uid=MCM,o=LTER,dc=ecoinformatics,dc=org all public read ADCP-ID.75 McMurdo Dry Valleys LTER: 2012-2013 Sub-ice Current Velocities Recorded with an Acoustic Doppler Current Profiler McMurdo Dry Valleys LTER http://mcmlter.org/ Devin Castendyk Castendn@oneonta.edu McMurdo Dry Valleys LTER http://mcmlter.org/ Inigo San Gil
2013-01-01 English
Between 26 November 2012 and 22 January 2013, a SonTek Argonaut-XR 1.5 MHz Acoustic Doppler Current Profiler (ADCP) was fixed at the bottom of the Limno Sampling Hole in Lake Hoare, looking downward through the water column. Every 30 seconds, the ADCP measured horizontal and vertical current velocities in six, 50-cm-thick cells between 0.5 and 3.5 m below the lake ice. The observation interval became deeper over time as the ADCP platform melted into the lake ice and the lake ice thinned. Data collected from 26 to 30 November represent pre-discharge data when wind and solar radiation were the only forces acting on the lake. Data from 30 November to 8 December transition from pre-discharge to spring freshet conditions on 6 December. Spring freshet was the most dynamic period observed with highest velocities recorded. Data from 8 to 13 December transitioned from the end of spring freshet on 10 December to summer diurnal discharge conditions. Data from the remaining datasets, 13 to 22 December, 22 to 29 December, 29 December to 6 January, 6 to 13 January, and 13 to 22 January, reflect conditions during summer diurnal stream discharge, especially data from 29 December to 6 January. From these observations, solar radiation, wind, glacial runoff during spring
http://gar.lternet.edu/content/2012-2013-sub-ice-current-velocities-recorded-acoustic-doppler-current-profiler Lake Hoare occupies a narrower portion of the Taylor Valley, dammed by the Canada Glacier. It would drain almost completely without this dam. There are a number of islands which may be related to an old terminal of Canada Glacier. The lake is fed primarily from direct runoff from the glacier, as well as meltwater streams. (Lake level rose ~1.5 m between 1972 and 1996). There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 15 Maximum Length (km): 4.2 Maximum Width (km): 1 Maximum Depth (m): 34 Surface Area (km^2): 1.94 Ice Thickness Average Surface (m): 3.1 - 5.5 Volume (m^3 * 10^6): 17.5 162.784423828125 162.935836791992 -77.623085021973 -77.639259338379 73 73 meter 2012-01-01 2013-12-31 o collect a long duration dataset of sub-ice currents spanning pre-discharge, spring freshet, and diurnal discharge events in order to identify the causes of sub-ice currents and seiche activity observed in 2009-2010. McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER LIMNO_ANCILLARY_ADCP2 LIMNO_ANCILLARY_ADCP2.csv 76606357 28 1 \n column , " http://gar.lternet.edu/sites/default/files/LIMNO_ANCILLARY_ADCP2.csv DATASET_CODE DATASET_CODE A code used to identify the entity table name and create lists of data holdings string A code used to identify the entity table name and create lists of data holdings LOCATION NAME LOCATION NAME Name of lake where measurement was made string Name of lake where measurement was made LOCATION CODE LOCATION CODE Location in the lake where measurement was made string Location in the lake where measurement was made DATE_TIME Attribute Label Date on which sample was gathered date mm/dd/yy H:M:S Required entry None given SAMPLE_ID SAMPLE_ID An internal identifier for the record string An internal identifier for the record MIN_DEPTH (m) MIN_DEPTH (m) Minimum Depth value for the measurement range meter real MAX_DEPTH (m) MAX_DEPTH (m) Maximum Depth value for the measurement range meter real Required entry None given Vx (cm/s) Vx (cm/s) the velocity component for the X-axis - East-West, where positive values mean fluid moving towards the west centimetersPerSecond 0.5 real Required entry None given Vy (cm/s) Vy (cm/s) the velocity component for the Y-axis - North-South, where positive values mean fluid moving towards the north centimetersPerSecond 0.5 real Required entry None given Vz (cm/s) Vz (cm/s) the velocity component for the Z-axis - Bottom-Up, where positive values mean fluid moving towards the bottom (down) centimetersPerSecond 0.5 real Required entry None given SPD_XY Speed_xy (cm/s) the magnitude of the velocity (the speed) on the horizontal plane for the x-axis centimetersPerSecond 0.5 real Required entry None given Dir Dir THe orientation of the velocity vector on the horizontal plane degree real Required entry None given