How to import TRMM global precipitation data

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.

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

• gettrmm.pl -> gets the last n files from the ftp site, and call 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

1. Download the attached scripts GetTRMM.zip and unzip
2. Edit gettrmm.pl, insert your e-mail address and set the number of most recent files to download
3. 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