README FILE FOR BERING STRAIT MOORING DATA 12 February 2007 ================================================================================ 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Bering Strait Moorings 2005 This is an archive of data from moorings deployed in Bering Strait from summer 2005 to summer 2006. The mooring program was a one-year deployment sponsored by NSF's Office of Polar Programs (ARC-0611967, Woodgate). This data set is a continuation of a time series started in 1990. For further details, see http://psc.apl.washington.edu/BeringStrait.html Bering Strait is bisected by the Russia-U.S. Exclusive Economic Zone (EEZ) boundary, requiring specific permission to work in the western channel of the strait. Although prior measurements exist from the western channel, this present data set is only from US waters. Note that in 2005, moorings were also placed in the Russian channel under NOAA sponsorship (PIs: Weingartner and Whitledge, UAF). Mooring location A2 is in the middle of the eastern (Alaskan side) channel. Mooring location A3 is just north of the strait, immediately east of the EEZ line. Experience has shown that site A3 samples both eastern and western channel water. Mooring location A4 is close to the Alaskan coast and allows measurement of the Alaska Coastal Current. Depth in Bering Strait is approximately 50-55 m. Moorings A2 and A3 carried an Aanderaa RCM current meter at about 47 m and a Sea-Bird Temperature-Conductivity recorder 1 m deeper. Mooring A4 carried an upward-looking ADCP at about 39 m and a Sea-Bird Temperature-Conductivity recorder 2 m deeper. Moorings were deployed from summer 2005 to summer 2006. Each data file contains the data from one instrument-year. The listed year is the year in which the mooring was deployed. Moorings A2 and A3 were equipped with an upward-looking sonar (PI: Moritz, UW), but these data are not included in this archive. The Sea-Bird instrument at Mooring A2 (indicated as wOptical in the following list) was equipped with optical sensors for fluorescence, turbidity and PAR (Photosynthetically Active Radiation) (PI: Whitledge, UAF). These data are included in this archive, although only minimal quality control of the data has been performed, as noted in the header files. This leaves to the user final judgments about which portions of the optical records are usable. Very basic tests suggest the PAR data is likely unusable. The A2 Mooring was also equipped with NAS-2E nitrate analyzer (PI: Whitledge, UAF), but these data are not included in this archive. ID Year - Latitude Longitude - Instrument S/N - Inst. Water Depth Depth A2-05 2005 - 65 46.78 N 168 34.50 W - RCM-7 11454 - 46m 55m A2-05 2005 - 65 46.78 N 168 34.50 W - SBE-16wOptics 1717 - 47m 55m A3-05 2005 - 66 19.54 N 168 58.02 W - RCM-11 0099 - 49m 57m A3-05 2005 - 66 19.54 N 168 58.02 W - SBE-16 1225 - 50m 57m A4-05 2005 - 65 44.73 N 168 15.68 W - ADCP 1495 - 39m 48m A4-05 2005 - 65 44.73 N 168 15.68 W - SBE-16 0008 - 41m 48m For RCMs and SBEs, data are recorded in one file per instrument per year. with naming convention: BeringStrait_yyyy_ID_III#####.txt yyyy=Deployment year; ID=mooring ID; III=instrument type; #####=serial number. For the ADCPs, there are multiple files per instrument. BeringStrait_yyyy__ID_ADCP#####.000 = Binary data downloaded from the ADCP The remainder are ASCII conversions of this file, corrected for clock drift and magnetic declination. BeringStrait_yyyy__ID_#####.btm = ASCII bottom track data (including ice range and velocity) BeringStrait_yyyy__ID_#####.ins = ASCII instrument data (e.g. heading, pitch, roll, temperature) BeringStrait_yyyy__ID_#####_bin01.rdat = ASCII water velocity data from Bin 1 BeringStrait_yyyy__ID_#####.bin02.rdat = ASCII water velocity data from Bin 2 etc. (Bin depths are given in the data files) Header information is included in each data file. ------------------------------------------------------------------------------- For details of the measurements and their interpretation, please see: Roach, A.T., K. Aagaard, C. H. Pease, S.A. Salo, T. Weingartner, V. Pavlov, and M. Kulakov (1995) Direct measurements of transport and water properties through Bering Strait, J. Geophys. Res., 100, 18,443-18,457. Woodgate, R.A., and K. Aagaard (2005) Revising the Bering Strait freshwater flux into the Arctic Ocean, Geophys. Res. Lett., 32, L02602, doi:10.1029/2004GL021747. Woodgate, R.A., K. Aagaard, and T. Weingartner (2005) Monthly temperature, salinity, and transport variability of the Bering Strait throughflow, Geophys. Res. Lett., 32, No. 4, L04601, doi:10.1029/2004GL021880. Woodgate, R. A., K. Aagaard, and T. J. Weingartner (2005) A year in the physical oceanography of the Chukchi Sea: Moored measurements from autumn 1990-1991,Deep-Sea Res., Part II, 52, 3116-3149, doi: 10.1016/j.dsr2.2005.10.016. Woodgate, R. A., K. Aagaard, and T. J. Weingartner (2006) Interannual changes in the Bering Strait fluxes of volume, heat and freshwater between 1991 and 2004, Geophys. Res. Lett., 33, L15609, doi:10.1029/2006GL026931. Aagaard, K., T.J.Weingartner, S.L. Danielson, R.A. Woodgate, G.C.Johnson, T.E.Whitledge (2006), Some controls on flow and salinity in Bering Strait, Geophys. Res. Lett., 33, L19602, doi:10.1029/2006GL026612. Serreze, M.C., A.P. Barrett, A.G.Slater, R.A.Woodgate K.Aagaard, R.Lammers, M.Steele, R.Moritz, M.Meredith, and C.Lee (2006) The Large-scale Freshwater Cycle of the Arctic, J. Geophys. Res., 111, C11010, doi:10.1029/2005JC003424. For an overview, please see: http://psc.apl.washington.edu/BeringStrait.html For queries, please contact: Rebecca Woodgate woodgate@apl.washington.edu (206) 221-3268 Polar Science Center, Applied Physics Lab, University of Washington 1013 NE 40th, Seattle, WA 98105-6698 USA FAX (206) 616-3142 ------------------------------------------------------------------------------ Meta data ========= 1) Platform: Subsurface oceanographic moorings 2) Project title: Bering Strait 3) Data collection dates: summer 2005 to summer 2006 4) PI: Rebecca Woodgate (woodgate@apl.washington.edu) 5) Data collection method: Year-round moorings carrying - Aanderaa recording current meters (RCM) - Sea-Bird temperature/conductivity recorders (SBE) - RDI 300kHz Workhorse Acoustic Doppler Current Profilers (ADCP) 6) Data calibration method: Timestamps have been corrected for observed instrument clock drift. All times are given in GMT. For RCMs and SBEs, calibration coefficients are given in header file. RCMs: Pre and post calibrated by the manufacturer (AA), by ESI, or at APL/UW. - pre-calibration used for data reduction, except for direction which uses post-calibration - as indicated in the headers, direction has been corrected by lookup table rather than fitted polynomial - direction corrected to true north, magnetic declination used is cited in the header - RCM11 data has been corrected for the temperature/pressure variability of the speed of sound using temperature data from the RCM SBEs: Generallly pre and post calibrated by the manufacturer. - pre and post calibrations linearly time-weighted through the deployment. - pre calibration only available for 1717 sensor with optics ADCPS: Tested by APL/manufacturer pre and post deployment. - compass calibrated as per manufacturer's specifications in Seattle prior to deployment. Estimated compass error is included in the header file. - direction corrected to true north, magnetic declination used is cited in the header. - data requiring speed of sound in water is corrected by the ADCP using the water temperature measured by the ADCP. - intensity of returned signals is not specially calibrated. 7) Instrumentation used: Aanderaa current meters RCM-7 and -11 -sampling hourly. Sea-Bird SBE16 recorders (some with optics sensors) sampling at 60 min interval. RDI 300 kHz Workhorse ADCP, recording every 30min (data averaged over the time interval) 8) Quality control procedures: Quality control variously provided by Rebecca Woodgate. In general, records are very clean and no despiking has been performed. RCM and SBE data checked against each other where possible. RCM-11 measurements of water velocity depend on the speed of sound in water. The manufacturer's default is to assume a sound speed of 1500 m/s. In data processing, we use RCM-11 temperature and mooring information of instrument depth to obtain a more accurate speed of sound at the RCM-11 during deployment, and thus recompute the water velocity (Cor Speed). SBE optical data is not quality controlled and should be treated with caution, especially the PAR data. ADCP data rely on ADCP internal temperature for speed of sound corrections. ADCP Data files are included for all bins up to the surface although bins near the surface contain much larger errors (likely due to surface effects) and should be treated with caution. The following are the shallowest good bins: last bin < 8 errors last bin < 100 errors A4-05 - bin 10, ~ 17m bin 12, ~ 13m 9) Data format: RCM and SBE data - ASCII, format given in individual headers ADCP data - BINARY download file from ADCP and ASCII conversion of these files 10) Data collection problems: SBE1225 on mooring A3-05 shows significant (~0.1 psu) change in calibration between pre and post calibrations. RCM11454 shows a 2-3 deg offset in compass calibration between 2004 and 2006. Instrument fouling is an concern in Bering Strait deployments, and precautions have been taken to mitigate problems. Fouling of mechanical rotors (RCM-7) has been a regular problem in the past. The present data show little obvious evidence of this problem. Standard anti-fouling techniques are used for the SBE instruments, and this has been generally successful for the temperature and salinity records. The optical sensor suite mounted on the Sea-Bird instruments at Mooring A3 consisted of one Chelsea/Seatech/Wetlabs Transmissometer, one WETLabs WETStar Fluorometer, and one LI-COR PAR/irradiance sensor, although the PAR data in this archive is likely unusable. It appears that records from these instruments are increasingly degraded by biofouling through the deployment year. However, records in this archive are unmodified, and the user is cautioned to use these data with care. Photographic documentation of biofouling on recovery is available via cruise reports and the Bering Strait website: http://psc.apl.washington.edu/BeringStrait.html. Generally, fluorescence seems to have survived the biofouling rather better than the other measurements. The transmissometer did not have shutters or wipers to clean the lenses, and generally suffered most from biofouling. The entire PAR record is highly suspect, showing no discernible difference between day and night, or season. 11) Other related data sets: This data set is a continuation of mooring measurements made in the Bering Strait almost continuously since 1990. Mooring data from 1990 to 2002, and 2002 to 2004 have already been archived via the SBI project, managed by JOSS/EOS. For details see http://psc.apl.washington.edu/BeringStrait.html http://www.eol.ucar.edu/projects/sbi/ http://sbi.utk.edu/ Since 2000, CTD sections have been run in the Bering Strait on the mooring cruises. This data is also accessible via the http links above. 12) Conditions for use or citation: Data freely available Please, as a courtesy, contact the PIs before using these data 13) Data qualifications or warnings: See also Data collection problems. The temperature (T) and conductivity (C) recorded by a RCM are significantly less accurate than those recorded by a SBE. In most instances, a SBE was located very close to a RCM, so that the former would provide the record of choice for T and C even when the RCM measured both parameters. For data issues relevant to a specific deployment, see the individual headers. In general: RCM data: Standard Aanderaa limitations apply - estimated accuracy 2 cm/s in speed, 5 deg in direction, 0.05 deg C in temperature, >= 0.01 S/m in conductivity (corresponds to >= 0.2 psu in salinity). SBE data: Standard Sea-Bird limitations apply - estimated accuracy 0.02 deg C, 0.0012 S/m (corresponding to 0.02 psu), and < 1 db. - see header files for difference between pre and post calibration ADCP data: Standard RDI limitations apply - estimated accuracy < 0.5 cm/s in speed for water velocities (115 pings per ensemble) Estimated errors (given in the data files) vary with bin and time < 1 cm/s in speed for ice velocities (5 pings per ensemble) Estimated errors (given in the data files) vary with time < 1 deg in direction (see header files) range to ice only accurate to 1% of range to surface (i.e. ~ 0.4 m) < 0.4 deg C in temperature Optical Sensor Data (fluorescence, beam transmission, beam attenuation, and PAR): These unmodified records are included, although no quality control of the data has been performed, as noted in the header files. This leaves final judgments about record quality to the user. 14) Grant numbers: Mooring sponsorship came from NSF (ARC-0611967, Woodgate) 15) Sample repository locations: National Ocean Data Center (http://www.nodc.noaa.gov) University of Washington (http://psc.apl.washington.edu/HLD) ============================================================================== FILE LISTING ============= This archive contains 33 data files, i.e., = 1 readme file (this file) Bering_Strait_Moorings_2005_ReadMe.txt = 2 cruise reports e.g. UWmooringreportSWL2005July.pdf = 2 RCM files e.g., BeringStrait_2005_A2_rcm11454.txt = 3 SBE files e.g., BeringStrait_2005_A2_sbe1717.txt The remaining 25 files relate to the ADCP. Specifically, there is: = 1 ADCP binary data file i.e., BeringStrait_2005_A4_ADCP01495.000 = 1 ADCP ascii files of bottom track data i.e., BeringStrait_2005_A4_01495.btm = 1 ADCP ascii files of instrument data i.e., BeringStrait_2005_A4_01495.ins = 22 ADCP ascii files of water data e.g., BeringStrait_2005_A4_01495_bin01.rdat The full file listing is: Name Size/bytes ========================== ========== Bering_Strait_Moorings_2005_ReadMe.txt 17691 BeringStrait_2005_A2_rcm11454.txt 765401 BeringStrait_2005_A3_rcm00099.txt 720280 BeringStrait_2005_A2_sbe1717.txt 1064602 BeringStrait_2005_A3_sbe1225.txt 747056 BeringStrait_2005_A4_sbe0008.txt 747056 BeringStrait_2005_A4_ADCP01495.000 12046221 BeringStrait_2005_A4_01495.btm 4197626 BeringStrait_2005_A4_01495.ins 2128512 BeringStrait_2005_A4_01495_bin01.rdat 3163074 BeringStrait_2005_A4_01495_bin02.rdat 3163074 BeringStrait_2005_A4_01495_bin03.rdat 3163074 BeringStrait_2005_A4_01495_bin04.rdat 3163074 BeringStrait_2005_A4_01495_bin05.rdat 3163074 BeringStrait_2005_A4_01495_bin06.rdat 3163074 BeringStrait_2005_A4_01495_bin07.rdat 3163074 BeringStrait_2005_A4_01495_bin08.rdat 3163074 BeringStrait_2005_A4_01495_bin09.rdat 3163074 BeringStrait_2005_A4_01495_bin10.rdat 3163074 BeringStrait_2005_A4_01495_bin11.rdat 3163074 BeringStrait_2005_A4_01495_bin12.rdat 3163074 BeringStrait_2005_A4_01495_bin13.rdat 3163074 BeringStrait_2005_A4_01495_bin14.rdat 3163074 BeringStrait_2005_A4_01495_bin15.rdat 3163074 BeringStrait_2005_A4_01495_bin16.rdat 3163074 BeringStrait_2005_A4_01495_bin17.rdat 3163074 BeringStrait_2005_A4_01495_bin18.rdat 3163074 BeringStrait_2005_A4_01495_bin19.rdat 3163074 BeringStrait_2005_A4_01495_bin20.rdat 3163074 BeringStrait_2005_A4_01495_bin21.rdat 3163074 BeringStrait_2005_A4_01495_bin22.rdat 3163074 UWmooringreportSWL2005July.pdf 1648339 UWmooringreportSWL2006July.pdf 1789726 ==============================================================================