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Measurement Uncertainty and Error Propagation
of Satellite-based Precipitation Sensors

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Project Description

Satellite-based precipitation measurements are critical for a wide range of applications, such as terrestrial hydrology, water resources, climate change, agriculture and natural hazards. However, their usefulness is ultimately determined by the uncertainties in these measurements (Fig. 1). This project focuses on quantifying the uncertainties, attributed to both systematic and random errors, and on tracking down the error sources in the upstream satellite sensors.

Fig. 1. Global precipitation measurement uncertainty estimated from an ensemble of six different datasets, for winter (DJF) and summer (JJA). Large uncertainties can be seen at higher latitudes, over winter U.S. and Europe, and over summer Himalayas (Tian and Peters-Lidard, 2010).

Fig. 2. Global coverage of the passive microwave sensors over a 6-hour window for Aug. 1, 2005. These sensors are used to measure precipitation. The TRMM PR (not shown) overlaps with the central 1/3 of the TRMM TMI swath.

NASA's precipitation ESDRs are produced in two levels: level 2 and 3. Level-2 products contain rainfall measurements directly derived from satellite sensors at their footprint scales, while level-3 products are typically merged data from multiple level-2 products and other sensors and mapped into a uniform space and time grid.

Fig. 3. Equator-crossing time of the passive microwave sensors (image courtesy: Eric Nelkin).

This project is sponsored by the National Aeronautics and Space Administration (NASA) under the ESDR-ERR Program (NASA Contact: Martha E. Maiden).

Earth System Science Interdisciplinary Center
5825 University Research Ct., Ste. 4001
College Park, MD 20740