Question

Choose the CORRECT statement(s) regarding microwave remote sensing.

• A. Spatial resolution of passive microwave remote sensor is coarser than that of active microwave remote sensor from the same platform
• B. The intensity of signal returned by an object depends on its geometric as well as dielectric properties
• C. It is possible to “see through” the dense forest canopy using X-band active microwave remote sensing (i.e.\ signals can penetrate the dense forest canopy)
• D. Microwave remote sensing can be used in soil moisture studies

Hint:

Penetration increases with wavelength: X (short) < C < L < P (long). Soil moisture strongly affects microwave dielectric properties \(⇒\) strong signal sensitivity.

Answer 1

The Correct Option is A

(A) True. Passive microwave radiometers need large antenna apertures to achieve fine IFOV; from the same platform their spatial resolution is much coarser than active SAR.
(B) True. Backscatter depends on geometry/roughness (surface slope, structure) and dielectric constant (moisture content), among other factors (wavelength, polarization, incidence angle).
(C) False. X-band (\(\sim\)3~cm wavelength) has poor canopy penetration; L-/P-band provide deeper penetration in vegetation.
(D) True. Both passive (brightness temperature) and active (backscatter) microwave methods are widely used for soil moisture retrieval.