERENCES 98

INITIAL DISTRIBUTION LIST 100

LIST OF TABLES

I. NEAR-SURFACE AND INTERMEDIATE- DEPTH WATERS OF THE NORTHERN
BAFFIN BAY-NARES STRAIT REGION 29

II. GEOSTROPHIC ESTUARINE CIRCULATION MODEL CALCULATIONS 79

LIST OF FIGURES

1.1 A chart of the northern Baffin Bay-Nares Strait region 14

1.2 The West Greenland Current and the Baffin Current (from
Muench, 1971, p. 2) 17

1.3 The approximate monthly mean extent of the North Water

(from Dunbar, 1970, P- 279) 21

2.1 The locations of CTD stations conducted during the September
1986 cruise of CCGS SIR JOHN FRANKLIN 24

2.2 The locations of transects used in the analysis 26

3.1 A composite temperature profile illustrating the shallow
thermocline characteristic of BBSW 31

3.2 The horizontal distribution of maximum temperatures in

the BBSW layer 32

3.3 A T/S transect northeastward across Melville Bay 33

3.4 A meridional T/S transect from Baffin Bay northward to

Kane Basin 35

3.5 A composite salinity profile illustrating the dilution of
WGCPW relative to ABPW 37

3.6 A composite density profile illustrating the dilution of
WGCPW relative to ABPW 38

3.7 A composite T/S curve illustrating knee salinities
characteristic of WGCPW and ABPW 39

3.8 A composite T/S curve illustrating the absence of a sharp

knee in stations north of Smith Sound 41

3.^ The horizontal distribution of ABPW and WGCPW in the NBB-NS

region 42

3.10 A composite temperature profile illustrating the interleaving
of ABPW and WGCPW in Smith Sound. Jones Sound and

Melville Bav 44

3.11 A T/S transect northward across Melville Bav 4 5

3.12 A T/S transect across Kane Basin 46

3.13 A T/S transect across the southern entrance to Kane Basin.... 48

8

3.14 A T/S transect across the mouth of Jones Sound 49

3.15 A T/S transect across the mouth of Lancaster Sound 50

3.16 A composite density profile illustrating the magnitude of
glacial meltwater- induced stair-stepped layering in Kane
Basin 51

3.17 A T/S transect in Robeson Channel 52

3.18 The horizontal distribution of NSAIW and WGCAIW in the

NBB-NS region 54

3.19 A meridional T/S transect from Kane Basin northward

through Kennedy and Robeson Channels 56

3 . 20 A T/S transect Jones Sound eastward to Thule 57

4.1 Surface circulation in the NBB-NS region 59

4.2 The surface dynamic topography referenced to 200

decibars , in dynamic centimeters 60

4.3 A baroclinic velocity cross section through Melville Bay 63

4.4 A baroclinic velocity cross section from Jones Sound
eastward to Thule 64

4.5 A meridional baroclinic velocity cross section from Baffin

Bay northward to Kane Basin 66

4.6 A baroclinic velocity cross section through a southern

part of Kennedy Channel 67

4.7 A baroclinic velocity cross section through the southern
portion of the Kane Basin Gyre 69

4.8 A baroclinic velocity cross section through Smith Sound 72

4.9 A baroclinic velocity cross section through Jones Sound 74

4.10 A baroclinic velocity cross section through Lancaster Sound.. 76

4.11 A schematic cross section of coastal upper layer flow

(from Leblond, 1980, p. 191) ' 77

4.12 Surface dynamic height anomalies in Lancaster Sound
(in dynamic cm) relative to 300 dbar level (from

Fissel et al . , 1982, p. 187) 80

4.13 Dvnamic topography of the surface relit r> to '><)<) dbars in
Jones Sound for various years (from Muench, l1'/!. p. 92) 83

9

4.14 Major baroclinic transports in the NBB-NS region 85

5.1 Enthalpy of the near-surface (upper 75 m) layer in the

NBB-NS region (referenced to -1.8°C) 90

10

ACKNOWLEDGEMENTS

Funding for the work described in this thesis was provided by the
Arctic Submarine Laboratory, Naval Ocean Systems Center, San Diego,
California under Work Order N-66001-86-WR00131 .

I wish to thank Dr. R.H. Bourke for initially providing me with the
opportunity to participate in this study, and, thereafter, for his
invaluable assistance and encouragement. Dr. R.G. Paquette is also
gratefully acknowledged for his advice and assistance and, in
particular, for this continued support during periods of severe personal
hardship.

The success of the cruise can be attributed to the enthusiasm and
dedication of the Captain and crew of the CCGS SIR JOHN FRANKLIN. I
also wish to thank A.M. Weigel , K.O. McCoy and Dr. P. Jones for their
innumerable personal contributions to this effort. Miss J.E. Bennett is
also gratefully acknowledged for her indispensable assistance in the
preparation of this manuscript.

Finally. I wish to thank my lovely wife, Karen, for being there when
I needed her.

11

I. INTRODUCTION

A. PURPOSE

During September 1986, the CCGS SIR JOHN FRANKLIN conducted an
oceanographic measurement program from Baffin Bay northward into Nares
Strait, to the southern reaches of the Lincoln Sea. This expedition
marked the first comprehensive use of continuous profiling conductivity-
temperature -depth (CTD) measurements throughout the region, and the
northernmost transit (82°09'N) of a surface ship through Nares Strait
since the 1971 voyage of the CCGS LOUIS S. ST. LAURENT. Sponsorship of
this endeavor was provided by the Arctic Submarine Laboratory, with
diplomatic concurrence from the governments of Canada and Denmark.

The principal objective of the cruise was to examine the
distribution of physical oceanographic variables from Baffin Bay
northward, in order to determine the circulation and water mass
characteristics of the region. The successful transit of the region by
the SIR JOHN FRANKLIN provides a data set from which it is possible,
essentially for the first time, to thoroughly define the baroclinic
circulation and water mass structure of the northern Baffin Bay-Nares
Strait region.

Specific objectives of the analysis will be to: (1) define the
trajectory, transport and extent of the West Greenland and Baffin
Currents; (2) describe the characteristics and extent of the water
masses found throughout the region: (3) characterize the role of
topographic steering and ba thyme trie boundaries on baroclinic

12

circulation and water mass penetration; (4) present a model which
explains the observed circulation in Smith, Jones, and Lancaster
Sounds ; and (5) present a hypothesis for the formation and maintenance
of the North Water, a large polynya located in Northern Baffin Bay.

B . BACKGROUND

The northern Baffin Bay-Nares Strait (hereinafter referred to as
NBB-NS) region is historically significant for a number of seemingly
unrelated reasons (Figure 1.1). Lancaster Sound, noted as the
traditional Atlantic entrance to the Northwest Passage and as a net
source of Arctic Ocean water inflow to the region, remains relatively
ice free during winter. Indeed, northern Baffin Bay as a whole was
thought to remain conspicuously unencumbered by ice during the winter
due to the presence of the North Water. The Humboldt Glacier, the
largest glacier in the northern hemisphere, is located on the eastern
side of Nares Strait and is the source for many of the icebergs which
are observed throughout the NBB-NS region. Once calved from the
glacier, many of these icebergs travel southward past Cape York, in
defiance of the northward flowing West Greenland Current. The most
comprehensive oceanographic analysis of the northern Baffin Bay region
is provided by Muench (1971). Muench ' s work serves as a summary of all
significant oceanographic research conducted prior to 1971, and has been
referenced in all subsequent analyses of the NBB-NS region.

Prior to 1972, all baroclinic oceanographic analyses in the NBB-NS
region were derived from bottle sampling techniques. The CCGS LOUIS S.
ST. LAURENT obtained discrete measurements of temperature and salinity
in Nares Strait during August 1971. reaching a latitude of 82°56'N

1 3

LINCOLN

65 w

55 w

Figure 1.1 A chart of the northern Baffin Bay-Nares

Strait region. Ice concentrations greater than
7/10 (during the FRANKLIN 86 cruise) are
represented as shaded areas.

14

(Sadler, 1976). During 1972, scientific personnel aboard the LOUIS S.
ST. LAURENT obtained the first winter oceanographic data from Davis
Strait utilizing an in situ salinity/temperature/depth unit (STD)
(Muench and Sadler, 1973). Transports through Nares Strait have been
investigated by Sadler (1976), providing the most accurate current meter
derived estimates of Lincoln Sea inflow to the region. In 1978 and
1979, the Eastern Arctic Marine Environment Studies ( EAMES ) program
utilized current meters and CTD stations to investigate the southward
flowing Baffin Current (Fissel et al . , 1982). Research concerning the
processes leading to the formation of the North Water has most recently
been conducted by Steffen and Ohmura (1985).
1. Bathymetry

The bottom topography of the NBB-NS region is complex and, as
such, has the potential to exert significant control over physical
oceanographic processes. The influence of glaciers on all aspects of
the morphology of this region is quite obvious.

Northern Baffin Bay is fed by Lancaster and Jones Sounds to the
west, and Smith Sound to the north. Shoaling to depths of less than
200 m occurs at some point in both Lancaster and Jones Sounds,
effectively restricting deeper Arctic Ocean inflow. A sill which ranges
in depth from 160 m to 200 m is present at the southern end of Kennedy
Channel, providing similar constraints on Lincoln Sea inflow to the
region. Similarly, shoaling to a depth of 250 m occurs at the Smith
Sound entrance to Kane Basin.

The deep, relatively flat central portion of northern Baffin
Bay is punctuated in its eastern portion l>v \ shallow < Mil) m) bank

15

located in Melville Bay. A deep (500 m to 900 m) channel passes
offshore from Cape York, terminating northward in Smith Sound. To the
west, the mouths of Jones and Lancaster Sounds reach depths of 700 m,
but the bottom northeast of Devon Island shoals to less than 200 m
approaching Smith Sound.

2 . General Circulation

The baroclinic circulation pattern in the NBB-NS region is
dominated by the northward flowing West Greenland Current (WGC) and the
southward flowing Baffin Current (Figure 1.2). Augmenting the transport
of the Baffin Current are net outflows from Jones and Lancaster Sounds,
coupled with southward flow through Nares Strait. The net baroclinic
transport through northern Baffin Bay has been computed to be
approximately 2.0 Sv (10em3s"1) southward (Muench, 1971). Muench
postulated that this transport is driven by a higher surface elevation
in the Arctic Ocean relative to that in Baffin Bay, presumed to be a
consequence of differing water structures in their respective upper
250 m layers.

Bottom topography, predominantly northerly winds, and meltwater
admixture are thought to play variable roles in the maintenance of a
cyclonic circulation pattern in northern Baffin Bay. The WGC, a
significantly barotropic current, may be enhanced baroclinically by
near-shore low salinity wedges of meltwater. Alternately, the Baffin
Current exhibits the increased baroclinic intensity characteristically
found in western boundary currents. The westward turning of the WGC off
Cape York, and the southward turning of Lancaster Sound outflow, are
both influenced by topographic steering (.Muench. le,71).

16

7CH

80*

04 f/J

STRAIT

7C"

65*

60*

55*

50*

Figure 1.2

The West Greenland Current and the Baffin
Current (from Muench, 1971, p. 2).

17

Circulation features in the NBB-NS region may be subject to
seasonal variations. Lemon and Fissel (1982) noted a general winter
weakening of near -surface baroclinic currents by a factor of two or
more. The WGC , which transports northward only 10% of the baroclinic
volume transported southward by the Baffin Current, is not always
present during late summer (Muench, 1971).

The directional components of some features of the surface and
baroclinic flow fields are temporally variable. Muench stated that
reversals of baroclinic flow have been observed in Smith and Jones
Sounds, while reversals of surface flow have occurred in Smith Sound.
Lancaster Sound, however, consistently provides net inflow to Baffin Bay
on the order of twice that of Smith or Jones Sounds (Muench, 1971).
Anticyclonic eddies (sometimes referred to as counter currents) have
been reported near Bylot Island (Fissel et al . , 1982), while cyclonic
eddies have been observed off Cape York (Muench, 1971).

Current speeds in the NBB-NS region, although variable, are
consistently greatest in magnitude near eastern Lancaster Sound. Fissel
et al . (1982), using current meters, found near-surface velocities of
0.75 m/sec in the portion of the Baffin Current located east of
Lancaster Sound. Directly measured current speeds in Nares Strait are
extremely variable in magnitude, with maximum near-surface values
ranging from 0.1 to 0.60 m/sec (Sadler, 1976). Maximum baroclinic
velocities in the WGC are on the order of 0.1 m/sec (Muench, 1971).

The nature and vertical extent of the flow regimes in the
NBB-NS region are spatially complex. Although the vertical extent of
volume flow in the WGC probably reaches .i depth ot 300 in . most

18

baroclinic flow is limited to the upper 100 m (Muench, 1971). The
Baffin Current nominally extends to a depth of 500 m, with flow reaching
the bottom (700 m to 840 m deep) in the region of its intrusion into
Lancaster Sound (Fissel et al . , 1982). Significant baroclinic flow in
this current is associated with the upper few hundred meters (Muench,
1971). The flow in Nares Strait has a substantial baroclinic component
which reaches to depths of 300 m (Sadler, 1976).
3. Water Masses

Adopting the usual convention for Arctic regions, Muench (1971)
divided the waters of northern Baffin Bay into three layers: a cold
(<0°C) upper Arctic Water layer; a warmer (>0°C) intermediate-depth
Atlantic Water layer; and a cold (<0°C) Deep Water Layer. The Arctic
Water, confined to the upper 200 m to 300 m, has an upper limit in
salinity of approximately 34.0. The Atlantic Water extends from the
bottom of the Arctic Water layer to depths of 700 m in Lancaster Sound
and 1300 m in northern Baffin Bay, exhibiting salinities of 34.2 to
34.5. Baffin Bay Deep Water extends from the bottom of the Atlantic
Layer to the seabed, and is characteristically isohaline at 34.48.

The density of water masses in the NBB-NS region, as in other
Arctic regions, is primarily determined by salinity. Surface and near-
surface layers, therefore, are usually characterized by strong
haloclines and associated pycnoclines. The delineation of a surface
(upper 75 m) layer of Arctic Water, which is modified by boundary layer
processes, has been suggested by Fissel et al . (1982). Since diverse
processes such as solar heating, meltwater admixture, and wind mixing

19

play roles in the formation of this layer, its temperature and salinity
characteristics vary seasonally.

The thermohaline characteristics of the water masses of the
region can generally be traced to their sources, while their horizontal
extent is often determined by bathymetric effects. Arctic Water is
water of Arctic Ocean origin which either entered Baffin Bay via Davis
Strait and was modified by cooling and admixture of runoff within
northern Baffin Bay, or was modified by cooling and freshening within
the Arctic Ocean prior to entering Baffin Bay from the north. Mixing of
inflowing Arctic Ocean Water and resident Baffin Bay Arctic Water of the
same density occurs in southern Smith Sound, Jones Sound, and Lancaster
Sound. Shallow sills present in Lancaster Sound, Jones Sound and
Kennedy Channel prevent southward flow of Arctic Ocean Atlantic Water
into Baffin Bay. Atlantic Water in northern Baffin Bay, therefore,
originates from the Atlantic Ocean via Davis Strait (Muench, 1971).
4. The North Water

Extensive interest has been focused on a persistent polynya,
termed the North Water, which is located in northern Baffin Bay
(Figure 1.3). Dunbar (1970) concluded that the polynya is defined by a
stable northern boundary at the Smith Sound entrance to Kane Basin, and
a consistent western ice edge which forms along Ellesmere Island. The
locations of the eastern and southern boundaries are seasonally
dependent. Significant penetration of the North Water occurs westward
into Lancaster Sound in June. The phenomenon is less well defined
during the summer season after ice break up commences. Contrary to
earlier reports, the North Water region i : not completely open during

20

ELLESMERE
ISLAND

ENLAND

BAFFIN
BAY

Figure 1 . 3

The approximate mean monthly extent of the North

Water in: March (...), April ( ), May

(---), June ( ); (from Dunbar, 1970, p.

279).

21

winter, and is characterized by extensive areas of new ice formation
(Dunbar, 1973). Steffen and Ohmura (1985) used thermal infrared
measurements from an airplane in winter to determine that the North
Water was mostly covered with new and young ice, and probably devoid of
first year ice until March. The ice surface, they surmised, was
approximately 20°C warmer than that of the surrounding fast ice.

The North Water essentially remains an unexplained phenomenon.
Muench (1971) computed a heat budget for the region and concluded that
insufficient heat is present in the Atlantic Water layer in northern
Baffin Bay to prevent ice formation. He similarly concluded that there
was not enough heat present in the surface Arctic Water layer either,
and postulated mechanical ice removal by northerly winds and currents as
the effects responsible for the formation of the North Water. Dunbar
(1973) reinforced this hypothesis by noting that the age and thickness
of ice increases from the Smith Sound ice arch southward. Steffen and
Ohmura (1985), however, computed more accurate heat budgets for the
region and concluded that oceanic heat of unknown origin is responsible
for the formation and maintenance of this polynya.

22

II. METHODS AND MEASUREMENTS

A. CRUISE SUMMARY

Between 7 and 27 September 1986, the CCGS SIR JOHN FRANKLIN
conducted the most extensive physical oceanographic survey ever
performed in the NBB-NS region. The SIR JOHN FRANKLIN covered over
4000 km in the course of conducting 145 CTD stations (Figure 2.1; refer
to Figure 2.2 for station number identification). Numerous transects
were performed while transiting from Lancaster Sound northward to
Robeson Channel, and subsequently southward to Melville Bay. Ice
reconnaissance was provided by the SIR JOHN FRANKLIN 's embarked
helicopter, which was instrumental in enabling the ship to penetrate
Robeson Channel to 82°09'N; the furthest northward of any ice breaker
since 1972.

B. INSTRUMENTATION

The instruments used were the Applied Micro Systems Limited
Conductivity-Temperature-Depth recorder, model STD-12. This instrument
has a stated accuracy of 0.02 mS/cm in electrical conductivity, 0.01°C
in temperature and no stated accuracy in depth. The resolutions were
stated to be 0.003 mS/cm, 0.001°C, and 0.05 dbar , respectively.

Three instruments, numbered 422, 433 and 467, respectively, were
utilized during the cruise. CTD #433 is the property of the Naval
Postgraduate School (NPS), and was calibrated both before and after the
cruise with resultant errors of 0.003°C in temperature and 0.007 mS/cm
in conductivity. Calibrations for the other two instruments were not
initially available, and were obtained empirically in the form of first

23

85" * b; " «

:; rt

Figure 2.1 The locations of CTD stations conducted during the
September 1986 cruise of CCGS SIR JOHN FRANKLIN.

24

degree polynomials by intercomparison with CTD #433 during simultaneous
lowerings. It is concluded that the absolute error in the variables
issmaller than 0.02°C, 0.02 mS/cm, and 2.0 dbars . The root mean square
error in salinity, therefore, is approximately 0.03.

The data were recorded internally in coded binary form, and were
downloaded into a Compaq computer for conversion into engineering units
and storage on 5.25 in. floppy diskettes. Each CTD was programmed to
sample the data stream every 0.8 dbar of pressure change. Significantly
finer resolution in pressure was not convenient because of computer
memory limitations and downloading time constraints.

The primary navigation aid was the ship's Magnavox MX 1107 Satellite
Navigation System. An average of two fixes per hour provided a mean
navigational accuracy of 0.5 km.

C. DATA REDUCTION AND ANALYSIS

Upon completion of the cruise, the data were transferred to mass
storage cartridges for further processing with the NPS IBM 3033
computer. Editing of spurious and mis-sequenced data points, the cause
of which is discussed by Tunnicliffe (1985), was subsequently performed.
Removal of dynamic response errors in temperature and salinity was
accomplished as prescribed by Bourke et al . (1986). The edited profile
data were then sub- sampled every 5 m for use in the production of
baroclinic velocity profiles and related volume transport estimates.

Transects used in the data analysis for the construction of vertical
sections are depicted in Figure 2.2. Temperature-salinity (T/S)
transects are oriented as noted, with temperature values (°C)
represented as solid lines and salinity values (Practical Salinity

25

65 «

Figure 2.2 The locations of transects used in the analysis
The dotted line denotes stations used for
construction of meridional cross sections.

26

Scale) represented as dashed lines. Baroclinic velocity cross sections
are oriented with velocities (cm/sec) "into" and "out of" the pagt
represented as solid (positive values) and dashed (negative values),
respectively.

Surface dynamic heights and baroclinic velocity profiles were
derived from the geostrophic approximation, assuming a level of no
motion of 200 dbars. The technique of Helland-Hansen (1934) was deemed
inappropriate for use in the NBB-NS region because of the inherently
shallow and irregular bathymetry, thereby precluding the selection of a
deeper reference level for regional application. Although a 200 dbar
reference level is suitable for estimating direction in near-surface
baroclinic currents, magnitudes were found to be underestimated by as
much as 25% when compared to those derived with a level of no motion of
400 dbars.

Baroclinic volume transports were calculated using variable
reference levels, determined by the maximum common sample depth in a
station pair. As the sample depths were occasionally limited by
mechanical rather than bathymetric considerations, the associated
transports may be subject to underestimation accordingly. The
transports were calculated by vertical trapezoidal integration of
baroclinic velocities over 5 m intervals.

27

III. IHfiRMOHALIEE STRUCTURE

A. INTRODUCTION

In order to more accurately characterize the near-surface and
intermediate depth waters of the NBB-NS region, a delineation of five
discrete water masses by vertical distribution of temperature and
salinity is required (Table I). Baffin Bay Surface Water (BBSW) js
derived locally and found seasonally in northern Baffin Bay at depths of
up to 75 m. It is present in both the Baffin Current and the WGC .
In general, the water masses which uniquely comprise the WGC are found
to be less saline than their counterparts which enter the NBB-NS region
through the Canadian Archipelago. Although the salinity difference
between the Polar Water fractions is small, it is useful as a
classification tool. Mixing of Arctic Basin Polar Water (ABPW) and West
Greenland Current Polar Water (WGCPW) should be expected to occur along
isopycnal surfaces in regions where their domains overlap. Although the
salinity distributions of Nares Strait Atlantic Intermediate Water
(NSAIW) and West Greenland Current Atlantic Intermediate Water (WCCAIW)
do not intersect, it is bathymetry which prevents mixing of these two
source fractions.

B. BAFFIN BAY SURFACE WATER

Baffin Bay Surface Water (BBSW) is locally derived from the combined
effects of meltwater admixture and solar heating. The large, ubiquitous
glaciers in the NBB-NS region serve as a continuous source of meltwater
during periods of insolation. Admixture of glacial runoff with Baffin
Bay Polar Water (BBPW) creates a significant halooline and resultant
pycnocline in the upper 50 m to 75 m of the water column. Concurrently,

28

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the effects of solar heating are essentially confined to this surface
layer due to its inherent buoyancy. The admittedly arbitrary
delineation of BBSW by the 0°C isotherm serves to distinguish it from
BBPW, rather than imply that the effects of insolation are restricted to
a discrete temperature range. BBSW is best identified, however, by the
presence of a strong, shallow thermocline (Figure 3.1). A seasonal
reversal of the processes which create BBSW, ultimately results in its
eliminat ion .

The distribution of BBSW is a regional phenomenon. The horizontal
distribution of maximum temperatures in the BBSW layer shows distinct
gradients in the meridional and offshore directions (Figure 3.2). This
result implies that BBSW is formed primarily by coastal processes, and
is subsequently advected throughout most of northern Baffin Bay. The
complete absence of BBSW north of Smith Sound is due to the widespread
occurrence of pack ice , which serves to raise the albedo of the region
and reduce insolation.

The considerable concentration of BBSW located in the shelf waters
of Melville Bay contributes significantly to the baroclinicity of the
WGC. A qualitative examination of a T/S transect through Melville Bay
not only indicates that a major portion of the baroclinicity occurs in
the upper 100 m, but that the isohalines (isopycnals) related to the
presence of BBSW assume a negative slope in the core of the WGC between
Stations 122 and 123 (Figure 3.3). The seasonal presence of BBSW.
therefore, would be expected to enhance the baroclinic transport of the
WGC.

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The presence of BBSW at an ice edge can be considered to represent
an equilibrium state. The northernmost extent of BBSW is precisely
correlated with the location of the pack ice edge. A meridional T/S
transect from Baffin Bay northward to Kane Basin graphically illustrates
this interaction between relatively warm surface water and an ice edge
(Figure 3.4). A filament of BBSW dives subsurface between Stations 44
and 47 beneath water of lower density at the ice edge. An equilibrium
state can exist if sufficient thermal advection is present to prevent
ice growth. Mitigation of thermal advection or atmospheric cooling will
cause the ice edge to advance or retreat, respectively.

C. POLAR WATER

Polar Water in the NBB-NS region is derived from two distinct
sources. Direct inflow from the Arctic Ocean through the Canadian
Archipelago is generically classified as Arctic Basin Polar Water
(ABPW) , whereas northward flow via the WGC through Davis Strait is
termed West Greenland Current Polar Water (WGCPW) . Subtle contrasts in
the thermohaline signatures of these two water masses are indicative of
their different origins, and serve as qualitative tracers of their
respective flow fields.

Although both forms of Polar Water have origins in the Arctic Ocean,
the flow of WGCPW follows a circuitous route around the southern tip of
Greenland before entering the NBB-NS region. The cumulative influence
of shelf and surf ace -driven processes on the thermohaline structure of
WGCPW is, therefore, of greater magnitude than the effect of similar
processes on ABPW. The primary modification which occurs is due to
meltwater admixture, resulting in a net dilution of the water column.

34

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Viewed simplistically , WGCPW can be considered a diluted form of ABPW.
The comparative decrease in salinity and, hence, density of WGCPW below
the surface layer is most apparent in vertical property profiles
(Figures 3.5 and 3.6). The maximum salinity of WGCPW is approximately
34.2, while ABPW reaches 34.8.

The presence of Polar Water with an underlying warm layer produces
a characteristic inflection, or knee, when temperature is plotted
against salinity. This knee can be viewed as a boundary between the
bottom of the arctic halocline, formed as a consequence of convective
overturn in winter, and a deeper thermocline, which marks the transition
to an underlying warm layer. The salinity and depth at which this knee
occurs are functions of the inherent thermohaline characteristics of the
particular Polar Water mass. The combination of relatively dilute WGCPW
and underlying Atlantic Intermediate Water results in a knee with a
salinity of 33.4 to 33.5, at depths ranging typically from 50 m to 120
m. As ABPW enters the NBB-NS region through Lancaster Sound, for
instance, it is subject to interleaving and mixing along isopycnal
surfaces. This comparatively undiluted inflow is characteristically
more dense than the resident Polar Water of northern Baffin Bay, and
consequently sinks. The resultant combination of comparatively saline
ABPW and underlying Atlantic Intermediate Water produces a knee with
salinities between 33.5 and 33.7, at depths of up to 250 m. A composite
T/S curve illustrates the contrasting knee salinity ranges of WGCPW and
ABPW (Figure 3.7) .

A reduction in significant insolation in the near-surface layer, or
the absence an underlying warm laver . will result in a weaker thermal

36

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gradient and a bend, rather than a sharply defined knee, in the curve.
This condition is apparent north of Smith Sound due to the widespread
occurrence of pack ice, with an associated increase in albedo
(Figure 3.8) .

The thermohaline characteristics of the two Polar Water masses can
be used to roughly estimate the horizontal extent of their flow
regimes. A plan view of Polar Water distributions indicates that inflow
of WGCPW represents the minority fraction of Polar Water in the NBB-NS
region (Figure 3.9). WGCPW is prevalent along the West Coast of
Greenland northward to Cape York, where a bifurcation in flow creates
one filament which extends to Smith Sound and another which projects
westward into Jones Sound. Northward passage of WGCPW into Kane Basin
was not observed.

ABPW is present from the Lincoln Sea to the southern end of Kane
Basin, and throughout the central and western portions of Baffin Bay.
The presence of ABPW at stations north of 77°N not only suggests that
Smith Sound is a mixing site for the two Polar Water masses, but is
indicative of southward passage of ABPW from Nares Strait into northern
Baffin Bay. Inflow of ABPW is restricted to the southernmost portion of
Jones Sound, implying significant mixing there as well. Inflow of ABPW
to the region is greatest in Lancaster Sound, as indicated by the
consistently high knee salinities encountered there. A filament of
ABPW can be seen in the southwestern corner of Melville Bay at Stations
132 and 133, which marks the location of a frontal boundary between an
extreme northeastern branch of the Baffin Current, possibly derived from
Lancaster Sound outflow, and a southward f Lowing branch of the WGC . The

40

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42

extensive interleaving which would be expected in regions such as these,
where ABPW and WGCPW coexist, is evident in composite temperature
profiles (Figure 3.10).

The presence of subsurface temperature extremes in the Polar Water
layer is associated with the contrasting effects of convective overturn
in winter and insolation in summer. Convective overturn during ice
formation creates a cold, isohaline layer which can project to a depth
of greater than 50 m locally. Lateral infusion of brine produced during
the freezing of shelf waters can increase the vertical extent of this
isohaline layer to over 100 m. Subsequent surface heating and meltwater
mixture produces significant enthalpy increases in the shallow
pycnocline layer only, isolating an underlying cold lens at depths
typically between 50 m and 150 m.

South of Smith Sound cold lenses are sharply defined by strong
temperature gradients. This is typically the case in Melville Bay,
where cold, isohaline water is sandwiched between an overlying layer of
BBSW and an underlying layer of Atlantic Intermediate Water
(Figure 3.11).

The absence of cold lenses north of Smith Sound is indicative of
the inherently persistent ice cover. The associated high albedo
results in steadily decreasing temperatures towards the surface and,
consequently, no subsurface cold lenses are apparent north of
Station 72, located at approximately 79.2°N (Figure 3.12).

Southward decreases in ice concentration result in the formation of
diffuse cold lenses in northern Smith Sound. A T/S transect taken at
the southern entrance to Kane Basin reveals tin- remnants of a subsurface

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46

cold lens on the western side, and alternating warm and cold layers to
the east (Figure 3.13).

Pronounced warm lenses are located on the southern side of
Lancaster Sound, and along both boundaries of Jones Sound. Conditions
in Jones Sound, with ambient air temperatures averaging -4°C and the
presence of new ice observed along both shores, indicate that the local
occurrence of subsurface lenses of BBSW is due to the initiation of
convective overturn (Figure 3.14). The warm lens in southern Lancaster
Sound is a sharply defined feature located at a depth of approximately
lOn m (Figure 3.15). The depth of this warm lens indicates that it is
probably an outflow jet of ABPW which dives subsurface upon
encountering a cooler, but comparatively less saline layer of resident
Polar Water. This effect further illustrates the point that ABPW is
more saline than the residual Polar Water mixture of northern Baffin
Bay, and is subject to mixing along isopycnals at deeper depths.

The major source of meltwater in the NBB-NS region is the Humboldt
Glacier, located on the eastern side of Kane Basin. All stations in
Kane Basin south of approximately 79°56'N (Station 84) have low surface
salinities, typically approaching 31.0, and exhibit significant stair-
stepped layering in vertical density structure (Figure 3.16). This not
only illustrates the magnitude of glacial influence in the region, but
suggests that extensive recirculation of near-surface waters may occur
in Kane Basin. A significant local source of meltwater is apparent in
the northwest corner of Robeson Channel, where surface salinities were
generally below 30.0, the lowest encountered in the NBB-NS region
(Figure 3.17) .

47

NW STA NO 55
O

200

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800

1000

78*57 9'N
075*00 OW

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40 60

DISTANCE (Km)

80

100

Figure 3.13 A T/S transect across the southern entrance to Kane
Basin. Note the remnant of a cold lens at Station
55, and alternating warm and cold layers to the
east .

48

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0

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DISTANCE (Km)

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Figure 3.14 A T/S transect across the mouth of Jones Sound

49

S STA. NO. 1
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60

Figure 3.15 A T/S transect across the mouth of Lancaster
Sound .

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Figure 3. 17 A T/S transect in Robeson Channel

52

D. ATLANTIC INTERMEDIATE WATER

The two Atlantic Intermediate Water fractions found in the NBB-NS
region exhibit inherently different salinity characteristics and
exclusive horizontal distributions. Nares Strait Atlantic Intermediate
Water (NSAIW) is derived from the Atlantic Layer of the Arctic Basin
and flows southward from the Lincoln Sea into Nares Strait. West
Greenland Current Atlantic Intermediate Water (WGCAIW) flows northward
through eastern Davis Strait, advected by the WGC into northern Baffin
Bay.

WGCAIW is warmer but less saline than NSAIW. Following the same
line of reasoning which requires subdivision of the Polar Water
fractions, WGCAIW is subject to more significant dilution effects by
shelf and surf ace -driven processes compared to direct inflow from the
Arctic Basin. Since CTD cast depths were not deep enough to reach the
bottom of the WGCAIW layer, the upper limit in salinity presented in
Table I for this water mass should be considered an estimate. The
maximum salinity encountered in WGCAIW was 34.44, at a depth of 562 m
(Station 124), whereas a maximum salinity of 35.24 was recorded for
NSAIW at a depth of 481 m (station 97). The comparatively lower
temperatures in NSAIW are a reflection of the general north-south
temperature gradient in the region. The highest Atlantic Layer
temperature recorded in NSAIW was 0.20°C at a depth of 715 m
(Station 95), in contrast with a maximum temperature of 1.81°C, recorded
at a depth of 445 m (Station 133) for WGCAIW.

The horizontal distributions of NSAIW and WGCAIW in the NBB-NS
region are primarily determined bv topographic influences 'Figure 5.18).

53

»oo*' 1

r\ )/ btlotV-''^;-' /'

Figure 3.18 The horizontal distribution of NSAIW and WCCAIW
in the NBB-NS region.

54

Southward passage of NSAIW into Kane Basin is prevented by shoaling of
the sea floor in southern Kennedy Channel (Figure 3.19). Although the
major portion of WCCAIW flow is turned cyclonically to the southwest by
the coastlines of Melville Bay and Cape York, northward transport of the
remainder is abruptly terminated by a shallow bank (200 m) located in
the vicinity of the Carey Islands. Northward flow of WGCAIW could
continue to follow a deep narrow channel around this bank (Figure 3.20).
but was not observed to do so. Once turned to the southwest, the flow
of WGCAIW throughout northern Baffin Bay is not restricted by
bathymetry. It should be noted that even with the hypothetical
occurrence of westward flow from Cape York, penetration into Jones Sound
by WGCAIW would be impossible because of shallow banks located east of
the mouth. The flow into Lancaster Sound, however, is not similarly
restricted. It is apparent that southeastern Lancaster Sound is a site
of significant interleaving of dissimilar water masses, as the
associated T/S cross section reveals the presence of BBSW, ABPW, and
WGCAIW in profile (refer to Figure 3.15). It is presumed that WGCAIW is
present at stations 7, 8, 9, 10 and 11, although the shallow CTD casts
at these stations precludes absolute confirmation.

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IV. CIRCULATION AND TRANSPORT

A. INTRODUCTION

Macroscale circulation in the NBB-NS region is dominated by the
northward flowing WGC and the southward flowing Baffin Current .
Although net southward flow in the region is maintained primarily by
baroclinic forcing (Muench, 1971), bathymetry exerts considerable
influence on the formation of mesoscale circulation patterns. An
examination of the surface circulation of the region, as deduced from
baroclinic velocity and dynamic height calculations, reveals the natuie
of this influence (Figure 4.1). Reference to this surface circulation
diagram is implied in the ensuing discussions.

B. DYNAMIC TOPOGRAPHY

An examination of the surface dynamic topography of the NBB-NS
region referenced to 200 dbars indicates a general westward increase in
dynamic heights (Figure 4.2). This trend is associated with the
influence of the Coriolis force on the net southward flow.

The shoreward gradient of the dynamic height contours, in northern
Baffin Bay lends a cyclonic appearance to the circulation pattern.
Meltwater runoff may be responsible for the increase in dynamic heights
along the coastline of Melville Bay. The complex circulation patterns
associated with the WGC are inferred from the reversal of gradients and
bending of contours in the vicinity of Cape York. Northwestward flow
around Cape York is diverted cyclonically to the south in the vicinity
of the Carey Islands, an event associated with the Limitation of
northward flow of WGCAIW in the region. A southward Mowing branch of
the WGC is clearly evident in Melville Bay. The flow reversal occurs on

58

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Figure 4.1 Surface circulation in the NBB-NS region as deduced from
baroclinic velocity and dynamic height calculations.

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60

the perimeter of a shallow bank, suggesting a possible topographic
influence. Westward intrusions of surface flow are apparent at the
northern sides of the entrances to both Lancaster and Jones Sounds.
Although net flow is eastward in both cases, the closer spacing of
contours in Lancaster Sound is associated with much greater baroclinic
velocities. A significant portion of the ABPW outflow from Jones Sound
into northern Baffin Bay is turned anticyclonically around the southeast
shore of Devon Island, augmenting the westward intrusion of flow into
Lancaster Sound.

The sharp bending of contours in Smith Sound marks the boundary
between two intersecting circulation regimes. A northward flowing
branch of the WGC turns cyclonically , coincident with the formation of
an ice-edge jet at the southern limit of the ice pack. The 0.36 dynamic
meter contour is representative of the impingement of the relatively
warm surface current on the ice pack, with a resultant density gradient
normal to the ice edge. The deflection of southward flow from Nares
Strait at the front is also apparent, but determination of associated
circulation patterns within Kane Basin is not possible at this
resolution. The meandering 0.28 dynamic meter contour in Kane Basin,
however, is suggestive of the potential for gyre formation in this
region.

C. THE WEST GREENLAND CURRENT

Circulation of the WGC in northern Baffin Bay appears to be
governed by conservation of potential vorticitv. As a typical eastern
boundary current, the WGC mav be assumed to h r\ a substantial
barotropic component of flow. Conservation of potential vorticity

61

requires barotropic flow to follow lines of constant f/H, where f is the
Coriolis parameter, and H is the water depth. Since mesoscale
variations in the Coriolis parameter can be considered negligible, flow
will tend to parallel isobaths.

Justification of the preceeding assumptions in the case of the WGC
is provided by a number of observations. Although the direction of mean
flow in the WGC is closely correlated with the 500 m isobath,
recurvature to the west and south is noted at three primary locations.
In Melville Bay the flow is observed to recurve southeastward around a
shallow bank. A cross section of baroclinic velocities in this area not
only indicates significant deep flow around the periphery of the bank,
but confirms the filamental nature of the return current (Figure 4.3).
The two distinct flow regimes on the southwest side of the bank are, as
stated in Chapter 3, of different origins. Flow between Stations 128
and 129 is a recurved branch of the WGC which, assuming conservation of
relative vorticity, probably forms a cyclonic gyre around the perimeter
of the bank. Southwest of an apparent frontal boundary, however, a
second axis of flow exists which has been shown to principally contain
ABPW.

Shoaling of the bottom in the vicinity of the Carey Islands causes
complete recurvature of WGCAIW. The baroclinic velocity cross section
from Jones Sound westward to Thule reveals that the core of the WGC is
found east of Station 22 (Figure 4.4). Since water of Atlantic Layer
origin has been confirmed between Stations 21 and 24. recurved flow of
WGCAIW must pass between Stations 21 and 22. Calculation of baroclinic
velocities between Stations 21 and .'.'. vi Hi a I <-•"<• I ol no motion assumed

62

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at 375 m, indicates that southward flow for this station pair is limited
to the upper 55 m of the water column. Northward flow between
Stations 22 and 23, calculated with a level of no motion at 400 m,
decreased from 0.12 m/s at the surface to less than 0.03 m/s at a depth
of 115 m. The implication of this result is that most baroclinici ty in
the WGC is confined to the surface and near -surf act- layers. Barotropic
currents are presumed to dominate below this level, hence, the
postulated influence of topographic steering on the WGC.

The remaining branch of the WGC is recurved at the northern extent
of the 500 m isobath in Smith Sound. A meridional velocity cross
section through the region further substantiates the classification of
the baroclinic component of this flow as an ice edge jet (Figure 4.5).
Baroclinic velocities between Stations 41 and 44, calculated with a
level of no motion at 400 m, decreased from 0.44 m/s at the surface to
approximately 0.04 m/s at 200 m. Below 200 m, predominantly barotroplc
flow is topographically steered to the west and south by rapid shoaling
of the bottom.

D. CIRCULATION IN NARES STRAIT

The macroscale circulation regime in Nares Strait generates net
southward flow of ABPW into Smith Sound. Mesoscale circulation patterns
in the region, however, can not be characterized so succinctly.

Inflow from the Lincoln Sea proceeds southward through Robeson and
Kennedy Channels. A baroclinic velocity cross section through a
southern part of Kennedy Channel indicates the relatively uniform nature
of this flow (Figure 4.6). Recalling that snut hwnrcl I 1 ow <>f NSAIW is
terminated by rapid shoaling just north ot this transect (refer to

65

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Figure 4.6 A baroclinic velocity cross section through a
southern part of Kennedy Channel .

67

Figure 3.19), it is probable that the relatively high current speeds in
this area are associated with constriction of flow. Furthermore,
shoaling is more extreme on the eastern side of the channel resulting in
correspondingly higher speeds. In contrast, the high baroclinic current
speed in Robeson Channel is probably due to the influence of the
previously described local concentration of meltwater.

Circulation in Kane Basin is characterized by southward flow in two
peripheral branches, surrounding a central cyclonic gyre. Circulation
along the eastern side of Kane Basin is topographically steered
southward along the inherently shallow seabed. Augmented by runoff from
the Humboldt Glacier, this eastern branch continues southwestward and
merges with recurved WGC water in Smith Sound. The flow of the western
branch is also bathymetrically influenced. A portion of this branch
turns cyclonically along the 200 m isobath forming a gyre, while the
remainder continues southward, merging with both the western branch and
the recurved WGC. The southern portion of the gyre is quite apparent in
a baroclinic velocity cross section through Kane Basin (Figure 4.7).

In contrast to its effect on the WGC, topographic steering does not
appear to play as strong a role in Kane Basin. This implies that
circulation within Kane Basin has a significant baroclinic component of
flow. This presumption is most apparent between Stations 74 and 76, at
the northern edge of the gyre. Baroclinic velocities between these
stations reverse from southward at the surface, to northward below 65 in
depth. This vertical shear in velocities is indicative of baroclinic
instability, which might serve as a potential energy source for either
the Kane Basin Gyre or smaller, undetected ►ddii-s.

68

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69

E. THE BAFFIN CURRENT

The Baffin Current originates in Smith Sound, where southwest ward
flow from Nares Strait merges with recurved WGC water. During its
progression southward, the Baffin Current is augmented by outflows
from Jones and Lancaster Sounds, and by WGC water which has recurved
sou h of Smith Sound.

As a typical western boundary current, the Baffin Current can be
considered highly baroclinic. A baroclinic velocity profile between
Stations 28 and 29, assuming a level of no motion at 400 m, indicates
surface flow of 0.19 m/sec steadily decreasing to 0.5 in/sec at 200 m.
Unlike the WGC, significant baroclinicity in the Baffin Current is not
conl ined to the upper 100 m.

Interaction between the Coriolis force and bathymetry provides the
primary steering influence for the Baffin Current. Throughout the
course of the current, the tendency for westward turning by the Coriolis
force is offset by the presence of a lateral boundary. At the northern
entrance to Jones and Lancaster Sounds, however, the removal of this
restriction permits the observed westward intrusion of flow. It should
be emphasized, however, that the barotropic component of flow associated
with the Baffin current is not negligible. An examination of the
baroclinic velocity cross section from Jones Sound eastward to Thule
provides three clear cases of topographic steering (in conjunction with
Figure 4.4, refer to Figure 4.]). Although a branch of the Baffin
Current turns westward into Jones Sound, the main core of the current
proceeds southward between Stations 18 and 1(| . restricted by

70

bathymetry. Also apparent are two cyclonic gyres; one around Coburg
Island, and the other in the vicinity of a 150 m bank.

Eastward outflow from the south side of Jones Sound subsequently
merges with the main core of the Baffin Current along the coast of Devon
Island. In contrast to the narrow filament entering Jones Sound, the
major branch of the Baffin Current forms the westward intrusion of flow
into Lancaster Sound.

F. CIRCULATION IN THE SOUNDS

1 . Introduction

Smith, Jones and Lancaster Sounds are all considered regions of
net volume inflow to northern Baffin Bay. An examination of the
circulation characteristics associated with each sound will provide a
basis for their comparison.

2 . Smith Sound

Within Smith Sound exists a frontal boundary separating
southward flowing ABPW and recurved WGC water. Circulation in this
region, therefore, is determined primarily by baroclinic influences. A
baroclinic velocity cross section through Smith Sound reveals a weak
core between Stations 41 and 42 which is actually the remaining branch
of the northward flowing WGC (Figure 4.8). Complete recurvature of this
branch occurs just north of Station 41. Southward flow between Stations
42 and 43 is a filament of ABPW from the east branch of circulation in
Kane Basin. The interaction between recurved BBSW and southwestward
flowing ABPW is marked by the presence of a distinct ice edge. Indeed.
the impingement of warm BBSW on the ice > dr.' create* a meltwater
gradient which locally elevates the dynamic heights, providing a strong

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baroclinic influence on flow direction. The resultant formation of an
ice edge jet between Stations 40 and 41 marks the origin of the Baffin
Current. Augmentation of the Baffin Current by ABPW occurs beneath the
shallow pycnocline, which is associated with relatively warm, buoyant
BBSW from the WGC (refer to Figure 3.4).

Significant bathymetric influence in Smith Sound is limited to
positioning of the frontal boundary between the two circulation regimes.
Although topographic steering along the 500 m isobath clearly influences
re< urvature of the WGC, baroclinic effects are responsible for the
formation of the Baffin Current. Smith Sound, therefore, is the site
where a significantly barotropic circulation regime is transformed into
a predominantly baroclinic one.
3. JorM?s Sound

The combined influence of bathymetry and the Coriolis force on
the circulation structure of Jones Sound is most apparent in a cross
section of baroclinic velocities (Figure 4.9). A filament of the Baffin
Current is deflected westward by the Coriolis force around the
southeast corner of Ellesmere Island and into Jones Sound north of
Station 15. Eastward outflow of ABPW is restricted to the south of
Station 15, continuing along the east coast of Devon Island. The
presence of a cyclonic gyre around Coburg Island (refer to Figure 4.1)
links the flow paths accordingly.

While eastward outflow from Jones Sound tends to follow the
500 m isobath, the westward intrusion is driven by the Coriolis force
over a 200 m bank, against prevailing westerlv winds. The baroclinic

73

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Figure 4.9 A baroclinic velocity cross section through Jones Sound

74

velocity cross section illustrates the relatively shallow nature of this
westward intrusion of flow.

4. Lancaster Sound

Circulation in Lancaster Sound is characterized by a westward
intrusion of flow between Stations 6 and 8, and an eastward return
current of greater magnitude between Stations 1 and 6 (Figure 4.10).
The increase in velocities towards the sides of the sound indicates the
effect of the Coriolis force on the inflow and outflow branches.
Baroclinic velocities in the outflow branch are the highest in the
entire NBB-NS region, reaching a maximum of 0.78 m/sec at the surface
between Stations 2 and 3 (assuming a level of no motion at 340 m) .

5. Geostrophic Estuarine Circulation

Although their thermohaline and bathymetric features are
inherently different, the general characteristics of circulation in
Smith, Jones and Lancaster Sounds are remarkably similar. In each case,
geostrophically balanced inflow is entrained, in estuarine fashion, by
geostrophically balanced outflow. A quasi -vertical frontal feature
initially separates the two current regimes, the slope of which is
determined by their respective velocity structures (refer, for example,
to Figure 4.10). The dynamic aspects of the ensuing model, hereinafter
referred to as Geostrophic Estuarine Circulation (GEC), are derived
from the work of Leblond (1980). Variations in the observed character
of the circulation in each sound can be explained in terms of how
closely local conditions approximate GEC.

In proposing a two layer "Coastal Current Model" to explain the
observed circulation in some channels of the Canadian Archipelago.

75

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Leblond showed that two geostrophically balanced, upper -layer flows
would coexist without interference in a channel whose width is
sufficiently large compared to the local internal Rossby radius of
deformation. Restriction of flow to the upper layer creates a sloped
interfacial surface, resulting in a characteristically wedge-shaped
velocity structure (Figure 4.11).

I

-•»(•)

Figure 4.11 A schematic cross section of coastal upper
layer flow (out of the page) of speed u,
driven by a sea surface slope r;(v) The
lower layer of density P2 is at rest because
the interface h(y) slopes in a direction
opposite to that of the free surface. YQ
is the distance from the coast at which the
thickness of the upper layer vanishes (from
Leblond, 1980, p. 191).

Additionally, Leblond found that purely geostrophic flow can turn

corners without separating from a coast if the radius of curvature of

the coast is large enough that the Rossby number remains well below

unity. As a conservative estimate of the width of a coastal geostrophic

current, YQ is defined as YQ - R/F; where R is the internal Rossby

radius of deformation and F is the internal Froude number. If the width

of a channel is shown to exceed 2 (Y0), two geostrophicall v balanced

upper-layer flows can theoretically exist without interference.

77

The results of applying L 'blond's equations to Smith, Jones and
Lancaster Sounds are listed in Table II, with the requisite
calculations presented in the Appendix. Since the computed Rossby
number (RQ) at the mouths of all three sounds is less than 0.1,
nonlinear effects may be locally neglected. It should be noted that
values of YQ are only calculated for the outflow regimes which, in each
sound, were the widest of the two currents.

Conditions in Lancaster Sound, with a minimum channel width (L)
of 80 km, and a geostrophic current width (Y0) of 20.35 km, most closely
approximate GEC. Referring to the baroclinic velocity cross section
through Lancaster Sound (Figure 4.10), it clear that although the
calculated value of YQ is considered an underestimation of the width of
the outflow current, interference between the two circulation regimes
appears negligible. The obvious wedge-shaped current structure implies
that flow is primarily restricted to the upper 150 m. The broadening of
the outflow wedge beyond the calculated value of YQ , however, indicates
that this restriction is not complete. Indeed, the likelihood of
significant flow occurring below 250 m depth is confirmed by the
presence of WGCAIW in western Lancaster Sound.

Entrainment of inflow results in cyclonic cross -channel flow.
The connection of inflow and outflow currents in Lancaster Sound by
cross-channel flow was most recently investigated by Fissel et al.
(1982), who found the westward extent of the inflow intrusion strongly
marked by dynamic height anomalies (Figure 4.12). This result
illustrates that, in GEC, cyclonic cross -channel t low associated with
entrainment of inflow is a geostrophicj 1 lv kilaneed process. The

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convergence of inflow and outflow regimes creates a local elevation in
the sea surface, generating geostrophic flow normal to the resultant
pressure gradient. With sufficient eastward outflow and the presence of
lateral boundaries, characteristic cyclonic flow will result. Since
convergence implies downwelling, a reduction in vertical density
gradients may occur along this frontal feature, thereby enhancing the
tendency for mixing.

In Lancaster Sound the eastward outflow branch of the
circulation illustrates the increase in volume and velocity typically
associated with estuarine entrainment. In GEC, however, the entrainment
is geostrophically , not turbulently, driven.

The application of GEC to Smith Sound is influenced by both
geometric constraints and significant horizontal density gradients.
Referring to Table II, it is apparent that L is approximately equal to
2 (YQ) . Since this is considered a minimum requirement, the potential
for interference between the inflow and outflow regimes may be
significant. This interference may manifest itself in the form of
baroclinic instability and associated eddy generation.

Within Smith Sound the inflow and outflow regimes are not
appreciably influenced by coastal boundaries. The absence of a
characteristically wedge-shaped velocity structure in this region is
probably a consequence of this fact. Geostrophy does influence the
direction of the inflow and outflow branches, however, resulting in
cyclonic cross-channel flow. As stated previously, recurvature of the
remaining branch of the WGC occurs as the result of an extreme
horizontal density gradient at the ice-ed;;e trout. Entrainment of WGC

81

Inflow in Smith Sound, while not directly attributed i.o convergence, is
nonetheless geostrophically balanced.

The limitations in applying GEC to Jones Sound are
considerable. Since L < 2(YQ). Jones Sound is wide enough to
accommodate only one geostrophically-balanced current Referring to the
33.0 isohaline in Figure 3.14, the formation of density and, hence,
baroclinic velocity wedges is evident at the sides of the channel;
however, a complete blurring of the structure occurs between Stations 14
and 15. Since these current branches can not coexist in Jones Sound, it
may be possible for complete intrusion of the westward inflow branch to
occur at times, resulting in reversal of the net eastward flow in Jones
Sound. Historical evidence of this occurrence has been cited by Muench
(1971) (Figure 4.13). In 1962, for example, the flow is entirely
westward, while in 1963 both inflow and outflow are present
simultaneously but with the outflow dominant.

The macroscale circulation pattern in the NBB-NS region can
also be envisioned as conforming to the GEC model. Viewed
simplistically , the inflowing waters of the WGC are geostrophically
entrained at various latitudes, subsequently resulting in the augmented
outflow which characterizes the Baffin Current. The predictably
cyclonic circulation pattern associated with GEC is identifiable as a
major macroscale feature in the region.

G. BAROCLINIC TRANSPORTS

Baroclinic transports derived from various arbitrary reference
levels should be used, onlv with great reluctance, to Infer continuity
of volume. This is especially true in eastern boundary current regions.

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like the WGC , where the baroclinicity is known to be weak. The main
purpose of this section, therefore, will be to qualitatively compare the
baroclinic components of flow for major currents in the NBB-NS region.
Unless otherwise specified, subsequent references to transports are
summarized in plan view and assumed to be baroclinic in nature
(Figure 4.14) .

The WGC achieves maximum transport in Melville Bay, prior to its
previously described pat tern of recurvature in northern Baffin Bay and
Smith Sound. Transport of the WGC consequently decreases from a
maximum of 0.7 Sv in Melville Bay, to 0.4 Sv in the vicinity of the
Carey Islands, and 0.2 Sv in Smith Sound. The major portion of
baroclinic transport is concentrated at the extreme inshore stations in
Melville Bay, further substantiating the assumption that glacial runoff
is primarily responsible for this component of WGC flow.

The Baffin Current is partially derived from the net southward flow
of Nares Strait. Southward transport increases from 0.2 Sv in Robeson
Channel to 0.7 Sv at the mouth of Kennedy Channel. This increase may be
attributed to admixture of meltwater runoff, in particular from
Petermann's Glacier, located on the eastern shore of Robeson Channel.
Southward transport through Kane Basin is primarily associated with the
western circulation branch (0.3 Sv) , while southward transport in the
eastern circulation branch is limited (0.1 Sv) . The swirl transport
within the Kane Basin Gyre is approximately 0.4 Sv, indicative of its
effect in recirculating meltwater from the Humboldt Glacier throughout
the basin. The cyclonic ice-edge jet in Smith Sound, with associated
transport of 0.5 Sv . can be considered as GEC outflow from Nares Strait

84

LINCOLN
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region.

85

which is augmented by entrainment of the remainder of the WGC (0.2 Sv) .
Net southward outflow from Kant Basin through Smith Sound, therefore, Is
inferred to be approximately 0.3 Sv.

The Baffin Current, which becomes an identifiable feature in Smith
Sound, continues southward along the coast of Ellesmere Island where
transport is measured as 1.0 Sv. The formation of a topographically-
induced cyclonic gyre is coincident with branching of the Baffin
Currentnortheast of Coburg Island. A westward flowing filament (0.1 Sv)
enters Jones Sound, where it is entrained and augmented by eastward
outflow (0.4 Sv) , resulting in net eastward transport of 0.3 Sv. A
southwestward flowing branch (0.2 Sv) probably follows the 500 m
isobath, subsequently merging with the main core of the Baffin Current.
The relatively large transport (0.7 Sv) indicated southwest of Melville
Bay is actually an algebraic summation of transports obtained between
Stations 127 and 132 (refer to Figure 4.3). Southeastward transport of
Baffin Current water (0.4 Sv) , probably derived from a branch of
Lancaster Sound outflow which is topographically steered eastward along
the 1000 m isobath (Muench, 1971), is apparent southwest of Station 130.
Flow of WGC water, which has recurved either around the shallow bank in
Melville Bay (0.2 Sv) or south of the Carey Islands (0.1 Sv) , is
indicated between Stations 127 and 129.

The main core of the Baffin Current, augmented by eastward outflow
from Jones Sound, follows the southwest coast of Devon Island westward
into Lancaster Sound (0.6 Sv) . GEC entrainment and subsequent
augmentation of outflow yields gross eastward outflow of 1.7 Sv . Net

86

transport In Lancaster Sound, therefore, is inferred to be 1.1 Sv
eastward .

87

V. THE NORTH WATER PROCESS

The North Water Process is characterized by complex interaction
between thermohaline and dynamic effects. The net result of this
process is the demarcation of an 80,000 km2 arctic region which is
conspicuously devoid of first year ice from the onset of winter until
March (Steffen and Ohmura . 1985). Following a brief examination of some
relevant factors, a qualitative description of the process will be
presented .

In southern Baffin Bay freezing is generally accompanied by the
formation of an isothermal isohaline near-surface layer approximately 75
m to 100 m in depth (Garrison et al . , 1976). Sea-ice production in the
NBB-NS region is similarly associated with the formation of such deep
mixed layers (Muench, 1971). In the weakly stratified waters of Nares
Strait, convective processes are sufficient to form this homogenous
layer. The region south of Smith Sound, however, is characterized by
the ubiquitous occurrence of BBSW. The resultant presence of such a
strong pycnocline would ordinarily limit the depth of convective mixing
associated with surface freezing to much less than 75 m. A combination
of turbulent and convective processes must be required, therefore, to
overcome the inherent stability of this buoyant layer and produce the
observed deep mixed layers.

Given a particular set of climatic conditions, the enthalpy present
in the near-surface layer determines the length of time required to
initiate surface freezing. Assuming heat flux onlv through the surface
and neglecting thermal advection, it is possible to evaluate this time
delay as a function of heat budget parameters St eft en and Ohmura

88

(1985) computed monthly and annual heat budgets for the North Water
region and concluded, assuming a reference temperature of -1.8°C, that
the amount of oceanic heat flux required to prevent ic<> formation is
337.4 MJM"2 in October and 445.1 MJM'2 in November. The enthalpy
contained in the 75-m deep, near-surface layer was calculated,
referenced to -1.8°C, for all FRANKLIN 86 stations (Figure 5.1). For 22
stations located southward of Smith Sound, between 76° N and 78° N, the
enthalpy in September averaged 475 MJ . Applying the aforementioned heat
budget at the onset of winter (October), implies that surface freezing
would be delayed by approximately five weeks in this region. In
contrast, the average enthalpy contained in the ice -covered, near-
surface layer north of 78°N (Nares Strait) was 120 MJ .

The presence of mechanical ice removal effects such as divergent
currents and winds will cause the rate of sea- ice production to greatly
exceed the rate of sea ice accumulation for a given area. This
phenomena is graphically illustrated in the vicinity of the Kane Basil
Gyre where cyclonic and, hence, divergent circulation results in an area
of reduced ice concentration. Ice concentrations within the gyre were
typically 3/10 or less, compared with surrounding concentrations of
greater than 5/10. The cyclonic macroscale circulation pattern
characteristic of northern Baffin Bay can be expected to provide a
similar mitigating influence on the accumulation of sea- ice. The
potential influence of persistent northerly winds on the reduction of
sea -ice concentration in northern Baffin Bay has been discussed by
Muench (1971) and Dunbar (1973).

89

rfc

65"

60 1

Figure 5.1 Enthalpy of the near surface (upper 75 m)
layer in the NBB-NS region (referenced to
- 1.8°C).

90

The North Water Process results from the combined influences of
near-surface layer enthalpy and mechanical ice removal. Since the North
Water is characterized by reduced ice coverage, the associated decrease
in albedo results in the largest annual net radiation for any region
within the Arctic Circle (Steffen and Ohmura , 1985). Admixture of
glacial runoff creates a strong, shallow pycnocline which effectively
confines insolation effects to the near-surface layer. Such inherent
stratification would normally restrict convective overturn associated
with surface freezing to shallower depths. Mechanical ice removal,
however, results in a proportionally greater rate of brine formation
which increases the vertical extent of mixing. Complete
removal of the enthalpy in this near surface layer delays significant
sea- ice formation accordingly. Divergent cyclonic currents and
northerly winds then serve to reduce sea- ice accumulation for the
remainder of winter. It is the self -perpetuating nature of the North
Water Process which accounts for its persistence.

91

VI. DlgCVSSIQN

The comprehensive nature of this analysis mandates further
examination of certain relevant topics. A combination of elaboration
and postulation will be employed in this regard.

The dilution of WGC water masses, relative to those which enter the
NBB-NS region through the Canadian Archipelago, is a consequence of the
more extensive shelf-driven modification effects inherent in the
former. The assertion by Muench (1971), that the major proportion of
Arctic Ocean Water is less dense than Baffin Bay Water, was derived from
point data sources, under the assumption that there are significant
differences in water structures between the upper 250 m layers of the
Arctic Ocean and Baffin Bay. Muench further concludes that these water-
structure differences create a proportionally higher surface elevation
in the Arctic Ocean, resulting in net southward transport.

An examination of the dynamic topography of the NBB-NS region
reveals an obvious lack of north-south dynamic height gradients (refer
to Figure 4.2). This is due to the fact that ABPW and WGCPW have a
common origin in the Arctic Basin, and are quite similar in thermohaline
character. What is apparent, however, is a distinct dynamic height
gradient normal to the coastline. Although the increase in dynamic
heights in the onshore direction can be viewed as a consequence of the
influence of the Coriolis force on the prevailing baroclinic flow, it
may alternately be considered as a driving force for the observed
circulation in the NBB-NS region.

The ubiquitous glaciers in the region provide a significant coastal
source of meltwater. an influence which may l>e sufficient to drive a

92

geostrophically-balanced current with the shoreline on the right, in the
direction of flow. The implication of this hypothesis is that a
progressive winter weakening in near-surface currents would be expected
throughout the NBB-NS region. Lemon and Fissel (1982) provided evidence
of just such an occurrence in northwestern Baffin Bay.

On a larger scale, the concentration of glacial mcltwater within
the NBB-NS region results in near-surface layer dilution relative to the
saltier waters of the North Atlantic. It is the difference in near-
surface water structure between these regions that may drive the net
southward baroclinic transport. A progressive winter decrease in this
net southward transport would be expected accordingly.

93

VII. CONCLUSIONS
The physical oceanography of the northern Baffin Bay - Naires Strait
region has been investigated using a dense network of CTD stations
occupied by the CCGS SIR JOHN FRANKLIN in September 1986. The following
major conclusions can be drawn:

* Five water masses can be delineated in the region. The WGC is ttv
source of WGCPW and WGCAIW, while ABPW and NSAIW are derived from
the Arctic Basin via the Canadian Archipelago. WGCAIW and NSAIW
are prevented by shoaling of the sea floor from entering Smith
Sound and Kane Basin, respectively. BBSW is found seasonally
throughout northern Baffin Bay.

* The waters unique to the WGC are subject to more extensive
dilution effects by shelf-driven processes and are comparatively
less saline than their Canadian Archipelago derived counterparts.

* Bathymetry provides a significant influence on the flow of the
WGC, which attains a maximum baroclinic transport of 0.7 Sv in
Melville Bay. Recurvature of component branches of the WGC occurs
primarily in Melville Bay (0.2 Sv) , south of the Carey Islands (0.1
Sv) , and ultimately in Smith Sound (0.2 Sv) .

* The Baffin Current originates as an ice -edge jet in Smith Sound,
subsequently proceeding southward along the coast of Ellesmere
Island and throughout northwestern Baffin Bay. Transport of the

94

Baffin Current is augmented by net outflow from Kane Basin, Jones
Sound and Lancaster Sound at rates of 0.3 Sv, 0.3 Sv and 1.1 Sv,
respectively.

* Circulation in Smith, Jones and Lancaster Sounds can be described
in terms of the GEC model, in which estuarine inflow, entrainment
and outflow are geostrophically balanced processes.

* Although a significant portion of the meltwater derived from the
Humboldt Glacier is recirculated by the Kane Basin Gyre (0.4 Sv) ,
the influence of glacial admixture on thermohaline structure and
near-surface circulation is apparent throughout the NBB-NS region.

* The North Water Process results from the combined influences of
near -surface layer enthalpy and mechanical ice removal.

95

APPENDIX
COMPUTATIONS ASSOCIATED WITH THE GEC MODEL

The computation of geostrophic current widths in Smith, Jones and
Lancaster Sounds is accomplished as prescribed by Leblond (1980). Tht
requisite equations and calculations are presented here.

The "Coastal Current Model" of Leblond (1980) assumes geostrophic
flow confined to the upper layer of a two- layer stratified fluid, in a
channel of width L and depth H (refer to Figure 4.11). Assuming the
upper layer is relatively thin with respect to the lower layer, the
speed of interfacial waves in the fluid may be approximated as:

C2 =

g(p2-pi) t(o)

n

where: g = the gravitational acceleration;
p^ =■= the density of the upper layer;
P2 = the density of the lower layer; and

t(o) = the thickness of the upper layer at the channel wall.
In Smith Sound: Pl - 1025.5 kg/m3 ; p2 = 1027.0 kg/m3 ; and t(o)

= 75 m.
In Jones Sound: p1 = 1026.2 kg/m3; p2 - 1027.0 kg/m3; and t(o)

= 75 m.
In Lancaster Sound: px = 1026.0 kg/m3; p2 - 1027.0 kg/m3; and t(o)

= 150 m.
The internal Rossby radius of deformation is defined as:

R = C/f (2)

where: f = the Coriolis parameter.

The internal Froude number is defined as:

%

F - u/C (3)

where: u - the speed of the upper layer flow.
In Smith Sound: u - 0.25 m/s.
In Jones Sound: u - 0.16 m/s.
In Lancaster Sound: u = 0.50 m/s.
The Rossby number is defined as:

Ro -fr (4)

where: r = the radius of curvature of the flow.
In Smith Sound: r - 25 km.
In Jones Sound: r = 75 km.
In Lancaster Sound: r = 60 km.
The width of the geostrophic current is then defined as:

Yo -f (5)

97

LIST OF REFERENCES

Aagaard , K., and L.K. Coachman, The East Greenland Current north of the
Denmark Strait, I, Arctic. 21, 181-200, 1968.

Bourke, R.H., R.G. Paquette, and A.M. Weigel , MIZLANT 85 data report:

results of an oceanographic cruise to the Greenland Sea, September,
1985, Tech. Rep. NPS 68-86-007, Dept. of Oceanography, Naval
Postgraduate School, Monterey, California, 1986.

Coachman, L.K. and K. Aagaard, Physical oceanography of Arctic and

subarctic seas, in Arctic Geology and Oceanography, edited by Y.
Herman, pp. 1-72, Springer -Verlag , New York, 1974.

Dunbar, I.M., Winter regime of the North Water, Trans . R. Soc . Can. .
4(9), 275-281, 1973.

Fissel, D.B., D.D. Lemon, and J.R. Birch, Major features of the summer
near-surface circulation of western Baffin Bay, 1978 and 1979,
Arctic. 35, 180-200, 1982.

Garrison, G.R., H.R. Feldman and P. Becker, Oceanographic measurements
in Baffin Bay, Unpublished manuscript, Applied Physics Laboratory,
University of Washington, February, 1976.

Leblond , P.H. , On the surface circulation in some channels of the
Canadian Arctic Archipelago, Arctic. 35, 189-197, 1980.

Lemon, D.D. and D.B. Fissel, Seasonal variations in currents and water
properties in northwestern Baffin Bay, 1978 and 1979, Arctic . 35,
211-218, 1982.

Melling, H., R.A. Lake, D.R. Topham, and D.B. Fissel, Oceanic thermal
structure in the western Canadian Arctic, Continental Shelf
Research. 3, 233-258, 1984.

Muench, R.D., The physical oceanography of the northern Baffin Bay

region. Baffin Bay-North Water Pro j . Arct. Inst. North Am. Sci.
Rep. , 1-72, 1971.

Muench, R.D., and H.E. Sadler, Physical oceanographic observations in
Baffin Bay and Davis Strait, Arctic. 26, 73-76, 1973.

Sadler, H.E., Water, heat, and salt transports through Nares Strait,
Ellesmere Island, J. Fish. Res. Board Can. . 33, 2286-2295, 1976.

Steffen, K. and A. Ohmura , Heat exchange and surface conditions in the
North Water, northern Baffin Bay. Ann. Glaciology. 6, 178-181.
1985.

98

Tunnicliffe, M.D., An investigation of the waters of the East Greenland
Current, Master's Thesis, Naval Postgraduate School, Monterey,
California, September 1985.

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iii - QJ$

Thesis

A24257

Addison

c.l

The physical oceano-

graphy of the northern

Baffin Bay-Nares Strait

region.