Online Access for GPCC Rain Gauge Analysis for GPCP
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1996
Contents
- Summary
Sponsor
Original Archive
Future Updates
Data Set Description
- Data Characteristics
Data Format
- References
Data Access
- Anonymous FTP
- Points of Contact
This README file contains information on the structure of a global data
set of area-averaged and time-integrated precipitation fields, based on
analysis of all surface rain gauge measurements. These measurements,
from approximately 6,700 stations world-wide, are interpolated using
the Spheremap code (Shepard, 1968;
Willmott et al., 1985) to provide global surface
monthly mean rainfall estimates on a 2.5 degree latitude by 2.5 degree
longitude grid for the period 1986 to 1996.
This data set was produced at the Global Precipitation Climatology
Center (GPCC) for the Global Precipitation Climatology Project (GPCP),
initiated under the World Climate Research Program. The GPCC, operated
by the Deutscher Wetterdienst (National Meteorological Service of
Germany), is a central element of the GPCP. The main purpose of the
GPCP (for details, see WMO, 1985;
WMO/ICSU, 1990) is to evaluate and provide global
gridded data sets of monthly precipitation, based on all suitable
observation techniques, to be used for:
- verification of climate model simulations
- investigations of the global hydrological cycle
- climate change detection studies
The distribution of this data set is being funded by
NASA's Mission To
Planet Earth program. The data are not copyrighted; however, we
request that when you publish data or results using these data, please
acknowledge as follows:
The authors wish to thank the Distributed Active Archive Center (Code 610.2) at the Goddard Space Flight Center, Greenbelt, MD, 20771, for
distributing the data; and the science investigator, Dr. Bruno Rudolf
at the GPCC, Deutscher Wetterdienst, Germany, for producing these data
products. Goddard's contribution to these activities was sponsored by
NASA's Mission to Planet Earth program.
This data set was originally archived at the Marshall Space Flight
Center. It was moved to the Goddard Space Flight Center Distributed Active Archive
Center (GSFC DAAC) in the fall of 1996. This data set is also accessible from the
GPCP archives at the World Data Center A (WDC-A) for Meteorology at the National
Climate Data Center (NCDC) in Asheville, North Carolina.
The Goddard DAAC will update this data set as new data are processed and
made available by the data producers.
The GPCP/GPCC land surface precipitation data set is derived from the
monthly precipitation totals based on conventional surface rain gauge
measurements. The GPCC collects monthly precipitation totals received
from CLIMAT and SYNOP reports via the World Weather Watch GTS (Global
Telecommunication System) of the World Meteorological Organization
(WMO). The GPCC also acquires monthly precipitation data from
international/national meteorological and hydrological
services/institutions. An interim data base of about 6,700
meteorological stations is defined. Surface rain gauge-based monthly
precipitation data from these stations are analyzed over land areas,
and an interpolated gridded data set is created
(Rudolf, 1993; Rudolf, 1996;
Rudolf et al., 1994) using a spatial objective
analysis, the Spheremap code (Shepard, 1968;
Willmott et al., 1985). The interpolation for
Antarctica is made separately from that for the other continents to
avoid any influence of distant stations.
Data Characteristics
| · Parameters: | Accumulated surface precipitation |
| · Units: | mm/month |
| · Typical Range: | 0-5500 |
| · Temporal Coverage: | January 1986 - December 1996 |
| · Temporal Resolution: | Monthly means |
| · Spatial Coverage: | Global |
| · Spatial Resolution: | 2.5° x 2.5° |
| · Number of Files per Granule: | 12 monthly data files and 12
systematic error files. Error files are independent of the year. |
| · Granule Size: | 3 Megabytes (ASCII) |
| · Granule Name: | gpcc_rain_gauge_analysis_yyyy
(where yyyy=1986..1996) |
| · File Names: | 101-mmyyyy.asc and error02.amm (where the
two-digit month code
mm=01 to 12 and the four-digit year code
yyyy=1986 to 1996. Examples of data files for
January 1986 and December 1996: l01-011986.asc and
l01-121996.asc, respectively. Examples of error files for
January and December: error02.a01 and error02.a12,
respectively. |
Data Format
Data Files:
For each grid cell, the data files contain global rainfall estimates
(format F 9.2) and the number of stations in that cell used in the
objective analysis (format I4). Grid cells with no results available
are filled by a missing data code of -99999.99. The grid cell values
are arranged in the data files from north to south and west to east as
follows: the first row of 144 grid cells are centered at 88.75 degree
north latitude and run from 178.75 degree west longitude to 178.75
degree east longitude; the second row of 144 grid cells are centered at
86.25 degree north latitude and run similarly from west to east; etc.
The following diagram schematically depicts the data grid. The 145th
record of a data file (i.e., "145.val.") is for the 2.5 degree
latitude/longitude grid cell centered at 86.25 degree north latitude
and 178.75 degree west longitude.
180W/90N 0 180E/90N
|--------------------------------------------------------------------|
| 1. val. | 2. val. | * | * | * | * | 144.val.|
|--------------------------------------------------------------------|
| 145.val.| * | * | * | * | * | * |
|--------------------------------------------------------------------|
| * | * | * | * | * | * | 10368. |
|--------------------------------------------------------------------|
180W/90S 0 180E/90S
- Image orientation: North to South
- Start position: (89.75N, 179.75W)
- End position: (89.75S, 179.75E)
The following is a sample of a partial monthly rainfall data file for
December 1992.
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
-99999.99 0
3.84 0
3.98 0
4.11 0
4.22 0
4.35 0
4.48 0
4.62 0
4.74 0
4.88 0
4.97 0
5.01 0
-99999.99 0
5.06 0
-99999.99 0
5.10 0
5.17 0
5.24 0
5.30 0
Error Files:
The error files contain systematic errors of the precipitation
measurements (based on the Legates (1987)
climatological data set). For each grid cell, there are two ASCII
values:
- 1. Absolute difference of grid cell precipitation estimates (format
F9.2):
- (Legates corrected - Legates uncorrected or measured) (mm/month)
- -99999.99 = not defined
- 2. Ratio (format I4):
- (Legates corrected / Legates uncorrected) * 1000.0
- 0 = not defined
- 9999 = > 9998
The grid pattern for the error files is the same as that for the data
files, i.e., data run in the order from north to south and from west to
east.
Bussieres, N., and W.D. Hogg, 1989. The objective
analysis of daily rainfall by distance weighting schemes on a meso-scale
grid. Canadian Meteor. and Oceanographic Soc., Atmos.-Ocean,
27(3), 521-541.
GPCC, 1992. Monthly precipitation estimates based
on gauge measurements on the continents for the year 1987 (preliminary
results) and future requirements. Rep.-No. DWD/K7 WZN-1992/08-1, WCRP
and Deutscher Wetterdienst, Eds., Offenbach.
GPCC, 1993. Global area-mean monthly precipitation
totals for the year 1988 (preliminary estimates, derived from rain
gauge measurements, satellite observations and numerical weather
prediction results). Rep.-No. DWD/K7/WZN-1993/07-1, WCRP and Deutscher
Wetterdienst, Eds., Offenbach.
Groisman, P.Y., and D.R. Legates, 1994. The
accuracy of United States precipitation data. Bull. Amer. Meteor.
Soc., 75(2), 215-227.
Legates, D.R., 1987. A climatology of global
precipitation. Publ. in Climatology, 40(1), Newark, DE,
85 pp.
Rudolf, B., 1993. Management and analysis of
precipitation data on a routine basis. Proc. Int. WMO/IAHS/ETH Symp.
on Precipitation and Evaporation, M. Lapin, and B. Sevruk, Eds.,
Bratislava, Slovak Hydrometeor. Inst., 1, 69-76.
Rudolf, B., 1996. Global Precipitation Climatology
Center activities. GEWEX News, 6(1).
Rudolf, B., H. Hauschild, M. Reiss, and U.
Schneider, 1992. Beitraege zum Weltzentrum fuer
Niederschlagsklimatologie - Contributions to the Global Precipitation
Climatology Center. Meteor. Zeitschrift N.F., 1(1),
7-84. (In German, with Abstract and Summary in English).
Rudolf, B., H. Hauschild, W. Rueth, and U.
Schneider, 1994. Terrestrial precipitation analysis: operational
method and required density of point measurements. Global
Precipitations and Climate Change, NATO ASI Series, 1(26),
173-186, M. Desbois and F. Desalmand, Eds., Springer-Verlag.
Shepard, D., 1968. A two-dimensional interpolation
function for irregularly spaced data. Proc. 23rd ACM Nat'l.
Conf., Princeton, NJ, Brandon/Systems Press, 517-524.
Willmott, C.J., C.M. Rowe, and W.D. Philpot, 1985.
Small-scale climate maps: a sensitivity analysis of some common
assumptions associated with grid-point interpolation and contouring.
The Amer. Cartographer, 12(1), 5-16.
WMO, 1985. Review of requirements for area-averaged
precipitation data, surface-based and space-based estimation techniques,
space and time sampling, accuracy and error; data exchange. WCP-100,
WMO/TD-No. 115, 57 pp. and appendices.
WMO/ICSU, 1990. The Global Precipitation
Climatology Project - Implementation and Data Management Plan.
WMO/TD-No. 367, Geneva, 47 pp. and appendices.
Anonymous FTP
The GPCP/GPCC Rain Gauge Analysis data set resides online and may be accessed either directly from this document,
 GPCP/GPCC Rain Gauge Analysis
- or via anonymous FTP at
- ftp daac.gsfc.nasa.gov
- login: anonymous
- password: < your internet address >
- cd http://disc.sci.gsfc.nasa.gov/data/hydrology/precip/gpcp/gpcc
DAAC Help Desk:
- The producer of this data set can be contacted as follows:
- Dr. Bruno Rudolf
- Global Precipitation Climatology Centre (GPCC)
- at Deutscher Wetterdienst
- Frankfurter Str. 135
- D-63067 Offenbach am Main
- Germany
- Email: brudolf@dwd.d400.de
- 49-69-8062-2765 (voice)
- 49-69-8236-1493 (fax)
- For information about or assistance in using any DAAC data, contact
the DAAC Help Desk at:
- EOS Distributed Active Archive Center (DAAC)
- Code 610.2
- NASA Goddard Space Flight Center
- Greenbelt, Maryland 20771
- Email: daacuso@daac.gsfc.nasa.gov
- 301-614-5224 (voice)
- 301-614-5268 (fax)
Data Producers:
- The producer of this data set can be contacted as follows:
- Dr. Bruno Rudolf
- Global Precipitation Climatology Centre (GPCC)
- at Deutscher Wetterdienst
- Frankfurter Str. 135
- D-63067 Offenbach am Main
- Germany
- Email: brudolf@dwd.d400.de
- 49-69-8062-2765 (voice)
- 49-69-8236-1493 (fax)
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Atmos Composition
