46 IRRIGATION AND WATER RESOURCES ENGINEERING
2.3.2.3. Satellite Measurement of Preciptation It is a common experience that gauge network for measuring precipitation in a large and inaccessible area (such as in desert and hilly regions) is generally inadequate, and non-existent in oceans. The satellite observation is the only effective way for continuous monitoring of precipitation events over a large or inaccessible area. Use of the meterological satellites for weather and water balance studies is, therefore, continuously increasing.
In satellite measurements, the precipitation is estimated by correlating the satellite-derived data and observed rainfall data. These relationships can be developed for a part of electromagnetic spectrum using cloud life history or cloud indexing approach. The first approach uses data from geo-stationary satellites that produce data at every half an hour interval. The second approach, based on cloud classification, does not require a series of consecutive observations of the same cloud system (2).
Microwave remote sensing techniques that can directly monitor the rainfall charac-teristics have great potential in rainfall measurement.
