Temporal and spatial variability of aerosol optical depth over South India as inferred from MODIS

Aerosols play a very significant role in determining earth's climate, but to study their quantitative effect is a challenging task due to their high spatial and temporal variability. The data from MODIS on-board Terra satellite during 2001–2008 have been used to study the spatial and temporal variability of AOD and also to identify homogeneous aerosol regions over South India. In this study we found two distinct regions within the selected study region that are characterised by low and high coefficients of variation (COV) of AOD values. The region with low COV is characterised by high AOD and vice versa. The spatial correlation is found to be symmetric for in-land locations but skewed towards Bay of Bengal for coastal locations. The spatial correlation is found to be significant for a radial distance of 150 km from the region of interest.

► Study of spatial homogeneity of aerosols over a large area has been attempted for the first time.
► Study region is classified into two distinct regions based on coefficient of variation of AOD.
► Spatial homogeneity of aerosols is found to be skewed towards Bay of Bengal for coastal locations.
► AOD can be considered to be homogeneous for a radial distance of 100–150 km.
► Spatial homogeneity of aerosols is very useful in assessing quality of the satellite data at different resolutions.