The text below was taken from technical report 90-3 of the Gradulate School of Oceanography, University of Rhode Island. The original report was prepared with LaTeX, but the LaTeX command was removed here along with all the figures. After the publication of the report, some of the data processing procedures were improved and were applied to the data. The data set here is the most recent version but the report and this file here does not reflect these improvements and the resulting changes in data statistics. GRADUATE SCHOOL OF OCEANOGRAPHY UNIVERSITY OF RHODE ISLAND NARRAGANSETT, RHODE ISLAND THE SYNOP EXPERIMENT Inverted Echo Sounder Data Report for October 1987 to May 1988 GSO Technical Report No. 90-3 by Xiaoshu Qian, Karen Tracey Erik Fields and D. Randolph Watts July 1990 This research program has been sponsored by the National Science Foundation under grant number OCE87-17144 and by the Office of Naval Research under contract N00014-87-K-0235. Abstract The SYNoptic Ocean Prediction experiment (SYNOP) was undertaken with the goal that increased understanding of the Gulf Stream obtained through coordinated observations could be integrated with numerical models, including predictive models of the Gulf Stream. Our moored experiment, which began in fall of 1987, consists of two separate arrays in the Gulf Stream. The ``Inlet'' array of inverted echo sounders (IES) and deep current meters consists in a 120 by 150 km rectangle. It measures key parameters that describe the variability of the Gulf Stream and deep western boundary current (DWBC) near Cape Hatteras. In this region the Gulf Stream first flows into deeper water and crosses over the DWBC. The ``Central'' array of IESs, a 300 by 320 km rectangle centered on the Gulf Stream near 68 W, monitors the thermocline structure of the Gulf Stream in the region of large meanders and frequent interactions with rings. Additionally, during this first deployment period, five of the IESs in the arrays are outfitted with bottom pressure gauges (PIES). The echo sounders were launched during the cruise aboard the R/V Endeavor, EN169 (October 9, 1987 to October 28, 1987), and recovered during the cruise aboard the R/V Oceanus, OC200 (May 20, 1988 to June 18, 1988). IES data recovered during OC200 is documented here by plots and tables of basic statistics and pertinent deployment information. Altogether 22 IES records are presented, plus pressure and temperature records at 5 sites. The plots are time series of measured travel time, pressure, temperature; the residual pressure; and low-pass filtered records of residual pressure, thermocline depth, and temperature. A brief description of the experiment and the standard steps of data processing is also given. Section 1. Experiment Description and Data Processing 1.1 Introduction In the region northeast of Cape Hatteras, NC, the Gulf Stream has large time-varying meanders. The current shifts within an envelope that grows downstream to several times the instantaneous width of the Gulf Stream itself, and it frequently interacts with powerful currents in eddies adjacent to the Gulf Stream. Fundamental questions remain regarding the dynamics and energy balances governing the meandering. A multi-investigator research effort SYNoptic Ocean Prediction (SYNOP) is being conducted to understand the physics of, and test predictive models of these energetic processes. Included in our field program is the three-year deployment of arrays of inverted echo sounders with bottom pressure gauges, plus deep current meters across the Deep Western Boundary Current(DWBC) off Cape Hatteras. The former is the subject of this report, and the deep current meters will be presented in a separate report. Additionally in our SYNOP study there is a two-year deployment of arrays of high-performance current meter moorings, reaching into the core of the Gulf Stream. The main objective of our program is a more complete, fundamentally improved understanding of the structure, energetics, and dynamics of the Gulf Stream in the region between 70 and 65 W, where meanders are of large amplitude and still growing, and where the adjacent ring and eddy field is vigorous. From this understanding the longer term goal is to guide and test predictive modeling capability for the Gulf Stream. The arrays of instruments in our field program are specifically designed for these objectives. Using data from current meters, inverted echo sounders (IESs) and IES/bottom pressure sensor combinations, we intend to determine how the path and structure of the Gulf Stream evolve, both according to its internal dynamics and instabilities, and as affected by eddies in the adjacent regions. The full three-dimensional structure of the fluctuations in relation to the mean (T, U, V) fields and their gradients determines the directions and strengths of the key energy exchanges. IES data, which span from the previous summer, were recovered during the summer of 1988. These records were launched on the cruise aboard the R/V Endeavor, EN169 (October 9, 1987 to October 28, 1987), and were recovered on the cruise aboard the R/V Oceanus, OC200 (May 20, 1988 to June 18, 1988). Figure 1 and Figure 2, as well as Table 1 and Table 2, present site locations and data returns for the IESs. Basic statistics for those records and pertinent deployment information are tabulated in Section 2. In Section 3 and 4, the data are presented in plots of travel times, thermocline depth measurements, and for IESs with additional sensors, bottom pressure and temperature. In Section 5, the low pass filtered records are presented in plots grouped by deployment line. Figure 1: [Array locations and instrument sites] Mooring and IES sites. IES sites are shown by open circles. Solid circles denote IES sites with bottom pressure gauges (PIESs). The dashed curve indicates the mean path of the Gulf Stream(1975 to 1986) from Gilman and Cornillon[1990]. Figure 2: [IES Deployment Chart] IES deployment Chart. The duration and temporal location of each IES is charted as a thin rectangle. The length of each rectangle and its horizonal position provide a calendar of data coverage from the first good sample to the last. The time axis is given in yearhours at the bottom, with large tics indicating 500 hr increments and smaller ones denoting 100 hr increments. Record G1 was recovered the next year (May 1989) and is presented in the GSO Technical Report 90-2. Table 1: [Site Locations and Data Returns for The Central Array] site lat(N) lon(W) 1st point last point notes IES88G1 see Report No. 90-2 for information about this site IES88G2 38 01.00 69 16.22 25-Oct-87 26-May-88 IES88G3 37 23.34 69 10.54 25-Oct-87 26-May-88 IES88G4 36 49.80 68 50.25 25-Oct-87 5-Jun-88 IES88G5 36 14.25 68 51.30 25-Oct-87 23-May-88 PIES88H1 recovered no data; all bits set PIES88H2 38 18.02 68 27.97 24-Oct-87 24-May-88 PIES88H3 37 38.71 68 19.31 24-Oct-87 8-Jun-88 IES88H4 37 00.52 68 07.74 24-Oct-87 7-Jun-88 IES88H5 36 22.13 67 58.00 24-Oct-87 6-Jun-88 IES88I1 39 00.12 67 48.70 23-Oct-87 25-May-88 PIES88I2 38 22.48 67 35.37 23-Oct-87 24-May-88 IES88I3 37 47.49 67 31.01 23-Oct-87 8-Jun-88 IES88I4 37 11.18 67 21.46 23-Oct-87 6-Jun-88 IES88I5 36 33.48 67 11.67 23-Oct-87 6-Jun-88 Table 2: Site Locations and Data Returns for The Inlet Array site lat(N) lon(W) 1st point last point notes IES88A1 35 18.56 74 36.94 16-Oct-87 30-May-88 two big jumps in travel times IES88A2 35 02.05 74 12.29 13-Oct-87 13-Jun-88 IES88B1 35 45.06 74 27.97 11-Oct-87 28-May-88 IES88B2 35 36.71 74 14.30 12-Oct-87 29-May-88 PIES88B3 35 28.81 74 02.84 12-Oct-87 29-May-88 temperature has steps of 128 counts PIES88B4 35 20.74 73 50.97 12-Oct-87 29-May-88 IES88B5a 35 11.98 73 40.01 12-Oct-87 19-Oct-87 accidentally released IES88B5b 35 12.07 73 40.09 19-Oct-87 15-Nov-87 redeployed, failed after 1 month, all 1's returned for travel times IES88C1 36 04.54 73 56.98 12-Oct-87 31-May-88 IES88C2 35 45.93 73 33.55 13-Oct-87 31-May-88 1.2 Site Naming Conventions Two arrays exist (Figure 1), an ``Inlet Array'' near Cape Hatteras consisting of 9 IESs on 3 lines designated A, B and C, and a ``Central Array'' centered on the Gulf Stream about 68 W with 3 instrument lines, G, H and I. There were 15 instruments in the Central Array, but one failed and one was left deployed until May 1989. Hence only 13 records from the Central Array are presented here, as noted in Table 1. Five of the instruments are outfitted with bottom pressure gauges, two in the Inlet, and one in the Central Array. These IESs are referred to as PIESs. The instrument naming convention is to specify the line and the relative position in the line (increasing seaward from the shelf) prefixed by the instrument type and year of recovery. For example, PIES88H3 would refer to the third instrument, a pressure outfitted IES, in the H line. 1.3 Inverted Echo Sounder Description A detailed description of the IES is presented in Chaplin and Watts (1984) and will not be repeated here. Briefly, however, the IES is an instrument which is moored one meter above the ocean floor and which monitors the depth of the main thermocline acoustically. A sample burst of acoustic pulses is transmitted every half hour. A sample burst consists of twenty-four 10 KHz pings at 10 sec intervals. The round trip travel times to the surface and back are recorded on a digital cassette tape within the instrument. For the PIESs, the measured bottom pressure and temperature are also written to tape. Pressure is an average measurement over a half-hour sampling period. For early model PIESs (URI types) the temperature is also an average measurement over a half-hour sample period. Later models (Sea Data types) average temperature for slightly less than one minute. Section sec:samptime will explain in detail the actual times associated with the various measurements. 1.4 Data Processing All processing steps were done on MicroVAX II and MicroVAX III computers. The basic steps include transcription, editing, and conversion into scientific units. The data processing is accomplished by a series of routines specifically developed for the IES. Since these programs are documented elsewhere (Fields, Tracey, and Watts, 1990), the steps are only outlined below and schematically illustrated in Figure 3. Figure 3: IES Data Processing Flowchart [RAW DATA CASSETTES]: Recorded within the instruments. Contain the counts associated with travel time, pressure, and temperature measurements as a series of integer words of varying lengths. [SDR]: Runs the Sea Data Reader which transfers the data from cassettes to the MicroVAX for subsequent processing. [BUNS]: Converts the series of integer words of varying lengths into standard length 32-bit integer words. [PUNS]: Produces integer listings and histograms of the travel time sample bursts. Provides an initial look at data quality and travel time distributions. The histogram is used to determine the limits for maximum and minimum acceptable travel times for an initial windowing operation in the following step. The listings are used to establish the first (after launch) and last (before recovery) `on bottom' samples essential for determining the exact time base. [MEMOD]: Establishes the time base. Determines the modal value of the travel time burst as the representative measurement after application of several windowing operations. Converts all travel time, pressure and temperature counts into specific units of seconds, decibars, and degrees Celsius, respectively. [FILL]: Checks for proper incrementing of the time base. Missing samples are inserted using interpolated values. [DETIDE]: From user-supplied tidal constituents specific to each site, determines the tidal contribution to the travel times and removes it from the measured values. [DESPIKE]: Identifies and replaces travel time spikes with interpolated values. [SEACOR]: Removes the effects of seasonal warming and cooling of the surface layers from the travel times. At this stage, plots of the half-hourly pressure, temperature and travel time are generated. [RESPO] : Removes the tides from the pressure records using tidal response analysis (Munk and Cartwright, 1977) to determine the tidal constituents for each record. [DEDRIFT] : Removes long term drifts associated with the pressure sensor and slight imperfection in the IES master clock frequency. [LOW PASS FILTERING]: Convolves the travel times, pressures, and temperatures with a 40 hour low-pass Lanczos filter. The smoothed series are subsampled at six hour intervals and plotted. [OBJECTIVE MAPPING]: Produces daily maps of the depth of the 12 C isotherm as documented in Watts, Tracey and Friedlander, 1989. The results of this step are not presented here. Rather, they will be presented in a subsequent data report. 1.4.1 Travel Time Calibration The acoustic travel times (tau) records are shown in Figures 5.1 -- 5.23. Variations in the travel times have been shown to be proportional to variations in the thermocline depth in the Gulf Stream (Watts and Rossby, 1977; Watts and Wimbush, 1981; Watts and Johns, 1982). Calibration XBTs were taken at each IES site in order to convert the travel times (tau) into thermocline depths (Z) according to the relation: Z = M tau + B, where M is a scale factor and the intercept B depends on the depth of the instrument. Regressions of tau versus Z, performed for several records, show that the constant (M) value, M = -19.0 m/msec for the 12 C isotherm, is appropriate for all these Gulf Stream sites. The values of B used for each instrument are listed in the tables in Section 2. For practical purposes the main thermocline depth can be represented by the depth of an individual isotherm. For this work, we have chosen the 12 C isotherm since it is situated near the highest temperature gradients of the main thermocline and correlates well with (Rossby, 1969; Watts and Johns, 1982). The low-pass filtered travel time records were scaled to the thermocline depths (tau) and these records are shown in Figures 12.1 -- 12.6. Since tau is resolved to 0.1 msec, the 40 HRLP scaled values are therefore resolved to plus/minu 2 m. However, the accuracy of the offset parameter B is estimated to be 25 m for most records, judged from the agreement between the several calibration XBTs taken at each site. Relative to this, the 40 HRLP values are resolved to plus/minus 2 m. 1.4.2 Temperature Temperatures (Figures 8.1 -- 8.5, 11.1 -- 11.3, and 14.1 -- 14.3) were measured using thermistors (Yellow Springs International Corp., model 44032 ) controlled by Sea Data Corp. (model DC-37B) electronics cards installed in the IESs. Their main purpose is to correct the pressure values for the temperature sensitivity of the transducer. The thermistor is inside the instrument, on the pressure transducer, rather than in the water. However, once the temperature probe has reached equilibrium with the surrounding waters, it also provides accurate measurements of the bottom temperature fluctuations (effectively low-pass filtered with a 2-4 hour e-folding equilibrium time). The first 24 half-hourly points were dropped prior to low-pass filtering, since the temperatures took 12 hours to reach equilibrium within 0.001 C. The accuracy of the temperature measurements is about 0.1 C, and the resolution is 0.0002 C. 1.4.3 Bottom Pressure Digiquartz pressure sensor (models 46K-017, 46K-023, and 76KB-032) manufactured by Paroscientific Inc. were used to measure bottom pressure. All pressure measurements were corrected for the temperature sensitivity of the transducer, using calibration coefficients purchased from the manufacturer. The half-hourly measured bottom pressures (Figures 6.1 -- 6.5) are dominated by the tides, however for some of the instruments, the pressures also drift, O(0.1 dbar/yr ), monotonically with time. Processing of the pressure measurements includes removing the long-term drift and tides. Tidal response analysis (Munk and Cartwright, 1977) was used to determine the tidal constituents for each instrument. The calculated (dbar), and phases, G (Greenwich epoch), of the constituents are given in the tables in Section 2. The pressure records were dedrifted in the manner developed by Watts and Kontoyiannis (1991) who have addressed pressure sensor drift and performance. In some records the first 10--40 days exhibit a drift of tenths of decibars. The rate of drift decayed with time and was best approximated by a exponential function of the form, Drift = P1 exp{- P2 t) + P3 A design matrix would be composed of (exp(-P2 t), 1). The overdetermined set of equations were solved for coefficients P1 and P3. These coefficients were found subject to the minimization of the rms error of the fit as a function of the decay rate, P2. Minimization was accomplished using the method of parabolic extrapolation and golden sections (Press et al., 1988) to optimally search for with a minimum of function evaluations (fits). The first 12 hours of pressure were ignored since the crystal's temperature was equlibrating. The dedrifted curves were found from 2-hour subsampled records for computational simplicity. The time of drift was referenced from 1 hour before the first sample on the ocean bottom, i.e. at a time when the instrument was sinking to the sea floor after launch. At a later stage, comparison of geostrophic currents, calculated from adjacent dedrifted pressure sensors versus nearby current meters will be used to verify the dedrift procedure's success. Four of the five PIES showed some sign of drift. The fitted drift parameters are listed for each instrument individually, in the site and record information tables of Section 2. The half-hourly pressures are resolved to 0.001 dbar and the mean pressure is accurate to within 1.5 dbar. We estimate that the residual (drift and tide removed) bottom pressure records, shown in Figures 7.1 -- 7.5 and Figure 10.1--10.3, have an accuracy (relative to their mean pressure) of better than 0.05 dbar (Watts and Kontoyiannis, 1991). The residual bottom pressure records were low-pass filtered and the results are plotted in Figures 13.1 -- 13.3. 1.4.4 Time Base The date and time were assigned to each sampling period. The Tables (Tables 4 -- 26) in Section 2 report the hours, minutes, and seconds associated with the first and last sampling period. All times are given as Greenwich Mean Time (GMT). For processing convenience, the times were converted into yearhours. A yearhour calendar (Table 3) lists the yearhours which correspond to 0000 GMT of each day for non-leap years. (For leap years, the yearhours can be determined by adding 24 to each day after February 28.) There are a total of 8760 hours in a standard year and 8784 hours in a leap year. The yearhours given in this report are referenced to January 1, 1988 at 0000 GMT. Table 3: Yearhour Calendar for Non-Leap Years. The yearhour listed corresponds to 0000 GMT. day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec day 01 0 744 1416 2160 2880 3624 4344 5088 5832 6552 7296 8016 01 02 24 768 1440 2184 2904 3648 4368 5112 5856 6576 7320 8040 02 03 48 792 1464 2208 2928 3672 4392 5136 5880 6600 7344 8064 03 04 72 816 1488 2232 2952 3696 4416 5160 5904 6624 7368 8088 04 05 96 840 1512 2256 2976 3720 4440 5184 5928 6648 7392 8112 05 06 120 864 1536 2280 3000 3744 4464 5208 5952 6672 7416 8136 06 07 144 888 1560 2304 3024 3768 4488 5232 5976 6696 7440 8160 07 08 168 912 1584 2328 3048 3792 4512 5256 6000 6720 7464 8184 08 09 192 936 1608 2352 3072 3816 4536 5280 6024 6744 7488 8208 09 10 216 960 1632 2376 3096 3840 4560 5304 6048 6768 7512 8232 10 11 240 984 1656 2400 3120 3864 4584 5328 6072 6792 7536 8256 11 12 264 1008 1680 2424 3144 3888 4608 5352 6096 6816 7560 8280 12 13 288 1032 1704 2448 3168 3912 4632 5376 6120 6840 7584 8304 13 14 312 1056 1728 2472 3192 3936 4656 5400 6144 6864 7608 8328 14 15 336 1080 1752 2496 3216 3960 4680 5424 6168 6888 7632 8352 15 16 360 1104 1776 2520 3240 3984 4704 5448 6192 6912 7656 8376 16 17 384 1128 1800 2544 3264 4008 4728 5472 6216 6936 7680 8400 17 18 408 1152 1824 2568 3288 4032 4752 5496 6240 6960 7704 8424 18 19 432 1176 1848 2592 3312 4056 4776 5520 6264 6984 7728 8448 19 20 456 1200 1872 2616 3336 4080 4800 5544 6288 7008 7752 8472 20 21 480 1224 1896 2640 3360 4104 4824 5568 6312 7032 7776 8496 21 22 504 1248 1920 2664 3384 4128 4848 5592 6336 7056 7800 8520 22 23 528 1272 1944 2688 3408 4152 4872 5616 6360 7080 7824 8544 23 24 552 1296 1968 2712 3432 4176 4896 5640 6384 7104 7848 8568 24 25 576 1320 1992 2736 3456 4200 4920 5664 6408 7128 7872 8592 25 26 600 1344 2016 2760 3480 4224 4944 5688 6432 7152 7896 8616 26 27 624 1368 2040 2784 3504 4248 4968 5712 6456 7176 7920 8640 27 28 648 1392 2064 2808 3528 4272 4992 5736 6480 7200 7944 8664 28 29 672 2088 2832 3552 4296 5016 5760 6504 7224 7968 8688 29 30 696 2112 2856 3576 4320 5040 5784 6528 7248 7992 8712 30 31 720 2136 3600 5064 5808 7272 8736 31 1.4.5 Note on Sample Times Two PIES models, URI and Sea Data (hereafter SD) were used during this deployment period. The URI models were used at sites H2, H3, and I2 and SDs at sites B3 and B4. In Section 2, the URI models are indicated in the tables by serial numbers less than 63 and SDs by serial numbers 63 or greater. The SDs were produced by Sea Data Corporation and designed after the URI model. Figure 4: [Sampling Sequences for URI and Sea Data Model IESs] Sampling Sequences for URI and Sea Data Model IESs. The horizontal length and postion of the boxes represent the duration and relative temporal location of the sampling periods, respectively. Each tic mark represents a minute. Although both models measure three variables, travel time, bottom pressure, and temperature, their sampling schemes are different. These are illustrated in Figure 4. Consider a typical 1800 s (0.5 hr) sampling interval. For comparison, it is useful to assign the time 0 s to the instant the previous sample is written to the tape. Then the time 1800 s corresponds to the instant the sample of interest is recorded. For both the URI and SD models, the travel time measurement consists of a burst of 24 pings at 10 s intervals and pressure is measured for the full 1800 s sampling interval. The URI models also measure temperature for the full 1800 s, whereas the temperature interval is reduced to only 56.25 s (a sixty-forth of an hour) in the SD models. The durations and relative temporal positioning of the three types of measurements are illustrated in Figure 4 for both models. The time base assigned to each variable coincides with the center of its measuring interval. In the URI model, since both pressure and temperature are measured for 1800 s, their centers occur at 900 s. The travel time burst actually begins at that time, and thus its center is offset by 115 s. The SD model PIES does its internal bookeeping and storage to tape in the first 11.25 s of the 1800 s sampling interval. The travel time burst begins after this processing, so its center is located at 126.25 s (i.e. 115 + 11.25 s). The center of the half-hourly pressure measurement will occur at 900 s. The shorter temperature measurement occurs at the end of the 1800 s sampling interval, with its center at 1771.875 s (1800 - 56.25/2 sec). Original processing of temperature and presure records was done under the wrong understanding that the SD model sampled in the same manner as the URI model. The difference was discovered when the phases of tidal constituents showed a quarter hour discrepancy between models. Hence the temperature and presure records on sites B3 and B4 were reprocessed from RESPO onward with the correct time base. The correct times and tidal constants are listed in the PIES tables (Tables 8, 9, 18, 19, and 23). 1.4.6 Note on Steppy Temperature at Site B3 The PIES at site B3 had a temperature record that was `steppy' because its 7 least significant bits were stuck and it counted temperature in increments of 128 counts rather than 1 count (see Figure 8.1 and 11.1). This introduces small error in the temperature correction of the pressure record. However, we simulated this error on a good temperature record (by integer truncation) and showed that the effect upon the pressure record was to introduce less than 0.003 dbar bias spikes of noise in the raw pressure data. This is illustrated in the IES Data Report for 1990 (Fields and Watts, 1990). After removing the mean, there is only about plus/minus 0.001 dbar noise, which is further reduced subsequently by low-pass filtering. 1.5 Data Recovery Tables 1 and 2 and Figure 2 summarize the data returns from each of the IESs. All 24 instruments were successfully recovered during May 1988. The data returns were also successful with the exception of two instruments. No data were obtained for the PIES at site H1. The sequence number recorded on the tape indicated that the instrument functioned for the full deployment period. However, the data words for travel time, pressure, and temperature were recorded with all bits set. At site B5, the instrument was accidentally released seven days after the initial deployment and was redeployed in aproximately the same location. The cpu board in the IES stopped functioning properly after about one month, and only 1's were recorded on the tape. Thus good travel time data were obtained for only a month at this site. At site A1, two large jumps occurred in the travel time record. Both jumps were toward longer times. We were unable to determine the exact cause of these jumps, but they might be explained by mudslides which moved the IES downslope. In order to obtain a usable record at this site, we subtracted 0.0387 s from all the travel times beginning with record 3929 and 0.0527 s (= 0.0387 s + 0.014 s) from all those beginning with record 8085. The overall data return was 92 for travel time and 83 for pressure and temperature. Section 2. Individual Site and Record Information Tables The tables that follow provide information about the location, dates, and basic statistics of the data records. Each table documents a single instrument deployment. General information, such as position, bottom depth, and launch and recovery times, is given first. Subsequently, details about the travel time, bottom pressure, temperature and thermocline depth records that are plotted in Sections 3 -- 5 are tabulated. Tables supply the times associated with the first and last data point of each plot. All yearhours are referenced to January 1, 1988 at 0000 GMT. Measurements made during the calendar year prior to the reference date are given as negative yearhours. The first order statistics (minimum, maximum, mean, and standard deviation) are tabulated for the half-hourly and six-hourly low-passed records (40 HRLP) of each variable of standard IESs and PIESs. Note that the travel time displayed should not be interpreted as the absolute time required for a signal to make the round trip in 3000 -- 5000m of water. The full round-trip time takes approximately 6 seconds and requires that minimum of 18 bits be recorded on the internal cassette tape. For storage economy, only the 13 least significant bits are recorded. As a results wrapping occurs and the full-scale range of the variation is approximately 200 msec. The variation in travel time is all that is required for subsequent interpretation and calibration against XBTs. After calibration to thermocline depth, the records from all IESs can easily be compared. Site and Record Information for IES88A1 Serial Number: 030 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 18.56 N DEPTH: 2475 m 74 36.94 W DATE GMT CRUISE LAUNCH: Oct 16, 1987 1848 EN169 RECOVERY: May 30, 1988 0344 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 16, 1987 19:36:55 -1828.3850 LAST DATA POINT: May 30, 1988 3:34:26 3603.5740 Number of Points: 10865 Sampling Interval: 0.50 hrs Minimum = 0.106 s Mean = 0.11411 s Maximum = 0.123 s Standard Deviation = 0.0030 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 2512.39 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 18, 1987 6: 0: 0 -1794.0000 LAST DATA POINT: May 28, 1988 18: 0: 0 3570.0000 Number of Points: 895 Sampling Interval: 6.00 hrs Minimum = 206.52 m Mean = 344.39 m Maximum = 463.95 m Standard Deviation = 54.47 m Site and Record Information for IES88A2 Serial Number: 060 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 02.05 N DEPTH: 3130 m 74 12.29 W DATE GMT CRUISE LAUNCH: Oct 13, 1987 0728 EN169 RECOVERY: Jun 13, 1988 0657 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 13, 1987 8:31:56 -1911.4680 LAST DATA POINT: Jun 13, 1988 6:28:37 3942.4771 Number of Points: 11709 Sampling Interval: 0.50 hrs Minimum = 0.168 s Mean = 0.173 s Maximum = 0.183 s Standard Deviation = 0.0018 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 4000.02 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 14, 1987 18: 0: 0 -1878.0000 LAST DATA POINT: Jun 12, 1988 0: 0: 0 3912.0000 Number of Points: 966 Sampling Interval: 6.00 hrs Minimum = 565.22 m Mean = 717.89 m Maximum = 789.93 m Standard Deviation = 33.51 m Site and Record Information for IES88B1 Serial Number: 052 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 45.06 N DEPTH: 1975 m 74 27.97 W DATE GMT CRUISE LAUNCH: Oct 11, 1987 1109 EN169 RECOVERY: May 28, 1988 0507 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 11, 1987 11:51:55 -1956.1350 LAST DATA POINT: May 28, 1988 4:49:45 3556.8291 Number of Points: 11027 Sampling Interval: 0.50 hrs Minimum = 0.217 s Mean = 0.226 s Maximum = 0.231 s Standard Deviation = 0.00205 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 4509.00 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 12, 1987 18: 0: 0 -1926.0000 LAST DATA POINT: May 26, 1988 18: 0: 0 3522.0000 Number of Points: 909 Sampling Interval: 6.00 hrs Minimum = 134.33 m Mean = 220.88 m Maximum = 357.91 m Standard Deviation = 34.66 m Site and Record Information for IES88B2 Serial Number: 062 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 36.71 N DEPTH: 2650 m 74 14.30 W DATE GMT CRUISE LAUNCH: Oct 12, 1987 1411 EN169 RECOVERY: May 29, 1988 2234 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 12, 1987 15: 6:55 -1928.8850 LAST DATA POINT: May 29, 1988 22: 4:33 3598.0759 Number of Points: 11055 Sampling Interval: 0.50 hrs Minimum = 0.357 s Mean = 0.368 s Maximum = 0.381 s Standard Deviation = 0.00432 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 7348.04 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 14, 1987 0: 0: 0 -1896.0000 LAST DATA POINT: May 28, 1988 12: 0: 0 3564.0000 Number of Points: 911 Sampling Interval: 6.00 hrs Minimum = 139.08 m Mean = 358.94 m Maximum = 536.73 m Standard Deviation = 80.66 m Site and Record Information for PIES88B3 Serial Number: 066 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: Pressure and Temperature Pressure Sensor Serial Number: 31162 POSITION: 35 28.81 N DEPTH: 2985 m 74 02.84 W DATE GMT CRUISE LAUNCH: Oct 12, 1987 1111 EN169 RECOVERY: May 29, 1988 1715 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 12, 1987 12: 1:12 -1931.9800 LAST DATA POINT: May 29, 1988 17: 1:12 3593.0200 Number of Points: 11051 Sampling Interval: 0.50 hrs Minimum = 0.380 s Mean = 0.388 s Maximum = 0.405 s Standard Deviation = 0.00393 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 7951.52 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 13, 1987 18: 0: 0 -1902.0000 LAST DATA POINT: May 28, 1988 6: 0: 0 3558.0000 Number of Points: 911 Sampling Interval: 6.00 hrs Minimum = 290.33 m Mean = 580.58 m Maximum = 710.87 m Standard Deviation = 73.76 m MEASURED BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 12, 1987 12:14: 6 -1931.7650 LAST DATA POINT: May 29, 1988 17:14: 6 3593.2351 Number of Points: 11051 Sampling Interval: 0.50 hrs Minimum = 3041.90 dbar Mean = 3042.42 dbar Maximum = 3043.46 dbar Standard Deviation = 0.37 dbar RESIDUAL BOTTOM PRESSURE RECORDS P_residual = P_measured - MEAN - DRIFT - TIDE DRIFT = P1 exp(-P2 t) + P3 where t = Time of sample in hours, starting with t = 13.0 hrs for the first data point P1 = -0.1352200 dbar P2 = -0.0004656 hr P3 = 0.0485570 dbar TIDE were calculated from the following constituents: M2 N2 S2 K2 K1 O1 P1 Q1 H (dbar): 0.43255 0.09749 0.08732 0.02033 0.09082 0.0717 0.02988 0.01591 G : 352.753 334.796 19.283 21.274 182.687 186.00 183.191 184.775 DATE UT YEARHOUR FIRST DATA POINT: Oct 13, 1987 0:14: 6 -1919.7651 LAST DATA POINT: May 29, 1988 17:14: 6 3593.2349 Number of Points: 11027 Sampling Interval: 0.50 hrs Minimum = -0.1077 dbar Mean = -0.0001 dbar Maximum = 0.1430 dbar Standard Deviation = 0.0379 dbar 40HRLP RESIDUAL BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 14, 1987 0: 0: 0 -1896 LAST DATA POINT: May 28, 1988 18: 0: 0 3570 Number of Points: 912 Sampling Interval: 6.0 hrs Minimum = -0.0752 dbar Mean = 0.0001 dbar Maximum = 0.0851 dbar Standard Deviation = 0.0318 dbar MEASURED BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 12, 1987 12:28:37 -1931.5229 LAST DATA POINT: May 29, 1988 17:28:37 3593.4771 Number of Points: 11051 Sampling Interval: 0.50 hrs Minimum = 2.33 C Mean = 2.71 C Maximum = 3.11 C Standard Deviation = 0.13 C 40HRLP BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 14, 1987 0: 0: 0 -1896 LAST DATA POINT: May 28, 1988 18: 0: 0 3570 Number of Points: 912 Sampling Interval: 6.0 hrs Minimum = 2.338 C Mean = 2.710 C Maximum = 3.059 C Standard Deviation = 0.132 C Site and Record Information for PIES88B4 Serial Number: 065 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: Pressure and Temperature Pressure Sensor Serial Number: 28197 POSITION: 35 20.74 N DEPTH: 3325 m 73 50.97 W DATE GMT CRUISE LAUNCH: Oct 12, 1987 0836 EN169 RECOVERY: May 29, 1988 1341 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 12, 1987 9:33: 8 -1934.4480 LAST DATA POINT: May 29, 1988 13:33: 7 3589.5520 Number of Points: 11049 Sampling Interval: 0.50 hrs Minimum = 0.0451 s Mean = 0.0522 s Maximum = 0.0611 s Standard Deviation = 0.00251 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 1710.35 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 13, 1987 18: 0: 0 -1902.0000 LAST DATA POINT: May 28, 1988 6: 0: 0 3558.0000 Number of Points: 911 Sampling Interval: 6.00 hrs Minimum = 573.27 m Mean = 718.80 m Maximum = 812.97 m Standard Deviation = 46.04 m MEASURED BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 12, 1987 9:46: 2 -1934.2330 LAST DATA POINT: May 29, 1988 13:46: 2 3589.7671 Number of Points: 11049 Sampling Interval: 0.50 hrs Minimum = 3406.19 dbar Mean = 3407.01 dbar Maximum = 3407.83 dbar Standard Deviation = 0.35 dbar RESIDUAL BOTTOM PRESSURE RECORDS P_residual = P_measured - MEAN - DRIFT - TIDE DRIFT = P1 exp(-P2 t) + P3 where t = Time of sample in hours, starting with t = 13.0 hrs for the first data point P1 = -0.2820000 dbar P2 = -0.00079121 /hr P3 = 0.0632400 dbar TIDE were calculated from the following constituents: M2 N2 S2 K2 K1 O1 P1 Q1 H (dbar): 0.43362 0.09801 0.08714 0.02030 0.09182 0.07084 0.03026 0.01523 G : 352.865 335.175 19.776 21.920 182.684 185.966 183.473 182.319 DATE UT YEARHOUR FIRST DATA POINT: Oct 12, 1987 21:46: 2 -1922.2332 LAST DATA POINT: May 29, 1988 13:46: 1 3589.7668 Number of Points: 11025 Sampling Interval: 0.50 hrs Minimum = -0.1716 dbar Mean = 0.0000 dbar Maximum = 0.1745 dbar Standard Deviation = 0.0458 dbar 40HRLP RESIDUAL BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 13, 1987 18: 0: 0 -1902 LAST DATA POINT: May 28, 1988 18: 0: 0 3570 Number of Points: 913 Sampling Interval: 6.0 hrs Minimum = -0.1092 dbar Mean = 0.0003 dbar Maximum = 0.1259 dbar Standard Deviation = 0.0420 dbar MEASURED BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 12, 1987 10: 0:33 -1933.9910 LAST DATA POINT: May 29, 1988 14: 0:33 3590.0090 Number of Points: 11049 Sampling Interval: 0.50 hrs Minimum = 2.20 C Mean = 2.30 C Maximum = 2.49 C Standard Deviation = 0.06 C 40HRLP BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 14, 1987 0: 0: 0 -1896 LAST DATA POINT: May 28, 1988 18: 0: 0 3570 Number of Points: 912 Sampling Interval: 6.0 hrs Minimum = 2.201 C Mean = 2.304 C Maximum = 2.455 C Standard Deviation = 0.058 C Site and Record Information for IES88B5A Serial Number: 031 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 11.98 N DEPTH: 3630 m 73 40.01 W DATE GMT CRUISE LAUNCH: Oct 12, 1987 0623 EN169 RECOVERY: OCT 19, 1987 2022 EN169 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 12, 1987 7:16:56 -1936.7180 LAST DATA POINT: Oct 19, 1987 17:46:56 -1758.2180 Number of Points: 358 Sampling Interval: 0.50 hrs Minimum = 0.0471 s Mean = 0.0509 s Maximum = 0.0544 s Standard Deviation = 0.00205 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 1761.16 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 13, 1987 18: 0: 0 -1902.0000 LAST DATA POINT: Oct 18, 1987 12: 0: 0 -1788.0000 Number of Points: 20 Sampling Interval: 6.00 hrs Minimum = 744.50 m Mean = 795.15 m Maximum = 843.52 m Standard Deviation = 36.85 m Site and Record Information for IES88B5B Serial Number: 031 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 12.07 N DEPTH: 3620 m 73 40.09 W DATE GMT CRUISE LAUNCH: Oct 19, 1987 2053 EN169 RECOVERY: May 29, 1988 1026 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 19, 1987 21:46:56 -1754.2180 LAST DATA POINT: Nov 15, 1987 6:16:56 -1121.7180 Number of Points: 1266 Sampling Interval: 0.50 hrs Minimum = 0.0506 s Mean = 0.0538 s Maximum = 0.0560 s Standard Deviation = 0.000998 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 1790.45 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 21, 1987 6: 0: 0 -1722.0000 LAST DATA POINT: Nov 14, 1987 0: 0: 0 -1152.0000 Number of Points: 96 Sampling Interval: 6.00 hrs Minimum = 747.91 m Mean = 768.78 m Maximum = 810.99 m Standard Deviation = 15.79 m Site and Record Information for IES88C1 Serial Number: 050 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 36 04.54 N DEPTH: 2850 m 73 56.98 W DATE GMT CRUISE LAUNCH: Oct 12, 1987 2025 EN169 RECOVERY: May 31, 1988 0305 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 12, 1987 21: 6:21 -1922.8940 LAST DATA POINT: May 31, 1988 2:36:18 3626.6050 Number of Points: 11100 Sampling Interval: 0.50 hrs Minimum = 0.185 s Mean = 0.199 s Maximum = 0.206 s Standard Deviation = 0.00395 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 4000.52 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 14, 1987 6: 0: 0 -1890.0000 LAST DATA POINT: May 29, 1988 18: 0: 0 3594.0000 Number of Points: 915 Sampling Interval: 6.00 hrs Minimum = 110.75 m Mean = 227.90 m Maximum = 451.10 m Standard Deviation = 73.24 m Site and Record Information for IES88C2 Serial Number: 057 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 35 45.93 N DEPTH: 3450 m 73 33.55 W DATE GMT CRUISE LAUNCH: Oct 13, 1987 0045 EN169 RECOVERY: May 31, 1988 0740 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 13, 1987 1:51:55 -1918.1350 LAST DATA POINT: May 31, 1988 6:47:38 3630.7939 Number of Points: 11099 Sampling Interval: 0.50 hrs Minimum = 0.191 s Mean = 0.201 s Maximum = 0.220 s Standard Deviation = 0.00498 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 4437.48 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 14, 1987 12: 0: 0 -1884.0000 LAST DATA POINT: May 30, 1988 0: 0: 0 3600.0000 Number of Points: 915 Sampling Interval: 6.00 hrs Minimum = 296.50 m Mean = 621.39 m Maximum = 777.77 m Standard Deviation = 93.87 m Site and Record Information for IES88G2 Serial Number: 040 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 38 01.00 N DEPTH: 3910 m 69 16.22 W DATE GMT CRUISE LAUNCH: Oct 25, 1987 0046 EN169 RECOVERY: May 26, 1988 0016 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 2: 1: 9 -1629.9810 LAST DATA POINT: May 26, 1988 0: 1: 9 3504.0190 Number of Points: 5135 Sampling Interval: 1.0 hrs Minimum = 0.382 s Mean = 0.400 s Maximum = 0.415 s Standard Deviation = 0.00911 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 7949.64 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 26, 1987 12: 0: 0 -1596.0000 LAST DATA POINT: May 24, 1988 18: 0: 0 3474.0000 Number of Points: 846 Sampling Interval: 6.00 hrs Minimum = 103.14 m Mean = 345.06 m Maximum = 670.57 m Standard Deviation = 172.77 m Site and Record Information for IES88G3 Serial Number: 046 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 37 23.34 N DEPTH: 4330 m 69 10.54 W DATE GMT CRUISE LAUNCH: Oct 25, 1987 0458 EN169 RECOVERY: May 26, 1988 0558 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 6:46:16 -1625.2290 LAST DATA POINT: May 26, 1988 5:46:16 3509.7710 Number of Points: 5136 Sampling Interval: 1.0 hrs Minimum = 0.160 s Mean = 0.169 s Maximum = 0.186 s Standard Deviation = 0.00549 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 3870.79 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 26, 1987 12: 0: 0 -1596.0000 LAST DATA POINT: May 25, 1988 0: 0: 0 3480.0000 Number of Points: 847 Sampling Interval: 6.00 hrs Minimum = 366.17 m Mean = 654.79 m Maximum = 795.47 m Standard Deviation = 102.94 m Site and Record Information for IES88G4 Serial Number: 061 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 36 49.08 N DEPTH: 4689 m 68 50.26 W DATE GMT CRUISE LAUNCH: Oct 25, 1987 0904 EN169 RECOVERY: Jun 5, 1988 2222 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 10:46:23 -1621.2271 LAST DATA POINT: Jun 5, 1988 21:46:23 3765.7729 Number of Points: 5388 Sampling Interval: 1.0 hrs Minimum = 0.218 s Mean = 0.227 s Maximum = 0.256 s Standard Deviation = 0.00835 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 5102.44 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 26, 1987 18: 0: 0 -1590.0000 LAST DATA POINT: Jun 4, 1988 12: 0: 0 3732.0000 Number of Points: 888 Sampling Interval: 6.00 hrs Minimum = 260.99 m Mean = 783.88 m Maximum = 927.97 m Standard Deviation = 154.62 m Site and Record Information for IES88G5 Serial Number: 033 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 36 14.25 N DEPTH: 4585 m 68 51.30 W DATE GMT CRUISE LAUNCH: Oct 25, 1987 1253 EN169 RECOVERY: May 23, 1988 0402 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 14:31:45 -1617.4709 LAST DATA POINT: May 23, 1988 3:31:45 3435.5291 Number of Points: 5054 Sampling Interval: 1.0 hrs Minimum = 0.0950 s Mean = 0.101487 s Maximum = 0.1277 s Standard Deviation = 0.006287 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 2667.81 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 27, 1987 0: 0: 0 -1584.0000 LAST DATA POINT: May 21, 1988 18: 0: 0 3402.0000 Number of Points: 832 Sampling Interval: 6.00 hrs Minimum = 263.54 m Mean = 741.26 m Maximum = 839.08 m Standard Deviation = 115.37 m Site and Record Information for PIES88H2 Serial Number: 056 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: Pressure and Temperature Pressure Sensor Serial Number: 17849 POSITION: 38 18.02 N DEPTH: 4080 m 68 27.97 W DATE GMT CRUISE LAUNCH: Oct 24, 1987 1418 EN169 RECOVERY: May 24, 1988 1420 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 16: 1:45 -1639.9709 LAST DATA POINT: May 24, 1988 14: 1:45 3470.0291 Number of Points: 10221 Sampling Interval: 0.50 hrs Minimum = 0.240 s Mean = 0.258 s Maximum = 0.269 s Standard Deviation = 0.00741 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 5195.47 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 26, 1987 0: 0: 0 -1608.0000 LAST DATA POINT: May 23, 1988 6: 0: 0 3438.0000 Number of Points: 842 Sampling Interval: 6.00 hrs Minimum = 78.45 m Mean = 257.53 m Maximum = 577.52 m Standard Deviation = 138.15 m MEASURED BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 15:59:49 -1640.0031 LAST DATA POINT: May 24, 1988 13:59:49 3469.9971 Number of Points: 10221 Sampling Interval: 0.50 hrs Minimum = 4176.72 dbar Mean = 4177.32 dbar Maximum = 4178.30 dbar Standard Deviation = 0.34 dbar RESIDUAL BOTTOM PRESSURE RECORDS P_residual = P_measured - MEAN - DRIFT - TIDE DRIFT = P1 exp(-P2 t) + P3 where t = Time of sample in hours, starting with t = 13.0 hrs for the first data point P1 = 0 dbar P2 = 0 /hr P3 = 0 dbar TIDE were calculated from the following constituents: M2 N2 S2 K2 K1 O1 P1 Q1 H (dbar): 0.4240 0.0956 0.0956 0.0231 0.08171 0.0640 0.0269 0.0141 G : 353.66 335.86 20.63 22.47 177.062 181.455 177.80 179.28 DATE UT YEARHOUR FIRST DATA POINT: Oct 25, 1987 3:59:49 -1628.0031 LAST DATA POINT: May 24, 1988 13:59:49 3469.9971 Number of Points: 10197 Sampling Interval: 0.50 hrs Minimum = -0.1619 dbar Mean = 0.0006 dbar Maximum = 0.1521 dbar Standard Deviation = 0.0544 dbar 40HRLP RESIDUAL BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 26, 1987 0: 0: 0 -1608 LAST DATA POINT: May 23, 1988 12: 0: 0 3444 Number of Points: 843 Sampling Interval: 6.0 hrs Minimum = -0.1215 dbar Mean = 0.0006 dbar Maximum = 0.1290 dbar Standard Deviation = 0.0521 dbar MEASURED BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 15:59:49 -1640.0031 LAST DATA POINT: May 24, 1988 13:59:49 3469.9971 Number of Points: 10221 Sampling Interval: 0.50 hrs Minimum = 2.21 C Mean = 2.23 C Maximum = 2.33 C Standard Deviation = 0.01 C 40HRLP BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 26, 1987 0: 0: 0 -1608 LAST DATA POINT: May 23, 1988 12: 0: 0 3444 Number of Points: 843 Sampling Interval: 6.0 hrs Minimum = 2.209 C Mean = 2.230 C Maximum = 2.277 C Standard Deviation = 0.013 C Site and Record Information for PIES88H3 Serial Number: 053 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: Pressure and Temperature Pressure Sensor Serial Number: 19327 POSITION: 37 38.71 N DEPTH: 4565 m 68 19.31 W DATE GMT CRUISE LAUNCH: Oct 24, 1987 0808 EN169 RECOVERY: Jun 8, 1988 0108 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 9:41:38 -1646.3060 LAST DATA POINT: Jun 8, 1988 0:41:39 3816.6941 Number of Points: 10927 Sampling Interval: 0.50 hrs Minimum = 0.0713 s Mean = 0.084367 s Maximum = 0.1048 s Standard Deviation = 0.00799 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 2168.05 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 18: 0: 0 -1614.0000 LAST DATA POINT: Jun 6, 1988 18: 0: 0 3786.0000 Number of Points: 901 Sampling Interval: 6.00 hrs Minimum = 201.47 m Mean = 565.86 m Maximum = 792.53 m Standard Deviation = 150.36 m Site and Record Information for IES88H4 Serial Number: 037 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 37 00.52 N DEPTH: 4877 m 68 07.74 W DATE GMT CRUISE LAUNCH: Oct 24, 1987 0421 EN169 RECOVERY: Jun 7, 1988 1023 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 5:31:56 -1650.4680 LAST DATA POINT: Jun 7, 1988 9:57:58 3801.9661 Number of Points: 10906 Sampling Interval: 0.50 hrs Minimum = 0.0752 s Mean = 0.086549 s Maximum = 0.1143 s Standard Deviation = 0.00869 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 2342.00 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 12: 0: 0 -1620.0000 LAST DATA POINT: Jun 6, 1988 0: 0: 0 3768.0000 Number of Points: 899 Sampling Interval: 6.00 hrs Minimum = 214.97 m Mean = 698.68 m Maximum = 887.10 m Standard Deviation = 164.49 m MEASURED BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 9:39:44 -1646.3380 LAST DATA POINT: Jun 8, 1988 0:39:44 3816.6621 Number of Points: 10927 Sampling Interval: 0.50 hrs Minimum = 4674.77 dbar Mean = 4675.81 dbar Maximum = 4676.33 dbar Standard Deviation = 0.43 dbar RESIDUAL BOTTOM PRESSURE RECORDS P_residual = P_measured - MEAN - DRIFT - TIDE DRIFT = P1 exp(-P2 t) + P3 where t = Time of sample in hours, starting with t = 13.0 hrs for the first data point P1 = 0.2176000 dbar P2 = -0.0062000 /hr P3 = -0.005200 dbar TIDE were calculated from the following constituents: M2 N2 S2 K2 K1 O1 P1 Q1 H (dbar): 0.4242 0.0952 0.0954 0.0229 0.08123 0.0635 0.0267 0.0139 G : 353.62 336.12 20.98 23.09 177.598 182.34 178.43 179.65 DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 21:39:44 -1634.3380 LAST DATA POINT: Jun 8, 1988 0:39:44 3816.6621 Number of Points: 10903 Sampling Interval: 0.50 hrs Minimum = -0.2080 dbar Mean = -0.0013 dbar Maximum = 0.1594 dbar Standard Deviation = 0.0655 dbar 40HRLP RESIDUAL BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 25, 1987 18: 0: 0 -1614 LAST DATA POINT: Jun 7, 1988 0: 0: 0 3792 Number of Points: 902 Sampling Interval: 6.0 hrs Minimum = -0.1685 dbar Mean = -0.0013 dbar Maximum = 0.1386 dbar Standard Deviation = 0.0639 dbar MEASURED BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 9:39:44 -1646.3380 LAST DATA POINT: Jun 8, 1988 0:39:44 3816.6621 Number of Points: 10927 Sampling Interval: 0.50 hrs Minimum = 2.37 C Mean = 2.43 C Maximum = 2.54 C Standard Deviation = 0.01 C 40HRLP BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 25, 1987 18: 0: 0 -1614 LAST DATA POINT: Jun 7, 1988 0: 0: 0 3792 Number of Points: 902 Sampling Interval: 6.0 hrs Minimum = 2.372 C Mean = 2.427 C Maximum = 2.471 C Standard Deviation = 0.011 C Site and Record Information for IES88H5 Serial Number: 035 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 36 22.13 N DEPTH: 4825 m 67 58.00 W DATE GMT CRUISE LAUNCH: Oct 24, 1987 0012 EN169 RECOVERY: Jun 6, 1988 0546 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 1:31:56 -1654.4680 LAST DATA POINT: Jun 6, 1988 5:27:36 3773.4600 Number of Points: 10857 Sampling Interval: 0.50 hrs Minimum = 0.0132 s Mean = 0.021367 s Maximum = 0.0503 s Standard Deviation = 0.00847 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 1146.83 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 12: 0: 0 -1620.0000 LAST DATA POINT: Jun 5, 1988 0: 0: 0 3744.0000 Number of Points: 895 Sampling Interval: 6.00 hrs Minimum = 225.35 m Mean = 746.05 m Maximum = 877.24 m Standard Deviation = 159.91 m Site and Record Information for IES88I1 Serial Number: 034 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 39 00.12 N DEPTH: 3625 m 67 48.70 W DATE GMT CRUISE LAUNCH: Oct 23, 1987 0226 EN169 RECOVERY: May 25, 1988 0323 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 23, 1987 3:31:33 -1676.4740 LAST DATA POINT: May 25, 1988 3: 1:33 3483.0259 Number of Points: 10320 Sampling Interval: 0.50 hrs Minimum = 0.0238 s Mean = 0.037667 s Maximum = 0.0473 s Standard Deviation = 0.00580 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 983.23 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 12: 0: 0 -1644.0000 LAST DATA POINT: May 23, 1988 18: 0: 0 3450.0000 Number of Points: 850 Sampling Interval: 6.00 hrs Minimum = 102.28 m Mean = 267.49 m Maximum = 505.00 m Standard Deviation = 109.29 m Site and Record Information for PIES88I2 Serial Number: 054 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: Pressure and Temperature Pressure Sensor Serial Number: 17911 POSITION: 38 22.48 N DEPTH: 4350 m 67 35.37 W DATE GMT CRUISE LAUNCH: Oct 23, 1987 0717 EN169 RECOVERY: May 24, 1988 0854 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 23, 1987 8:16:16 -1671.7290 LAST DATA POINT: May 24, 1988 8:46:16 3464.7710 Number of Points: 10274 Sampling Interval: 0.50 hrs Minimum = 0.197 s Mean = 0.222128 s Maximum = 0.235 s Standard Deviation = 0.01086 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 4552.47 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 18: 0: 0 -1638.0000 LAST DATA POINT: May 23, 1988 0: 0: 0 3432.0000 Number of Points: 846 Sampling Interval: 6.00 hrs Minimum = 117.70 m Mean = 330.65 m Maximum = 777.52 m Standard Deviation = 203.81 m MEASURED BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 23, 1987 8:14:21 -1671.7610 LAST DATA POINT: May 24, 1988 8:44:20 3464.7390 Number of Points: 10274 Sampling Interval: 0.50 hrs Minimum = 4462.96 dbar Mean = 4463.88 dbar Maximum = 4464.69 dbar Standard Deviation = 0.35 dbar RESIDUAL BOTTOM PRESSURE RECORDS P_residual = P_measured - MEAN - DRIFT - TIDE DRIFT = P1 exp(-P2 t) + P3 where t = Time of sample in hours, starting with t = 13.0 hrs for the first data point P1 = -0.3058000 dbar P2 = -0.0004547 /hr P3 = 0.1009000 dbar TIDE were calculated from the following constituents: M2 N2 S2 K2 K1 O1 P1 Q1 H (dbar): 0.4218 0.0950 0.0953 0.0229 0.07934 0.0632 0.0262 0.0139 G : 353.47 335.80 20.83 22.84 176.834 181.329 177.76 177.86 DATE UT YEARHOUR FIRST DATA POINT: Oct 23, 1987 20:14:20 -1659.7610 LAST DATA POINT: May 24, 1988 8:44:20 3464.7390 Number of Points: 10250 Sampling Interval: 0.50 hrs Minimum = -0.1711 dbar Mean = 0.0173 dbar Maximum = 0.2608 dbar Standard Deviation = 0.0629 dbar 40HRLP RESIDUAL BOTTOM PRESSURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 18: 0: 0 -1638 LAST DATA POINT: May 23, 1988 12: 0: 0 3444 Number of Points: 848 Sampling Interval: 6.0 hrs Minimum = -0.1558 dbar Mean = 0.0173 dbar Maximum = 0.1869 dbar Standard Deviation = 0.0591 dbar MEASURED BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 23, 1987 8:14:21 -1671.7610 LAST DATA POINT: May 24, 1988 8:44:20 3464.7390 Number of Points: 10274 Sampling Interval: 0.50 hrs Minimum = 2.18 C Mean = 2.21 C Maximum = 2.33 C Standard Deviation = 0.01 C 40HRLP BOTTOM TEMPERATURE RECORDS DATE UT YEARHOUR FIRST DATA POINT: Oct 24, 1987 18: 0: 0 -1638 LAST DATA POINT: May 23, 1988 12: 0: 0 3444 Number of Points: 848 Sampling Interval: 6.0 hrs Minimum = 2.185 C Mean = 2.211 C Maximum = 2.259 C Standard Deviation = 0.011 C Site and Record Information for IES88I3 Serial Number: 044 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 37 47.49 N DEPTH: 4730 m 67 31.01 W DATE GMT CRUISE LAUNCH: Oct 23, 1987 1109 EN169 RECOVERY: Jun 8, 1988 0602 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 23, 1987 12:31: 5 -1667.4821 LAST DATA POINT: Jun 8, 1988 6: 1: 5 3822.0181 Number of Points: 10980 Sampling Interval: 0.50 hrs Minimum = 0.277 s Mean = 0.296594 s Maximum = 0.313 s Standard Deviation = 0.0108 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 6095.22 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 24, 1987 18: 0: 0 -1638.0000 LAST DATA POINT: Jun 6, 1988 18: 0: 0 3786.0000 Number of Points: 905 Sampling Interval: 6.00 hrs Minimum = 170.19 m Mean = 459.52 m Maximum = 817.36 m Standard Deviation = 203.81 m Site and Record Information for IES88I4 Serial Number: 047 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 37 11.18 N DEPTH: 4913 m 67 21.46 W DATE GMT CRUISE LAUNCH: Oct 23, 1987 1518 EN169 RECOVERY: Jun 7, 1988 0005 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 23, 1987 16:36:55 -1663.3850 LAST DATA POINT: Jun 6, 1988 23:35:13 3791.5869 Number of Points: 10911 Sampling Interval: 0.50 hrs Minimum = 0.140 s Mean = 0.152108 s Maximum = 0.176 s Standard Deviation = 0.00973 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 3556.09 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 0: 0: 0 -1632.0000 LAST DATA POINT: Jun 5, 1988 18: 0: 0 3762.0000 Number of Points: 900 Sampling Interval: 6.00 hrs Minimum = 237.58 m Mean = 665.65 m Maximum = 855.65 m Standard Deviation = 185.11 m Site and Record Information for IES88I5 Serial Number: 058 Type of Travel Time Detector: TTC Number of Pings per Sampling: 24 Additional Sensors: None POSITION: 36 33.48 N DEPTH: 4979 m 67 11.67 W DATE GMT CRUISE LAUNCH: Oct 23, 1987 1936 EN169 RECOVERY: Jun 6, 1988 1401 OC200 TRAVEL TIME RECORDS DATE GMT YEARHOUR FIRST DATA POINT: Oct 23, 1987 21: 1:53 -1658.9690 LAST DATA POINT: Jun 6, 1988 13:31:52 3781.5310 Number of Points: 10882 Sampling Interval: 0.50 hrs Minimum = 0.233 s Mean = 0.240292 s Maximum = 0.265 s Standard Deviation = 0.00626 s 40 HRLP THERMOCLINE DEPTH RECORDS Z12 Conversion equation: Z12 = -19000 m/s tau + B where B = 5358.97 m tau = Travel Time (sec) with tide removed DATE GMT YEARHOUR FIRST DATA POINT: Oct 25, 1987 6: 0: 0 -1626.0000 LAST DATA POINT: Jun 5, 1988 6: 0: 0 3750.0000 Number of Points: 897 Sampling Interval: 6.00 hrs Minimum = 352.16 m Mean = 792.98 m Maximum = 914.30 m Standard Deviation = 118.79 m Section 3. Half-Hourly Individual Plots Plots are presented for the individual time series of travel time, bottom pressure, residual bottom pressure (detided and dedrifted), and temperature. A nominal half-hourly sampling interval applies to all measurements. The plots for each sensor are displayed in a standardized window. All sensors have a common time axis which starts at --2448 (21-Sept-1987 referenced to 1-Jan-1988) and extends to 9264(21-Jan-1989 referenced to 1-Jan-1988). This time period is displayed in four panels, two per page. Each panel covers 2928 hr (one third of a leap year). A small tic is placed at each day (0000 GMT) and larger tics denote weeks (168 hr). All IES records in this report were encompassed by this period. For comparison, labels indicating specific dates are centered about their yearhour equivalents (for example a label associates ``1-Jan-89'' with 0.0 yearhour). Vertical axes for each sensor will be either common or have a common increment. Travel time is plotted within a 40 msec window in increments of 5 msec. Pressure is plotted in a 2 dbar window centered about zero. The mean pressure was removed from the series for the purpose of plotting and its value is indicated in the y-axis label. After detiding and dedrifting, the residual bottom pressures are plotted within a 0.8 dbar window centered about zero. A 0.15 C window, adjusted vertically to enclose all the record's variation, is used for each temperature record except for the case of B3 and B4, where 0.8 C windows are used. Half-Hourly Travel Time Plots [IES88A1] Half-Hourly Travel Time. IES88A1 [IES88A2] Half-Hourly Travel Time. IES88A2 [IES88B1] Half-Hourly Travel Time. IES88B1 [IES88B2] Half-Hourly Travel Time. IES88B2 [PIES88B3] Half-Hourly Travel Time. PIES88B3 [PIES88B4] Half-Hourly Travel Time. PIES88B4 [IES88B5A] Half-Hourly Travel Time. IES88B5A [IES88B5B] Half-Hourly Travel Time. IES88B5B [IES88C1] Half-Hourly Travel Time. IES88C1 [IES88C2] Half-Hourly Travel Time. IES88C2 [IES88G2] Half-Hourly Travel Time. IES88G2 [IES88G3] Half-Hourly Travel Time. IES88G3 [IES88G4] Half-Hourly Travel Time. IES88G4 [IES88G5] Half-Hourly Travel Time. IES88G5 [PIES88H2] Half-Hourly Travel Time. PIES88H2 [PIES88H3] Half-Hourly Travel Time. PIES88H3 [IES88H4] Half-Hourly Travel Time. IES88H4 [IES88H5] Half-Hourly Travel Time. IES88H5 [IES88I1] Half-Hourly Travel Time. IES88I1 [PIES88I2] Half-Hourly Travel Time. PIES88I2 [IES88I3] Half-Hourly Travel Time. IES88I3 [IES88I4] Half-Hourly Travel Time. IES88I4 [IES88I5] Half-Hourly Travel Time. IES88I5 Half-Hourly Bottom Pressure Plots [PIES88B3] Half-Hourly Bottom Pressure. PIES88B3 [PIES88B4] Half-Hourly Bottom Pressure. PIES88B4 [PIES88H2] Half-Hourly Bottom Pressure. PIES88H2 [PIES88H3] Half-Hourly Bottom Pressure. PIES88H3 [PIES88I2] Half-Hourly Bottom Pressure. PIES88I2 Half-Hourly Residual Bottom Pressure Plots [PIES88B3] Half-Hourly Residual Bottom Pressure. PIES88B3 [PIES88B4] Half-Hourly Residual Bottom Pressure. PIES88B4 [PIES88H2] Half-Hourly Residual Bottom Pressure. PIES88H2 [PIES88H3] Half-Hourly Residual Bottom Pressure. PIES88H3 [PIES88I2] Half-Hourly Residual Bottom Pressure. PIES88I2 Half-Hourly Bottom Temperature Plots [PIES88B3] Half-Hourly Bottom Temperature. PIES88B3 [PIES88B4] Half-Hourly Bottom Temperature. PIES88B4 [PIES88H2] Half-Hourly Bottom Temperature. PIES88H2 [PIES88H3] Half-Hourly Bottom Temperature. PIES88H3 [PIES88I2] Half-Hourly Bottom Temperature. PIES88I2 Section 4. Half-Hourly Line Plots Line plots display all records from a given section across the Gulf Stream on a single page. Travel time, residual bottom pressure, and temperature are plotted in this section, grouped according to instrument lines, A, B, C, etc. The time axis of all line plots extends from -2500 hr to 4500 hr in increments of 500 hr. As with the individual plots, labels indicating specific dates are centered about their yearhour equivalents (for example a label associates ``1-Jan-89'' with 0.0 yearhour). For the line plots of travel time and bottom pressure, the vertical axes for all IESs will have common increments. This is also true for the temperature records except for those on line B and H. The individual records that compose the line plots are labeled with the site at the right, centered within the record's vertical axis. The records of travel time of B5a and B5b are plotted together in the same panel rather than separately. Half-Hourly Travel Time Plots By Lines Half-Hourly Travel Time Plots By Lines [A line] Half-Hourly Travel Time. A line [B line] Half-Hourly Travel Time. B line [C line] Half-Hourly Travel Time. C line [G line] Half-Hourly Travel Time. G line [H line] Half-Hourly Travel Time. H line [I line] Half-Hourly Travel Time. I line Half-Hourly Residual Bottom Pressure Plots By Lines [B line] Half-Hourly Residual Bottom Pressure. B line [H line] Half-Hourly Residual Bottom Pressure. H line [I line] Half-Hourly Residual Bottom Pressure. I line Half-Hourly Bottom Temperature Plots By Lines [B line] Half-Hourly Bottom Temperature. B line [H line] Half-Hourly Bottom Temperature. H line [I line] Half-Hourly Bottom Temperature. I line Section 5. 40HRLP Line Plots Line plots display all records from a given section across the Gulf Stream on a single page. 40HRLP thermocline depth, residual bottom pressure, and temperature are plotted in this section, grouped according to instrument lines, A, B, C, etc. The time axis of all line plots extends from -2500 hr to 4500 hr in increments of 500 hr. As with the individual plots, labels indicating specific dates are centered about their yearhour equivalents (for example a label associates ``1-Jan-89'' with 0.0 yearhour). The vertical axis for all Z12 plots ranges from 1000m depth to the surface in increments of 100 m. Also as in the non-filtered plots (section 4), vertical axes for all 40HRLP residual bottom pressure records have a common increment, and this is also true for the temperature records except for those on line B and H. The individual records that compose the line plots are labeled with the site at the right, centered within the record's vertical axis. The records of Z12 of B5a and B5b are plotted together in the same panel rather than separately. 40HRLP Z12 Plots By Lines [A line] 40HRLP Z12. A line [B line] 40HRLP Z12. B line [C line] 40HRLP Z12. C line [G line] 40HRLP Z12. G line [H line] 40HRLP Z12. H line [I line] 40HRLP Z12. I line 40HRLP Residual Bottom Pressure Plots By Lines [B line] 40HRLP Residual Bottom Pressure. B line [H line] 40HRLP Residual Bottom Pressure. H line [I line] 40HRLP Residual Bottom Pressure. I line 40HRLP Bottom Temperature Plots By Lines [B line] 40HRLP Bottom Temperature. B line [H line] 40HRLP Bottom Temperature. H line [I line] 40HRLP Bottom Temperature. I line Acknowledgments The SYNOP Experiment was supported by the Office of Naval Research under contract number N00014-87-K-0235 and the National Science Foundation under grant number OCE87-17144. We thank the crews of the R/V OCEANUS and R/V ENDEAVOR for their efforts during the deployment and recovery cruises. The successful deployment and recovery of the inverted echo sounders is due to the instrument development and careful preparation done by Gerard Chaplin and Michael Mulroney. It is a pleasure to acknowledge their efforts. Special thanks goes to Stephen Wood who helped in the data processing. REFERENCES Brook, D. A. 1976. (Editor). Fast and Easy Time Series Analysis at NCSU. Technical Report. Center for Marine and Coastal Studies. North Carolina State University. Raleigh, NC. Chaplin, G. and D. R. Watts. 1984. Inverted echo sounder development. Oceans '84 IEEE Proceeding. 1, 249--253. Gilman, C. and P. Cornillon 1990. Gulf Stream Position Time Series. J. Geophys. Res. (Submitted). Munk, W. H. and D. E. Cartwright. 1977. Tidal spectroscopy and prediction. Philos. Trans. R. Soc. London, 259, 533-581. Press, W.H., B.P. Flannery, S.A. Teukolsky,, and W.T. Vetterling. 1988. Numerical Recipes. Cambridge University Press, New York. Rossby, T. 1969. On monitoring depth variations of the main thermocline acoustically. J. Geophys. Res. 74, 5542-5546. Fields, E., K.L. Tracey, and D. R. Watts. 1990. Inverted echo sounder processing procedures. University of Rhode Island. GSO Technical Report 91-3. Watts, D. R. and W. E. Johns. 1982. Gulf Stream meanders: observations on propagation and growth. J. Geophys. Res. 87, 9467-9476. Watts, D. R. and H. Kontoyiannis. 1991. Deep-ocean bottom pressure measurement: drift removal and performance. J. Atmos. Ocean. Tech. 296-306. Watts, D. R. and H. T. Rossby. 1977. Measuring dynamic heights with inverted echo sounders: Results from MODE. J. Phys. Oceanogr. 7, 345-358. Watts, D. R., K. L. Tracey and A. I. Friedlander. 1989. Processing accurate maps of the Gulf Stream thermal front using objective analysis. J. Geophys. Res. 94, 8040-8052. Watts, D. R. and M. Wimbush. 1981. Sea surface height and thermocline depth variations measured from the sea floor. International Symposium on Acoustic Remote Sensing of the Atmosphere and Oceans, Proceedings, Calgary, Alberta, Canada.