Question

The geophysical variables that can be measured/derived from the Global Navigation Satellite System observations is/are

• A. ocean color
• B. precipitable water vapor
• C. soil moisture
• D. seismic motion

Hint:

GNSS isn't just for positioning—it's also a powerful tool for atmospheric and environmental monitoring, especially where electromagnetic signals interact with the Earth's surface or atmosphere.

Answer 1

The Correct Option is B, C, D

From Global Navigation Satellite System (GNSS) observations, the following geophysical parameters can be derived: (B) Precipitable Water Vapor (PWV): GNSS signals are delayed by atmospheric water vapor, and this delay can be used to estimate PWV. (C) Soil Moisture: GNSS-Reflectometry (GNSS-R) uses reflected GNSS signals from the ground surface, which are sensitive to soil moisture. (D) Seismic Motion: High-rate GNSS observations can track ground displacements, making them useful in detecting and monitoring seismic events. (A) Ocean Color: This is typically measured using optical sensors aboard remote sensing satellites and not from GNSS observations.