Publications

Gharekhan, D; Nigam, R; Bhattacharya, BK; Desai, D; Patel, P (2022). Estimating regional-scale daytime net surface radiation in cloudless skies from GEO-LEO satellite observations using data fusion approach. JOURNAL OF EARTH SYSTEM SCIENCE, 131(2), 73.

Abstract
Net surface radiation (R-n) at earth surface comprises of outgoing and incoming components of longwave and shortwave radiation fluxes at the surface. This influences energy and mass exchange over earth surface at sub-daily, seasonal and annual time scales. This is a critical component for land surface models which characterize climatic, ecological and biological processes. Measured net radiation datasets are rarely available and can be subjected to errors and high uncertainties due to equipment malfunctions and failure. In this study, a regional-scale model is developed and implemented to estimate the net surface radiation fluxes over Indian landmass under cloudless sky conditions using the data from an Indian Geostationary (GEO) Meteorological satellite (INSAT 3D) and polar-orbiting (LEO) MODIS-Aqua for daytime conditions. The estimates were evaluated over a 6-month period (Nov 2019-Apr 2020) during winter and summer months, at three in situ measurement sites, located in cropland and grassland. The results showed a correlation of 0.86 between satellite-based R-n estimates and in situ measurements with a root mean square error (RMSE) of 40.4 W m(-2) (4.6% of measured mean) and a mean absolute error (MAE) of 5.6% of measured mean. The modelled estimates were compared with NCEP (National Center for Environmental Protection) reanalysis global surface radiation estimates diurnally. The NCEP model tends to under- or over-estimate during the study time period especially in the month of January.

DOI:
10.1007/s12040-021-01806-9

ISSN:
0973-774X