Data Set Documentation

Former Soviet Union Monthly Precipitation Archive, 1891-1993

Summary

This archive consists of monthly totals of precipitation measurements from 622 stations located in the Former Soviet Union (FSU). The archive spans the years 1891 to 1993, although most stations have shorter records. The archive initially contained data from 594 stations. Another 28 stations and gauge posts situated in the grain belt and central regions of the FSU were added to the archive by the State Hydrological Institute. Work on the archive began at the State Hydrological Institute in 1977. The data, in ASCII format, are available via ftp in three files. The first file contains the precipitation data. The second file contains station positions, elevation, and names, while the third contains the correction factors to adjust the precipitation data.

Please note that the original documentation incorrectly stated that the K2 (wind) correction had been applied to the data in this archive. The K2 correction values are included in the corrections file but were not applied to the data. Users of this data set should apply the K2 values to the data if they want to make corrections for wind effect. The information in this document has been updated and is correct.

For more information about the data set, please contact NSIDC User Services.

1. Data Set Overview
2. Investigators
3. Theory of Measurements
4. Equipment
5. Data Acquisition Methods
6. Observations
7. Data Description
8. Data Organization
9. Data Manipulations
10. Errors
11. Notes
12. Application of the Data Set
13. Future Modifications and Plans
14. Software
15. Data Access
16. Output Products and Availability
17. References
18. Document Information

1. Data Set Overview

Data Set Identification

Former Soviet Union Monthly Precipitation Archive, 1891-1993

Data Set Introduction

The Former Soviet Union Monthly Precipitation Archive, 1891-1993, contains data derived from rain gauge measurements taken at 622 stations throughout the FSU.

Objective/Purpose

P. Groisman of the National Climatic Data Center (NCDC) in Asheville, North Carolina compiled the data that comprise the archive. The data are useful for climatological studies.

Summary of Parameters

precipitation

Discussion

This data set has been subjected to comprehensive quality control by P. Groisman (NCDC, Asheville, North Carolina) in an attempt to make it as homogeneous as possible.

During the late 1940s and early 1950s, the FSU changed to a Tretiyakov shielded gauge, which was determined to provide for more accurate measurements. Earlier measurements relied on a Nipher gauge. From parallel measurement between the two gauges, a correction factor (K1) was determined. These corrections were applied to data collected by the Nipher gauge.

During 1966 and 1967, a correction began to be applied for gauge wetting. To further improve the homogeneity of the time series, a second set of wetting corrections (K3) was adopted and applied to the complete data set. A third set of corrections (K2) that adjust for biases associated with the aerodynamic effects of wind around the gauges have been supplied in the separate corrections data file, but not applied to this data set. The K2 corrections can be large. To adjust for winds, the user must multiply the provided precipitation values by the K2 coefficients.These correction factors, as well as information on problems that may influence the time series, are described in detail by Groisman et al. (1991).

2. Investigators

Investigators' Names and Titles

Pavel Y. Groisman, NCDC, Asheville, North Carolina, U.S.A. (formerly at the State Hydrological Institute, St. Petersburg, Russia)

V. V. Koknaeva, State Hydrological Institute, St. Petersburg, Russia

T. A. Belokrylova, Center for Hydrometeorological Data (VNIIGMI) WDC-B, Obninsk, Russia

A. T. Sanina, Center for Hydrometeorological Data (VNIIGMI) WDC-B, Obninsk, Russia

Title of Investigation

Archive of Monthly Precipitation Sums on the USSR Territory for the Period of 1891-1989(90)

Contact Information

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org

3. Theory of Measurements

This section is not applicable.

4. Equipment

Sensor/Instrument Description

Please see rain gauge.

Collection Environment

ground

Source/Platform

fixed land stations

Key Variables

precipitation

5. Data Acquisition Methods

The original archive was acquired by the State Hydrological Institute. Work on the archive began in 1977. P. Groisman compiled detailed information on station histories (e.g., the timing of gauge changes and station moves) that may influence the homogeneity of this precipitation time series.

6. Observations

Documentation containing detailed information on station histories is available in rich text format. Hard copies of the same documentation are available from NSIDC User Services.

7. Data Description

Spatial Characteristics

Spatial Coverage

The stations are located in the Asian, European, and Russian territories of the FSU. A total of 622 stations are in the archive. The number of years of available data differs widely between stations.

Spatial Coverage Map

Temporal Characteristics

Temporal Coverage

Precipitation data included in this data set span from 1891 to 1993. The number of years of available data differs widely between stations.

Temporal Coverage Map

A temporal coverage map is not included in this document.

Temporal Resolution

Data are available as monthly precipitation totals by year. The monthly totals were derived from daily data. The number of times per day that precipitation was measured has varied through time. Beginning in the 1930s, measurements were made twice, rather than once per day. After January 1996, precipitation was generally measured four times daily. In 1986, the sampling period fell to twice per day at most stations. Details regarding the temporal sampling are provided by Groisman et al. (1991).

Data Characteristics

Parameter/Variable

precipitation

Variable Description/Definition

snow, rain

Unit of Measurement

millimeters

Data Source

Please see rain gauge.

Data Range

minimum = 0
maximum = 998.5

Sample Data Records

"stations.txt"


1 61.23  46.63   57 22887 Kotlas              

2 61.40  46.32   50 99999 Fedotovo Arkhan.area

3 61.50  38.93  124 22845 Kargopol            

4 62.10  42.90   47 22768 Shenkursk           

5 62.17  49.08   71 22798 Yarensk             

6 63.90  38.12   11 22641 Onega               

7 64.22  41.67   10 22559 Kholmogory          

8 64.58  40.50    3 22550 Arkhangelsk         

9 64.70  43.40   26 22563 Pinega              

10 64.75  47.65   63 22583 Koynas

"precipitation.dat"


1 1941   22.1  18.5  21.6  35.5  50.1 100.7  50.3  67.2 104.9  42.9  15.4  21.9

1 1942   15.9   9.3  18.4  18.4  62.1  74.2  41.6  51.9  54.9  44.4  31.4  18.6

1 1943   34.9  15.6  10.8  64.4  42.1  74.2  27.0 144.8  81.3  62.8  21.9  40.5

1 1944   41.2  26.4  13.7  71.0  69.1  91.9  16.0  59.6  44.4  33.7   9.3  14.1

1 1945   14.1  21.8  27.5  32.9  32.1  77.9  17.6  19.3  78.5  50.9  32.8  14.1

"corrections.dat"


1             1.37 1.36 1.38 1.16 1.00 1.00 1.00 1.00 1.00 1.11 1.33 1.37   

1 1951 09  3  1.62 1.62 1.50 1.29 1.06 1.04 1.04 1.04 1.07 1.23 1.44 1.62   

1             0.15 0.14 0.11 0.13 0.11 0.08 0.07 0.08 0.10 0.11 0.17 0.13   

2             1.50 1.50 1.50 1.25 1.00 1.00 1.00 1.00 1.00 1.17 1.42 1.50   

2 9999 99  3  9.99 9.99 9.99 9.99 1.06 1.04 1.04 1.04 1.07 9.99 9.99 9.99   

2             99.9999.9999.9999.99 0.11 0.08 0.06 0.08 0.1099.9999.9999.99   

3             1.23 1.22 1.22 1.10 1.00 1.00 1.00 1.00 1.00 1.00 1.12 1.21   

3 1955 10  2a 1.63 1.60 1.47 1.27 1.06 1.05 1.04 1.04 1.07 1.13 1.33 1.55   

3             0.14 0.14 0.12 0.12 0.12 0.08 0.07 0.07 0.10 0.14 0.14 0.13   

4             1.12 1.12 1.12 1.06 1.00 1.00 1.00 1.00 1.00 1.04 1.10 1.12   

4 1955 08  1a 1.22 1.22 1.17 1.10 1.03 1.02 1.02 1.02 1.03 1.08 1.15 1.22   

4             0.16 0.15 0.12 0.12 0.11 0.08 0.07 0.08 0.10 0.12 0.19 0.15   

5             1.13 1.14 1.15 1.06 1.00 1.00 1.00 1.00 1.00 1.05 1.13 1.14   

5 1954 01  2a 1.35 1.35 1.31 1.17 1.03 1.03 1.03 1.03 1.04 1.15 1.25 1.36   

5             0.14 0.15 0.14 0.14 0.12 0.09 0.08 0.09 0.10 0.12 0.17 0.12   

6             1.17 1.17 1.16 1.08 1.00 1.00 1.00 1.00 1.00 1.00 1.09 1.14

8. Data Organization

Data Granularity

A granule is the smallest aggregation of data that is independently managed (i.e., described, inventoried, or retrievable). The archive consists of three files:

precipitation.dat: 5.3 mb (uncompressed)
corrections.dat: 0.15 mb (uncompressed)
stations.txt: 0.03 mb (uncompressed)

Data Format

The Former Soviet Union Monthly Precipitation Archive, 1891-1993 is in ASCII format.

File "precipitation.dat"

The data format is (I4,1X,I4,1X,12F6.1)

The variables are the station number, the year, and the 12 values of monthly precipitation in millimeters. Missing precipitation values are 999.0.

File "stations.txt"

The data format is (I8,F6.2,1X,F6.2,I5,1X,I5,A30)

The variables are, respectively, the station number, latitude, longitude, elevation, World Meteorological Organization (WMO) code and station name. Latitude and longitude are given in hundredths of degrees, while elevation is in meters. Missing values for WMO codes are 9999. There are no missing values for other variables.

File "corrections.dat" of correction coefficients

The first data line of format (I3, 14X, 12F5.2) provides, respectively, the station number and 12 monthly coefficients to adjust the data from the Nipher-shielded rain gauge to measurements from the Tretiyakov gauge (K1 corrections). This coefficient is equal to 1 during the months with liquid precipitation, and, as a rule, >1 during the months with solid and mixed precipitation. In some southern regions of the FSU (Middle Asia, Moldavia) this coefficient is also 1, as no significant systematic changes were noted after switching to the new gauge. Missing values are 9.99.

The second data line of format (I3, I5, I3, 2X, A2, 2X, 12(1X,F4.2)) provides, respectively, the station number, the year and the month when the Nipher-shielded rain gauge replaced the Tretiyakov gauge, the type of station protection according classification by Shver (1976), and coefficients (K2) of wind correction with respect to normals measured with the Tretiyakov gauge. Missing values are 9.99.

The third data line of format (I3, 14X, 12F5.2) provides, respectively, the station number and 12 monthly coefficients (K3), adjusting for the share of mean monthly precipitation that remains in the gauge bucket after it has been emptied (corrections for wetting). Missing data values are 99.99.

The K1 and K3 corrections have already been applied to the data. To adjust for winds, the user must multiply the provided precipitation value by the K2 coefficients. Details on the corrections are provided by Groisman et al. (1991).

9. Data Manipulations

The primary data manipulations involve application of the K1 and K3 coefficients (see Discussion) to adjust for changes in gauge type and wetting losses. Details regarding these coefficients and their applications are provided by Groisman et al. (1991).

Processing Steps

The initial archive was changed as follows:

The monthly total precipitation values, which had been provided as percents of different normals, were restored to true precipitation values.
Information was compiled on station histories, including the timing of gauge changes, station moves, and other factors that can influence the time series.
The measurements from the Nipher-shielded rain gauge were adjusted to be consistent with data from the Tretiyakov gauge with the use of Kl coefficients.
Correction for wetting losses were applied using K3 coefficients.

More detailed information is provided by Groisman et al. (1991).

Processing Changes

The original archive contained 594 stations; another 28 stations and gauge posts were added to the archive by the State Hydrological Institute.
Originally, the archive data were presented in the form of percents of various normals. These were based on mean values for two periods--1891-1940 (Nipher rain gauge) and 1941-1960 (Tretiyakov gauge normal).
The original archive included a time series with broken homogeneity due to the change from the Nipher to the Tretiyakov gauge.

10. Errors

Sources of Error

The primary sources of error in this data set are those associated with the original precipitation measurements, including problems of gauge undercatch due to winds and wetting losses and inhomogeneities relate to changes in gauge type. Coefficients have been created to adjust for these errors. Further details are provided by Groisman et al. (1991).

Quality Assessment

Confidence Level/Accuracy Judgement

Raw Arctic precipitation measurements are prone to severe error. This archive is considered to be of higher accuracy as it contains corrections for the effects of winds, gauge changes, and wetting losses. The user may adjust for winds by multiplying the provided precipitation values by the K2 coefficients. The monthly values in the corrected archive are likely to be accurate to within 5 millimeters of true precipitation.

11. Notes

Limitations of the Data

See Confidence Level/Accuracy Judgement.

12. Application of the Data Set

Data from the Former Soviet Union Monthly Precipitation Archive, 1891-1993, are useful for time series analyses of precipitation and climate change studies. . The advantage of this precipitation data set is its improved temporal homogeneity.

13. Future Modifications and Plans

Plans are to update the files to include more recent years.

14. Software

Software Description

No software are distributed with these data.

15. Data Access

Contact Information

Data Center Identification

National Snow and Ice Data Center (NSIDC)

Procedures for Obtaining Data

The Former Soviet Union Monthly Precipitation Archive, 1891-1993 data are available via anonymous ftp.

16. Output Products and Availability

This section is not applicable.

17. References

Golubev, V. S. 1969. Research on precipitation measurement accuracy. Proc. SHI 176: 149-64.

Groisman, P. Ya., V. V. Koknaeva, T. A. Belodylova, and T. R. Karl. 1991. Overcoming biases of precipitation measurement: A history of the USSR experience. Bull. Amer. Meteor. Soc. 72(11): 1725-33.

Neushkin, A. I., ed. 1987. Calendar of monthly precipitation anomalies in percentage of normals for the USSR stations over the 1977-1984 period. Obninsk.

Reference book on USSR climate. 1966-1969. L.: Gidrometeoizdat. 1-34(2): 4.

Shver Ts. A. 1976. Precipitation over the USSR territory. L.: Gidrometeoizdat.

18. Document Information

Revision Date: 20 April 1998; 12 February 2001
Review Date: 20 April 1998; February 2001
Document ID: NSIDC-0059
Citation:: Please contact the Data Compiler or Principal Investigator for information about how to cite this data set.
Document Curators: NSIDC Writers
Document URL: http://nsidc.org/data/docs/daac/nsidc0059_fsu_precipitation.gd.html

Service Interruption

Former Soviet Union Monthly Precipitation Archive, 1891-1993

Summary

Table of Contents

1. Data Set Overview

2. Investigators

3. Theory of Measurements

4. Equipment

5. Data Acquisition Methods

6. Observations

7. Data Description

8. Data Organization

File "precipitation.dat"

File "stations.txt"

File "corrections.dat" of correction coefficients

9. Data Manipulations

10. Errors

11. Notes

12. Application of the Data Set

13. Future Modifications and Plans

14. Software

15. Data Access

16. Output Products and Availability

17. References

18. Document Information