Brightness temperature and emissivity retrieved from a portable L-band radiometer

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.

Acknowledgements

The authors acknowledge the support through DST-Centre of Excellence in Climate Studies at IIT Bombay (Project No: DST/CCP/CoE/140/2018 (G)) for carrying out this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the DST Centre of Excellence in Climate Studies [DST/CCP/CoE/140/2018 (G)].