Impact of 3-D topography on downwelling surface radiation flux using MODIS products and SRTM digital elevation model
Libeesh Lukose (92313011)
Impact of 3-D topography on downwelling surface radiation flux using MODIS products and SRTM digital elevation model
The aim of this study is to estimate the incoming shortwave radiation fluxes over different physiographic set-up of Indian sub-continent using Aqua MODIS product, digital terrain model and parameterization schemes. The study also assesses the spatial and temporal variability of the radiation fluxes on different physiographic divisions, aspect angles, slopes and altitudes including Himalayan ranges. The method not only eliminates the need for ancillary ground data but also explicitly recognizes the need for spatially varied input parameters. Zillman (1972) parameterization scheme, as reported in Niemela, Raisanen, and Savijarvi (2001) and Bisht et al. (2005), has been used to estimate incoming shortwave radiation flux considering the surface is horizontal with respect to incident radiation. However, in case of mountainous topography, to include the effect of slope and aspect, solar zenith angle was replaced with angle of incidence which is the angle between the incident sun rays and normal to the surface as was given by Gates 1980. The modeled shortwave flux was validated using limited sets of radiometric data collected from India Meteorological Department website.
REMOTE SENSING
TOPOGRAPHY
DIGITAL ELEVATION MODEL
Impact of 3-D topography on downwelling surface radiation flux using MODIS products and SRTM digital elevation model
The aim of this study is to estimate the incoming shortwave radiation fluxes over different physiographic set-up of Indian sub-continent using Aqua MODIS product, digital terrain model and parameterization schemes. The study also assesses the spatial and temporal variability of the radiation fluxes on different physiographic divisions, aspect angles, slopes and altitudes including Himalayan ranges. The method not only eliminates the need for ancillary ground data but also explicitly recognizes the need for spatially varied input parameters. Zillman (1972) parameterization scheme, as reported in Niemela, Raisanen, and Savijarvi (2001) and Bisht et al. (2005), has been used to estimate incoming shortwave radiation flux considering the surface is horizontal with respect to incident radiation. However, in case of mountainous topography, to include the effect of slope and aspect, solar zenith angle was replaced with angle of incidence which is the angle between the incident sun rays and normal to the surface as was given by Gates 1980. The modeled shortwave flux was validated using limited sets of radiometric data collected from India Meteorological Department website.
REMOTE SENSING
TOPOGRAPHY
DIGITAL ELEVATION MODEL