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Brightness temperature and emissivity retrieved from a portable L-band radiometer
Journal
International Journal of Remote Sensing
ISSN
01431161
Date Issued
2022-01-01
Author(s)
Krishnan, Sooraj
Nair, Akhilesh S.
Indu, J.
Jove-Casulleras, R.
Gonzalvez-Foguet, R.
Abstract
L-band microwave radiometry is one of the globally accepted techniques to estimate surface soil moisture by measuring upwelling brightness temperature (TB) from the surface. L-band radiometers have been historically used for ground truth validation of space-borne missions. Existing devices are distinguished by using huge and bulky antennas to conduct precise multi-angular measurements at the cost of portability. The current work demonstrates that a portable ground-based L-band microwave radiometer can be used to measure high-resolution TB, soil temperature and emissivity in a case study area in India as an alternative to a traditional huge ground-based radiometer. To show the influence of surface soil moisture (SM) on TB, a controlled experiment was conducted to investigate the temporal variation of TB over a bare soil surface. Spatial analysis of the measured data shows that the compact radiometer can efficiently capture the linear relationship between emissivity and TB, while temporal analysis of TB over a small area shows the variation in TB dynamics with SM.