Soroosh Sorooshian Professor and Head Dept. of Hydrology and Water Resources University of Arizona
____________________________________ | Contact 1 | ______________|_____________________| 2.3.1 Name | Mr. Dan Braithwaite | 2.3.2 Address | Dept. of Hydrology | | and Water Resources | | Harshbarger Bldg. | | Univ. of Arizona | City/St.| Tucson, Arizona | Zip Code| 85721 | 2.3.3 Tel. | (602) 621-9944 | 2.3.4 Email |dank@hwr.arizona.edu | ______________|_____________________| 2.4 Requested Form of Acknowledgment. Streamflow data of major river basins, Ver. 0, Dept. of Hydrology and Water Resources, University of Arizona, in cooperation with Dr. Wolfgang Grabs of the Global Runoff Data Center, Koblenz, Germany. 3. INTRODUCTION 3.1 Objective/Purpose. The purpose of making this data set available is to give climate and hydrologic researchers better access to the historical record of runoff from some of the world's major river systems. 3.2 Summary of Parameters. This report includes the monthly average runoff from 129 gauging stations for different periods of record, some of which span much of the last 200 years. However, only 14 gauges fully cover the study period (1987 - 1988) of the ISLSCP Initiative 1. These gauges were selected because of the regional significance (not necessarily volume) of the river in question. Gage location, contributing area and period of record are also given. 3.3 Discussion. The hydrologic cycle is a critical component of global climate studies but is poorly quantified globally in space and time. Hydrologists have used river runoff as a natural space/time integrator at the basin scale for years and it is possible to extend this concept to larger scales given the appropriate data set. The monumental task of locating, acquiring, digitizing and editing runoff data from around the world is being managed by the Global Runoff Data Center (GRDC) under the auspices of the World Meteorological Organization (WMO) as part of the World Climate Program. The aim of this project is to provide a global data set for the validation of climate simulations by global General Circulation Models (GCM's) [Max Planck-IFM, 1993]. The GRDC has made a portion of their data base of major world rivers available to this CD-ROM data set. Of the rivers included in this release, the full period of record is given and, where needed, daily flows have been converted to monthly averages. Although these basins represent less than 30% of the land surface area, they contribute approximately 46% of the estimated annual global runoff of 40,670 km3 [WRI, 1990]. While monthly average flow is appropriate for most model applications, the presence of extreme events is not preserved so this data set will be of less use to those interested in historical climate extremes. 4. THEORY OF MEASUREMENTS Stage-discharge relations (discharge ratings) at gauging stations are usually developed experimentally from measurements of stage and discharge. The discharge ratings for a stream or channel may consist of a simple relation between stage and discharge, or for a complex situation, it may be composed of several relation curves defining discharge as a function of stage, slope, rate of change of stage, or other variables. The stage-discharge relations developed at one point in time are usually not permanent nor do they often represent long-time conditions. Changes in the stream channel such as scour and fill or changes in channel roughness, aquatic growth, debris, or backwater from ice, all result in changes in the stage- discharge relation. Hence, frequent discharge measurements are necessary to define the shape and/or changes in the discharge rating. Discharge measurements are usually made by the current-meter method; however, it is sometimes necessary to resort to indirect measurements of flood flow (USGS Office of Water Data Coordination, 1977) to define the upper portion of the stage-discharge relation. For additional information on stream gauging procedure, see Corbett and others (1945) 5. EQUIPMENT The equipment and methods used to measure streamflow probably vary substantially depending on the country and organization conducting the measurements. The specific details for the gauges in this data set are not available at this time. For general information on equipment and methods used to measure streamflow, see (USGS Office of Water Data Coordination, 1977). 5.1 Instrument Description. 5.1.1 Platform (Satellite, Aircraft, Ground, Person...). Not available. 5.1.2 Mission Objectives. Not available. 5.1.3 Key Variables. Not available. 5.1.4 Principles of Operation. Not available. 5.1.5 Instrument Measurement Geometry . Not available. 5.1.6 Manufacturer of Instrument. Not available. 5.2 Calibration. 5.2.1 Specifications. Not available. 5.2.1.1 Tolerance. Not available. 5.2.2 Frequency of Calibration. Not available. 5.2.3 Other Calibration Information. Not available. 6. PROCEDURE 6.1 Data Acquisition Methods. This data was acquired from Dr. Wolfgang Grabs at the Global Runoff Data Centre in Koblenz, Germany. 6.2 Spatial Characteristics. Streamflow measurements were made at significant points in most major river basins around the world. The contributing area above each gauge and the gauge location are given in G_GAUGES.FLR (see section 8 for details). 6.2.1 Spatial Coverage. Streamflow measurements at significant points of the major river basins around the world recording the cumulative output of the contributing basin. 6.2.2 Spatial Resolution. The data values represent an areal integration over the contributing catchment. The size of each catchment is listed in the file G_GAUGES.FLR. 6.3 Temporal Characteristics. A water year covers portions of two calendar years, beginning in October of a year and ending in September of the following year. (e.g. wateryear 1991 consists of Oct-Dec of 1990 and Jan-Sep of 1991). 6.3.1 Temporal Coverage. The period of record varies for each gauge. Over the entire data set: earliest wateryear 1807 latest wateryear 1991 latest starting year 1986 earliest ending year 1961 longest span 178 wateryears shortest span 1 wateryear Note: Only fourteen gauges fully cover the period 1987 to 1988. 6.3.2 Temporal Resolution. Monthly averages. 7. OBSERVATIONS 7.1 Field Notes. Not available. 8. DATA DESCRIPTION 8.1 Table Definition With Comments. The file G_GAUGES.FLR is a table that contains the gauge list (for all gauges in this data set) with gauge number, gauge location and additional information (see section 8.2, 8.3 and 8.4). The G#######.FLR files, each contain a table that has one record for every water year, consisting of the water year and 12 flow rate values (one for each month of a year). Each G#######.FLR file contains all the flow data for a specific gauge. 8.2 Type of Data. -------------------------------------------------------------------------------- | 8.2.1 | | | | |Parameter/Variable Name | | | | -------------------------------------------------------------------------------- | | 8.2.2 | 8.2.3 | 8.2.4 | 8.2.5 | | |Parameter/Variable Description |Range |Units |Source | -------------------------------------------------------------------------------- |WYEAR | | | | | |The water year (e.g. wateryear 1991|min = 1807, |[years] | | | |consists of Oct-Dec of 1990 and |max = 1991 | | | | |Jan-Sep of 1991). | | | | -------------------------------------------------------------------------------- |FLOW | | | | | |Streamflow in monthly averages |min = 0, |[meters^3]|gauge | | | |max = 246000 |[sec^-1] | | | | |missing = | | | | | |-9999.00 | | | -------------------------------------------------------------------------------- |GAGE_ID_NUMBER | | | | | |The gauge identification number |Not |Not | | | | |applicable |applicable| | -------------------------------------------------------------------------------- |RIVER_NAME | | | | | |Name of the river the gauge is |Not |Not | | | |located on. |applicable |applicable| | -------------------------------------------------------------------------------- |STATION_NAME | | | | | |Name of the gauge station. |Not |Not | | | | |applicable |applicable| | -------------------------------------------------------------------------------- |COUNTRY | | | | | |Name of the country the gauge is |Not |Not | | | |located in. |applicable |applicable| | -------------------------------------------------------------------------------- |LATITUDE | | | | | |Geographic latitude location of |min = 0, |[dec deg] | | | |the gauge. |max = 9000 |[100] | | -------------------------------------------------------------------------------- |LONGITUDE | | | | | |Geographic longitude location of |min = 0, |[dec deg] | | | |the gauge. |max = 18000 |[100] | | -------------------------------------------------------------------------------- |CATSIZE | | | | | |The contributing area upstream from|min = 97, |[kilo | | | |the gauge. |max = 4640300, |meters^2] | | | | |missing = blank| | | -------------------------------------------------------------------------------- |ELEVATION | | | | | |The elevation of the gauge. |min = 0, |[meters] | | | | |max = 2000, | | | | | |missing = -99 | | | -------------------------------------------------------------------------------- |FIRST_WYEAR | | | | | |The first water year for the gauge |min = 1807, |Not | | | |location. |max = 1986 |applicable| | -------------------------------------------------------------------------------- |LAST_WYEAR | | | | | |The last water year for the gauge |min = 1961, |Not | | | |location. |max = 1991 |applicable| | -------------------------------------------------------------------------------- |NOTE | | | | | |Note whether the original data was |Not |Not | | | |monthly or daily. |applicable |applicable| | -------------------------------------------------------------------------------- The WYEAR and FLOW parameters are located in each G#######.flr file. All other parameters, listed above are located in the G_GAUGES.FLR file. 8.3 Sample Data Base Data Record. For header file (G_GAUGES.FLR): 1134100 Niger Koulikoro MI 1287N 755W 120000 20 1907 1991 D 1134300 Bani Douna MI 1322N 590W 101600 271 1922 1991 M 1147010 Zaire Kinshasa ZR 430S 1530E 3475000 58 1903 1984 M 1159100 Oranje Vioolsdrif ZA 2876S 1773E 850530 -99 1965 1986 M For data files (G#######.FLR): 1897 258.00 220.00 164.00 218.00 224.00 1220.00 3710.00 4510.00 657.00 332.00 245.00 195.00 1898 201.00 223.00 144.00 130.00 191.00 182.00 2430.00 3520.00 1650.00 441.00 287.00 186.00 8.4 Data Format. The length of each record, in the G_GAUGES.FLR file, is 131 characters long and the parameters are space delimited. The record format and parameters are: column # parameters 1-7 GRDC gauge identification number. 9-48 River name padded with spaces. 49-89 Station name padded with spaces. 90-91 Two letter country abbreviation. AG - Argentina LT - Lithuania AU - Australia MI - Mali BJ - Benin MW - Malawi BM - Burma (Aynmar) MX - Mexico BW - Bangladesh MZ - Mozambique BZ - Brazil NR - Nigeria CD - Chad PK - Pakistan CG - Congo PL - Poland CI - China RO - Romania CN - Canada RS - Russia CO - Columbia SG - Senegal CZ - Czech Republic SN - Sweden EG - Egypt SP - Spain FI - Finnland SU - Sudan FR - France TH - Thailand HU - Hungary UG - Uganda IN - India US - United States IQ - Iraq VN - Venesuela IY - Italy ZA - South Africa KZ - Kazakstan ZR - Zaire LA - Laos 93-96 Latitude in decimal degrees x 100. 97 N or S for North or South hemisphere. 99-103 Longitude in decimal degrees x 100. 104 E or W for East or West hemisphere. 106-112 Catchement size in square kilometers [km^2]. 114-118 Elevation in meters (unknown values -99). 120-123 First water year in record. 125-128 Last water year in record. 130 M or D for to note whether the original data was. monthly or daily. Data converted from daily data may contain monthly values derived from some interpreted daily values. Below is a description of the Global Runoff Data Centre (GRDC) identification code. GRDC-Code (for example 1447150): 1 = WMO-Region (1 = Africa) 4 = GRDC-Country code (4 = Congo) 47 = GRDC-Subregion; main river basin (47 = Zaire/Congo) 150= GRDC-Station code The length of records, in each G#######.FLR data file, is 126 characters long and the data values are spaced delimited. The record format and parameters are: column # parameters 1-6 wyear 7-16 October flow (missing flow data values -9999.00) 17-26 Nov. flow 27-36 Dec. flow 37-46 Jan. flow 47-56 Feb. flow 57-66 Mar. flow 67-76 Apr. flow 77-86 May flow 87-96 Jun. flow 97-106 Jul. flow 107-116 Aug. flow 117-126 Sep. flow 8.5 Related Data Sets. There are other streamflow data sets generally available. Some prominent examples: Hydro-Climatic Data Network: Streamflow data set USGS Water-resources investigations report 93-4076 Wallis, J.R., Lettenmaier, D.P., and Wood, E.F., 1991. A Daily Hydro- Climatological Data Set for the Continental U.S. Water Resources Research Bol. 27(7)1657-1663. Global Runoff Data Centre (GRDC): Global Runoff Data Centre Bundesanstalt F|r Gewasserkunde Kaiserin-Augusta-Anlagen 15-17 W-5400 Koblenz Federal Republic of Germany Fax: +49 261 1306302 Tel: +49 261 1306-1 European Water Archive Institute of Hydrology Crowmarsh Gifford, Wallingford Oxon OX10 8BB United Kingdom 9. DATA MANIPULATIONS 9.1 Formulas. 9.1.1 Derivation Techniques/Algorithms. Where monthly averages had to be calculated from daily averages, an algorithm was employed to handle gaps in the daily record. The days in the gap were linearly interpreted if a) (# days in gap <= 20) & (%change < 10%) or b) (# days in gap <= 10) & (%change < 50%) The daily values for a given month were then averaged if a) # original measured values >= 2/3 # days in month or b) (total # vals (meas.+interp) >= 3/4 # days in month) & 1) (# meas >= 1/10 # days in month) & (cum. %change <= 10%) or 2) (# meas >= 1/2 # days in month) & (cum. %change < 50%) Otherwise monthly value classified as missing (-9999.00) 9.2 Data Processing Sequence. 9.2.1 Processing Steps and Data Sets. Daily flow data were converted to monthly flow data using the algorithm in 9.1.1 The monthly tables were reorganized from the January to December original order to a water year format of October to September. Water years with at least one monthly value were retained and any missing values were filled in with -9999 as a no data value. 9.2.2 Processing Changes. None. 9.3 Calculations. 9.3.1 Special Corrections/Adjustments. See section 9.1.1. 9.4 Graphs and Plots. None. 10. ERRORS 10.1 Sources of Error. Many gaps in the record were caused by freezing conditions, and ice bound flows. Standards of observation have changed through time but this information is not available. European observations during World War I and II, however, might be suspect. No corrections have been made for the anthropogenic effects of damming and pumping but these effects are often readily apparent (as on the Nile around the time the Aswan High Dam was constructed). Climate modelers are cautioned that this data set is not representative of all, particularly more arid, regions of the world so reproduction of these runoffs, although laudable, does not guarantee effective global climate simulation. In addition, small basins are not well represented and likely would show greater interannual variability. 10.2 Quality Assessment. 10.2.1 Data Validation by Source. Not available. 10.2.2 Confidence Level/Accuracy Judgment. Not available. 10.2.3 Measurement Error for Parameters and Variables. Not available. 10.2.4 Additional Quality Assessment Applied. Not available. 11. NOTES 11.1 Known Problems With The Data. None reported at this revision. 11.2 Usage Guidance. None. 11.3 Other Relevant Information. None. 12. REFERENCES 12.1 Satellite/Instrument/Data Processing Documentation. None. 12.2 Journal Articles and Study Reports. Corbett, D. M., and others, 1945. Stream-gauging procedure: U.S. Geol. Survey Water-Supply Paper 888, 245 p. Max-Planck-Institut fur Meteorologie, Report No. 100. Discharge data from 50 selected rivers for GCM validation, L. Dumenil, K. Isele, H.-J. Liebscher, U. Schroder, M. Schumacher, K. Wilke. USGS Office of Water Data Coordination, 1977. National handbook of recommended methods for water-data acquisition, USGS, Reston VA. World Resources Institute, 1990, World Resources: 1990-91, Oxford University Press, 383p. 12.3 Archive/DBMS Usage Documentation. Contact the EOS Distributed Active Archive Center (DAAC) at NASA Goddard Space Flight Center (GSFC), Greenbelt Maryland (see Section 13 below). Documentation about using the archive or information about access to the on-line information system is available through the GSFC DAAC User Services Office. 13. DATA ACCESS 13.1 Contacts for Archive/Data Access Information. GSFC DAAC User Services NASA/Goddard Space Flight Center Code 902.2 Greenbelt, MD 20771 Phone: (301) 286-3209 Fax: (301) 286-1775 Internet: daacuso@eosdata.gsfc.nasa.gov 13.2 Archive Identification. Goddard Distributed Active Archive Center NASA Goddard Space Flight Center Code 902.2 Greenbelt, MD 20771 Telephone: (301) 286-3209 FAX: (301) 286-1775 Internet: daacuso@eosdata.gsfc.nasa.gov 13.3 Procedures for Obtaining Data. Users may place requests by accessing the on-line system, by sending letters, electronic mail, FAX, telephone, or personal visit. Accessing the GSFC DAAC Online System: The GSFC DAAC Information Management System (IMS) allows users to ordering data sets stored on-line. The system is open to the public. Access Instructions: Node name: daac.gsfc.nasa.gov Node number: 192.107.190.139 Login example: telnet daac.gsfc.nasa.gov Username: daacims password: gsfcdaac You will be asked to register your name and address during your first session. Ordering CD-ROMs: To order CD-ROMs (available through the Goddard DAAC) users should contact the Goddard DAAC User Support Office (see section 13.2). 13.4 GSFC DAAC Status/Plans. The ISLSCP Initiative I CD-ROM is available from the Goddard DAAC. 14. OUTPUT PRODUCTS AND AVAILABILITY 14.1 Tape Products. None. 14.2 Film Products. None. 14.3 Other Products. None. 15. GLOSSARY OF ACRONYMS CD-ROM Compact Disc Read Only Memory. DAAC Distributed Active Archive Center EOS Earth Observation System GCM Global Circulation Model. GRDC Global Runoff Data Center. GSFC Goddard Space Flight Center IMS Information Management System ISLSCP International Satellite Land Surface Climotology Project NASA National Aeronautics and Space Administration WMO World Meteorological Organization.