TR-107 ASWEPS REPORT NO. 1 THE OCCURRENCE AND VELOCITY DISTRIBUTION OF SHORT-TERM INTERNAL TEMPERATURE VARIATIONS NEAR TEXAS TOWER NO. 4 ROY D. GAUL Formulation Branch Oceanographic Prediction Division MAY 1961 GC / .TH3 ww. 1 K-107 U. S. NAVY HYDROGRAPHIC OFFICE i WASHINGTON, D. C. rice 50’ cents Encl {/77) to HYDRO +487 9-7 I Nis ie 196s ABSTRACT This report describes a study of the occurrence, speed, and direction of short-term changes in water temperature near Texas Tower No. 4 off New York. Measurements made during two-week periods in the fall of 1959 and the spring of 1960 reveal common occurrences of internal solitary wave forms indicated by temperature changes at fixed levels of several degrees centigrade within several-minute intervals. Internal temperature wave forms observed in both seasons were typically moving onshore at speeds ranging from 0.75 to 1.30 knots. Comparison of observed speeds with values calculated from internal solitary wave theory exhibits reason- able agreement considering the limitations of the field experimental phase of the study, sd by the author while __ laprnewimice. The manuscript was prepared by the author while associated with the Department of Oceanog- raphy and Meteorology, Agricultural and Mechanical College of Texas. TR- 107 TECHNICAL REPORT ASWEPS REPORT NO. 1 THE OCCURRENCE AND VELOCITY DISTRIBUTION OF SHORT-TERM INTERNAL - TEMPERATURE VARIATIONS NEAR TEXAS TOWER NO. 4 ROY D. GAUL Formulation Branch Oceanographic Prediction Division MAY 1961 ine 0 0301 oo4oas? j ABL/WH NON | U. S. NAVY HYDROGRAPHIC OFFICE WASHINGTON, D. C. Price 50 cents ABSTRACT This report describes a study of the occurrence, speed, and direction of short-term changes in water temperature near Texas Tower No. 4 off New York. Measurements made during two-week periods in the fall of 1959 and the spring of 1960 reveal common occurrences of internal solitary wave forms indicated by temperature changes at fixed levels of several degrees centigrade within several-minute intervals. Internal temperature wave forms observed in both seasons were typically moving onshore at speeds ranging from 0.75 to 1.30 knots. Comparison of observed speeds with values calculated from internal solitary wave theory exhibits reason- able agreement considering the limitations of the field experimental phase of the study. The data upon which this report is based were collected by the author while Head, Special Research Group, Hydrographic Office. The manuscript was prepared by the author while associated with the Department of Oceanog- raphy and Meteorology, Agricultural and Mechanical College of Texas. TR- 107 TECHNICAL REPORT ASWEPS REPORT NO. 1 THE OCCURRENCE AND VELOCITY DISTRIBUTION OF SHORT-TERM INTERNAL | TEMPERATURE VARIATIONS NEAR TEXAS TOWER NO. 4 ROY D. GAUL Formulation Branch Oceanographic Prediction Division MAY 1961 - U.S. NAVY HYDROGRAPHIC OFFICE WASHINGTON, D. C. Price 50 cents ABSTRACT This report describes a study of the occurrence, speed, and direction of short-term changes in water temperature near Texas Tower No. 4 off New York. Measurements made during two-week periods in the fall of 1959 and the spring of 1960 reveal common occurrences of internal solitary wave forms indicated by temperature changes at fixed levels of several degrees centigrade within several-minute intervals. Internal temperature wave forms observed in both seasons were typically moving onshore at speeds ranging from 0.75 to 1.30 knots. Comparison of observed speeds with values calculated from internal solitary wave theory exhibits reason- able agreement considering the limitations of the field experimental phase of the study. The data upon which this report is based were collected by the author while Head, Special Research Group, Hydrographic Office. The manuscript was prepared by the author while associated with the Department of Oceanog- raphy and Meteorology, Agricultural and Mechanical College of Texas. TR-107 TECHNICAL REPORT ASWEPS REPORT NO. 1 THE OCCURRENCE AND VELOCITY DISTRIBUTION OF SHORT-TERM INTERNAL , TEMPERATURE VARIATIONS NEAR TEXAS TOWER NO. 4 ROY D. GAUL Formulation Branch Oceanographic Prediction Division MAY 1961 U. S. NAVY HYDROGRAPHIC OFFICE WASHINGTON, D. C. Price 50: cents ABSTRACT This report describes a study of the occurrence, speed, and direction of short-term changes in water temperature near Texas Tower No. 4 off New York. Measurements made during two-week periods in the fall of 1959 and the spring of 1960 reveal common occurrences of internal solitary wave forms indicated by temperature changes at fixed levels of several degrees centigrade within several-minute intervals. Internal temperature wave forms observed in both seasons were typically moving onshore at speeds ranging from 0.75 to 1.30 knots. Comparison of observed speeds with values calculated from internal solitary wave theory exhibits reason- able agreement considering the limitations of the field experimental phase of the study. The data upon which this report is based were collected by the author while Head, Special Research Group, Hydrographic Office. The manuscript was prepared by the author while associated with the Department of Oceanog- raphy and Meteorology, Agricultural and Mechanical College of Texas. TR- 107 TECHNICAL REPORT ASWEPS REPORT NO. 1 THE OCCURRENCE AND VELOCITY DISTRIBUTION OF SHORT-TERM INTERNAL TEMPERATURE VARIATIONS NEAR TEXAS TOWER NO. 4 ROY D. GAUL Formulation Branch Oceanographic Prediction Division MAY 1961 U.S. NAVY HYDROGRAPHIC OFFICE WASHINGTON, D. C. Price 50 cents ABSTRACT This report describes a study of the occurrence, speed, and direction of short-term changes in water temperature near Texas Tower No. 4 off New York. Measurements made during two-week periods in the fall of 1959 and the spring of 1960 reveal common occurrences of internal solitary wave forms indicated by temperature changes at fixed levels of several degrees centigrade within several-minute intervals. Internal temperature wave forms observed in both seasons were typically moving onshore at speeds ranging from 0.75 to 1.30 knots. Comparison of observed speeds with values calculated from internal solitary wave theory exhibits reason- able agreement considering the limitations of the field experimental phase of the study. The data upon which this report is based were collected by the author while Head, Special Research Group, Hydrographic Office. The manuscript was prepared by the author while associated with the Department of Oceanog- raphy and Meteorology, Agricultural and Mechanical College of Texas. a 84). “ae FRONTISPIECE—TEXAS TOWER NO.4 OFF NEW YORK (COLLAPSED 15 JANUARY 1!961) he be he FOREWORD Of great importance to a variety of naval operations is the knowledge of density distribution in the ocean at particular points in space and time. The field studies conducted at Texas Tower No. 4 in support of the AntiSubmarine Warfare Environmental Prediction System (ASWEPS) were designed to detect and provide a fund of field data for the analysis of regular and irregular variations in temperature structure beneath the water surface. The primary emphasis of this report is on anomalous short-term transitions giving the appearance of internal solitary waves. > Go N Rear Admial, U. S. Navy Hydrographer ah) A 7 r evew 2.0 ey PAE oe Ra MOG DY ate “abA 69H qarnyasgyorbyh lt oe 5 a! Ae 7h 7 mt ¥ M4 ! CONTENTS Frontispiece SOCHHOHHSHOHSHHOHHSSOSOCOHSSHHOHOCHTHSHOHFOHOCHOSOHOHOOHOLEOSEHE Foreword SHOHSHSSSHSHSHSHHHHHHOHHSHSHHHHSHHSHSHHOHHHHOHHSHHTCHHOHHSHSHLOHSOSHOOESOE Figures alolalatelolelalcicieloteleicisiaisicleleislelalniaielaioieialelsicialelaiotelatelsisielsisisicielaieisieieleisis APPendixes esvecvecvcccccsecrcccccccs reecccece sc cecce cee ees ecole Ie Th WAI VIl. INTRODUCTION eccocccccccccccccccccevccccecesceccc cece lee RESEARCH OBJECTIVES AND PROCEDURE eeecccoceecocece FIELD MEASUREMENTS ceccoccccecvcaceccecesreceeccccece DATA PROCESSING AND ANALYSIS coccccccccccecccccccce RESULTS AND DISCUSSION eccccecccrcccesccccccccccccece A. Signature Characteristics O2COHLOCHHHLHLOCODSO8EODOOCC ODO B. Signature Velocity Distribution eececececececccccccevcsce C. Analytical Comparisons of Signature Speed secscccccccee CONC IMISIOINS conoco0s000 00 DcD OD ODD dR OOODD0D0DDD00050000050000 ACKNOWLEDGEMENTS SCOGSCSSTHSSCHESCHAOSHCHSHHHTAOSGH8HOSH8H888SE8OK0 BIB LIOGRA PHY. or00000ccec 00000000000 00000000000 00800 e00 Le LeeC” vii — —- Oo warANn wo wm NW N NR ~] onan ff W NW 10. Wl 17250 Sh 14, EDS: FIGURES Locations of Texas TOWeLrs esecececccrccccccervcsncvecescecves Schematic Elevation of Submerged Buoy Station secscecscccece Layout of Temperature Stations, September - October 1959 ec. Layout of Temperature Stations, May - June 1960 -ccroecececc Sample of Single-level Three-station Temperature Recording Sample of Single-level Three-station Temperature Recording Sample of Well-Defined Temperature Variations ecvecceecceees Sample of Poorly Defined Temperature Variations at Three Levels cceccescsccc cc 0000000000000 000080000 00500800000 nsees Sample of Well-Defined Temperature Variations above and below a Level of Little Variation ceecceececcccccrccccccccecvccsce Sample of Well-Defined Temperature Variations at Two Levelseccccccccccccccscccccce vec cccc cece cece reece ceeccce cee Sample of Well-Defined Temperature Variations eesseccecccee Sample of Well-Defined Temperature Variations ececeeeccecee Cumulative Frequencies of Internal Temperature Signatures, September - October 1959 eereccccvccccrcccccccccsccccccccees Cumulative Frequencies of Internal Temperature Signatures, May - June 1960 ccceccccccccccccccccccccccccccccceccccoccesese Cumulative Frequencies of Internal Temperature Signatures, All Observations SOHOSESHSHSSHSHSHOHHOHHSHHSOHHSHOCHOSEHEHHLCHHHHH EH EOOSD vili Page 13 14 15 16 17 18 i. 20 21 22 23 (45, 24 25 26 tile III. IV. APPENDIXES Ocean Currents Measured 100 Feet below the Water Surface at Texas Tower No. 4, April 1960 -ccccesseccccceces Velocities of Internal Temperature Signatures at Texas Tower No. 4, 28 September - 15 October 1959 --cccccccccces Velocities of Internal Temperature Signatures at Texas Tower No. 4, 13 May - 4 June 1960 --.------ aiodoododooUDUOS Daily Salinities at Texas Tower No. 4, 13 May - 3 June 1960 ix Page 29 33 35 38 I. INTRODUCTION The Texas Tower No. 4 research operations during 1959-1960 were intended to provide data from a convenient and particular ocean region in sufficient detail to support analytically sound interpretation of long- and short-term environmental transitions. To expedite initial information acquisition in a largely unknown region, every attempt was made to use readily available techniques and instrumentation. The experience and information gained is now the basis for establishing more adequate field systems for fixed-station observation. This report is concerned with only one of the more readily observed phenomena: short-term, usually anomalous variations of the water temperature structure hereafter referred to as “signature” associated with a special variety of internal waves. The existence of internal waves beneath the sea surface has long been known but only recently has observation technology advanced to the point of making controlled detection practical. Ekman (1904) theoretically explained “dead water” in terms of internal waves generated by a vessel moving slowly through a shallow overlying layer of low density water. Free wave speeds that he derived (which happen to closely correspond to results cited in this report) were shown to be inadequate to account for propagation ofinternal waves of tidal character until Haurwitz (1950) and Defant (1950) introduced the effect of earth rotation. Meanwhile, Fjeldstad (1933) developed a theoretical analysis of internal waves within a continuously varying density structure as opposed to the simplified two-layer system. These works and others too numerous to cite (see Davis and Patterson, 1956) were chiefly concerned with oscillatory waves of relatively long period. The works of Keulegan (1953) and Long (1956), which specifically consider the shallow-water internal solitary wave, will be given more detailed attention later in this report. Several attempts have been made to use ships for observing internal waves in deep water over sufficient time periods to allow significant statistical analysis. Reid (1956) set up repetitive measuring stations off the southern California coast; a multiple ship survey was conducted in the Atlantic (Brown, Corton, and Simpson, 1955); and more recently, detailed time series were obtained in a special deepwater anchoring system (Magnitzky and French, 1960). The difficulty of performing these operations has intensified interest in use of shallower water fixed stations using bottom-mounted sensors (Haurwitz, Stommel, and Munk, 1959) and fixed platforms (LaFond, 1959) as well as photographic observation of sea slicks from shore sites (Dietz and LaFond, 1950; Ewing, 1950). The degree to which investigations of nearshore and deepwater internal wave phenomena are similar must await further scientific study. Il. RESEARCH OBJECTIVES AND PROCEDURE Aside from operational development of fixed platform environmental research, an initial step in this study was to determine the existence of internal temperature variations and subsequently to gain sufficient knowledge to design an observation system. Minimal single-station measurement at a single level in July 1959 provided the basis for layout of the three-station system described in the following section. This was specifically arranged for detecting the passage of “discrete” internal temperature variations (or signatures) which retained sufficient identity of form to be recognizable at all three stations. Through observation over extended periods, continuity or regularity of occurrence could be established and a comparison could be drawn between fall and spring features of the internal phenomena. From the analysis of data collected during a multiple ship survey made in conjunction with observations at Texas Tower No. 4 during April 1960, it isintendedina future report to estimate the degree of horizontal uniformity within a distance of 15 miles from the tower. Ill FIELD MEASUREMENTS Field data considered in this report were collected during the fall of 1959 and the spring of 1960 in the vicinity of Texas Tower No. 4. The tower (hereafter designated TT4) was located about 70 miles southeast of New York Harbor on the north shoulder of the Hudson Canyon in a water depth of 185 feet (Figure 1). The sensing system consisted of a taut-wire submerged buoy with platinum resistance thermometers affixed at pre-selected levels (Figure 2). A spherical, 14-inch-diameter, Japanese, glass fishing float provided vertical lift. The net woven around the float was attached to a 3/32-inch steel cable which in turn was linked to a 100- to 150-pound gravity anchor, The 3/8-inch electrical lead cable from each resistance thermometer was taped or tied to the 3/32-inch cable and spliced near the anchor to a common cable laid on the ocean bottom to the tower. The array used during the fall of 1959 consisted of two buoys 500 feet apart forming an equilateral triangle with the vertical guide cables below the hydrographic room of the tower (Figure 3). The two buoys on the east-west base of the 500-foot triangle supported resistance thermometers at nominal depths of 65 and 100 feet below mean water level (MWL). Thermometers at the tower were placed at 65, 80, 100, and 130 feet below MWL. During the spring of 1960, the array consisted of three buoys positioned as shown in Figure 4 with resistance thermometers placed at approximately 50, 70, 90, and 110 feet below MWL. Note that the equilateral triangle was 400 feet on a side instead of 500 feet and the vertex was 225 feet south of the tower to minimize influences of the structure. The buoy arrays were manually installed from a 26-foot surfboat. Sextant angles taken from the boat, supplemented by sight lines relative to tower caissons, were used in the fall to position the two buoys. Considering drift rate, sea conditions, sextant and sighting errors, and the 40- to 50-foot freedrop of the buoy when cut loose over station, the actual positions of the buoys are estimated to be within 40 feet of the predetermined positions. Two azimuth instruments accurately located at the end points of an east-west 100-foot baseline of the tower’s flight deck were used for horizontal control in positioning the three buoys in the spring. Azimuth angles were computed to the nearest 15 minutes of arc —equivalent to the precision with which the sighting instruments could be preset. The relative locations of these buoys are estimated to be within 10 feet of the calculated stations. Two 4-channel “Brown” balancing potentiometer recorders were used during the fall to record resistance thermometer output on a 0° to 30°C full scale. The sampling rate for a given channel depended on the temperature differences between the four channels and normally averaged 6 to 10 seconds. For the spring survey, the outputs from the four thermometer levels of all three buoy positions were recorded on a single Brown recorder modified to handle 12 different information channels. The sampling interval for an individual information channel was usually from 18 to 30 seconds. GMT marks were manually added to the records at one- to eight-hour intervals to serve as time control between recorders and supplementary observations. Precision of these marks is estimated to be +3 seconds for the majority of chart speeds, The selection of resistance thermometers for temperature sensing was largely a matter of convenience. Thermometers and recorders were readily available and the normalized readout on a scaled strip chart promised a reduction in data processing effort. The main objection to the type of resistance thermometer used for this application is its long time constant as compared to those of other temperature sensors currently on the market. In the course of the TT4 field program, a step change calibration of the temperature recording system was accomplished by transferring the thermometers from a water bath at 18.5°C to a bath at 1.5°C. The lack of experimental control, normal to the laboratory, precluded exact determination of the response deviation from the exponential relationship, Hi pes TF fname each (1) where T(t) is indicated temperature at time t, T , is the initial ambient temperature, T> is the secondary ambient temperature, and tT is the so-called “time constant.” The results of field calibration indicated that the actual response curve differed from Equation (1) with t becoming larger with increased time after the step change. It appeared that an equivalent time constant of about 60 seconds could be realistically taken for the system used in these studies. In addition to fixed-level water temperature measurements, a variety of supplementary observations was made. Bathythermograph drops were made at the tower at intervals varying from hourly to daily. Many 15- to 30-minute surface wave records were obtained with a 15-foot resistance-wire wavestaff. Wind records were continuously recorded from an anemometer mounted on a bracket about 30 feet above the water surface on the hydrographic guide cables. Attempts to measure ocean currents with Roberts current meters were generally unsuccessful except for a 3-week period in April 1960 when a “Modified Roberts Current Meter II” furnished by Marine Advisers and Pruitt Manufacturing was used. These data are tabulated in Appendix I. Water samples at 3 to 6 levels were taken periodically during the spring for salinity analysis. Routine weather observations by Air Force weather observers rounded out the field program, All of these data are on file in the Oceanographic Prediction Division of the U. S. Navy Hydrographic Office. IV. DATA PROCESSING AND ANALYSIS Briefly, the data analysis technique consisted of subjectively selecting cases from the temperature records wherein identifiable “signatures,” i.e., distinctive temperature variations related in form (but not necessarily amplitude), could be ascertained witha high degree of certainty to have occurred at all three measuring stations ina single horizontal plane. The times of passage at each known station were then used to calculate the speed and direction of the signatures. A total of 95 cases were selected during the fall period (28 September - 15 October 1959) and 201 cases from the spring period (13 May-4 June 1960). In an attempt to preserve some measure of statistical significance, all records were examined during each data period and every case was recorded where the signature relative to background “noise” was distinctive enough to almost completely assure nonambiguous occurrence at each station. In cases where a “train” of several signatures occurred, the most distinctive one was selected for analysis or several were averaged. The magnitude of temperature variation was not considered; distinctive features and uniform shape of the signature observed at each station was responsible for selection. The middle of the temperature peak or crest (internal wave trough) was normally used to index the time of passage at each station. Signature speed and direction were computed on an LGP-30 digital computer. No attempt was made to ascertain the effect of horizontal water motion on signature speeds since accurate ocean current observations were normally not taken concurrently. Appendix I indicates the importance of accounting for the effect of field motion on individual Signature velocities. The lack of simultaneous current observations leaves only the alternative of computing average speeds in each quadrant for the single two-week period of reasonably good data. This problem is further discussed in the following sections, V. RESULTS AND DISCUSSION A. SIGNATURE CHARACTERISTICS Figures 5 through 12 are typical sections of temperature records selected to represent a cross section of observed activity. Figures 5 and 6 are samples of temperatures recorded ina single plane (or level) at all three stations during 1.5-hour time spans. Note that although the two records are separated by an interval of only 1.5 hours, Figure 5 contains distinctive large amplitude temperature variations while Figure 6 reveals little activity and no apparent correlation between stations. Figure 7 is an example of very well defined temperature variations at two levels, clearly signifying the passage of a regular wave form whereas the temperature changes at three levels shown in Figure 8 are small and show little coherence between measuring stations, The case illustrated in Figure 9 is particularly interesting because there seems to be a temperature “node” at the 70-foot level. Inspection of the mean thermal structure reveals a dual thermocline and the measuring levels (50, 70, and 95 feet) are located such that if the entire thermal structure moved down about 15 feet there would be no temperature change at mid-depth while the upper and lower levels would change as observed. The fact that the changes are in phase significantly supports the argument for vertical migration of the water column as a unit. In many other cases, however, this phenomenon is by no means discernable. Lee (1960) has indicated the occurrence of similar cases at the U. S. Navy Electronics Laboratory’s tower in 56-foot depth off Mission Beach, California. Figure 10 is an example of close coherence between different levels in a constant thermal gradient—another indication of synchronous vertical movement of the water column. Two almost identical single temperature crests occurring at the same level on two different days are shown in Figures 1] and 12. Note that the mean thermal structure has the same form on both days. The computed travel directions of the two cases are somewhat different; viz., 335° for Figure 11 and 300° for Figure 12. Comparison of individual signature forms recorded at each of the three stations raises the question of uniformity. Temperature amplitudes and “hump lengths” are not usually identical. Three possible explanations are offered: (1) the internal waves are short- crested relative to the 400- and 500-foot station spacings, (2) the preset elevations of sensing elements at each station were not uniform enough to initially be or to subsequently remain in horizontal planes, and (3) elevations along individual internal wave crests were not always constant, With regard to the second explanation, it is certainly unlikely that the prefabricated buoys would have been exactly uniform or the bottom perfectly flat but vertical tolerances of two feet in sensor planes seem quite reasonable and any error of this kind, other than current-induced dip of the taut wire buoy, would cause a consistent amplitude deviation at a particular station. From perusal of the records, it seems more reasonable to assume that the first and third explanations both apply. The internal wave surface or zone might therefore be analogous to the sea-swell regime of the air-sea interface. B. SIGNATURE VELOCITY DISTRIBUTION Computed signature speeds and directions are summarized in Appendix II for the fall data and in Appendix III for the spring data. Cumulative frequencies of occurrence of speed within 45° sectors of direction (set) have been calculated from these data and the results are graphically displayed in Figures 13 and 14 for the fall of 1959 and the spring of 1960, respectively. The assessment of internal wave or temperature signature velocity distribution must be tempered by an estimate of the motion of the medium itself. The only reasonably reliable current data collected are given in Appendix I, and cover the period 12-25 April 1960. These data represent about five-minute averages observed every hour with a meter suspended at 100 feet from one of the guide cables. The meter support (bracket and cable) was not completely free from lateral movement, In tank tests, the meter was found incapable of orienting to within 30° at constant tow speeds less than about 0.15 knots. Both of these factors contribute to uncertainty of the data. In addition, the effect of the platform on magnetic reference of the meter was not determined. The following averages for current speeds greater than 0.01 knot have been computed from the data in Appendix I: NE = 0.23 knot; SE = 0.27 knot; SW = 0.31 knot; and NW = 0.38 knot. Of the 268 observations used, 7.5% were in the NE quadrant, 26.0% in the SE, 27.5% in the SW, and 39.0% in the NW. Less than 8% of all hourly observations were at speeds below 0.1 knot. These ranges of speed correspond reasonably well to the vector spread of velocities summarized in Figures 13, 14, and 15. The statistical treatment of the current data allows for the approximate nature of the basic data in that rough estimates are made of average speeds within broad bands of direction. There are several breaks in the hourly observations for which no adjustments were made. It is felt that the single record period of two weeks at least gives some notion as to probable speed ranges and can serve as a guide in the absence of better evidence. The consistency of the data definitely indicates a clockwise rotary current ellipse with the major axis oriented approximately NW-SE. The observations were made during a period of comparatively isothermal conditions so that maximum correlation of currents to tidal motion might be expected. C. ANALYTICAL COMPARISONS OF SIGNATURE SPEED The recorded internal fluctuations of temperature throughout this field study characteristically appear in groups of one to four temperature “humps” at irregular intervals. This strongly suggests the application of solitary internal wave theory after Long (1956) and Keulegan (1953) in order to compare observed speeds; both of these theoretical developments assume a two-layer system. Long further imposes a rigid boundary at the water surface as wellas at the bottom. Keulegan’s work was therefore selected as being most appropriate. His equations are summarized below and then applied to several observed cases of temperature-salinity structures for comparison with measured signature speeds. Consider a two-layer fluid medium of thickness h, and density P, between the free surface and the internal density discontinuity overlying a layer of thickness hj and density hz between the discontinu- ity and a rigid bottom. It is shown that a solitary wave of infinitesimal height occurring at the internal discontinuity will travel at a phase speed, Cy, given where g is acceleration due to gravity. As a matter of interest this is the same equation as derived by Defant (1950) and Haurwitz (1950) for the oscillatory internal longwave neglecting the effect of earth rotation, Ekman (1904) also applied this equation to explain the “dead water” effect on vessels moving slowly in a shallow, low-density surface layer. The phase speed, c, of the internal wave of finite amplitude 7, is found to be 1/2 where 7, is referenced to the undisturbed level of the density discon- tinuity. From Equation (3), it is seen that when the discontinuity is at mid-depth the phase speed is independent ofinternal wave amplitude. Since the above equations apply to a free surface, the internal wave crest or trough must be accompanied by a solitary surface wave trough or crest, respectively. In practically all observed cases near TT4, signature passage was indicated by positive humps or crests in temperature measured at a fixed level. Under normal conditions of a negative temperature gradient and positive salinity or isohaline profile, this would correspond to an internal wave trough accompanied by an imperceptible crest on the water surface. A precise comparison of individually observed signature speeds to Keulegan’s theory is not possible since salinity was neither measured continuously nor at the same depths as temperature. Water samples for salinity analysis were taken at several depths daily from 13 May to 3 June 1960 to provide a gross picture of the mean salinity structure. These data are tabulated in Appendix IV from which the average salinity is found to vary from 31.4% at the surface to about 32.5% at and below a depth of 90 feet. For purposes of two-layer calculation of wave speeds during the spring period, values of 31.5% for salinity in the upper layer (S,) and 32.5% for salinity in the lower layer (S>) have been assumed, Salinity is assumed to be 32.0% in both layers for calculated speeds during the data period in the fall of 1959. The average speed given in Appendix II for the signatures shown in Figure 7 is 0.95 knot. Replacement of the mean thermal structure in Figure 7 with a sharp discontinuity at 70 feet, temperatures of 20°C in the upper layer and 10°C in the lower layer, and a constant salinity of 32% result in density values of p, = 1.0225 and p, = 1.0247. The mean temperature gradient at 65 feet as shown in Figure 7 is about 0.25°C per foot. The observed temperature changes at that level were approximately 7°C indicating an internal wave height, No Of 28 feet. Substitution of these values in Equations (2) and (3) gives an average speed of 0.96 knot as compared to the 0.95 knot observed. A second direct comparison may be made for the wave shown in Figure 8. The discontinuity level at 60 feet is chosen and average temperatures and salinities are taken as follows: T, = 10°C, Ss) = 31.5%, T, = 4°C, and S> = 32.5%. The mean temperature gradient from 40 to 100 feet was approximately 0.1°C per foot and the tempera- ture range at 70 feet was about 2.5°C inferring an internal wave height of 25 feet. The speed calculated from these assumptions is 0.85 knot as compared to the measured speed of 0.65 knot, Similar assumptions and calculations for the waves shown in Figures 9 through 12 provide the following comparisons; Figure Calculated Measured Speed Speed 9 0.45 L525 10 0.80 gadis 11 0.88 1.00 12 0.87 0.90 The cases shown in Figures 7 through 12 were selected to illustrate various wave forms rather than as a statistical basis for speed comparison. Computed speeds may not be truly representative but considering assumptions and data limitations the results are believed to be sufficiently indicative of reasonable agreement between observed and computed speeds. The above comparisons are not intended to prove that observed temperature signatures correspond to internal waves that comply closely with solitary wave theory. The partially subjective simplifica- tions required to reduce the actual density structure to a two-layer system preclude such expectations. Simultaneous and continuous measurement of ocean currents and a more detailed network of temperature and salinity sensing devices would also be required. It is believed, however, that sufficient evidence has been presented to strongly indicate a close correspondence of the measured temperature variations to internal wave theory presented by Keulegan. VI. CONCLUSIONS This report is pertinent to internal temperature variations observed at one site only — Texas Tower No. 4 in 185 feet depth off New York. The conclusions drawn from analysis of the data may be considered applicable only to that locality until studies elsewhere reveal the presence of similar “solitary signatures.” The following specific conclusions are drawn from the studies at Texas Tower No. 4: 10 1. Under conditions of vertical stability indicated by a negative thermal gradient, the passage of short-term internal disturbances resembling solitary waves is quite common. 2. These temperature wave forms or signatures occur irregularly in identifiable groups of one to four temperature humps (density troughs) moving onshore at a speed of approximately one knot, 3. The conspicuous onshore (normal to depth contours) orientation of the signatures as well as the reasonable agreement of travel speeds with shallow water internal wave theory verifies the direct association of signatures with long internal waves originating offshore from the measuring station. 4. Measured ocean currents are predominantly rotary clockwise; average speeds are about one-fourth those of the internal temperature signatures. This combination seems to account for most of the spread in signature velocities. 5. The design of future field experiments should include provisions for simultaneous and continuous measurement of temperature, salinity, and current velocity to a frequency resolution better than 10 seconds. A greater number of sensing units should be placed vertically at each measuring station. Additional observations should be made at positions up to several miles away from the main station to determine the horizontal uniformity of the water medium, 6. To establish the probability for predicting internal variations of the type discussed in this report, more detailed long-term descriptive and diagnostic field studies will be required in several different oceanic regions. Vil. ACKNOWLEDGEMENTS Cooperation between the U. S. Navy Hydrographic Office and the Agricultural and Mechanical College of Texas has made possible the support and information exchange necessary for this work which was begun at the former and concluded at the latter. Among the many members of the oceanographic staff at the Hydrographic Office who have contributed to this study, particular note is due Mr. R. B. Elder for his major part in field operations and data analysis; Mr. H. V. French was a constant source of encouragement; and the field work of Mr. W. A. Garth is gratefully acknowledged. 1l This work could not have been performed without the cooperation and assistance of the 4604th Support Squadron at Otis Air Force Base, Massachusetts. Credit is especially due to Captain Gordon T. Phelan, USAF, the tower commander who rendered considerable service to this study. Captain Phelan was subsequently killed when the structure collapsed in January 1961. 12 iH Ht | 3undl4 | SYSMOL SVX3SL 4O SNOILVOO) +4+4++-+}+4+444 ie = 13 SEA SURFACE SEE GO? 5. Ce? /4"GLASS FLOAT TAUT BUOY CABLE PLAT/NUM TES STANCE THERMOMETER SUBMARINE CABLE TO TT4 j= GRAV/TY ANCHOR BOTTOM:-/85 FEET MLW - FIGURE 2 SCHEMATIC ELEVATION OF SUBMERGED BUOY STATION 14 below water surface 3. Resistance thermometers at 65 and |OO feet below water surface at each buoy N NOTES: |. Depth= 185'+ 2" 2. Buoy floats submerged 40 STATION B (HYDROGAPHIC GUIDE CABLES) o- BUOY A ~ “BUOY C FIGURE 3 LAYOUT OF SUBMERGED TEMPERATURE MEASURING STATIONS, SEPT—OCT 1959 15 2 NOTES: ae |. Depth= 185+2 2. Buoy floats submerged 40 below water surface. 3. Resistance thermometers 50, 70, 90, and I10 feet below water surface at each buoy. FIGURE 4 LAYOUT OF SUBMERGED TEMPERATURE MEASURING STATIONS, MAY-JUNE I960 16 MEAN THERMAL STRUCTURE TEMPERATURE (°C) 10 20 30 a oo So eco esest’ oo ese. eee cc0te e 0430 0440 0450 0500 LEGEND ——LOCATION A --—-—-LOCATION B eccccee LOCATION C TEMPERATURE (°C) 0500 0510 0520 0530 100 FEET 0530 0540 0550 0600 HOUR (GMT) FIGURE 5 SAMPLE OF SINGLE-LEVEL THREE-STATION TEMPERATURE RECORDING — 30 SEPTEMBER I959 17 MEAN THERMAL STRUCTURE TEMPERATURE (°C) ° 10 20 30 ° 60 0740 0750 0800 TEMPERATURE (°C) 100 FEET 5 0800 0810 0820 0830 LEGEND LOCATION A —-—-LOCATION B eccccee LOCATION C 5830 0840 0850 0900 HOUR (GMT) FIGURE 6 SAMPLE OF SINGLE-LEVEL THREE-STATION TEMPERATURE RECORDING— 30 SEPTEMBER 1959 18 aya 2040 2050 2100 ) ee uJ W 65 FEET = Fe 5 rs Ww 20 < THERMAL STRUCTURE a TEMPERATURE ¢¢), i LEGEND LOCATION A ==— —LOCATION B LOCATION C 10 100 FEET 5 2030 2040 2050 2100 HOUR (GMT) FIGURE 7 SAMPLE OF WELL-DEFINED TEMPERATURE VARIATIONS — 10 OCTOBER 1959 19 TEMPERATURE (°C) 15 0950 0955 1000 70 FEET LEGEND LOCATION A —-—-— LOCATION B eeceeee LOCATION C 95 FEET MEAN THERMAL STRUCTURE TFMPERATURE (°C) ° 10 20 DEPTH (FEET) >i Gea me 120 FEET 0950 0955 1000 HOUR (GMT) FIGURE 8 SAMPLE OF POORLY DEFINED TEMPERATURE VARIATIONS AT THREE LEVELS — I9 MAY I960 20 TEMPERATURE (°C) 0735 0740 0745 50 FEET MEAN THERMA TRUCT! = ERMAL STRUCTURE cece, TEMPERATURE (°C) SCeeeecoeveses oo. 10 20 LEGEND LOCATION A ——— LOCATION B eceeeeee LOCATION C DEPTH (FEET) no @ 70 FEET 95 FEET Meee ee ee aces ee” ES eee eet 0735 0740 0745 HOUR (GMT) FIGURE 9 SAMPLE OF WELL-DEFINED TEMPERATURE VARIATIONS ABOVE AND BELOW ALEVEL OF LITTLE VARIATION — 20 MAY 1960 21 TEMPERATURE (°C) 2145 20 Oo 2145 2 = wi w Se re = Bio r-) 2 ' 2150 2155 LEGEND 70 FEET LOCATION A ae oe == LOCATION B eeceesceee LOCATION C 95 FEET 2150 2155 HOUR (GMT) FIGURE |O SAMPLE OF WELL-DEFINED TEMPERATURE VARIATIONS AT TWO LEVELS— 2I MAY I960 22 MEAN THERMAL STRUCTURE TEMPERATURE (*C) LEGEND | ° LOCATION A =—==<==LOCATION B eoooee LOCATION C 70 FEET Fea w w ge x8 = a 10 wi one 1 TEMPERATURE (°C) 2245 2250 2255 HOUR (GMT) FIGURE || SAMPLE OF WELL-DEFINED TEMPERATURE VARIATIONS 30 MAY I960 70 FEET THERMAL STRUCTURE N TEMPERATURE(C) . L E G E N D | ) Ss) LOCATION A O- ====u-=LOCATION B ae eeceee LOCATION C DEPTH (FEET) an 0 a > TEMPERATURE (°C) © Coccvcccccccccccccce ct, 1040 1045 HOUR (GMT) FIGURE I2 SAMPLE OF WELL-DEFINED TEMPERATURE VARIATIONS — 31 MAY 1960 (43) G22 SSAYNLVNOSIS SYUNLVYSdWSL IWNYSLNI SO SSIONSNOSYS SAILVINWND ¢!1 3yNdIS (SLONM) G33dS S3YNLVNOIS 00'2 SZ Os’! Gel 0O| GL OS" SS3u90u"d JO NOILOSYIC AS G3dNOYS SASVD S6 NO G3asv¢g (6S61 190 Si—1d3S 82) vVLVd WV4 G2" oO Le) Oo + (AWIL TWLOL JO LN30Y3d) AONSNOSYS ZSAILVINWND O i = = = D al cs) = [s) =z Oo 50 75 1.00 1.25 1.50 1.75 2.00 SIGNATURE SPEED (KNOTS) FIGURE 15 CUMULATIVE FREQUENCIES OF INTERNAL TEMPERATURE SIGNATURES 26 BIBLIOGRAPHY BROWN, A. L., CORTON, E. L. and SIMPSON, L. S. Power spectrum analysis of internal waves from Operation Standstill, U. S. Navy Hydrographic Office Technical Report No. 26. 20 p. 1955. DAVIS, P. A. and PATTERSON, A.M. The creation and propagation of internal waves; a literature survey, Pacific Naval Laboratory, Technical Memorandum No. 56-2. 1956. pros DEFANT, ALBERT. On the origin of internal tide waves in the open sea, Journal of Marine Research, vol. 9, no. 2, p. 111-119, 1950. DIETZ, R.S. and LAFOND, E. C. Natural slicks on the ocean, Journal of Marine Research, vol. 9, no. 2, p. 69-76, 1950. EKMAN, V. W. On dead water, Scientific Results of the Norwegian North Polar Expedition, 1893-1896, vol. 5, no. 15. 152p. 1904. EWING, GIFFORD. Slicks, surface films and internal waves, Journal of Marine Research, vol. 9, no. 3, p. 161-187, 1950. FJELSTAD, J. E. Interne wellen, Geofysiske Publikasjoner, vol. 10, HO, Sp jo, Loss, WSs, HAURWITZ, B. Internal waves of tidal character, Transactions of the American Geophysical Union, vol. 3l, no. 1, p. 47-52, 1950. HAURWITZ, B., STOMMEL, H. and MUNK, W.H. On the thermal unrest in the ocean; contribution to the atmosphere and the sea in motion. New York: The Rockefeller Institute Press. 509 p. 1959. KEULEGAN, G. H. CESS AGISELIAISE of internal eee waves, Journal LAFOND, E. C. How it works - the NEL oceanographic tower, U.S. Naval Institute Proceedings, vol. 85, no. 11, p. 146-148, 1959. LEE, OWEN S. Unpublished data,U.S. Navy Electronics Laboratory. LONG, R. R. Solitary waves in one- andtwo-fluid systems, Tellus, vol. 8, p. 460-471, 1956. 27 MAGNITZKY, A. W. and FRENCH, H. V. Tongue of the ocean research experiment, U. S. Navy Hydrographic Office Technical Report No. 94) "132 ‘p." 1960: rae REID, J. L. JR. Observations of internal tides in October 1950, Transactions of the American Geophysical Union, vol. 37, no. 3, C—O S|, p. 278-286, 1956. 28 APPENDIX I OCEAN CURRENTS MEASURED 100 FEET BELOW THE WATER SURFACE AT TEXAS TOWER NO. 4 April 1960 29 OCEAN CURRENT OBSERVATIONS AT TT4 DURING APRIL 1960 Modified Roberts Current Meter II 100 feet below the water surface Tabulated values for speed and set represent averages over approximately five-minute periods. TIME SPEED SET TIME SPEED SET TIME SPEED SET (GMT) (knots) (deg. (GMT) (knots) (deg. (GMT) (knots) (deg. day/hr mag, ) day/hr mag. ) day/hr mag.) 12/0205 5 atl 160 13/1505 34 150 15/0305 catia! 075 0305 245 205 1605 044 165 0405 223 100 0405 ool 195 1705 233 175 0505 ee 140 0505 » 39 185 1805 228 195 0605 242 155 0605 a Le 275 1905 14 210 0705 234 175 0705 290 285 2005 aS 260 0805 5a) 205 0805 249 300 2105 5B) 275 0905 5 ais) 260 0905 Piroye) 305 2205 248 295 1005 245 305 1005 Pacis 320 2305 28 320 1105 2-06 315 1105 238 330 14/0005 232 335 1205 239 310 1205 222 010 0105 5 10) 2S 1305 28 300 1305 222 055 0205 10 == 1405 5 ilal 290 1505 238 140 0305 230 150 1505 5 Alo) --- 1605 242 145 0405 043 165 1605 . 20 155 1705 ool 170 0505 202 165 1705 228 150 1805 10 --- 0605 045 175 1805 38 175 1905 236 290 0705 042 210 1905 047 195 2005 244 330 0805 5 SS) 230 2005 240 210 2105 ~60 335 . 0905 Oe, 260 2105 2 36 250 2205 61 350 1005 5 a2 265 2205 A tSi/ 280 2305 202 360 1105 60 285 2305 5S 300 13/0005 19 030 1205 46 295 16/0005 Stee 300 0105 40 070 1305 «295 300 0105 55s} 310 0205 206 095 1405 bye i 220 0205 oe) 310 0305 64 120 1505 5 235 0305 230 SHS 0405 208 135 1605 225 190 0405 10 --- 0505 243 145 1705 232 190 0505 5 al) 075 0605 538) 150 1805 . 30 210 0705 18 145 0705 14 210 1905 .28 230 0805 ~ 10 --- 0805 - 30 300 2005 ~40 270 0905 5 Je) === 0905 5 SS 295 2105 202 290 1005 Aes) 250 1005 229 315 2205 262 310 1105 239 290 1105 26 330 2305 246 305 1205 234 Shil's) 1205 15 330 15/0005 206 335 1305 229 310 1205 14 100 0105 242 335 1405 18 305 1405 224 130 0205 oS 010 1505 5 A) --- i eee ooo: TIME SPEED SET TIME SPEED SET TIME SPEED SET (GMT ) (knots) (deg. (GMT) (knots) (deg. (GMT) (knots) (deg. day/hr. mag. ) day/hr. mag. ) day/hr. mag. ) 16/1605 -10 =S> 18/1405 woe 315 20/1100 16 150 1705 28 190 1505 2 34 330 1200 alls 155 1805 40 190 1605 229 005 1300 ~10 160 1905 246 195 1705 24 010 1400 -10 --- 2005 = 50) 210 1805 oil 075 1500 oe! 225 2105 aul, 200 1905 sath 060 1600 ele 245 2205 A ait/ 240 2005 222 070 1700 218 275 2305 256 265 2105 Gals! 110 1800 .10 ——— 17/0005 ABS} 285 2205 a dley 120 1900 ~10 --- 0105 Aiets) 295 2305 10 SSS 2000 ad l(o) --- 0205 249 330 19/0005 10 Sa5 2100 A Mi? 245 0305 aéil 310 0105 ae 270 2200 <20 225 0405 APT 320 0205 . 30 330 2300 32 195 0505 Alito) =o 0305 oes 330 21/0000 ae 195 0605 nls 165 0405 2 34 345 0100 aoe 215 0705 19 170 0505 a2} 190 0200 19 230 0805 os} 155 0605 5 PAL 050 0300 244 255 0905 wee 190 0705 19 100 0400 AB 290 1005 223 215 0805 29 090 0500 238 320 1105 . 20 190 0905 222 115 0600 42 320 1205 239 275 1005 woe 110 0700 042 340 1305 240 275 1105 sibs} 115 0800 Acul 350 1405 - 38 270 1205 16 120 0900 a ilz 045 1505 229 275 1305 10 === 1000 24 095 1605 Avail 270 1405 20 S1S%s) 1100 ail 105 1705 LO =S5 1505 o22 330 1200 Bets 135 1805 -10 === 1605 pes) 340 1300 Sail 140 1905 Ants} 265 1705 Azail 345 1400 19 200 2005 A730) 230 1805 oals 110 1500 Lo 215 2105 224 240 1905 19 125 22/0400 . 30 205 2205 Areal 245 2005 220 145 0500 5 Ais) 250 2305 ~ a4 275 2105 aval 135 0600 e21 300 18/0005 238 280 2205 Ral) 170 0700 241 Airis) 0105 240 300 2305 asul 190 0800 39 315 0205 039 320 20/0005 250 280 0900 41 335 0305 Aalt 340 0100 As) 210 1000 239 325 0405 - 30 345 0200 woe 245 1100 eeD 020 0505 229 345 0300 250 315 1200 18 055 0605 mtr, 050 0400 50 285 1300 ABO) 080 0705 14 ES 0500 250 305 2100 29 025 0805 ~10 135 0600 Bt 290 2200 24 090 1005 ae, 125 0700 15 325 2300 OT 120 1105 - 10 --- 0800 A alls) SS 23/0000 30 145 1205 16 315 0900 pa ts 125 0100 40 150 1305 ACH 305 1000 5 dle 150 0200 nek) 165 VEMPREATORE , i, APPENDIX II VELOCITIES OF INTERNAL TEMPERATURE SIGNATURES AT TEXAS TOWER NO. 4 28 September - October 1959 35 INTERNAL TEMPERATURE SIGNATURE VELOCITIES 28 September - 15 October 1959 Note: Time given is appropriate to all cases selected within the hour. Some values are average for several signatures in the same “train,” TIME SPEED SET TIME SPEED SET TIME SPEED SET (GMT) (knots) (Degrees (GMT) (knots) (Degrees (GMT) (knots) (Degrees day/hr. true) day/hr. true) day/hr. true) 28/1600 1.55 290 29/2200 265 310 4/1800 IL Bie 320 1600 Ue 6) 280 30/0100 200 265 2000 90 300 1700 1,40 310 0100 ~60 280 2100 -30 315 1700 ass) 305 0200 260 305 2100 A 7/0) 310 1700 2,05 290 0200 -60 300 5/1700 1,20 315 1900 1,50 225 0200 80 310 1800 1,45 315 2000 270 230 0400 1b 35) 300 2200 2/0 265 2100 5/8) 200 0400 oS 300 6/0500 5 TAY) 350 29/0300 -60 330 0500 ao Sto) 260 2200 M5 As) 020 0400 1,00 300 0500 1.15 270 7/2000 1b fo) 350 0500 1,05 275 0500 1,30 310 2200 1,00 295 0500 ih 3s} 305 0500 1,10 320 8/0700 1,10 310 0600 1,20 300 0600 2 One SOG 8/2100 095 345 0600 1,00 285 1800 1.60 080 9/0700 1.10 305 0600 095 280 1900 1,40 300 1100 ats 330 0700 1,20 300 1900 1,70 300 1200 P10) 330 0700 moo 290 2100 Io Ao 305 10/0000 A) 325 0700 1,05 280 2100 eso 320 0900 1,05 305 0800 285 315 2100 1,40 320 1100 A (hs) 315 0900 Pi=10) 270 1/0800 5248) 090 2000 woo 335 0900 70 315 2/1100 0/5) 200 2100 ba als 310 1100 1,00 305 1100 16 SIs) 310 11/1000 1,20 310 1800 2! 290 1200 1,10 325 1000 Ws) 300 1800 1,00 325 1900 230 305 1300 .-60 010 1800 1,00 235 2000 152) 305 2200 “Qe 335 1900 1,20 290 3/1400 20 290 12/1500 52s 295 1900 1,10 285 1500 085 275 13/1400 65 325 2000 1.80 275 1800 60 345 14/0500 60 340 2000 280 015 4/0100 ib) 290 1900 90 265 2000 95 360 0500 265 330 15/1800 50 335 2000 1,00 010 1200 -60 300 1900 245 335 2100 290 295 1700 1,25 335 37 APPENDIX III VELOCITIES OF INTERNAL TEMPERATURE SIGNATURES AT TEXAS TOWER NO. 4 13 May - 4 June 1960 39 ; Te ) by iS : 7 TAVTAHAIMGT JAMASTU! TO BAIIOOIay » OV RAWOT SaAxXaT TA 2RAPAMDIe \ | ; . ar ae i" ‘W™ INTERNAL TEMPERATURE SIGNATURE VELOCITIES 13 May - 4 June 1960 Note: Time given is appropriate to all cases selected within the hour. Some values are average for several signatures in the same “train.” TIME SPEED SET TIME SPEED SET TIME SPEED SET (GMT ) (knots) (degrees (GMT) (knots) (degrees (GMT) (knots) (degrees day/hr. true) day/hr. true) day/hr. true) 13/1900 1,25 285 17/1800 e 00 295 21/0900 1 BHO) 280 1900 1,30 275 1800 a 7A9) 335 2100 116305) 320 2000 1,25 270 1900 -60 285 2200 79 355 14/0100 1.30 330 18/0300 1,25 290 22/1500 90 325 0200 .60 320 0300 1,20 295 24/0600 5135) SHS 1400 230 320 0400 1.30 345 1800 5S) 325 1600 280 315 0400 30) 310 25/1800 1.40 315 1700 200 300 0400 1,00 295 1900 1,40 315 1700 isis) 280 0500 20 305 1900 1,00 340 1700 1,25 290 0600 Pr=10) 295 2000 UWA PASI 350 15/0200 285 350 1200 95 280 2300 Os 340 0700 ~ 60 350 1200 1,00 260 26/0100 ates) 325 0700 260 315 18/1600 1,45 330 0100 285 330 1300 1,10 350 1600 1,00 345 0300 90 295 1300 1,20 310 2000 5/8) 290 0800 OD) 005 1300 290 300 2100 1.50 305 1500 260 345 16/0000 1,90 335 19/0400 1486 325 1600 270 325 0300 0 5) 305 0400 1,25 290 2000 ibs tbs) 300 0400 Pirsie) 305 0900 BOD) 315 2200 OD) 340 0500 » 50 310 ~ 1100 65 350 2300 25 310 1000 270 270 1100 200 325 2300 eo) 315 1000 095 315 1200 oh) 330 2300 aco 305 1100 265 360 1800 ab dls) 280 27/0200 a) 290 1800 265 330 1900 1,30 310 0400 2-65 320 2200 4 (2) 260 2000 1,05 290 0700 230 305 2200 1,10 280 2000 P=is) 280 1000 -60 000 2200 Fists) 320 20/0200 1,10 280 1200 16 BS 290 17/0000 090 270 0300 270 265 1200 1,40 315 0500 90 300 0500 1,05 285 1200 nes 280 0500 95 295 0600 95 300 1900 1.05 290 0600 1,00 320 0700 1.25 290 28/0000 1 AAS 315 0600 230 280 1800 1,30 280 0000 285 315 0600 285 280 1800 90 280 0100 90 305 0700 265 310 21/0600 1,25 310 0400 250 305 1000 «70 275 0700 1.45 290 0600 240 215 1600 095 310 0700 1,45 305 0700 5 2B 210 1800 ~60 300 0800 ib Ai 290 0800 -65 260 1800 2 DO 330 0900 095 270 1400 95 305 TIME SPEED SET TIME SPEED SET TIME SPEED SET (GMT) (knots) (degrees (GMT) (knots) (degrees (GMT) (knots) (degrees day/hr true) day/hr true) day/hr true) 29/0000 1.30 300 31/0700 50 025 2/0200 1,05 340 0000 T16 300 0900 =1,05 340 0300 TO5 335 Otaoyy) 26 0 300 1000 90 300 0300 1,10 315 0100 1,25 290 1100 90 305 0300 1,00 300 0600 .95 040 1100 1.00 310 0300 .95 325 1300 95 345 1200 275 305 0400 isis 340 30/0000 1,00 310 1400 “2.55 335 0500 1,05 310 0200 1,00 350 1500 .95 340 0500 .90 330 0300 80 350 1600 .65 345 0600 .85 305 0400 v0 325 1700 70 345 0700 50 335 0500 255 320 1800 50 305 0800 50 355 0700 50 330 2000 .65 305 1000 90 305 1100 .95 320 2000 .60 280 1100 .90 310 1200 .90 - 320 2100 oD 285 1200 1,45 2575 1400 .90 320 2300 70 320 1200 1.95 245 1500 a,15 335 1/0000 .95 310 1400 1.00 275 1500 90 315 0100 1,30 325 1500 . 70 260 1700 .65 325 0400 1,00 315 1600 1,20 315 1700 a70 325 0400 80 325 2100 1, 05 270 1800 255 290 0400 95 290 2300 50 215 2200 75 285 1100 50 045 3/0200 90 325 2200 .90 350 1100 .90 310 0600 .80 325 2200 1.00 335 T1000 W265 260 1100 o55 225 2300 .95 290 1200), “GA05 320 1200 .40 030 2300 1,20 300 1200 1,00 310 1300 80 290 2300 1.20 315 1700 .80 290 1800 50 275 31/0000 1.00 330 2100 155 275 4/0000 . 70 315 0000 1,95 340 2/0000 1.30 295 0100 .95 280 0200 .90 295 Ou0g) HES 310 0700 50 285 0200 W05 ~ MaHlo 42 APPENDIX IV DAILY SALINITIES AT TEXAS TOWER NO. 4 13 May - 3 June 1960 43 DAILY TITRATED SALINITIES AT TEXAS TOWER NO. 4 13 May - 3 June 1960 Depth below MWL (feet) 0) 45 90 120 May 13 31,56 Sil, HO) 32,10 32,48 14 Seo) 31.38 32,14 3 BY 15 31,50 31.63 32,28 32,00 16 31,50 31.90 32.47 32.60 17 31,64 31,60 32.38 32,54 18 31.68 BE S2 32,64 32,62 19 31,48 31,44 B2) 522 Seo 20 Sale 31.80 32) 3S) 321,02 21 30.96 SIL SY 32,54 32.64 22 Sil, Ail Sil, CY 32.56 32,56 23 31,34 31,42 32.63 32,64 24 30.99 32,98 32.64 32.62 29 Sil, Sil 73 32.62 32.58 26 31,08 32,14 B15 Gil 32,62 PAT] 31,53 S225) 32.60 32.68 28 31.90 31,94 32,58 32.67 29 32,00 32.07 32.65 32.68 30 31,67 32.40 Bei 5 Val 32.69 Sil Srleorls B14 (dl 32,76 32). 75) June 1 Salt 32.68 32,74 32 18 2 31,18 32.65 SZ iO 32,69 3 Sales 32,49 32.65 32577 Average 31.4 32,0 Sa) S26 45 150 32,55 32,56 31,54 32.61 32,53 32.58 32.52 32.60 32.63 32.52 32.63 32,62 32),61 32.60 32,69 32,66 32.68 32,68 32.70 32, 72 32.68 32.70 32.6 /Ha RSA toy D2 qmned ‘q Aoy ‘:10ujne } ON IaeMO] sexay I1eau suOTJeIIeA aanjeradui3y [eurdIUT UII9}-j10YS JO uotngtajystp Ay190]9A pue 20ueatINd90 ayy 3119 SdaMSV Aydeadouras9 anjeiraduray [eutsquy SOAeM [PUIZIUT LOT-UL “OH qIned ‘q Aoy ‘:az0yjne py ON tamoy sexay ie3u SUOTJEIIPA JINj}e1aduUI3} JeUIezIUI UII94-j10Ys jo uonqtaystp Ay1I90[eA pue go0uetINd390 ayy 731319 SdaMSV Aydersoues20 aanjereduraz [eutajuy S9APM [BUTI] = “THY a: “Tt “tT + Cal _ = *saxtpuedde ay} ut uaAtd are satjtutjes pue ‘sarjioojaa aanjeudts aanjetaduraz [eutazut ‘sjuarind uo Pj}ep yeuotytppy ‘“Atoayy aaAem Aapzjos jeuroqur wiory pazeynoyTeo sanyea yITAr pereduiod aie spaeds pedArasqO ‘surtoj aAem ArezIJOS [euUIazuT Jo saouetin390 uourIuIOS TeaAat Q96T FO sutads ay} pue 6S61I JO ITey ay} ut spotzed yaam-omy dutinp epeur szuauIainseeyy ‘yIOK MAN JJO f 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“dop“1961 AEN ‘med ‘qd sow Aq ‘p “ON YAMOL SVXAL UVAN SNOIL -VIUVA FUNLVUAAWAL TVNUALNI WHAL-LYOHS AO NOILNGIULSIG ALIOOTAA GNV AONAUYANIOO AHL *a0T7JO oTydeadoapAy AAeN *S ‘“N LOITSUL +O) “Hi qnedD ‘q Aoy :104jne F} ‘ON Tamoy, sexe] re9u suoTJeIqeA 9injyertaduis4 [eutezUI UIIa}-j10Ys jo uotnqtaystp Ay1d07eA pue aouetind9:0 ay 7319 SdaMSV Aydeadsourss9 2ainjeredura} [eutaquy SOAEM [PUTS LOI-UL “O “H qned ‘q Aoy :10yjne % “ON Tamo]y sexe] 1e3u SUOT}JEIIeA JInjetadurs4 [euIaJUT UIIa}-j1IOYS jo uotjngt43stp AjID0[eA pue aouarIind50 ayy, ‘91913 SdaMSV Aydeas0ueasQ aainjyerodurey yeutzojuy S3APM [PUTIIUT ee “TIT “Wr maa m3 oI - a = *soxtpuedde oyj ut uaAtd aie satjlutTes pue ‘gatqIoojaA aanjeudts aanjetoduia, [euteyur ‘sqyuarind uo ejzep yeuottppy ‘“Artoay, aaem Azeytjos yeuraqur woiy payetnoyeo senteaA Yim pareduios aie spaads paarasqo “surzoj aaem ArezI[Os [euUrazUT Jo saouatInd90 uourur0d Teaver Q96T jo Burads ay} pue 6G61 JO ITeF ay} ut spotted yaam-om}z Butinp apeur sjueuIeInseaW "yIOk 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JJO pP “ON AaMO] sexey eeu ainjoNIjs aanjeraduia} 19je" ut sadueyd ulia}-j10Ys JO uoT}DaI1Ip pue ‘paeds ‘aouarins90 9243 jo Apnys e saqtioseq sextpueddy Aydeasoriqrg *(}¥ (O(N LUOdaY SdAMSV ‘LOI-UL ‘O “H) “S813 gt Surpnjour “dsp-1961 Ae ‘med ‘qd fou fq ‘p “ON UAMOL SVXAL UVAN SNOIL -VINVA AMALVYAMNAL TVWNUALNI WUAL-LYOHS 40 NOILNGIYLSICG ALIOOTAA CNV AONAUMANDOO AHL *2013J0 OTydeadoapAH AneN "SN *saxtpuedde ay} ur uaats aie satjylurjes pue ‘gatjIoo[aA aanjeudts aanjeroduiaz jeutaqur ‘squaiin9 uo ejyep yeuotjyippy ‘“Artosy} aaem Arejtjos jeuiszur wIloIy pajyetMoyeo senyeA yjIm pereduioo aie speeds paadasqoO ‘surioy aaem AxezI[OS TeurIazUT Jo saduetINd50 UOUIUIOD TeIASI Q96T jo Sutads ayj3 pue 6G61 JO I1eF ay} ut spotzed yaem-omy Bulinp apeur sjzuaurainseaW ‘yIOK MON JJO F “ON TaMO] sexe, eeu aanjon1j3s aanjeraduiay 193eM ut sadueyd ulta}-y10Ys Jo uoTjIaIIp pue ‘paads ‘aouarino90 2ay3 jo Apnys e saqtioseq soxtpueddy Aydeasoryqrg *“(¥ ON LUYOdaU SdaAMSV ‘LOI-UL ‘O *H) ‘S317 GT Burpnour 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