Satellite Center: Tropical Rainfall Measuring Mission (TRMM)

Orbital Altitude: 400 km (after re-boost)

Orbital Inclination: 35°

More about orbits

TRMM is the first mission dedicated to measuring tropical and subtropical rainfall.
Measurements from TRMM are used to find out where it's raining, and how hard it's raining. Not all clouds cause rain, and when rain does fall, it falls through various heights in the atmosphere, sometimes not reaching the ground at all!
Because rain is so variable, we have never known before just how much rain actually falls across the earth, but it is something we need to know if we are going to be able to predict wind patterns and ocean currents, floods and droughts.
TRMM won't be used for the daily rainfall measurements in your city, but it will be used by atmospheric scientists and weather forecasters to understand better how rainfall happens and why, so they can improve their forecasts in the future.