Observations for


a) Daily precipitation estimates for the selected region from Jan 2010 to currently available data.

b) Dekadal (10 day) average precipitation estimates with the addition of the recent short-term average precipitation for the same region (grey dotted line). The blue (red) bars are indicative of estimates that are above (below) the short-term average. Note that the short-term average precipitation data has been smoothed.

NASA TRMM Rainfall Monitoring

This map shows global daily precipitation estimates.

The Tropical Rainfall Measuring Mission and Satellite (both referred to as TRMM) combine multiple sensor wavelengths, coverages and resolving capabilities to produce accurate measurements of precipitation in the tropics and sub-tropics.

Rainfall profiles are known to predict geographical risk of meningitis in some regions including north and west Africa (Molesworth et. al.). Furthermore, there is evidence that interannual epidemics disappear with the onset of the rainy season.

Dataset Documentation

Global daily precipitation estimates on a 0.25° x 0.25° lat/lon grid
Data Source

The Tropical Rainfall Measuring Mission (TRMM) is a joint space project with Japan. TRMM is designed to measure tropical precipitation and its variation from a low-inclination orbit combining a suite of sensors and land observations to overcome many of the limitations of remote sensors previously used for such measurements from space.

TRMM data availability is delayed for a period of 2 to 3 months. For example; the data for May 2012 would not be available until August 2012 due to extra inputs, variables and quality control measures.


Access the dataset used to create this map.


Contact help@iri.columbia.edu with any technical questions or problems with this Map Room, for example, the forecasts not displaying or updating properly.


The TRMM interface consists of a clickable map that allows users to generate customized time series graphs in different contextual perspectives. When a desired African location is clicked, 2 time series graphs will provide contextual analysis in the following perspectives:

a. Seasonal perspective - A single time series from Jan 2010 until present.

b. Recent Historical perspective - Recent precipitation averages in comparison to smoothed short-term averages.

By placing the current aerosol index in a recent historical and seasonal perspective, comparisons can be made to past outbreaks and useful early warning information can be developed for epidemic prone regions.