Microwave Propagation and Remote Sensing

6

Rain Attenuation and Its Application at Microwaves

6.1 Introduction

It is known that most of the water in air remains as water vapor rather than as liquid or solid hydrometeors. It is understood that if the ambient temperature at a certain height is 0°C or below, the hydrometeors are ice. But below this height where temperature is 0°C, ice starts melting and transfers into rain. But the fall of rain is prevented by the rising air currents. As water condenses, it forms ice crystals that are small enough to be supported by air currents. These particles are clubbed together until they become too heavy for rising currents to support. These heavy particles fall as rain. The weather radar can have a strong return echo from this height, which ...