README FILE FOR BERING STRAIT MOORING DATA ANNUAL & MONTHLY MEAN PRODUCTS 1990-2022 vers May 2023 ============================================================================= 12345678901234567890123456789012345678901234567890123456789012345678901234567 Bering Strait Annual and Monthly means Sept 1990 - August 2022 This is an archive of data products from moorings deployed in the Bering Strait from Fall 1990 and to Summer 2022. The mooring data themselves (typically hourly) are archived separately. These products allow the user quick access to consitent and quality controlled annual and monthly means of the mean water properties in and fluxes (volume, heat relative to -1.9deg C, and freshwater relative to 34.8psu) through the strait. This product is updated periodically. For the latest version, visit our website psc.apl.washington.edu/BeringStrait.html and navigate to 'Data access', then the mooring data page, and then data products. Creation of this product version was supported by the NSF-Arctic Observing Network award PLR-1758565 (PIs: Woodgate and Peralta-Ferriz). For an overview of previous and on-going Bering Strait mooring work, please see http://psc.apl.washington.edu/BeringStrait.html. Products are based on data from 4 mooring sites in the Bering Strait region, = 3 sites in the 2 channels of the ~85km wide strait itself,viz: A1 - in the center of the western (Russian) channel A2 - in the center of the eastern (US) channel A4 - in the east of the eastern channel (to measure the Alaskan Coastal Current (ACC)) and = 1 site A3 - in the center of the strait and ~35km north of the strait proper at a site which has been shown to give a useful average of the flow through the two channels (Woodgate, 2018). Although in some years other moorings have been deployed in the strait, these 4 sites are those with the most years of deployment. Moorings are usually serviced annually, some time between July and October, and may move a few 10s of m, (or very rarely ~100m). Positions are approximately: A1 = 65deg 54.0min N, 169deg 26.0min W in ~51m of water A2 = 65deg 46.9min N, 168deg 34.1min W in ~55m of water A4 = 65deg 44.4min N, 168deg 15.8min W in ~48m of water A3 = 66deg 19.6min N, 168deg 57.5min W in ~57m of water Because of seasonal sea ice in the region in winter, all instrumentation is subsurface. These products use data from - Velocity sensors (Aanderaa RCM and (since 2007) RDI workhorse ADCP) - Temperature, salinity and pressure sensors, primarily from Seabird (SBE16 or 37) but occasionally in the 1990s also from Aanderaa. These instruments are positioned in the lower layer of the typically two layer water column, ~15-20m off the bottom. To ensure consistency with the early part of the record that only used single point current meters, only a single bin of the ADCP record is used here. The data presented are the means of the calibrated data (typically interpolated in time between the pre-cruise and post-cruise calibrations from the manufacturer). In addition, further data products are presented which correct for: 1) a change in depth of the velocity measurement used, due to changes in mooring design to accomodate ADCPs in ~ 2007. 2) salinity drift and anomaly issues due to biofouling. Errors cited are standard errors in the monthly or annual mean, calculated using an integral timescale to determine the relevant degrees of freedom. These errors are always greater than the measurement accuracy of the instrument. See Woodgate 2018 for details and discussions of all these corrections. All files are ascii with their own headers. Please read the headers. NaN indicates insufficient data available to compute a meaningful mean. == The following Annual mean data are presented: BeringStrait_Annualmeans_TEMPERATURE_May2023.txt - separate columns for each of the 4 moorings. BeringStrait_Annualmeans_SALINITY_May2023.txt - separate columns for each of the 4 moorings. - extra columns for A3 giving also data corrected for biofouling BeringStrait_Annualmeans_TRANSPORT_May2023.txt - estimate of total volume transport through the strait as calculated from - mooring A2 - mooring A3 - mooring A3 with corrections for instrument depths and data dropouts - does NOT include a correction for the ACC (which likely contributes an additional ~0.1Sv) - for our best estimate of the flow through the strait use A3estv4 (penultimate column) with uncertainty estimate A3estv4err (last column) and add ~0.1Sv for the ACC. BeringStrait_Annualmeans_HEAT_May2023.txt - estimate of oceanic heat flux through the strait relative to -1.9degC with versions calculated from - hourly A3 data - hourly A3 data corrected for instrument depths and data dropouts (A3v4) - extra columns for low (Hoff1) and high (Hoff2) estimated corrections for the combined effects of seasonal stratification and the ACC. - final two columns present the A3v4 data combined with the low or high stratification/ACC corrections BeringStrait_Annualmeans_FW_May2023.txt - estimate of oceanic freshwater flux through the strait relative to -34.8psu with versions calculated from - hourly A3 data - hourly A3 data corrected for instrument depths and data dropouts (A3v4) and biofouling - extra columns for low (FWoff1) and high (FWoff2) estimated corrections for the combined effects of seasonal stratification and the ACC. - final two columns present the A3 velocity and biofouling corrected data combined with the low or high stratification/ACC corrections BeringStrait_Annualmeans_TRANSPORTwithPHWindFit_May2023.txt - estimate of total volume flux through the strait calculated from A3 hourly data corrected for instrument depths and data dropouts (A3v4) (as in files above) - separation of this into the pressure head and wind terms as per Woodgate 2018. == The following Monthly mean data are presented BeringStrait_Monthlymeans_TEMPERATURE_May2023.txt - from mooring A3 BeringStrait_Monthlymeans_SALINITY_May2023.txt - from mooring A3 - with extra columns for data corrected for biofouling BeringStrait_Monthlymeans_VVEL_May2023.txt - from mooring A3 - with extra columns for data corrected for instrument depths and data dropouts BeringStrait_Monthlymeans_TRANSPORT_May2023.txt - from mooring A3 - with extra columns for data corrected for instrument depths and data dropouts (without corrections for the ACC - See Woodgate 2018 for ACC correction climatology) BeringStrait_Monthlymeans_HEAT_May2023.txt - estimate of oceanic heat flux through the strait relative to -1.9degC with versions calculated from - hourly A3 data - hourly A3 data corrected for instrument depths and data dropouts (A3v4) (without corrections for the ACC - See Woodgate 2018 for ACC correction climatology) BeringStrait_Monthlymeans_FW_May2023.txt - estimate of oceanic freshwater flux through the strait relative to -34.8psu with versions calculated from - hourly A3 data - hourly A3 data corrected for instrument depths and data dropouts (A3v4) and biofouling (without corrections for the ACC - See Woodgate 2018 for ACC correction climatology) BeringStrait_Monthlymeans_PH_May2023.txt - estimate of the pressure head driven component of the flow with versions calculated from - hourly A3 data - hourly A3 data corrected for instrument depths and data dropouts (A3v4) See Woodgate 2018 for details. ----------------------------------------------------------------------------- For details of the measurements and their interpretation, please see: Woodgate, R.A., K.M.Stafford and F.G.Prahl (2015) A synthesis of year-round interdisciplinary mooring measurements in the Bering Strait (1990-2014) and the RUSALCA years (2004-2011), Oceanography 28(3):46-67, doi:10.5670/oceanog.2015.57 and Woodgate, R.A., 2018, Increases in the Pacific inflow to the Arctic from 1990 to 2015, and insights into seasonal trends and driving mechanisms from year-round Bering Strait mooring data, Progress in Oceanography, 160, 124-154, doi:10.1016/j.pocean.2017.12.007. Please use both 2015 and 2018 citations for these data. ----------------------------------------------------------------------------- For an overview of cruises and project, please see: http://psc.apl.washington.edu/BeringStrait.html For relevant papers, 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. Woodgate, R. A., T. Weingartner, and R. Lindsay (2010), The 2007 Bering Strait oceanic heat flux and anomalous Arctic sea-ice retreat, Geophys. Res. Lett., 37, L01602, doi:10.1029/2009GL041621. Woodgate, R.A., T. Weingartner, and R. Lindsay (2012), Observed increases in Bering Strait oceanic fluxes from the Pacific to the Arctic from 2001 to 2011 and their impacts on the Arctic Ocean water column, Geophys. Res. Lett., 39, L24603, doi:10.1029/2012GL054092. Woodgate, R.A., (2018), Increases in the Pacific inflow to the Arctic from 1990 to 2015, and insights into seasonal trends and driving mechanisms from year-round Bering Strait mooring data, Progress in Oceanography, 160, 124-154, doi:10.1016/j.pocean.2017.12.007. Woodgate, R.A., and C.Peralta-Ferriz, (2021), Warming and Freshening of the Pacific Inflow to the Arctic from 1990-2019 implying dramatic shoaling in Pacific Winter Water ventilation of the Arctic water column, Geophysical Research Letters, doi:10.1029/2021GL092528 For queries, please contact: Rebecca Woodgate woodgate@uw.edu (206) 221-3268 Polar Science Center, Applied Physics Lab, University of Washington 1013 NE 40th, Seattle, WA 98105-6698 USA ------------------------------------------------------------------------------