Conclusions

Radars can potentially be used to monitor soil moisture, plant moisture content, and vegetation production. For example, it has been demonstrated that drought conditions can be inferred from scatterometers by calculating soil moisture anomaly indicators or by using the remotely sensed parameters as input to the more complex crop-growth models to capture cumu-

SWI February 1999 GPCC Frebruary 1999

SWI February 1999 GPCC Frebruary 1999

Figure 8.2 Spatial drought pattern of an extreme winter drought that hit China in 1999 as reflected in scatterometer data and gridded precipitation data. Left: difference of February and March 1999 profile soil moisture to the 1992-2000 average derived from scatterometer data; right: difference of February and March 1999 gridded precipitation (GPCC, 1998) to the 1992-2000 average.

lative effects of droughts. However, applications of radars in monitoring drought stress have been limited due to the relative newness of radar technology, the lack of operational radar sensor systems, and the complex interaction of radar waves with natural surfaces. Realistically, much more research and preoperational demonstrations need to be carried out before radars can be accepted as dependable information providers for drought monitoring systems. Nevertheless, a greater understanding of the radar capabilities will lead to the more intelligent use of the SAR systems such as RadarSat-2 (scheduled to be launched in 2005) or METOP (scheduled to be launched in 2005) for operational drought monitoring.

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PART III

THE AMERICAS

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