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Data Set ID:
G01171
Central Asian Snow Cover from Hydrometeorological Surveys, Version 1
This data set provides observations of end of month snow depth, snow density, and snow water equivalent from three river basins in Central Asia: Amu Darya, Sir Darya, and Naryn. Temporal coverage varies for each snow point, with the longest station record extending from 1932 through 1990.
This is the most recent version of these data.
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Geographic Coverage |
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As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.
Bedford, D. and B. Tsarev. 2001. Central Asian Snow Cover from Hydrometeorological Surveys, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: https://doi.org/10.7265/N51Z4291. [Date Accessed].Collapse All / Open All
Overview
The Central Asian Snow Cover from Hydrometeorological Surveys data are based on observations made by personnel for three river basins: Amu Darya, Sir Darya, and Naryn. These observations include end of month snow depth, snow density and snow water equivalent. Only snow depth is included for additional snow points measured by helicopter landings. Temporal coverage varies for each snow point, with the longest station record extending from 1932 through 1990. Data were provided to NSIDC by the State Hydrometeorological Service (Russian acronym SANIGMI) in Tashkent, Uzbekistan.
The original analog records were digitized at SANIGMI, Tashkent, under the leadership of Dr. Boris Tsarev. Snow depth, snow density, and snow water equivalent were measured manually at snow points at the end of each month. Snow depth was measured from helicopter landings at additional points within the same river basins, also at the end of each month. Snow depth measurements were made using a snow measuring rod. Snow water equivalent measurements were made using a snow weighing balance.
Detailed Data Description
The data for each river basin contains two different file types: ground based snow point data and snow depth data from helicopter landings. Both types of files are ASCII.
Ground Based Snow Points
These files contain snow depth, snow water equivalent and snow density for a single snow point. The file name indicates the data type, the river basin, and the snow point. For example gsp_03037-27.dat indicates ground snow point data from station 27 within the Suusamir tributary (number 03037) of the Naryn river. In all cases, "9999" indicates missing data. Each file contains the following parameters:
| Header record | |
|---|---|
| Column 1 | Tributary basin: The numeric code assigned to the tributary river basin into the primary basins were divided. Please see the file k-sp.eng file for a complete listing |
| Column 2 | Snow point - the numeric code assigned to a snow point within a tributary basin |
| Column 3 | Elevation - elevation of the snow point (meters above sea level) |
| Column 4 | Latitude - latitude of the snow point (degrees North) |
| Column 5 | Longitude - longitude of the snow point (degrees East) |
| Data records | |
|---|---|
| Column 1 | Year - years of the snow season |
| Column 2 | Month - month of the measurement |
| Column 3 | Snow Depth: measured snow depth (cm) |
| Column 4 | Snow Water Equivalent: snow water equivalent (mm) |
| Column 5 | Snow Density: snow density (kg/m3) |
Helicopter Measured Snow Points
To increase the spatial coverage of the data, several additional snow points were measured from aircraft. These files contain only snow depth. The file name indicates the data type, the river basin, and the snow point. For example asp_03037-27.dat indicates an airborne snow point data from station 27 within the Suusamir tributary (number 03037) of the Narin river. In all cases, "9999" indicates missing data. These files contain the following parameters:
| Header record | |
|---|---|
| Column 1 | Tributary basin: The numeric code assigned to the tributary river basin into the primary basins were divIded. Please see the file k-asp.eng file for a complete listing |
| Column 2 | Snow point - the numeric code assigned to a snow point within a tributary basin |
| Column 3 | Elevation - elevation of the snow point (meters above sea level) |
| Column 4 | Latitude - latitude of the snow point (degrees North) |
| Column 5 | Longitude - longitude of the snow point (degrees East) |
| Data records | |
|---|---|
| Column 1 | Year - years of the snow season |
| Column 2 | December Snow Depth (cm) |
| Column 3 | January Snow Depth (cm) |
| Column 4 | February Snow Depth (cm) |
| Column 5 | March Snow Depth (cm) |
| Column 6 | April Snow Depth (cm) |
| Column 7 | May Snow Depth (cm) |
File Size
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Error Sources
In November 2004, Lev Kitaev, an NSIDC data user, noticed discrepancies in latitude and longitude values between the metadata files and the data files. The following example highlights the discrepancies. The errors will vary, depending upon the specific metadata and data files.
Data file name: asp_01009-13.dan (located in the amudarya.tar file)
Latitude and Longitude values: 45.667, 81.4333
Corresponding metadata file name: k-ask.eng
Latitude and Longitude values: 38.460, 69.746
Dr. Kitaev believes that the coordinate values provided in the metadata files are the more accurate values. NSIDC apologizes for any confusion or inconvenience that results from these errors. Please contact User Services if you require assistance with these data.
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Quality Assessment
This data set is based on hand-digitized analog records. Degradation of the original records and human error can cause missing or inaccurate data values. These data were examined by the principal investigator and compared to expected climatological values to identify and remove large errors before being archived by NSIDC.
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Sample Data Record
Sample Ground Based Snow Points Data
03037 27 3015 46.733 75.683 1960-1961 12 9999 9999 9999 1960-1961 1 38 9999 210 1960-1961 2 58 9999 240 1960-1961 3 68 9999 220 1960-1961 4 24 9999 360
Sample Helicopter Measured Snow Points Data
03037 27 15 46.733 75.683 1976 1977 9999 67 75 73 0 9999 1977 1978 90 97 100 120 83 9999 1978 1979 72 80 102 105 75 9999 1979 1980 35 52 80 82 53 9999 1980 1981 65 60 98 100 70 9999
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References and Related Publications
Contacts and Acknowledgments
Daniel Bedford
Department of Geography
Middlebury College
Middlebury, VT 05752 USA
Boris Tsarev
SANIGMI
72 Observatorskaya St.
Tashkent 70052 Uzbekistan
Acknowledgments:
Development of this data set was funded by the NOAA Environmental Services, Data, and Information Management (ESDIM) program, through the NOAA/NESDIS National Geophysical Data Center (NGDC). This set is maintained at NSIDC with support from the NOAA National Geophysical Data Center.
Document Information
Document Authors
The original version of this documentation was written by R. Welsh based on information provided by D. Bedford.
Document Creation Date
October, 2001
Document Revision Date
In July 2006, this document was reformatted and edited. The data set title and citation were changed slightly. F. Fetterer oversaw these changes.
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Questions? Please contact:
NSIDC User Services
Phone: 1 303 492-6199
Email: nsidc@nsidc.org
NSIDC User Services
Phone: 1 303 492-6199
Email: nsidc@nsidc.org
