Data summary
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Data summary |
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| This is a brief summary of the snow and ice
data files that are available on this CD-ROM. For each data set, information
is presented on the instrument used, the uncertainty, the file format, and
a point of contact. Links are provided to a more
detailed description of each data set. Information of the directory
structure is also available.
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Snow: Intensive observation period
Instrument: Assorted Uncertainty: Varied; check individual files File format: Files are in the directory SNOWIOP Contacts: msturm@crrel.usace.army.mil
Snow: Time series surveys
Instrument: Ski pole, magnaprobe Uncertainty: 1 cm File format: A directory SNOWSURV contains the subdirectories for each snow line. Results from each snow survey is in a separate file. All files are ASCII comma separated variable format. The first line of the file is the date, and the second is the column headers for position along the line (m) and snow depth (cm). Then there is a string of position-depth pairs. The filename convention is SXXXDDMM, where S stands for snow, XXX is the individual code for each snow line, DD is the day, and MM is the month. The codes are MLE (Mainline) BLT( Baltimore), ATL (Atlanta), TUK (Tuk), MLS (Mainline spur), and ABS (lbedo spur). Contact: perovich@crrel.usace.army.mil
Optics: Total albedo Instrument: Kipp & Zonen albedometer. Uncertainty: 0.01 File format: Files are in the subdirectory TOTALB of the OPTICS directory. The filename convention is ALBTmmdd.csv where mm is month and dd is day. The file ALBTMay.csv has all the data from May 1998, and the file ALBTsum.csv has all the data from June 1998 through September 1998. The first line of the file has the date. In subsequent lines, the first column is the position along the albedo line followed by the albedo for each date. Contact: perovich@crrel.usace.army.mil
Optics: Spectral albedo Instrument: Spectron Engineering SE-590 spectroradiometer Uncertainty: 0.01 File format: Files are in subdirectory SPECALB of the OPTICS directory. ASCII files containing spectral albedo observations along the albedo line. The filename convention is ALBxmmdd.csv where mm is month, dd is day and x has three options: U for ultraviolet (300-400 nm), V for visible (400-1000 nm), and I for infrared (1000-2200 nm). The first line of these files has the date, the second the positions along the albedo line, and the following lines contain wavelength followed by albedos along the line. File ALBVmisc.csv contains miscellaneous spectral albedos. Contacts: perovich@crrel.usace.army.mil tcg@atmos.washington.edu
Optics: Transmittance Instrument: Analytical Spectral Devices Ice-1 spectroradiometer Uncertainty: Variable, check individual files. File format: Files are in the subdirectory TRANS of the OPTICS directory. Contact: perovich@crrel.usace.army.mil
Aerial: Aerial photographs Instrument: Nikon 35 mm camera Uncertainty: Not-applicable File format: There were 14 helo photograph flights, 12 survey flights and 2 mosaic flights. The more than 3000 aerial photographs from these flights have been archived on a series of CD-ROMs. Contacts: wtucker@crrel.usace.army.mil perovich@crrel.army.mil
Aerial: KT-19 Instrument: Heimann Kt-19 infrared radiometer recording in a wavelength band of 8-14 microns Uncertainty: The relative radiometric accuracy of the measurements is approximately ± 1oC. File format: The data files are designated as KT19mmdd.csv, where mm denotes the month and dd the day. Each file contains observed infrared brightness temperature in degrees Celsius versus the local time in decimal hours. Contact: tcg@atmos.washington.edu
Mass balance: Ice temperature
Instrument: Thermistor strings (YSI44080) Uncertainty: Temperatures are accurate to 0.1oC for most of the year. There were some problems during summer melt due to solar heating of the probes. File format: The temperature data from the thermistor strings is in the directory THERM. There is a separate file for each temperature site. All files are ASCII comma separated variable format. The first row of the file is the position of the thermistors when installed. The ice surface is zero with postive positions above the surface and negative below. Subseqent rows have the date-time in the first column and temperatures in the following columns. Contacts: belder@crrel.usace.army.mil perovich@crrel.usace.army.mil |
Mass balance: Thickness gauges
Instrument: Ablation stake, thickness gauge Uncertainty: Variable, +/- 1 cm for well behaved gauges. File format: Files are in directory GAUGES. The data in the file are date, P, Q, theta, and sensor temperature. Contacts: perovich@crrel.usace.army.mil tcg@atmos.washington.edu
Mass balance: Melt ponds
Instrument: Survey lines used 100 m tape and meter stick. Uncertainty: +/- 1 cm File format: Files are in directory POND. Albedo line results have names of the form ALMPmmdd.csv where mm is the month and dd is the day. Contacts: jrichtermenge@crrel.usace.army.mil hajo@gi.uaf.edu
Mass balance: Ridges
Instrument: Survey lines, meterstick Uncertainty: +/- 1-2 cm File format: There is a file called SurfRdg in the mass directory. It contains the time series of summer surface ablation profiles of a new ridge. Contact: jrichtermenge@crrel.usace.army.mil
Mass balance: EM-31
Instrument: EM-31 Accuracy: Thickness approximately 0.05 m for 2-m thick ice.Co-location error between the same point at different dates is less than <2 m for all SEA, TP, and APL profiles, and less than <5 m for the ATL and MAI profiles. File convention: There is a directory EM31 with subdirectories for each site. The filename indicates the day of the year (1998) of the profile measurements (digits 3-5) and a three-letter code (digits 6- 8) identifies the location of the profile. These are: APL or ALn, where n is an integer from 1 to 3: Sarah's Lake. Three parallel profiles have been measured perpendicular to the lead's edge. Profile AL1 is at the center and originates at ablation gauge 300 (originally about 5 m away from the lead's edge). Profile AL2 is 10 m closer towards the ship and profile AL3 is 15 m further away from the ship. Contacts: hajo@gi.uaf.edu wtucker@crrel.usace.army.mil
Mass balance: Water level recorder
Instrument: Paroscientific pressure sensor and Global Water Level Logger, Model WL14. Uncertainty: The absolute accuracy of the readings was approximately 10 mm, but the relative accuracy was better than 0.3 mm.. File format: There are 2 files, WLRQUE.CSV and WRLDOG.CSV, in ASCII comma separated variable format in the directory WATERLEV. Contacts: tcg@atmos.washington.edu
Ancillary: Ice physical properties
Instrument: YSI model 30 conductivity sonde (salinity) Uncertainty: <0.02 psu or <1 % of the bulk salinity, whichever is larger File format: All files are ASCII comma separated variable format. The file name indicates the day of the year in 1998 on which sampling took place (digits 2-4) as well as the sampling location identified by a three-letter code (digits 5-7). The first data column indicates the midpoint depth of the ice sample, the second column the salinity specified in practical salinity units (psu). Salinities below the detection limit (0.01) are listed as zero. If stable-isotope data are available, they are listed in the third column in parts per thousand according to the delta-18-O notation. The three-letter site indicators are: APL (Sarah’s Lake), BLB (Blue Bio Lead between i and Blue Bio Containers), CHT (final location of CRREL Hut), LSH (Lake SHEBA beyond Blue Bio Containers), PIT ( Pittsburgh), QUE (Quebec), RDG (level ice near the intersection between The Ridge and the main mass balance profile), SDC (towards Sediment City). All cores have been drilled in level ice. Contacts: wtucker@crrel.usace.army.mil hajo.eicken@gi.alaska.edu
Ancillary: Internal ice stress
Instrument: Geokon vibrating wire stress sensor Uncertainty: 15%, 20 kPa resolution; Direction: 2.5 degrees; Instrument temperature sensitivity: 5kPa/oC File format: All files are ASCII comma separated variable format. In directory STRESS the filename convention is STRXXX where XXX is the code for the experiment site: MIL (Milford), REH (Rehoboth), DOV (Dover), DEL (Delaware), WIL (Wilminton), BAL (Baltimore), RM9 (remote site 9), and RM11 (remote site 11). Contact: jrichtermenge@crrel.usace.army.mil
Ancillary: Ice topography
Instrument: Laser leveling instrument Uncertainty: +/- 1 cm. File format: All files are ASCII comma separated variable format. In directory TOPO, data files have the form Tdddxx where ddd is the day in 1998 when the measurements were taken and XX is the profile number. The first column indicates the location of the measurement point along the profile in meters. The second column gives the depth of melt ponds at that location (m) (lack of data in this column indicates that no melt pond was present at this location). The third column gives the surface elevation (m) of either the snow/ice surface or the melt pond water surface. Note that in file T166P1, the water depth (at all locations where meltwater is present) indicates the depth of the meltwater table in the snow cover. The same holds for water depth data in file T173P1 at locations 24 to 26 m, 66 to 71 m, 77 to 79 m, at 84 m, and at 89 m along the profile, as well as in file T170P2 at locations 54 to 57 m along the profile. In all these cases, surface elevation refers to the top surface of the snow cover. Contacts: hajo.eicken@gi.alaska.edu msturm@crrel.usace.army.mil
Ancillary: Ice permeability
Instrument: Laser leveler, meterstick Uncertainty: Errors in elevation are less than 1 cm. File format: All files are ASCII comma separated variable format. The files are in directory PERM. The first two columns in the data file indicate the day of the year in 1998 and the cardinal number of the measurements. The third and fourth columns list the thickness of the ice layer underlying the bottom of the measurement hole and the total ice thickness (m). The fifth column indicates the intrinsic permeability in square meters, and the sixth column indicates the location of the measurement sites. Contact: hajo.eicken@gi.alaska.edu |
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