Arctic Ocean ARGOS Salinity Buoys 1985 - 1994 James Morison, Principal Investigator (morison@apl.washington.edu) Roger Andersen (roger@apl.washington.edu) Polar Science Center Applied Physics Laboratory University of Washington 1013 NE 40th Seattle, WA 98105-6698 USA Telephone (206) 543-6613 FAX (206) 543-3521 Between 1985 and 1994, the Polar Science Center at the University of Washington deployed 24 ARGOS data buoys in ice floes on the Arctic Ocean, from which six temperature and conductivity sensor pairs were suspended as deep as 300 meters to allow calculation of salinity and density. Each sensor was sampled into a circular buffer every 12 minutes; one sample was transmitted every minute and the polar region coverage by ARGOS satellites provided sufficient redundancy to ensure that nearly every data point would get through. Subjected to all the stresses and strains of Arctic pack ice, these buoys varied greatly in their longevity, but the result is a substantial hydrographic record of the Arctic Ocean for a decade. The data is available here in an ASCII file of the original 12-minute samples. An ARGOS position fix is calculated once for each satellite pass, so latitude and longitude are interpolated to the time of each sample. Only some sensor levels, always including the bottom, were provided with pressure sensors to directly measure the depth. Depths of intervening layers were calculated from a catenary model of the cable hanging beneath the buoy hull Each "hydrofile", for example Hydro.12795.1093, contains one month of data. In this example the file contains the complete set from the buoy with ARGOS ID number 12795 during October 1993. Here is the first sample of this file: 1993 296.917 75.363 216.855 1011.520 -22.800 12795 9.7993 -1.5480 22.8280 28.2796 22.7169 40.3643 -1.2590 24.3740 30.0738 24.1678 70.6376 -1.0690 25.8770 31.8952 25.6394 121.2271 -1.4070 26.1710 32.6299 26.2447 203.4886 -1.4890 26.6340 33.3065 26.7962 11,1 Top Each sample block consists of 1 header line and six depth-level lines samples at its 12-minute sample time. In the sample listed above, the header line is 1993 296.917 75.363 216.855 1011.520 -22.800 12795 1993 is the year 296.917 is the day and fraction of day of this year, 1.000 = 1 January at 0000 GMT 75.363 (degrees North) Latitude 216.855 (degrees East of Greenwich) Longitude (degrees East of Greenwich) 1011.520 (millibars) Atmospheric Pressure -22.800 (degrees Celsius) Air Temperature 12795 is the ARGOS ID Number The fifth depth level line (to choose a sample) in the first sample is 203.4886 -1.4890 26.6340 33.3065 26.7962 203.4886 (meters) Ocean Depth of this sensor level -1.4890 (degrees Celsius) Ocean Temperature at this level 26.6340 (Siemans/meter) Conductivity 33.3065 (PSU) Salinity 26.7962 (sigma-theta) Density In the not unusual case of an individual sensor failing while the remainder of the buoy continued to function, the missing data point is flagged as -99.0000 for any variable. An effort was made to edit out obviously erroneous samples. However, idiosyncrasies of ARGOS data transmission occasionally result in redundant samples for a particular time that disagree. Some such erroneous samples likely remain, and may be detected by an unreasonable departure from the same sensor 12 minutes before and after. Biofouling was generally found to not be too serious in the Arctic, but is occasionally is an issue for shallow sensor levels during the summer. Buoy 12798 is a bizarre special case. That buoy's bottom pressure sensor abruptly failed on 8 March 1994 (day 67) and abruptly began reporting again on 26 May 1994 (day 146). Since pressure at level 6 is critical for calculating the depths of all sensor levels, the ocean sensors for this period are unavailable for this period. File Hydro.12798.9403 ends with the last pressure sample, file Hydro.12798.9404 is missing completely, and Hydro.12798.9405 picks up when the depth sensor wakes up. Here is a bit larger sample from the start of Buoy 12795: 1993 296.917 75.363 216.855 1011.520 -22.800 12795 9.7993 -1.5480 22.8280 28.2796 22.7169 40.3643 -1.2590 24.3740 30.0738 24.1678 70.6376 -1.0690 25.8770 31.8952 25.6394 121.2271 -1.4070 26.1710 32.6299 26.2447 203.4886 -1.4890 26.6340 33.3065 26.7962 306.8454 -0.2650 28.6420 34.5883 27.7879 1993 296.933 75.363 216.857 1011.760 -22.800 12795 9.7993 -1.5480 22.8280 28.2796 22.7169 40.3643 -1.2680 24.3650 30.0707 24.1655 70.6376 -1.0830 25.8670 31.8965 25.6409 121.2271 -1.3990 26.1770 32.6294 26.2440 203.4886 -1.4870 26.6353 33.3061 26.7959 306.8454 -0.2640 28.6420 34.5872 27.7870 1993 296.942 75.363 216.858 1011.800 -23.200 12795 9.7993 -1.5470 22.8920 28.3654 22.7866 40.3643 -1.2660 24.3750 30.0822 24.1748 70.6376 -1.1010 25.7990 31.8234 25.5822 121.2271 -1.4040 26.1770 32.6349 26.2486 203.4886 -1.4860 26.6360 33.3060 26.7957 306.8454 -0.2643 28.6430 34.5889 27.7884 1993 296.958 75.363 216.860 1011.920 -23.600 12795 9.7939 -1.5490 22.8280 28.2805 22.7177 40.3363 -1.2660 24.3600 30.0619 24.1583 70.6201 -1.1110 25.8760 31.9385 25.6757 121.2271 -1.4140 26.1650 32.6294 26.2444 203.4886 -1.4870 26.6290 33.2974 26.7888 306.8454 -0.2650 28.6420 34.5883 27.7879 1993 296.975 75.363 216.862 1012.000 -25.200 12795 9.7884 -1.5497 22.8280 28.2812 22.7183 40.3079 -1.2700 24.3980 30.1174 24.2034 70.5774 -1.1210 25.8640 31.9329 25.6714 121.1604 -1.4270 26.1623 32.6399 26.2533 203.4010 -1.4890 26.6317 33.3034 26.7937 306.7316 -0.3250 28.6420 34.6565 27.8459 1993 296.983 75.363 216.863 1012.080 -23.600 12795 9.7857 -1.5500 22.8280 28.2815 22.7185 40.2940 -1.2720 24.3430 30.0450 24.1447 70.5563 -1.1260 25.8580 31.9301 25.6693 121.1275 -1.4110 26.1610 32.6207 26.2372 203.3578 -1.4900 26.6330 33.3064 26.7961 306.6755 -0.2660 28.6420 34.5896 27.7890 and so on... 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