Introduction
This guide describes how to retrieve data from the Tropical Rainfall Measuring Mission (TRMM) (http://trmm.gsfc.nasa.gov/data_dir/data.html) and import them into Delft-Fews.
A series of quasi-global, near-real-time, TRMM-based precipitation estimates is available to the research community via anonymous ftp. The estimates are provided on a global 0.25 ° x0.25 ° grid over the latitude band 50 ° N-S within about seven hours of observation time. Three products are being provided: A TRMM-calibrated merger of all available TMI, AMSR-E, SSM/I, and AMSU-B precipitation estimates (three-hourly accumulations); a geosynchronous infrared estimate which is calibrated by the merged-microwave data (hourly estimates); and a combination of the first two fields (three-hourly accumulations). The data are available under ftp://trmmopen.gsfc.nasa.gov/pub/merged . Users are urged to download the README first for additional details.
The attached scripts are examples only and should be customized by the user. The scripts are supplied without ANY warranty. This is NOT production quality software!
Data type and location
The scrips use the 3B42RT product (merged IR and Microwave) but may be adapted to use the other products. The data is located at: trmmopen.gsfc.nasa.gov/pub/merged/mergeIRMicro . Please visit the original site for details of the data (http://trmm.gsfc.nasa.gov/data_dir/data.html).
Scripts
Please note that you must have perl installed to run these scripts. In testing we used the perl version that came with cygwin but other (windows native) distributions are also available. Most linux distributions already have perl installed.
- gettrmm.pl -> gets the last n files from the ftp site, and calls the trmmconv.pl converted to convert to arcview ascii that can be imported into Delft-Fews (see http://public.deltares.nl/display/FEWSDOC/ArcInfoAscii)
- trmmconv.pl -> converts the files
How to get it working
- Download the attached scripts GetTRMM.zip and unzip this archive
- Edit gettrmm.pl, insert your e-mail address and set the number of most recent files to download
- Run gettrmm.pl -> you should get the original data (in rawdata) and the converted data (in fewsimport). These directories can be configured.
An example configuration of the import module (ImportTRMM 1.00 default.xml) plus id mapping (IdImportTRMM 1.00 default.xml) is also attached to this page.
Example
