The Tropical Rainfall Measuring Mission (TRMM) is a joint U.S.-Japan
satellite mission to monitor tropical and subtropical precipitation
and to estimate its associated latent heating. TRMM was successfully
launched on November 27, 1997 at 4:27 PM (EST) from the Tanegashima
Space Center in Japan.
The purpose of the TRMM Ground Validation (GV) program is to develop
validation methods and to obtain reliable surface-based data during the
TRMM mission, with which the TRMM satellite measurements can be verified.
The TRMM GV network consists of four primary or direct data (DD) sites
and seven direct product (DP) sites. The four DD sites are Darwin,
Australia; Melbourne, Florida; Houston Texas; and Kwajalein. The seven
DP sites are located in Taiwan, Israel, Thailand, Brazil, Guam, and
special climatology-multiple radar sites in Florida and Texas.
TRMM_GV_1C51 represents quality controlled reflectivity fields of
TRMM_GV_1B51. The algorithm removes non-meteorological radar echoes,
such as clutter associated with insects, birds, chaff, wildfires, and
anomalous propagation (AP), that adversely affect the quality of the
higher level products. The design and implementation of the algorithm
are discussed in Rosenfeld et al. (1995) and is described in more
detail in the JCET home page
"). Eight adjustable
parameters, three echo height thresholds, and five radar reflectivity
thresholds are used to optimize the performance of the algorithm. Only
volume scans with four or more tilt angles (full volumes) are retained
from TRMM_GV_1B51. Every full volume is saved a half hour before or
after the satellite passes over the site (satellite coincidence);
otherwise, two full volumes are saved during non-coincidence, one full
volume in the first half hour and another in the second half hour.
The data, storing multiple volume scans, are in the Hierarchical Data
Format (HDF), which includes both core and product specific
metadata. The file size is about 5 MB for Darwin and about 1 MB for
the other sites (compressed). There are 24 files per day.
200 km radius from Ground Validation radar location