Microwave Propagation and Remote Sensing

5

Absorption of Microwaves

5.1 Introduction

Generally, it is known that solar radiation starts to pass down from the top of the atmosphere and, hence, scattering and absorption take place due to the presence of several molecules in the atmosphere. The abundance of different molecules in the lower troposphere is much larger than those in the upper atmosphere. It was discussed in previous chapters that the presence of water vapor molecules, although small, produces a sizable attenuation in the microwave band.

The absorption exhibited by gaseous molecules, possessing permanent electric and magnetic dipole moment, is due to the coupling of electric dipole and magnetic dipole with electric component and magnetic component of the incoming electromagnetic ...