DTJ1 "OX LIBRARY SCHOOL J3-6002 NPS 68-37-002 NAVAL POSTGRADUATE SCHOOL Monterey, California **t« THESIS MESOSCALE VARIABILITY IN THE WEST SPITSBERGEN CURRENT AND ADJACENT WATERS IN FRAM STRAIT by Alan M. Wei gel March 1987 Th ssis Advisor R. H. Bourke Approved for public release; distribution is unlimited. Prepared for: Director, Arctic Submarine Laboratory, Naval Ocean Systems Center, San Diego, Ca. , 92152 T 233163 NAVAL POSTGRADUATE SCHOOL Monterey, California Rear Admiral R. C. Austin David A. Schrady Superintendent Provost This thesis prepared in conjunction with research sponsored by the Arctic Submarine Laboratory, Naval Ocean Systems Center, San Diego, CA under Work Order N66001-86-WR-00131. Reproduction of ail or par- dz this ceport authorized leiaasea bv ; L o ^CLASSIFIED A L'Sirv CLASSIFICATION O f Thi? PaGf REPORT DOCUMENTATION PAGE re°ort security classification INCLASST^TFD lb RESTRICTIVE MARKINGS SECURITY Classification authority DECLASSIFICATION / DOWNGRADING SCHEDULE 3 DISTRIBUTION/ AVAILABILITY OF REPORT Approved for public release; distribution unlimited. ERFQRMiNG ORGANIZATION REPORT NUMBER(S) NPS 63-87-002 5 MONITORING ORGANIZATION REPORT NuVBER(S) NAME OF PERFORMING ORGANIZATION val Postgraduate School 60 OFFICE SYMBOL (if applicable) Code 63 7a NAME OF MONITORING ORGANIZATION Arctic Submarine Laboratory T |*ODRESS City. State ana ZIP Code; *f a, r o v 'A - I ? 9 4 1 'b AODRFSSfCrv. SfJfe, and ZIP Code) :ode 19 Bldg. 371 Naval Ocean Systems Jan liorn ""7 '■ Tl - "> SAME )F -UNDiNG/ SPONSORING Organization fctic Submarine L.ab ■> PROCUREMENT NSTRUMENT DEN TiFiCAflON IUM9EH do DFFiCE ;ymbOL It jODIlCaOl*! Zode kQORESSiGry r-ne jna ZIP' oae> xvai Ocean Systems '6ntsv PROGRAM ELEMENT NO ^"OjEC; NO ACCE< HDSCALE VARrABILLTY [E 7e: - igel, Alan M 'Y?f QF REPORT ster ' s Thesis ' 3d fiME COVERED fOQM TO 4 DATE OF REPORT {Year Month Oay) 19 37 March S PAGE COl>NT 100 SlP'lEVENTARy notation epared in conjunction with P..H. Bourke and R.G. Taquette COSATi codes EiO GROUP Sw8-GR0UP 18 Su8jECT TERMS (Continue on revene if neceisary and identify by b'ccfc number) West Spitsbergen Current NOP.THWIND East Greenland Current Tram. Strait ABSTRACT (Continue on revene if neceuary and identify by block number) A dense network of conductivity-temperature-depth (CTD) measurements as carried out between 76*N and 81*N in order to define the distribution f temperature and salinity in Fram Strait. Although weakly baroclinic, he WSC flow was found to be strongly influenced by the 2000 m deep ipnovich Ridge which separated the flow into several streams. In ddition, filaments of warm Atlantic Water (AW) were found to spread out ver the top of the Greenland Gyre. The WSC branches near 80 *N. pproximately 20% of the baroclinic transport enters the Arctic Ocean orth of Spitsbergen as the eastern branch. The other branch ( 80% of he baroclinic transport) turns westward, apparently under the influence f the Yermak Plateau, and joins with the southward flowing East reenland Current (EGC). The entire turning takes place south of 81' N ear the ice edge with baroclinic speeds of up to 0. 03 m/s. The D S'R'BuTiON / AVAILABILITY OF ABSTRACT jL'NCLASSiFiEO-TjNL'MlTEO □ SAME AS RPT D DTlC USERS 21 ABSTRACT SECURITY CLASSIFICATION UNCLASSIFIED NAME OF RESPONSIBLE 'NOiV.OUAL *. H. Bourke 22b TELEPHONE (include Area Code) 408-646-3270 »C OFUCt SYMBOL 68Bf ORM 1473. 84 mar 83 APR edition n^ay be used until e«hausted All otner editiom are obsolete SECURITY CLASSIFICATION QF 'h0 Km and a closed baroclinic circulation up to 0.15 m/s was found associated with the front. Also associated with the front was extensive temperature and salinity fmestructure which occurred near the maximum temperature in the water column. This fmestructure was often associated with strong double diffusive activity. 'T TABLE OF CONTENTS INTRODUCTION 11 A. PURPOSE 11 B. BACKGROUND 12 C. BATHYMETRY 12 D. GENERAL CIRCULATION 15 E. WATER MASSES 20 METHODS AND MEASUREMENTS 25 IRUISE SUMMARY 25 3. DATA ACQUISTION 25 :. DATA REDUCTION AND ANALYSIS 2" [II. rEMPERATURE-SALINTTY DISTRIBUTION 29 A. INTRODUCTION 29 B. WEST SPITSBERGEN CURRENT 29 1. Water Mass Characteristics 29 2. East Branch 32 3. Westward Turning 34 C. HISTORICAL COMPARISONS 36 D. EAST GREENLAND CURRENT 42 1. Water Mass Characteristics 42 2. East Greenland Polar Front 44 3. Mesoscale Features 45 E. FINESTRUCTURE 46 IV. CIRCULATION AND TRANSPORT 63 A. INTRODUCTION 63 B. DYNAMIC HEIGHT 64 C. BAROCLINTC FLOW 68 D. CIRCULATION 70 V. CONCLUSIONS 83 LIST OF REFERENCES 85 INITIAL DISTRIBUTION LIST 90 LIST OF TABLES 1. A SUMMARY OF THE DEFINITIONS OF WATER MASSES FOUND IN FRAM STRAIT 22 LIST OF FIGURES 1.1 Bathymetric features of Fram Strait (from Hurdle, 1986, p. 699) 13 1.2 A chart showine the bathvmetrv of Fram Strait (from Bourke et al., 1986). Depths are in hundreds of meters 14 1.3 The general circulation and bathymetry of the Greenland Sea (from Paquette et al, 1985) 16 1.4 Temperature- ^aiinitv limits defining the basic water masses found in Fram Strait ( from Greisman, L976J 21 1.5 Temperature- saiimtv envelopes for :he water mass regimes in Fram Strait ( from Greisman. 19761 23 3.1 NORTHWTND 1985 cruise track and location of CTD stations. The leavy aasned line shows the position oi the ice edge 36 3.1 \ :hart showing the locations of transects made in Fram Strait. The lashed line is [tie location of the ice edge 30 3.2 A temperature.' .saiinitv plot for stations in the core of the WSC. Svmodis are at 50 m intervals 32 3.3 Surface temperature I °C) distribution 37 3.4 Surface salinity distribution 33 3.5 The maximum temperature at each station 39 3.6 The temperature of the 28.0 sigma-t surface 40 3.7 The depth of the 28.0 sigma-t surface 41 3.8 A temperature-salinity plot of stations along 78°N in the vicinity of the EGPF 43 3.9 Stations exhibiting significant vertical structure. The solid line is the location of the EGPF and the dashed line is the ice edge. Other symbols are defined in the text 47 3.10 Temperature profiles for stations along 80°30'N 48 3.1 1 Salinity profiles for stations along 80°30'N 49 3.12 The Turner angle for Station 96 in the EGPF 52 3.13 Transect 1. along 78°N. The 2000 m feature between Stations 21 and 22 is the Kipnovich Ridge. The arrow at the top indicates the location of the ice edge 53 3.14 Transect 2 along 79°N. Note the effect of the Kipnovich Ridge between Stations 31 and 32 creating a wave-like structure in the isotherms and isohalines 54 3.15 Transect 3 along 79°30'N. The Kipnovich Ridge is very pronounced at this latitude 55 3.16 Transect 5 along 80°N 56 3.17 Transect 4 along the top of the Yermak Plateau 57 3.18 Transect 6 north of Spitsbergen 58 3.19 Transect 7 along 81°N 59 3.20 Transect 8 along 80°30'N ■. ' 60 3.21 Transect 9 along 2°E shows the core of westward turning as the 3° lens between Stations 36 and 99 61 3.22 Transect 10 along 2°W through the center of the eddy 62 4.1 Surface dynamic topography referenced to 150 decibars in dynamic centimeters 65 4.2 Surface dynamic topography referenced to 500 decibars in dynamic centimeters 66 4.3 150 decibar dynamic topography referenced to 500 decibars in dynamic centimeters . 67 -i.4 A plan view of Fram Strait summarizing the transport calculations 71 4.5 A not of the surface circulation suggested bv the dynamic topography ana geostrophic velocities ' .' I 4.6 Section I. alone 78°N. Southward .low is indicated by postive isotachs spaced" at 0.01 m/s intervals .' . ' 73 4." Section 2. aiong 79°N 74 4.8 Section 3. along 79°30'N 75 4.9 Section 4, along the top of the Yermak Plateau 76 4. 10 Section 5, along 80°N 77 4.11 Section 6, extending northwestward from the Spitsbergen coast 78 4. 12 Section 7, along 81°N 79 4.13 Section 8, along 80°30'N 80 4.14 Section 9, along 2°E, showing the core of the westward turning 81 4.15 Section 10 along 2°W, through the center of the eddy 82 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.G. Paquette for his careful reading of this thesis and for many of the computer programs which were used in it's preparation. M.D. Tunnicliffe also provided programs, programming assistance and helpful advice. The assistance of K.O. McCoy and Or. J.L. Newton was instrumental in the data acquistion as was the assistance and enthusiasm oi" the crew of the LSCGC NORTHWIND. especially the Marine Science Technicians ana her Commanding Officer. Captain W. Caster. The success or' this thesis was due. in large measure, to the advice and guidance of Dr. R..H. Bourke. He continues to be a fine friend and shipmate and a source of inspiration to all vno know him. Finally, i wish to acknowledge the love and support of my wife, Diana. Without her numerous nersonai sacrifices and many hours of typing throughout the past year this thesis would never have been completed. 10 I. INTRODUCTION A. PURPOSE During September 1985 the USCGC NORTH WIND conducted an oceanographic measurement program, MIZLANT 85, in the northern Greenland Sea between Greenland and Spitsbergen. A relatively dense network of conductivity- temperature-depth profiler (CTD) stations provided extensive information on the circulation and water mass structure of the major oceanograDhic features in the region known is Fram Strait. MIZLANT 35 was [he fourth in a series of hydrographic surveys under the sponsorship of the Arctic Submarine Laboratory designee to investigate the oceanograDinc characteristics of the Greenland Sea north of75°N. This thesis is an analysis of :he data set acquired during the 1985 cruise. The overall Dbjective of the cruise was to quantify the physical oceanographic properties i: the northern Greenland Sea waters and to define the oceanograDhic processes responsible for property distributions and their variability. Specific objectives Dfthe measurement program included: I l) study of the westward turning of the warm, saline "Vest Spitsbergen Current ~T-"SC'; ina :[G interaction with the cold, fresh southward flowing East Greenland Current (EGC); (2) measurement of the temperature and salinity distribution across Fram Strait in at least two locations to define the water mass characteristics and structure of water entering and exiting the Arctic Ocean; (3) assessment of the bathymetric effects of the shallow Yermak Plateau on the flow of warm Atlantic Water (AW) into Fram Strait and the Arctic Ocean; and (4) study of the dynamic characteristics of the East Greenland Polar Front (EGPF), a sharp boundary between the EGC and the warmer water of the Greenland Sea, north of 79°N. A secondary objective was the assessment of the circulation in the area of the Molloy Deep, a 5500 m depression located near 79° 10' N, 003°E where a large cyclonic eddy has frequently been observed. To a large extent, all these objectives were met. The objectives of the CTD data analysis presented in this thesis will be to: (1) infer the water masses of Fram Strait using temperature-salinity transects; (2) describe the baroclinic circulation and transport in Fram Strait using contours of the geostrophic current velocity field; (3) describe the role of bathymetric steering on the 11 baroclinic circulation in Fram Strait; and (4) assess the characteristics and formation processes of mesoscale eddies and temperature-salinity finestructure usually found in or near the EGPF. B. BACKGROUND Fram Strait is the major connection for the transfer of heat, mass, and momentum between the Arctic and Atlantic Oceans. Aagaard and Greisman (1975) have shown that the WSC provides the major inflow of mass, salt, and thermal energy into the Arctic Basin. Aagaard and Coachman (1968a) have shown that the EGC is the major outlet for Arctic Ocean surface water into the Atlantic Ocean. Carmack (1972) cites the work of Zordrager. in 1723, as the earliest known description of the Greenland Sea. The first modern description of the physical oceanography of the region was done by Heiland-Hansen and Nansen ( 1909) who descnbed the Greenland and Norwegian Seas gyres. KiUerich ( 1945) discussed the hydrography and circulation of the Greenland Sea based .m aata acquired from 1S91 _o [933. Other reviews have been conducted by Lee (1963), Trangeleu (1974), Carmack 1972) and Coachman and Aagaard (1974) Aagaard and Coachman (1968a) provided a comprehensive review of the studies of the EGC and me waters of the Greenland Sea. More recently Paquette et al. (1985), Tunnicliffe (1985), and Bourke et al. (in press, a) have studied the characteristics of the EGC and the Polar Front, while Greisman (1976) and Hanzlick (1983) have done in- depth studies of the characteristics of the WSC. C. BATHYMETRY Fig. 1.1 shows the geographic setting and major bathymetric features of the northern Greenland Sea. The bathymetry of the region is characterized by deep basins separated by submarine ridges; glaciated continental shelves form the lateral boundaries. A detailed bathymetry of Fram Strait is shown in Fig. 1.2. Perry (1986) provides a comprehensive discussion of the bathymetry of the Greenland Sea; only the salient features will be summarized here. The bathymetry of the continental shelf and slope in Fram Strait is based on limited soundings by ships with ice-strengthend hulls because the area is ice covered most of the year. The East Greenland continental shelf is a region of shallow banks and local depressions with large troughs extending seaward from the shore line. The continental slope has an average relief of approximately 1:10 and varies in depth from 12 50* «©• JO* 20" / *>& * * —-■ vv*w • v -J MUM »l*i»o«i.<\ -v */<£♦,,• k- c- if V« 'T-VV/ ,.. / 10* \ \ »• "• 3* / \ ^-WTVILLl-TMOMSO" »I0«€ Figure 1.1 Bathymetric features of Fram Strait (from Hurdle, 1986, p. 699). 13 CO OS cc OJ -^ £| ra*o — - ^ >->c £c <-» t-l C3 cS w Cu o r^ 14 400 to 3400 m (Perry, 1986, p.219). The Yermak Plateau, on the eastern side of Fram Strait, is an extension of the Barents Sea continental slope projecting into the Arctic Ocean (Perry, 1986, p. 219) The shallowest depth measured on a ridge topping the plateau is 425 m. The western slope of the plateau drops to the floor of the Lena Trough and the Spitsbergen Fracture Zone, a northwest-southeast tending trough with a maximum depth of 4532 m. The Boreas Basin is a small abyssal plain lying in the southern end of Fram Strait. The basin is bordered on the east by the Knipovich Ridge, an extension of the Mid- Atlantic Ridge system. The ridge is characterized by widely spaced groups of seamounts. most of which are between 900 and 1600 m deep. A rift valley 3200 to 3400 m deep lies aiong the length of the ridge. To the north of the Boreas 3asin is [he Greenland-Spitsbergen sill. Perry I 1986, p. 232) describes this feature as a "damlike" structure with a maximum depth of 2650 m. The sill may limit the exchange of deep bottom water between the Greenland Sea ana the Arctic Ocean although Aagaard et ai. (1985) present evidence for exchange through Fram Strait )f intermediate-depth waters above the sill. The soutnern part of the sill contains the Hovgaard and Molloy Fracture Zones. The Hovgaard Fracture zone consists of a 2600 m deep '.rough between two ridges which shoal to an average depth of 1250 m. The Molloy Fracture Zone contains an elliptical depression, the 5570 m Molloy Deep, and is ringed to the north by three 1500 m deep seamounts named the Molloy Ridge. D. GENERAL CIRCULATION Helland-Hansen and Nansen (1909) first defined the cyclonic surface circulation of the Greenland Sea. The Greenland Gyre is centered on the prime meridian between 74°-76°N (Fig. 1.3). The northward flowing WSC forms the eastern boundary of the gyre while the southward flowing EGC forms the western boundary. The eastward zonal flow known as the Jan Mayen Polar Current closes the circulation to the south and the westward turning of the WSC into the EGC closes the circulation to the north in a flow known as the Return Atlantic Current (RAC) (Paquette et al.,1985). The WSC is formed when warm, saline water from the North Atlantic enters the Norwegian Sea and flows northward along the continental slope as the Norwegian Atlantic Current. Off the southern tip of Spitsbergen near 74°N it mixes with colder, fresher water from the Jan Mayen Polar Current and the East Spitsbergen Current and 15 82«N 20#W mWhi Figure 1.3 The general circulation and bathvmetry of the Greenland Sea (from Paquette et al, 1985). 16 continues flowing north along the west coast of Spitsbergen. Along the continental slope the flow is deep, extending to about 800 m (Hanzlick, 1983, p. 7). North of about 75°N it loses heat and is diluted as it spreads out in a thin layer over the top of the Greenland Gyre. Near 80°N one branch of the current turns northeastward (Aagaard and Foldvik, 1985), sinking to about 200 m depth as it passes under the ice edge, and eventually enters the Arctic Basin (Johannessen et al., 1983) This branch of the current is the principal supply for the warm Atlantic layer observed throughout the Arctic Ocean (Aagaard et al., 1985b). The second branch of the current turns westward and mixes with the southward flowing EGC as the RAC. The RAC forms the eastern boundary of the EGPF. Hanzlick (1983) summarized che transport calculations of earlier investigators. Based on hydrographic data from 1933 to 1960, as gleaned from various sources (Hill and Lee. 1957: Kislyakov, I960; and Timofeyev. 1962). the mean barociinic transport across the WSC was estimated to be 3 to 4 Sv1 northward. Greisman 1 1976) estimated the mean total transport, using long-term direct current measurements, obtained during 1971-72. as about Sv nortnward. with a 10.7 Sv maximum ;n Seotember ana a 3 5v minimum in February. Using hydrographic data Greisman estimated the mean barociinic transport to be 3.5 Sv, or about one-half of the total. During 1°76-"~ Hanzlick (1983) estimated a mean transport of 5.6 Sv from current meter data, with a maximum in the fall and a minimum in the spring. The mean barociinic transport for the same period was only 1 Sv. The WSC is rich in temporal and spatial variability. Greisman (1976) and Hanzlick (1983) have shown that both volume flow and core temperatures of the WSC are variable over time scales that range from days to years. For example, Hanzlick (1983) showed evidence, based largely on hydrographic data, that the interannual variability in the volume and heat transport was on the order of 50%. He also presented data showing that for 1976-77 the volume transport ranged from 1.4 Sv southward to 11.9 Sv northward, while the core temperature of the WSC ranged from a maximum of 6°C to a minimum of -PC. There is also evidence to suggest that there is significant short term variability in the WSC flow. Hill and Lee (1957) reported barociinic transports west of Bear Island which changed from 0.1 Sv southward to 1.0 northward within 48 hours. Direct current measurements made in Fram Strait during 1984-85 (Aagaard et al, 1985a) showed a northward flow in the core of the WSC in 1106m3s"1 17 excess of 0.4 m/s in the latter half of August 1984. By the first week in September 1984 the flow had reversed, with southward speeds of approximately 0.05 m/s being observed. An important conclusion which arises from these various data sets is that the changes between successive yearly surveys may in fact be due to short term variability and are not true interannual changes. Various investigators have also shown evidence of spatial variation in the WSC flow and temperature. Dickson (1972) discussed the spatial variability of the Norwegian Atlantic Current. This variation takes the form of banded structures or northward flowing filaments. The spatial variability of the WSC is probably an extension of this structure. Hanzlick (1985, p. 23) suggested that the scale of the lateral structures is about 15 km. The mean wind stress over the Greenland-Norwegian sea region is apparently the major factor affecting the interannual and shorter time scale variability of the WSC (Greisman, 1976; Hanzlick. 1983). Aagaard (1970) coniDuted the wind-driven transport in the Greenland Sea for 1965 and found a circulation which quantitatively resembiea the known circulation. Greisman and Aagaard ( 1979) suggested that the WSC is driven by large scale variations in the atmospheric forcing over the Greenland and Norwegian Seas on time scales of less than one month and that there was considerable month to month variation in the forcing. Hanzlick (1983) suggested that baroclinic instability and coastally trapped waves were also possible contributors to shorter time scale variability. Greisman (1976) showed that the WSC also has a strong tidal component. The cold, fresh EGC together with the warmer, saltier RAC form the western branch of the Greenland Gyre. The ECG originates in the Arctic Ocean and carries Arctic surface water and ice southward, through Fram Strait and over the East Greenland continental shelf. The eastern boundary of the EGC is tied to the shelf break south of 79°N and is separated from the RAC by the EGPF, a zone exhibiting sharp horizontal gradients of water properties. On the eastern side of the front the RAC has a width of approximately 100 km and is submerged under the EGPF to depths of 50-300 m (Paquette et al, 1985). Paquette et al. (1985) and Bourke et al. (in press, a) found a high speed jet associated with the EGPF, with baroclinic speeds as high as 0.96 m/s, but more typically 0.40 to 0.60 m/s. Aagaard and Coachman (1968b) computed a volume transport of 35 Sv for the EGC based on current meter measurements made from the ice island ARLIS II and bv 18 the EDISTO in 1965. More recent observations, however, do not support this estimate. Paquette et al. (1985) estimated the baroclinic transport in 1981 to be approximately 2 Sv. Bourke et al. (in press, a) found the baroclinic transport of the EGC in 1984 to be approximately 1 Sv. Current meter measurements taken by Muench et al. (1986) suggest that the total transport may be twice the baroclinic component, rather than the order of magnitude suggested by Aagaard and Coachman (1968b). The EGC also shows considerable spatial and temporal variation. Aagaard and Coachman (1968a) have shown that the position of the EGPF. which they define by the location of the 0°C isotherm at 50 m. can vary up to 100 km in severai days, most probably a result of wind forcing. As :he surface manifestation of the front moves, the RAC may be overrun by [he colder water of the EGC (Perdue, 1982). Associated with the front are mesoscaie ice-ocean meanders and eddies. These eddies have been studied extensively by Wadhams and Squire I i9S3). Johannessen et ai. (1983). Paauette et al. (1985), Bourke et ai. » in press, b) and others. Of particular interest is a quasi- stationary cycionic eddy occunng at about "9° 10'N. 001°E. which appears to be associated with the complex bathymetry near the Mo Hoy Deep. Various theories have been suggested concerning the generation of these eddies including baroclinic instability (Griffiths and Linden, 1981), barotropic instability (Johannessen et al., 1983), topographic interaction (Smith et al., 1984), differential Ekman pumping along the ice edge (Hakkinen, 1986) and advection of open ocean eddies into the Greenland Sea (Davidson et al., 1986). Another important mesoscaie feature found along the EGPF is temperature and salinity fmestructure. These features consist mainly of an interleaving of the warm water of the RAC with the colder water of the EGC. Paquette et al. (1985) found alternating lenses of warm and cool water with peak-to-peak temperature differences of 0.5°C to 1.0°C at depths between 75 and 300 m. They suggest that the average length of these lenses is 27 km. Tunnicliffe (1985) found similar structures in his data with peak-to-peak variations up to 3.5°C. Paquette et al. (1985) proposed that these structures form when warm water east of the EGPF descends along isopycnal surfaces from at or near the surface. They also proposed that these fmestructure elements dissipate through double diffusive processes. 19 E. WATER MASSES For an area so dynamically active and so well studied, it is not suprising that Swift and Aagaard report "the water mass terminology for the entire area is rich and often confusing." (1981, p. 1110) The basic water masses of the EGC and the WSC have been defined by Coachman and Aagaard (1974) and while their definitions have been accepted by much of the succeding literature, the definitions have also been successively modified. Fig. 1.4 shows the basic water masses, which will also be adopted for this thesis, as well as the modifications proposed by other authors. Table 1 summarizes the temperature and salinity limits for the various water masses. The temperature-salinity envelopes for the water mass regimes found in Fram Strait are portrayed in Fig. 1.5. Two water masses are found in the WSC. Atlantic Water (AW) extends from the surface to about S00 m and is warmer than 0°C. Surface temperatures in summer may be higher than 6°C, while during the winter the surface temperatures are typically warmer chan 2°C keeping the west coast oi Spitsbergen ice free. The salinity of the AW increases in the upper 100 m so that at the core of the WSC the salinity may be greater than 35.2." Beiow iOO m the salinity decreases to about 34.95. Warm water, properly called AW, can aiso be found with salinities as low as 34.7. This low salinity fraction of AW is primarily a surface phenomenon and is the result of dilution by ice melt. This area of low salinity is generally found near the ice edge or in more southerly areas where ice melt water has been advected. Beneath the AW is found Greenland Sea Deep Water (GSDW). This water mass forms a large dome at the center of the Greenland Gyre with temperatures colder than 0°C and salinity between 34.87 and 34.95. Carmack (1972) proposed that GSDW was formed by convective subsurface modification of AW. Carmack and Aagaard (1973) and Aagaard et al. (1985b) suggest that chimney formation and double-diffusive mixing between PW and AW may also be involved with the production of GSDW. PW is generated in the Arctic Ocean, but over the Greenland shelf is modified by local processes such as ice melt and mixing (Bourke et al., in press, a). Thus, the water masses of the EGC are similar to those of the Arctic Ocean. Polar Water, colder than 0°C, extends from the surface to below 150 m. In summer the effects of insolation create a temperature minimum at a depth of about 50 m. The surface salinity may be "Salinitv will be reported in the practical salinity scale (gm/kg) as dimensionless quantities (UNESCO, 1981) 20 T 7 6 5 4- 3- 0 -1 ^f.\j w> sJ. >J ST GREENLAND GREENLAND GYRE 35 34.6 35.0 Figure 1.4 Temperature-salinitv limits defining the basic water masses found in Fram Strait (from Greisman, 1976). 21 ""» o CD Kl crs iH A 0 T3 re H L. re r ^■^ 0l< 2 co S < re < o H r c t ^5 , LU 2 ! 5 s U- ^, 2 ■er- Os ~— <-\ Q — 2 •D L. 3 .tS 0) o A — hi < z -o c/3 Ul c ' T ■• tr re 1U C/0 u. c C/5 OS E Kl • - < I re c CO 0 re re u 0) 0) re re •Q < < c re "O ■o c "D re re re eo so c re c 0 re o u ■D c 5 ■3) IS t/3 o 1-1 X z fs z Cvl Cs E rs. l-( Os M • M • > • < • < v* _1 M\ •er o <3- 3 sj- _l Kl Kl E E Kl o Kl Kl E 1 E V 1 -a- 1 © 1 a 1 ai U OS hs. H h- o Os o u • o u * 1 u <* > o r-. > a • © o eo o K 0 o 0 sj" LD o o c 0 o • 0 Kl sT o o • o W o * CO o Kl r-k o sj" in o •3- .0 CM .0 1 Kl CO O vT CO 2 Q. O A Kl V V V V A Kl r-l A Kl a V Kl a O A V V Kl A K E o. H CO a »- CO o f- CO a 1-UD h» CO a f- CO a »-WQ w ^ 0m% Q Z < z < w 3 -1 X z *" *^ H t-t L C < O o z •f *» a O re re CO c. z z C9 0 ^ ^ +> z a a > n co •^ +» c z < re a 0 c£ .H M-l •f a T3 T> I < •f c 0 a ^ « at E E S X •■■« *> E c a < •D n e 0 S 01 z •** +> « s z £ c c a L a. L. a M H D M a _ 19 u « - L •*■* +> re 0 0 «i 00 a re u C <♦- •»4 ■H V). -** z 0 M L +» ** M -rf (A IT) ■K 3 0 0 L 1 <. oo 2 o re 0 co u L. a «t •rH z •M < < •* re £ 0 0 c c c 0 ■H c C re z c tt re re re re *< 35.1) water between 50 and 100 m. Seaward of the wedge the warm water spreads out, for almost 200 km, into a surface layer 50-75 m deep. The saline water defined by the 35 isohaline is aiso found as a tongue spreading out almost halfway across Fram Strait, but generally deeper than the 3°C isotherm, at 100 to 400 m. At the western end of the wedge the surface salinity decreases to less than 34.9 as the AW mixes with PW and becomes diluted. Farther northward Transect 2 (Fig. 3.14), along 79°N, snows the 3°C AW wedge to be wider tl40 km) and shallower (210 m), with the 35.1 isohaline stiil found in the core of the wedge between 50 ana 100 m. Seaward of the wedge the surface layer is still present. but it is thicker and narrower with a second stream of 35.1 salinity water found at Station 31. The 35 isohaline tongue is again found to extend almost halfway across Fram Strait, with a large portion below the 3°C isotherm. Along the coast the isotherms slope upward, in contrast to Transect 1 where they slope downward. In Transect 3 (Fig. 3.15), along 79°30'N, the warm wedge extends seaward 100 km and the isotherms again slope downward along the coast to a depth of 360 km. A single 35.1 saline core is found at Station 119. In both Transects 2 and 3 a "tongue" of warm water extends under an "eddy-like" surface feature. In Transect 2 this feature is located between Stations 127 and 123; in Transect 3 it is located between Stations 132 and 136. The characteristics of this feature will be discussed in more detail later. The distribution of AW in Transects 1, 2, and 3 appears to be controlled, at least in part, by bathymetry. In Transect 1, the isotherms and isohalines appear to be pushed up by the 2000 m isobath defining the Kipnovich Ridge. The core of the WSC is located to the west of the shelf break, while the largest part of the 35.0 isohaline tongue is located over the western slope of the ridge. In Transects 2 and 3 the isotherms and isohalines also appear to be pushed up by the ridge, with a warm saline stream located over the shelf break. In each of these transects the western slope of the ridge appears to control the western limit of AW, with the steeper bathymetry in Fig. 3.14 and 3.15 exerting a larger influence. 31 to 1 C\2C\2 win|nicvjUiB x\ * t G 2 I (0) 3HniVH3ciK3I I- Z- n U CO o o irt z w£ •— CC 1— ■ .~ CO « O so^ ^£ p^ r!co ra t— 0) Cu i-« c • 1> 4-> < 0°C) flowing northward under the ice, over and on both sides of the Yermak Plateau. It is this water that provides the body of Atlantic layer water in the Arctic Ocean. The northward extent of the westward turning is found just north of 81°N. Transect 7 (Fig. 3.19), along 81°N, shows a very smaii trace of AW at 100 m at Station 63. Transects 8 and 9 cross through the center of the westward turning, in the zonal and meridional directions, respectively. Transect S (Fig- 3.20), at 80°30"N. shows a narrow surface layer of warm water between Stations 102 and L04. West of Station 102 the AW is found projecting under the PW ot cne 3GC. The western limit of AW in cms transect apoears ciosely tied to the 2200 m deep riage .ocatea near cne center of Fram Strait, in Transect 9 (Fig. 3.21), at 2°E. the core of the warm westward turning is seen centered at 100 m between Stations 101 and 99. just at the ice edge, and well to rhe north of the seamounts between Stations 34 and 36. This is the farthest north that warm AW is found. Also in this transect are smaller "lenses" or "filaments" of warm water to the south seen in the earlier transects. The locations of these "filaments" appear also to be controlled by bathymetry. One "filament" is found at Station 35, between the seamounts, while the others are found well to the south. The core of the warm westward turning is found below the surface in Transects 4, 7, 8 and 9. This can be accounted for in two possible ways. The warm, saline AW may have submerged under the cold, fresh PW. This could occur if the salinity of the AW were high enough to offset the density of the cold PW. The AW would then sink as it turned westward into the EGC. Another possibility is that the AW is cooled and freshened by the presence of the ice edge as it turns westward. This would then result in finding a temperature maximum below the cold surface layer. Horizontal plots of water mass properties may also be used to describe the branching and westward turning of warm AW. The distribution of various water properties in Fram Strait shows the influence of bathymetry and, especially in the case of surface properties, the presence of the ice edge. Plots of the surface temperature and 34 salinity show warm, saline water along the west and north coast of Spitsbergen, corresponding closely to the 1000 m isobath. The plot of surface temperature (Fig. 3.3) shows a wide, warm surface layer in the southern part of Fram Strait. The EGPF, occuring where the isotherms are closely packed together, runs in a generally northeastward direction from the southern end of Fram Strait. North of 80'°10'N the surface manifestation of the west branch of the WSC as defined by its AW content can be. seen where the 3°C isotherm pushes west against the EGPF. The plot of surface salinity (Fig. 3.4), although less detailed, shows the same general pattern of water mass distribution. There is a wide surface layer more saline than 34.0 across much of Fram Strait. Along the west coast of Spitsbergen there is a surface manifestation of AW more saiine than 35.0 that corresponds weil to the 6°C isotnerm in Fig. 3.3 and the 1000 m isobath. In Fig. 3.4 the 33.0 isohaiine corresponds closely to the ice edge except near 80°30'N where the 34.0 isonaiine pushes to the west in a surface manifestation of the westward turning. The distribution of surface properties is strongly influenced by the presence of che ice eage. Thus, other properties must be used to demonstrate the westward turning of warm, saiine AW without the contamination by surface Drocesses. One such property to be considered :s the maximum temperature at each station, which will be referred to as Tmax (Fig. 3.5). The narrow warm core of the WSC, defined in this figure by the 5° and 6°C isotherms, is confined to the Spitsbergen continental shelf and slope. The detached area warmer than 5°C, to the west of the core, may be evidence of a separate filament of the WSC. To the north of Spitsbergen the 5°C isotherm moves up onto the continental shelf. The westward turning of the western edge of AW shows up well in the 4°C isotherm. A cool area, defined by the 3°C isotherm, is located near the prime meridian between 79° and 80°N. It appears to be detached from the colder water over the Greenland continental slope. A comparison with Fig. 3.3 shows that this cool area is a sub-surface feature with surface temperatures colder than 0°C and, thus, mostly ice covered. The presence of this detached lens suggests a sub-surface cyclonic flow along 0°E between 79°N and 80°N. An analysis of the property profiles at each station revealed that the maximum temperature in the water column was nearly coincident with the maximum salinity at over 110 of the 156 stations occupied. Those stations where the correlation was closest occurred in the core of the WSC. The density of these stations, expressed as sigma-t, has a mean between 27.9 and 28.0. For this reason, and to compare with historical 35 data presented by Aagaard and Coachman (1968b), the temperature of the 28.0 sigma-t surface (Fig. 3.6) and the depth of the 28.0 sigma-t surface (Fig. 3.7) were plotted. Fig. 3.6 shows similar features to the plot of Tmax. The westward spread of the 2.0°C isotherm is seen between 80° and 81°N, with 81°N as the maximum extent of the westward flow. The area of water warmer than 2°C corresponds to the detached pool of cool water described above. (Aagaard and Coachman (1968b) presented data from 1965 which showed virtually identical features, although the maximum temperatures were warmer in 1965.) Perhaps the best evidence of westward turning, based on horizontal distributions of temperature and salinity, is seen in the depth of the 28.0 sigma-t surface. This figure indicates that a zone of westward turning takes place north of 78°N with little westward flow north ot 81°N. To the north ana west, behind the ice edge, the depth of this surface is greater than 500 m. C. HISTORICAL COMPARISONS There is a rich body of Jterature describing the summertime hydrographic conditions in the ice-free waters 'vest of Spitsbergen and south of 80°N. For example. from hydrographic data obtained during 1966-69 west ol Spitsbergen along 79°N, Dickson and Doddington ('1968. 1970) presented vertical sections of temperature and salinity which showed a warm, saline subsurface core, warmer than 6"C ana more saline than 35.1, at a depth between 50 and 200 m. This is to be compared with Transect 2 where the warm core is only 5°C and is found above the subsurface high- salinity core. More recently, based on August 1984 observations Bourke (1984) presented a section across Fram Strait, at 78°N, with a WSC core temperature greater than 6°C at the surface, and a subsurface salinity maximum of 35.1 at 60 m. This is similar to the structure seen in Transect 1 at the same latitude. In the ice-covered region north and northwest of Spitsbergen few oceanographic studies have been published. Johannessen et al. (1983) conducted CTD sections near the ice edge north of Spitsbergen in September and October 1979. They found the warm core of AW to be located between 100 and 400 m over the Spitsbergen continental shelf break. This is in contrast to Transect 5 where the warm core is located at the surface. Perkin and Lewis (1984) presented three CTD sections obtained north of Spitsbergen in April 1981. They show two filaments of AIW warmer than 2°C, and more saline than 34.5, entering the Arctic basin along the Spitsbergen continental slope. Quadfasel et al. (in press) described the temperature and salinity 36 5[ Figure 3.3 Surface temperature (°C) distribution. 37 BE 5 W Figure 3.4 Surface salinity distribution. 38 Figure 3.5 The maximum temperature at each station. 39 5 W 5*E 10 E Figure 3.6 The temperature of the 28.0 sigma-t surface. 40 .(_6go/. 5 w 10 E 5"E Figure 3.7 The depth of the 28.0 sigma-t surface. 41 distribution in the upper 600 m of Fram Strait north of 77°N based on CTD and XBT data acquired during the Marginal Ice Zone Experiment (MIZEX) in July 1984. They showed two branches of AW crossing 0°E; one between 78° and 79°N and another between 79° 30' and 80°N. The core of the WSC, warmer than 6°C and more saline than 35.1, was found from the surface to a depth of 200 m along the Spitsbergen continental slope. The warm, saline AW spread across Fram Strait in wave-like structures, some of which are apparently a result of bathymetric forcing by the Kipnovich Ridge similar to Transects 1, 2, 3 and 4. A recent workshop addressed the role of exchanges and dynamics in the circulation in Fram Strait (Aagaard and Reed, in press). There was agreement among the workshop participants that the bathymetry of the Kipnovich Ridge influences, at least in pan, the spatiai variability of the WSC. D. EAST GREENLAND CURRENT 1. Water Mass Characteristics A detailed description ox r:ie :haracteristics of 'he EGC and the 5GPF have already been maue (Aagaard ana Coachman, L968a,b; Paquette et ai. 1985: TunniclifFe, 1985; and BourKe. in press, a). They are included here for continutity. [n addition. this cruise mapped the course of the EGPF across Fram Strait in greater detail :han previous cruises. Fig. 3.8 is a T/S plot of stations along 78°N near the EGPF. Stations 5 through 1 1 show the characteristic "double minimum" temperature feature discussed by Paquette et al (19S5) and Tunnicliffe (1985). The first minimum is characterized by water colder than -1.5°C and salinities between 32.5 and 33.5. The second minimum occurs at a salinity of between 33.9 and 34.2 at a depth of about 100 m near the bottom of the PW layer. Paquette et al. (1985) suggest that this second minimum is formed when AIW, advected from the east under the PW, is modified by double diffusion. Station 14 is illustrative of stations to the east of the EGPF and shows the warm, saline fraction of AW and AIW often found in the core of the RAC. GSDW is found only in Stations 12 and 14, seaward of the shelf, and generally below 800 m. A typical distribution of water mass properties in the EGC is seen in Transect 1, along 78°N. Cold, fresh PW, defined by the 0°C isotherm and the 34.5 isohaline, is found over the Greenland continental shelf, to a depth of 180 m. The PW extends seaward of the shelf break, defined by the 400 m isobath, about 40 km and is separated from the warmer water to the east by the EGPF. A warm filament of AW, diluted to a 42 to CO 2o w; 't'OQ O < — i N ^ co z> CJ OS — -( i-H T-H -H 2 2 2 2 2 £ 2 2 O o O o O o O o >— ( M 1—4 H H P— i p-< :— i H F-H H < < < E X CO z o 5 n 2 ._ - r: — _^ — -*~ !_.— 3 > « " i-j^ — ■— 3 — - U o~-^ o o i/3 w>- v: — I»>| \-/ :; ON c> u, *> ei}=! r " ' . — i — . ■ O H „££ 47 TEMPERATURE (C) -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 100 200- 3C0- ^OO-i z: SQO - 3G0- 700- .800 - 900- ■0.06' 1000 a 0. 96 1+0.32 -0.29 -0.28 Figure 3.10 Temperature profiles for stations along 80°30'N. 48 30.0 32.0 SALINITY 34.0 36.0 38.0 40.0 — 500- 800- 900 1000 Figure 3.11 Salinity profiles for stations along 80°30'N. 49 Station 90 is located over the Greenland continental slope. A cold, fresh PW layer is located close to the surface. The temperature maximum at 200 m, of less than 0.5°C and salinity of 34.9, is similar to the Atlantic layer at the end of its cyclonic path in the central Arctic. GSDW is found at this station below 650 m. Station 97, located just at the ice edge but seaward of the EGPF, shows cooling and dilution at the surface. The maximum temperature at this station is still greater than 3°C but a strong positive thermocline and halocline have developed as a result of ice melt. Station 96 in the center of the front shows more extensive cooling and dilution. Warm AW is still present; however the thermocline and halocline now extend to 75 m, runner eroding the AW layer from above. In addition, a lens oi' cooi ( < l°C) water at 150 m is eroding the AW from below. Station 94 is well behind che EGPF; here the cooling and dilution extend to 200 m. No AW is present, che maximum temperature at the station is only t.5"C. With the exception of the small temperature :mestructure above and beiow the thermociine, this station is characteristic of m EGC water mass distribution. As can be seen in .Stations 94, 96, 97. and 103 rinestructure is usually associated with the depth zone of che maximum temperature in che water column. A notabie examoie of this type of fmestructure is seen in Scation 96, located -it the EGPF. The ;ool lens beiow the AW creates a temperature change of greater than 2°C in 10 m, as well as other interleaving regions above and beiow the lens. The density ratio, R = adTz/ P^SZ (eqn 3.1) where a = the thermal expansion coefficient; p = the salinity expansion coefficient and dTz and dSz are the temperature and salinity gradients, is the single most important parameter in determining the nature and strength of double diffusive activity. Laboratory measurements have shown that RQ > 1.0 but < 2.0 is unstable to salt-fingering and R„ < 1.0 is diffusively unstable (Ruddick, 1983). Several disadvantages exist, however, in using the density ratio. The first is that RQ has an infinite scale, with the diffusive region smaller than the fingering region. In addition, an indeterminate value exists for RQ when dSz = 0. In order to overcome the inadequacies of the density ratio Ruddick (1983) suggests the use of a new quantity: the Turner angle (Tu). The Turner angle is defined as the four quadrant arctangent of 50 '(NT2 + NS2> (eqn 3.2) where NT2 = ±gadT/dz (eqn 3.3) and Ns2 = ±g$dS;dz. (eqn 3.4) i Note that Ny~ and NV can be considered the temperature and salinity contributions to the Brunt-Vaisaia frequency.) The Tu is reiated to the density ratio such that R„ = -tan(Tu - 45°). The stability properties of the iocal stratification ire determined by R^ and are represented by the four Tu regions in Fig. 3.12 where Tu| > 90° is gravitationaiiy unstable, 45° < Tu < 90° is unstable to sait-fingering, |Tu| < 45° is staoie. and -90 < Tu < -45 is diffusively unstable. In order to determine the roie double diffusion plays in effecting fmestructure aiong the EGPF the Turner angle Tu) was computed for Station 96 -Fig. 3. 2.) "" smoothing the temperature and salinity profiles with a 5 - point (approximately 1.5 m) running mean and then calculating the gradients. Station 96 shows generally stable conditions in the thermocline. The interleaving between the region of AW > 3°C and the cool lens between 80 m and 120 m is associated with alternating strong fingering and diffusive regions. The cool lens between 120 m and 180 m, however, shows stable conditions. Below the lens are two areas of alternating activity that are associated with regions of fmestructure. One, between 180 m and 320 m, is located in AIW resulting from mixing between PW and AW. Another is located between 470 m and 550 m with generally stable contitions between the two regions of activity. Below 550 m the fmestructure decreases as does the strength of the double diffusive activity. 51 -J o ID" O *■ ~ „ o CJ r>- — ' LJ 5 o LJ C_ 2= O LJ •_ t— — v — '^_ o / "~^--____ o~ o — " o ™_ 1 1 I ! 1 I - V) JJ o C u, 3 H p 1- oo 001 003 00£ D0> (U] HId30 oos 009 00^ 008 52 u C -J — o utso" N C~ u — 5 ~-2~ X3 — -) r*^. -. oxr^i U c (N ■a CQ c *^ C3 C ~ ~ c *-' N u u u ir. C -. — i H5^ m v- (>") Hld30 53 I V v S 4> ■■J— ■ '-> ' -A *5 aOt/> « 5 o (NC apex o ,j2 «m wC O O e5 2^ He u *— * -4-* u DO U* (w) Hld3Q OIUIUO 54 119 118 117 116 200 400 500 r- 300 h 1000 34 9 35 0 33 0 33 0 0 20 003* 14.8'W 100 120 140 160 180 200 220 240 DISTANCE (Km) 008* 30.0'E Figure 3.15 Transect 3 alone 79°30"N. The Kipnovich Ridge is very pronounced at this latitude.. 55 o 10 - BO r t o F iO C3 H 00 < t— (>") Hld3d 5 56 NW 61 60 107 108 109 SE 112 113 114 115 STfl No — U 1 1 L 200 h 400 H u 3 500 t- 800 X347 >34 8 1349 J5.0 _L _L J_ 1000 220 200 180 160 140 120 100 80 60 40 20 0 002*5I.8'E DISTANCE (Km) 006*55. 5'E Figure 3.17 Transect 4 along the top of the Yermak Plateau. 57 NW ♦ STA No. 51 50 49 SE 46 45 1000 0 20 012°10.6'E 40 60 80 DISTANCE (Km) 100 015°01.8'E Figure 3.18 Transect 6 north of Spitsbergen. 58 o .z r- — "J "J 1 3 t_i H ■— — («u) Hld30 iMiHKia 59 .STA No 89 90 200 - 400 r oOOh 800 1000 ° «ooo 0 20 40 006*31. 4'W 80 100 120 140 160 180 200 220 DISTANCE (Km) 005*49.3'E Figure 3.20 Transect 8 along 80°30'N. 60 Figure 3.21 Transect 9 along 2°E shows the core of westward turning as the 3° lens Between Stations 36 and 99. 61 STA No. 125 200 - 400 a. UJ 500 800 - 1000 0 20 40 60 80 100 120 140 79° 08. 1' N 79° 57.9' N DISTANCE (Km) E 2000 - &4000 Figure 3.22 Transect 10 along 2°W through the center of the eddy. 62 IV. CIRCULATION AND TRANSPORT A. INTRODUCTION Current meter moorings have been made a number of times in the WSC off the coast of Spitsbergen. The first estimate of the WSC transport using direct, long-term current measurements was made at 79°N by Greisman (1976). From these measurements and hydrographic data obtained during 1971-72 he found that the average baroclinic component of the WSC was approximately one half of the total flow. Based on similar current meter and hydrographic data Dbtained in 1976-77, Hanzlick 1983) estimated the mean baroclinic component to be much less, only 18% oi :he total flow. Hanzlick aiso showed that 'he degree of baroclinicity vanes significantly. Using the vertical shear calculated from direct current measurements obtained during 1976-31, and assuming no baroclinicity in [he ieer part of the vater column, he .buna that the mean baroclinic contribution to "lie mean total transport .: 79°N varied from 14% to 38%. During 1984-35 a series of three current meters was deployed across the WSC at 78°45'N (Aagaard et al., 1986a). The total transport Tor this section for a one week average current taken in August 1984 was calculated using the method outlined by Hanzlick (1983). This time period corresponded to the time when NORTH WIND acquired hydrographic data at the locations of these current meters. This time also corresponded to a period of very strong northward flow in the WSC, resulting in a transport estimate of 16.5 Sv northward. The baroclinic component calculated from the hydrographic data, using the method described in Chapter II, was 1.5 Sv northward, resulting in a baroclinic contribution to the total flow of only 9%. Unfortunately, the series of current meters was removed prior to September 1985. Thus, no direct comparison can be made with the data presented in this thesis. There are no moored current meter records from locations further north than 79°N. While there is a large body of ice drift data in this region, this provides little indication of the flow within the warm WSC. Recently, Quadfasel et al. (in press) presented direct current observations, using surface and subsurface floats, in the region of the westward turning of the WSC. Satellite-tracked drifters were deployed at 78°N and showed two separate streams of the WSC, one at 6°E and another at 10°E. 63 Subsurface floats deployed between 79°30'N and 80°N showed westward flow across the prime meridian of about 0.1 m/s. Baroclinic calculations, however, were not presented for this data set so no direct comparison can be made here as well. It can only be assumed that high baroclinic variability also occurs in this region. Long-term current meter moorings have also recently been made in the EGC over the Greenland continental slope. Muench et al. (1986) presented data obtained from moorings positioned at 100 m and 400 m, within and beneath the core of the core of the frontal jet associated with the EGPF at about 78°35'N and 004°40'W in 1984-85. When compared with the geostrophic data from Tunniclifle (1985), it is evident that the EGC is strongly baroclinic, especially within the frontal jet but only to a deprh of 100 m. 3eneath rhe highly baroclinic zone the baroclinic component in 1984 decreased to about one half of the total flow. As with the series of current meters in the WSC. the current meters in the EGC 'vere also removed prior to Seprember 1985. making direct comDanson with the cresent data difficult. 3. DYNAMIC HEIGHT The dynamic topograpny was computed using the methods described in Chapter II. Dynamic heights were computed for rhe surface referenced :o 150 decibars I Fig. 4.1) anu 500 decibars '.Fig. 4.2) in order :o determine the oarociinic structure or' the surface flow and to allow comparison with previous work. Dynamic heights were also computed for the 150 decibar surface referenced to 500 decibars (Fig. 4.3) in order to assess the depth variation of the baroclinic current. The surface dynamic topographies referenced to 150 and 500 decibars show the weak baroclinicity of the WSC in comparison to the EGC. The northern limb of the cyclonic Greenland Sea gyre can be seen in the southern part of Fram Strait. The high gradient region in both figures is the EGPF. A prominent feature along the EGPF is the anticyclonic eddy located at 79°30'N and 001°W. The dynamic height gradient across the EGPF would suggest a baroclinic flow of between 0.20 and 0.30 m/s, while the gradient in the eddy would support a flow of 0.10 to 0.20 m/s. The sluggish WSC flow can be seen along the coast of Spitsbergen. The dynamic height gradient here is much reduced from that in the EGC indicating a baroclinic flow of 0.06 to 0.08 m/s. Fig. 4.2 clearly shows the branching of the WSC just north of 80°10'N. Westward flow is indicated between 79° and 81°N with the core of the westward turning crossing 5°E just north of 80°30'N and merging with the southward flowing EGC. Fig. 4.1 shows 64 Fieure 4.1 Surface dynamic topoeraphv referenced to 150 decibars m dynamic centimeters. 65 Figure 4.2 Surface dynamic topography referenced to 500 decibars in dvnamic centimeters. 66 5° W Figure 4.3 150 decibar dynamic topography referenced to 500 decibars in dynamic centimeters. 67 this westward turning core as a slightly wider flow with the core of the turning occuring across 5°E at 79°30'N. All three figures show that all of the current turns westward at or south of 81°N. Even at 150 decibars there is evidence that the sub- surface portion of the WSC which turns west does so south of 81°N. Fig. 4.2 also shows some evidence of a baroclinic cyclonic flow north of Spitsbergen. Comparison of surface dynamic topography with 150 m dynamic topography shows westward turning to be a surface layer phenomenon. The WSC flow can be seen along the coast of Spitsbergen. At depth most of the westward turning has occured between 78° and 79°N. C. BAROCLINIC FLOW To further investigate the geostrophic velocity and volume transport in Fram Strait, ten vertical baroclinic velocity sections were constructed corresponding to the ten transects of temperature ind salinity. Sections 1-10 are presented as Figs. 4.6 - 4.15 at the 2nd of this chapter. As described in Chapter [I, a reference level of 500 decibars was selected Tor the sections, with horizontal extrapolation made for shallower bottom depths. Section 1 I Fig. 4.6), along 78°N, shows the weakly baroclinic XVSC with a core speed of 0.07 m/s located over the center of ".lie Kipnovich Ridge. The riiamentai nature of the WSC can be seen in a second, much weaker, northward stream between Stations 19 and 20, extending only to a depth of about 80 m. The northward transport resulting from this flow is 1.3 Sv. The EGC shows strong baroclinic flow over the Greenland continental shelf with a speed of almost 0.2 m/s. The core of the RAC is located at a depth of 50 m at Station 16 with a maximum speed of 0.13 m/s. The combined transport for this section for the EGC and the RAC is 3.1 Sv southward. Section 2 (Fig 4.7), along 79°N, and Section 3 (Fig 4.8), along 79830'N, also show a weakly baroclinic WSC, with northward speeds of 0.02 to 0.03 m/s. The northward transport for these sections is 0.5 Sv, indicating that some of the flow has turned westward between 78° and 79°N. These sections also clearly show the presence of a baroclinic, anticyclonic eddy extending from the surface to 150 m. The eddy has rotational speeds of between 0.05 and 0.09 m/s, the asymetric character of which may be a result of southward advection of the eddy by the mean flow of the EGC. The EGC is seen in the left hand corner of these Figures having a southward flow of greater than 0.16 m/s. Also seen in Figs. 4.7 and 4.8 is a weak southward flow of low salinity 68 water at the surface near the coast of Spitsbergen, probably the result of glacial run off. Section 4 (Fig. 4.9), along the ridge of the Yermak Plateau, and Section 5 (Fig. 4.10), along 80°N, show the branching of the WSC into two streams, with one branch flowing north along the Spitsbergen continental shelf and the other along the western slope of the Yermak Plateau. The northward speeds in both branches is 0.02 to 0.03 m/s, while the transport for each section is 0.5 Sv northward. Section 6 (Fig. 4.11), extending northwestward from the coast of Spitsbergen, shows the WSC over the continental slope with a speed of 0.02 m/s. The orientation of this section results in a transport of 0.1 Sv coward the northeast, indicating that approximately 20% of the barociinic rlow or' the WSC has turnea into the Arctic arouna cne northern coast af Spitsbergen. Fig. 4. ii also shows a southward ilow of 0.05 m/s; this is part of :ne cyclonic How north of the Spitsbergen continental slope discussed earlier in c:'j. 4.2. Section 7 Fig. -.12). along 81°N, ail of which is behind the ice edge; snows that it this latitude the flow is dominated by the southward flowing EGC with i ;peed >f 0.14 m/s. The speed of the WSC in "his section is at most ).01 m/s. Section ] Fig. 4.13), along 80°30'N, is aiso dominated by the southward flow of the EGC. A much stronger :st than in Fig"-. 12 is .oeated between Stations ,J5 and 100 with a speed of 0.2 m/s. The maximum speed of the WSC in this section is 0.05 m/s ana centered over the western slope of the Yermak Plateau near Station 104. The southward transport for Fig. 4.12 is 1.2 Sv and for Fig. 4.13 is 1.1 Sv. The northward transport in the WSC for Fig. 4.12 is less than 0.1 Sv, while for Fig. 4.13 it is 0.4 Sv. Also present in these two sections is a shallow northward flowing current over the Greenland continental slope between 5° and 7°W. The cause for this northward flow is probably a meander in the EGC that is not fully resolved by the data. Section 9 (Fig. 4.14), along 2°E between 79° and 81°N, shows the core of the westward turning is predominantly north of 80°N, between Stations 38 and 99, with a speed of 0.03 m/s. There is also a westward flow south of Station 34, indicating that some westward turning is taking place south of 79°N. The transport for the northern core of westward turning is 0.4 Sv, while that south of Station 34 is about 0.1 Sv westward. Section 10 (Fig. 4.15) extends through the eddy along 2°W. This section shows a much more symetric pattern to the anti-cyclonic rotation, although the rotational speed of 0.15 m/s is somewhat in contrast to the slower speeds discussed earlier. The swirl transport calculated from these velocities is about 0.4 Sv. 69 Fig. 4.4 shows a plan view of Fram Strait and summarizes the transport measurements just disscussed. The solid arrows indicate the transports calculated from the present data. The dashed-dot line indicates the latitude band where there is little or no westward flow. Assuming continuity of the flow, 0.8 Sv must turn westward south of 79°N. This is indicated by the dashed arrow with the transport value in parenthesis. The splitting of the WSC is indicated by the arrow pointing westward at 80°N and the second arrow pointing northeastward north of Spitsbergen. Included for comparison are transport calculations from data obtained in 1984 (TunniclifTe, 1985) shown as open arrows. The 1.5 Sv southward found in 1984 included contributions from the flow over che sheif and out :o the EGPF but little, if any. of the RAC The 3.1 Sv southward ibund in .985 included the EGPF and the RAC. Assuming ;ne flow is che same in both years, an uncertain assumption at best, then the RAC carries at least 1.5 Sv southward, whica is similar in magnicude to the transport of the EGPF jet. D. CIRCULATION The surtace 'jircuiation oattern suggested by the dynamic height anu geostroohic velocity calculations is shown in rig. 4.5'. The arrow lengths and widths ire representitive oi rhe magnitude of the flow as snown m the accompanying scaie. A weakly barociinic WSC flows north in several streams jontroilea In part by bathymetry. Some westward turning takes place south of 79°N, with a second core of westward turning between 80° and 81°N. 70 n „gr^£2 a V3 t-i o '> C .5 a, < ■qr ■qr S-i 00 in N 0LL N 09Z N fiL 71 —XT 7~ r i iooow i | | 2000M /\ \ .\ .000- j / / \ 2 ^ 4. ^" 10 w ~^* ■ 0 cm/5 = 5 W \ :1 \ A \ \ V c — ^. "■"* \ "2000M . \ \ , \ l_ I - ^ 'v " \ .V 5"C i»hV, / \ \ I0OOM ' i 2000M / V i i > I \ I I i IOOOH' : • "Ve IOOOM \ \ ^ \ 15 E Figure 4.5 A plot of the surface circulation suegested by the dynamic topography and geostrophic vefocities. 72 a) o > > 2 y -^ V) _ r: ',1 n ^— : — -j P< oo^ in ^a o O0"> C t/5 o^; «s — t— ' — o V) O o-- 00 o CX VD T *A .o in _ m O'O CTOS- CT00I- O'DSI- CT002- CT0S2- O'OOZ- 0'0S£- CTOOfr- O'OSV-O'OOS- (W) HId3Q z iU c/3 00 74 !_ [Z D ^ ^D U J/? CO 3 0*0 O'OS- 0*001- O'OSl- 0'OOS- O'OSS- O'OOC- 0'0S£- 0*0O"»- 0'0SHJ" (Ul) Hld3Q oos- 75 Station Number 61 60 107 108 109 110 111 112 113 0.0 25.0 50.0 75.0 100.0 125.0 DISTANCE (KM) 150.0 175.0 Figure 4.9 Section 4, along the top of the Yermak Plateau. 76 Station Number s?1 a d _ a in o o u">. ,0" o 38 39 40 \\ 42 43 o J - 1 \ o o / ". a . • c o- 1 o \ © *-* d i f ' \ O 'o o • c 1 . '. 8 I t? 1 r. ~ % c>' i 3 5- - 3 = 1 3 _ — " \ 0.0 25.0 50.0 75.0 100.0 125.0 DISTRNCE (KM) 150.0 175.0 200. Figure 4.10 Section 5, along 80°N. 77 Station Number 25.0 50.0 DISTRNCE (KM) 75.0 Figure 4.11 Section 6, extending northwestward from the Spitsbergen coast. 7S m ■R- 3 -a O.OG /^ ■^ VZ s ifl Z • ^ r* '-J J __ 2 r -■ _ a — O C/0 o (TO O'OS- O'OOI- O'OSI- 0-OOJ- O'OSZ- O'OOE- 0'0S£- (TOOV- 0-0SV-0'COS- (W) HId3Q 79 c CD _2 en Z X3 30 0*0 O'OS- 0*001- O'OSI- 0*002- 0-OSS- 0"00£- 0-0S£- O'OOV- O'OSV-0' (W) HId3Q oos- 80 Station Number 0.0 25.0 50.0 75.0 100.0 125.0 DISTANCE (KM) 150.0 175.0 196.7 Figure 4.14 Section 9, along 2°E, showing the core of the westward turning. 81 o LO I •Si OJ ' — "O - 3J — i r, CD o o ro i o LO to I o o o I o LO 6 o o LO StatLon Number 134 145 137 144139 140 $> £L o o 0.0 25.0 50.0 75.0 DISTRNCE (KM) 100, Figure 4.15 Section 10 along 2°W, through the center of the eddy. 82 V. CONCLUSIONS The West Spitsbergen Current and adjacent waters in Fram Strait .have been examined using a dense network of CTD stations occupied by NORTHWIND in September 1985. The distribution of water masses in Fram Strait was examined in detail. Baroclinic transports were calculated from geostrophic velocities based on the distribution of these water properties. The following conclusions can be drawn: • The WSC was found as a weakly baroclinic flow in several streams along the Spitsbergen continental slope. Northward geosirophic velocity at the surface along 78°N was found :o be 0.07 m/s. • Bathymetric steering apoears co play an important role in the location ji the separate streams ;f the WSC. The Kipnovich Ridge, a 2000 m deep feature to she west of che Spitsbergen continental sheif. exerts an influence on the distribution of water mass orooerties. especially north of 78°N. • North of 80°N the WSC splits into two oranches. with approximately 20% sir' :nn baroclinic slow following she Spitsbergen continental shelf into she Arctic Basin ana 50% ot sue .low turning westward over she western slope oi' the Yermak Plateau. • Some westward turning of the WSC takes place south of 79°N. A core of westward turning was located between 80° and 81°N along the prime meridian with baroclinic speeds of 0.03 m/s. Several filaments of AW were found turning westward between 79° and 80°N, although these contributed little to the net westward transport. • South of 79°N the EGPF is found close to the 400 m isobath. North of 79°N the front turns northeastward and crosses the Yermak Pleateau into the Arctic Ocean. • North of 79°N the EGPF was found split into surface and subsurface sections, probably as a result of the cooling and dilution of AW by melting sea ice. • An anti-cyclonic, cold core eddy with a diameter of approximately 60 km and a depth of 180 m was found along the EGPF. This eddy had geostrophic velocities of up to 0.15 m/s resulting in a swirl transport of 0.4 Sv. 83 • Notable temperature and salinity fmestmcture was found along the EGPF and in the vicinity of the ice edge, with the temperature signal often varying by more than 2°C peak-to-peak.. Strong interleaving of water masses was often found to occur resulting in alternating regions of strongly diffusive and fingering activity. 84 LIST OF REFERENCES Aagaard. K.. Wind-driven transports in the Greenland and Norwegian seas. Deep-Sea Res., I7t 281-291, 19~0. Aagaard. K.. and L.K. Coachman. The East Greenland Current north of the Denmark Strait.I. Arctic, 21, IS 1-200, 196Sa. Aagaard. K.. and L.K. Coachman. The East Greenland Current north of the Denmark. Strait.II, Arctic, 21, 267-290, Aagaard, K... and A. Foidvik, The West Spitsbergen Current in Fram Strait: what happens to the water. £:c. 86, 1262, 1985. igaard, ... ind P jhreisman. I"oward new mass and heat audgei r - jrctic ;ean, ■ Res.. : 382 - I" -":. Aagaard, K.., and R. Reed, Fram Strait: exchange md iynamics, 'a?::' )n a "::: hop, Aagaard, K.. C. Darnaii. A. Foidvik, and T. Torresen, Fram Strait current measurements 19S4-19S5. Report No. 63. Dept. of Oceanography. Geophysical Institute. University of Bergen. Bergen. Norway. 19S5a. Aagaard. K., J.H. Swift, and E. Carmack, Thermohaline circulation in the Arctic mediterranean seas. J. Geophys. Res.. 90, 4S33-4846, 19S5b. Bourke. R.H.. Preliminary results of the oceanographic cruise of the USCGC Northwind to the Greenland Sea: August - September. 19S4. Tech. Rep. NPS 68-84-019. Dept. of Oceanography. Naval Postgraduate School. Monterey. California, 19S4. Bourke. R.H.. J.L. Newton, R.G. Paquette. and M.D. Tunnicliffe . Circulation and water masses of the East Greenland shelf, J. Geophys. Res., in press a. Bourke, R.H.. M.D. Tunnicliffe. J.L. Newton. R.G. Paquette. and T.O. Manley. Eddy near the Molloy Deep revisited, J. Geophys. Res., in press b. 85 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. NTS 68-86-007, Dept. of Oceanography, Naval Postgraduate School, Monterey, California, 1986. Carmack, E., On the hydrography of the Greenland Sea, Ph.D Thesis, University of Washinton, Seattle, Washington, 1972. Carmack, E., and K. Aagaard, On the deep water of the Greenland Sea, Deep-Sea Res., 20, 687-715, 1973. 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. Davidson. K., and others. MIZEX 3uiletm VIII: A science plan for a winter marginal ice zone experiment in the "ram Strait: Greenland Sea: 1987/89, CRREL Special Report 86-9, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover. New Hampshire. 1986. Dickson, R.R., Variability ma :ontmuiaty within the Atlantic Current or' the Norwegian Sea, Rap p. Cons. Explor. Mer, 162, 167-183, 1972. Dickson, R.R., and T.C. Doddington, Hydrographic conditions off Spitsbergen in the summers of 1966 and 1967, Ann. Biol., 24, 24-29, 1968. Dickson, R.R., and T.C. Doddington, Hydrographic conditions off Spitsbergen in the summers of 1968 and 1969, Ann. Biol., 26, 26-32, 1970. Fomin, L.M., The Dynamic Method in Oceanography, Elsevier Publishing Company, New York, 1964. Greisman, P., Current measurements in the eastern Greenland Sea, Ph.D. Thesis, University of Washington, Seattle, Washington, 1976. Greisman, P., and K. Aagaard, Seasonal variability of the West Spitsbergen Current, Ocean Modelling, 19, 3-5, 1979. 86 Griffiths, R.W., and P.F. Linden, The stability of buoyancy-driven coastal currents, Dyn. Atmos. Oceans, 5, 281-306, 1981. Hakkinen, S., Coupled ice-ocean dynamics in the marginal ice zones: upwelling, downwelling, and eddy generation, J. Geophys Res., 91, 819-832, 1986. Hanzlick, D.J., The West Spitsbergen Current: transport, forcing and variability, Ph.D. Thesis, University of Washington, Seattle, Washington, 1983. Helland-Hansen. B., The Sognefjord Section - oceanographic observations in the northernmost part of the North Sea and the southern part of the Norwegian Sea. James Johnstone Memorial Volume, Lancashire Sea - Fish. Lao.. Liverpool. 1934. Heiland- Hansen. 8. and F. Nansen, The Norwegian Sea. Report on Norwegian Fishery una Marine Investigations, vol. 2. part I, no. 2, Bergen. Norway, 1909. Hill, ri.W. and -..J. 2~e. The affect Df wind on ^vater Transport in the region Df he Bear island fisher: . Proc. Roy. Soc. 3. 148. 104-116, 1957. Johannessen, O..VL. J. A. Johannessen. J. Monson, 3. A. Farreily. and E.A.S. Svenasen. Oceanogrnpnic conditions :n r.he marginal ice zone north of Svalbard :n early all 1979 with an emphasis on mesoscaie processes, J. Geophys. Res., 88, 2155-2169, 19S3. Kiilerich, A.B., On the hydrography of the Greenland Sea, Meddelser om Gronland, 144, 63 pp., 1945. Kislyskov, A.G., Fluctuations in the regime of the Spitsbergen Current, Translation: Soviet Fisheries Investigations in North European Seas, 39-49, 1960. Lee, A., The hydrography of the European Artie and Subartic Seas, Oceanogr. Mar. Biol. Ann. Rev., 1, 47-76, 1963. Muench, R.D., G.S.E. Laagerloef, and J.T. Gunn, 1984-85 Current observations in the East Greenland Current: A preliminary description, MIZEX Bulletin VII, CRREL Special Report 86-3, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire, 1986. 87 Paquette, R.G., R.H. Bourke, J.L. Newton, and W.F. Perdue, The East Greenland Polar Front in Autumn, J. Geophys. Res, 90, 48866-4S82, 1985. Perdue, W.F., Oceanographic investigation of the East Greenland Polar Front, Master's Thesis, Naval Postgraduate school, Monterey, California, March, 1982. Perkin, R.G. and E.L. Lewis, Mixing in the West Spitsbergen Current, J.Phys. Oceanogr., 14, 1315-1325, 1984. Perry, R.K., Bathymetry, in: The Nordic Seas, edited by B.G. Hurdle, pp. 211-234, Springer- Verlag, 1986. Quadfasel, D., J.C. Gascard, mci K.P. Koitermann. Large scale oceanograpny in "ram Strait during MIZEX 84, J. Geophys. Res., in press. Ruddick. 3.. A practical indicator or" the stability of the water column to double- iifTusive activity. Deep-Sea Res.. ,0. 1 105-1107. 1983 Smith, D.C., J.H. VIonson. J. A. Johannessen. and N. L'nterstemer. Topographic generation of an eddy at the edge of the East Greenland Current. J. Geophys. Res.. 39. 8205-8208, 19S4. Swift, J.H., and K. Aagaard, Seasonal transitions and wa'ter mass formation in the Iceland and Greenland Seas, Deep Sea Res., 28A, 1107-1129, 1981. Timofeyev, V.T., The movement of Atlantic water and heat into the Artie Basin, Deep- Sea Res., 9, 358-361. 1962. Trangeled, S., Oceanography of the Norwegian and Greenland Seas and adjacent areas, NATO SACLANTCEN memorandum SM-47, 1974. TunniclirTe, M.D., An investigation of the waters of the East Greenland Current, Master's Thesis, Naval Postgraduate School, Monterey, California, September, 1985. Turner, J.S., Buoyancy Effects in Fluids, Cambridge University Press, New York, 1973. UNESCO, Background papers and supporting data on the practical salinity scale, 1978, UNESCO Tech. Pap. in Mar. Sci., No. 37, 1981. 88 Wadhams, P., and V.A. Squire, An ice-water vortex at the edge of the East Greenland Current, J. Geophys. Res., 88, 2770-2780, 19S3. Wadhams, P., A.E. Gill, and P.F. Linden, Transects by submarine of the East Greenland Polar Front, Deep-Sea Res., 26, 1311-1329, 1979. 89 INITIAL DISTRIBUTION LIST No. Copies 1. Director Applied Physics Laboratory Attn: Mr. Robert E. Francois 1 Mr. E.A. Pence 1 Mr. G.R. Garrison 1 Library 1 University of Washington 1013 Northeast 40th Street Seattle, Washington 98105 2. Director 5 Arctic Submarine Laboratory Code 19, Building 371 Naval Ocean Systems Center San Diego, California 92152 3. Superintendent "Java: 'ostgraduate School Attn: Or. R.H. Bourke, loae 68Bf 5 Dr. R.G. Paquette, Code 68Pa 5 D r . D..C . Smi t h I V , Co de -53S i 1 Monterey, California 93943 4. Polar Research Laboratory, Inc. 1 6309 Carpinteria Ave. Carpinteria, California 93103 5. Chief of Naval Operations Department of the Navy Attn: N0P-02 1 N0P-22 1 N0P-964D2. 1 N0P-095 1 N0P-098 1 Washington, District of Columbia 20350 6. Commander 1 Submarine Squadron THREE Fleet Station Post Office San Diego, California 92132 7. Commander 1 Submarine Group FIVE Fleet Station Post Office San Diego, California 92132 8. Dr. John L. Newton 2 10211 Rookwood Drive San Diego, California 92131 90 9. Director Marine Physical Laboratory Scripps Institution of Oceanography San Diego, California 92132 10. Commanding Officer Naval Intelligence Support Center 4301 Suitland Road Washington, District of Columbia 20390 11. Commander Space and Naval Warfare Systems Command Department of the Navy Washington, District of Columbia 20360 LC, /Jooas Hole Oceanographic Institution •Joods Hole, Massachusetts 02543 13. Commanding jfficer 1 Naval Coastal Systems .aboratory Panama City, Florida :2401 14. Commanding Officer 'laval Submarine School "lava; Submarine Base, New London Proton, Connecticut 06249-5700 15. Assistant Secretary of the Navy 1 (Research and Development) Department of the Navy Washington, District of Columbia 20350 16. Director of Defense Research and Engineering 1 Office of Assistant Director (Ocean Control) The Pentagon Washington, District of Columbia 20301 17. Commander, Naval Sea Systems Command 1 Department of the Navy Washington, District of Columbia 20362 18. Chief of Naval Research Department of the Navy Attn: Code 102-0S 1 Code 220 1 Code 1125 Arctic 1 800 N. Quincy Street Arlington, Virginia 22217 91 19. Project Manager 1 Anti -Submarine Warfare Systems Project Office (PM4) Department of the Navy Washington, District of Columbia 20360 20. Commanding Officer 1 Naval Underwater Systems Center Newport, Rhode Island 02840 21. Commander 1 Naval Air Systems Command Headquarters Department of the Navy Washington, District of Columbia 20361 22. Commander Naval Qceanographic Office Attn: Library Code 3330 1 Washington, District )f Columbia 20373 23. Director 1 Advanced Research Project Agency 1400 Wilson Sou levari Arlington, Virginia 22209 24. Commander SECOND Fleet 1 Fleet Post Office New York, New York 09501 25. Commander THIRD Fleet 1 Fleet Post Office San Francisco, California 96601 26. Commander Naval Surface Weapons Center White Oak Attn: Mr. M.M. Kleinerman 1 Library 1 Silver Springs, Maryland 20910 27. Off icer-in-Charge 1 New London Laboratory Naval Underwater Systems Center New London, Connecticut 06320 28. Commander Submarine Development Squadron TWELVE 1 Naval Submarine Base New London Groton, Connecticut 06349 92 29. Commander Naval Weapons Center Attn: Library China Lake, California 93555 30. Commander Naval Electronics Laboratory Center Attn: Library 271 Catalina Boulevard San Diego, California 92152 31. Director Naval Research Laboratory Vttn: Technical Information Division Washington, District of Columbia "0375 32. Director )rdnance Research Laboratory -'ennsyl vania State University >tate College, Pennsylvania 16801 33. '^manner Submarine rorce I.S. \t1 antic "ee<; Norfolk , Virginia 23511 34. l;nmander Sunmar^ne Torce U.S. Pacific Fleer Attn: N-21 Pearl Harbor, Hawaii 96860-6550 35. Commander Naval Air Development Center Warminster, Pennsylvania 18974 36. Commander Naval Ship Research and Development Center Bethesda, Maryland 20084 37. Commandant U.S. Coast Guard Headquarters 400 Seventh Street, S.W. Washington, District of Columbia 20590 38. Commander Pacific Area, U.S. Coast Guard 630 San some Street San Francisco, California 94126 39. Commander Atlantic Area, U.S. Coast Guard 159E, Navy Yard Annex Washington, District of Columbia 20590 93 40. Commanding Officer 1 U.S. Coast Guard Oceanographic Unit Building 159E, Navy Yard Annex Washington, District of Columbia 20590 41. Scientific Liaison Office 1 Office of Naval Research Scripps Institute of Oceanography La Jolla, California 92037 42. Scripps Institution of Oceanography 1 Attn: Library P.O. Box 2367 La Jolla, California 92037 43. 3cnooi of Iceanography University of Washington \tzr\: Dr. L.K. Coachman Or. 3. Martin 1 Or. J. Swift 1 Library 1 Seattle, Washington 38195 44. Schooi of Oceanography 1 Oregon State University Ittn: Library Corvailis, Oregon 97331 45. CRREL U.S. Army Corps of Engineers Attn: Library 1 Hanover, New Hampshire 03755-1290 46. Commanding Officer 1 Fleet Numerical Oceanography Center Monterey, California 93943 47. Commanding Officer 1 Naval Environmental Prediction Research Facility Monterey, California 93943 48. Defense Technical Information Center 2 Cameron Station Alexandria, Virginia 22304-6145 49. Commander 1 Naval Oceanography Command NSTL Station Bay St. Louis, Mississippi 39529 94 50. Commanding Officer Naval Ocean Research and Development Activity Attn: Technical Director 1 NSTL Station Bay St. Louis, Mississippi 39529 51. Commanding Officer 1 Naval Polar Oceanography Center, Suitland Washington, District of Columbia 20373 52. Director 1 Naval Oceanography Division Naval Observatory 34th and Massachussetts Ave. NW Washington, District )f Columbia 20390 53. Commanding Officer Naval Oceanograohic Command NSTL Station Bay St. Louis, Mississippi 39522 54. Scor.t °olar ^ese^rc:1 [nstitute Jniversity if Cannr^ idge Attn: Library 1 Sea Ice Crouo 1 Cambridge, ENGLAND C82 1ER 55. Chairman 1 Department of Oceanography U.S. Naval Academy Annapolis, Maryland 21402 56. Dr. James Mori son 1 Polar Science Center 4057 Roosevelt Way, NE Seattle, Washington 98105 57. Dr. Kenneth Hunkins 1 Lamont-Doherty Geological Observatory Palisades, New York 10964 58. Dr. David Paskowsky, Chief 1 Oceanography Branch U.S. Department of the Coast Guard Research and Development Center Avery Point, Connecticut 06340 59. Science Applications, Inc. Attn: Dr. Robin Muench 1 13400B Northrup Way Suite 36 Bellevue, Washington 98005 95 60. Institute of Polar Studies Attn: Library 1 103 Mendenhall 125 South Oval Mall Columbus, Ohio 43210 61. Institute of Marine Science University of Alaska Attn: Library 1 Fairbanks, Alaska 99701 62. Department of Oceanography University of British Columbia Attn: Library 1 Vancouver, British Columbia CANADA VfiT 1W5 63. institute of Marine Science Universi ty of Al aska Yttn: Dr. K.J. Niebauer 1 r3irbanks, Alaska 99701 64. Bedford Institute of Oceanography Attn: Or. 3 . Jones 1 Library I P.O. Box 1006' Dartmouth, Nova Scotia CANADA B2Y 4A2 65. Carol Pease 1 Pacific Marine Environmental Lab/NOAA 7600 Sand Point Way N.E. Seattle, Washington 98115 66. Department of Oceanography 1 Dalhousie University Halifax, Nova Scotia CANADA B3H 4J1 67. Dr. Richard Armstrong 2 MIZEX Data Manager National Snow and Ice Data Center Cooperative Institute for Research in Environmental Sciences Boulder, Colorado 80309 68. Dr. Eddy Carmack 1 Institute of Ocean Sciences P.O. Box 6000 Sidney, British Columbia CANADA V8L 4B2 96 70. Dr. Knut Aagaard NOAA/PMEL NOAA Bldg. #3 7600 Sand Point Way, N.E. Seattle, Washington 98115 71. Department of Ocean Engineering Attn: Library Mass. Institute of Technology Cambridge, Massachusetts 02139 72. Dr. Theodore D. Foster Center for Coastal Marine Studies •Jn i vers i ty ] f la \ i fori i 3 Ian:a >uz, California 95064 7 3 . Re search Admi ni strati on :.)ne 012 ^laval Postgraduate School lonterey . Ca 1 i forni a r^9£% ;000 74. )r. Hugh 9. .ivingston ■ioons Hole teeanographic [nstitution /voous -lole, ^assacnuser-t3 92543 ";. Dr. T.0. v/lanley Lamont-D oh erty Geological Observatory Palisades, New York 10964 76. Dr. A. Foldvik Geophysical Institute University of Bergen Bergen, NORWAY 77. \)r. Preben Gudmandsen Electromagnetics Institute Technical University of Denmark Building 349 DK-2800 Lyngby, DENMARK 78. Dr. D. Hanzlick Flow Industries, Inc. Kent, Washington 98064 79. Dr. W.D. Hibler Thayer School of Engineering Dartmouth College Hanover, New Hamsphire 03755 Ofo , 97 80. Dr. J. Meincke Inst, fur Meereskunde Universistat Hamburg Heimhunder Strasse 71 2000 Hamburg 13 WEST GERMANY 81. Or. B. Rudels Norwegian Polar Research Institute P.O. Box 158 1330 Oslo Lufthaven NORWAY 32. LT A.M. Wei gel 4332 Great Oak Drive Charleston, South Carolina 29413 33. Superintendent Naval Postgraduate Scnool Vttn: Library 'Code 0142) Monterey, California ?39&3-5002 93 8070 ■ r r ^ *A e SCHOOL MOjT ORNIA 93943-6002 Thesis W35?.3 Weieel c.l Mesoscale variability in the West Spitsbergen Current and adjacent waters in Fram Strait.