Question

Discuss briefly the process of remote sensing in the microwave region of the electromagnetic spectrum.

Answer 1

In the microwave region of the electromagnetic spectrum (wavelengths 1 mm to 1 m), remote sensing relies on both passive and active sensing.

• Passive microwave sensing involves detecting natural microwave energy emitted by Earth’s surfaces (like soil and water). It’s useful for studying sea ice, snow cover, soil moisture, and ocean salinity.
• Active microwave sensing (like radar and synthetic aperture radar/SAR) sends out microwave pulses from the sensor, which then bounce back after hitting Earth’s surface. By analysing these backscattered signals, we can map terrain, vegetation, water bodies, and man-made structures.

Microwave remote sensing is unique because microwave energy can penetrate clouds, rain, and even vegetation. This makes it extremely valuable for monitoring Earth’s surface under all weather conditions and at night.