Data Set Description
- Data Characteristics
- Sample Software
- Anonymous FTP
SummaryThis README file describes the Jaeger Global Monthly Mean Precipitation data, including information on the file structure, pertinent scientific references, and contact information for obtaining the data.This data set contains the monthly mean of climatological precipitation values estimated over a 2.5 degree latitude by 5 degree longitude grid.The climatology used for this data set covers the period from 1931 to 1960, over the continents, and the period from 1955 to 1965, over the oceans.
The authors wish to thank the Goddard Earth Science Data and Information Services Center (GES DISC), (Code 610.2) at the Goddard Space Flight Center, Greenbelt, MD, 20771, for distributing this data; and the science investigator, Dr. Lutz Jaeger, for producing these data products.
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.
The Goddard DAAC will update this data set as new data are processed and made available by the data producers.
The monthly mean rainfall estimates over the whole globe are based on climatology (data from 1931 to 1960 over the continents, and 1955 to 1965 over the oceans) and a gridding technique (See Jaeger (1983) for a general description of the method.).The data file consists of 2.5 degree latitude by 5 degree longitude gridded monthly means of estimated rainfall.
For the continental regions, the grid cell values were derived from visual estimates of isopleth maps prepared from up-to-date climatic atlases containing annual and monthly rainfall values, supplemented by other data sets.
Over the oceans, rainfall values were estimated using Moller's method. Monthly percentage frequencies were derived using the U.S. Marine Climatic Atlas (U.S. Naval Weather Service, 1955-1965) for isoline data and their interpolated values at the grid points.These monthly frequencies were converted to annual percentages, which were then scaled to rainfall depth units, using Geiger's (1965) precipitation map, to generate monthly precipitation means.
|Monthly mean precipitation
|January 1931 - December 1965
|2.5° latitude x 5° longitude
|0.126 Megabytes (ASCII, compressed)
Each rainfall field within the file begins with a month identifier (E15.8), followed by a 72 by 73 array of monthly mean precipitation estimates (in mm/month). Each estimate represents the climatological mean precipitation value for that month for a 2.5 degree latitude by 5 degree longitude grid cell.The data grid ranges in latitude from 90 degree south to 90 degree north and in longitude from 0 degree to 355 degree.
The sample FORTRANprogram listed below describes the data structure of this file that should be used in reading the data.The data are in ASCII format and are easy to display.All months are contained in a single file, compressed using LZ (unix-default).The file must be uncompressed before using the read program described in the next section.
An example program in FORTRAN to read the Jaeger precipitation data set is shown below:
real prec (72, 73), month
do nm = 1, 12
read (iunit, 100) month, ((prec (lon, lat), lon = 1, 72), lat = 1, 73)
100 format (5e15.8)
Geiger, R., 1965.The earth's atmosphere:mean annual precipitation.Map 5, World Maps,Scale 1:30M, Justus perthes.
Jaeger, L., 1983.Monthly and areal patterns of mean global precipitation.Variations in the Global Water Budget, A. Street-Perrott, M. Beran, and R. Ratcliffe, Eds., D. Reidel Publ. Co., Dordrecht, 129-140.
The Jaeger Precipitation data set resides online and may be accessed either directly from this document,
Jaeger Monthly Mean Precipitation Data
- or via anonymous FTP at
- ftp daac.gsfc.nasa.gov
- password:< your internet address >
- cd http://disc.sci.gsfc.nasa.gov/data/hydrology/precip/jaeger