Spatio-temporal synoptic variability of aerosol optical depth and cloud properties over the Central North region of India through MODIS collection V satellite sensors

Aerosol optical depth ( AOD) values at 550 nm derived from the Moderate-resolution Imaging Spectroradiometer ( MODIS) sensors have been analyzed in the present study. The retrieved MODIS satellite data have been used to investigate the temporal heterogeneity in columnar aerosol characteristics over the Central North region of India with a resolution of 1 degrees x 1 degrees grid in magnitude for the 10-year period of 2003-2012. Seasonal and inter-annual variations of AOD values are examined in light of regional synoptic climatic meteorology. On an annual basis, high annual average AOD values (>0.5) are found at Delhi (similar to 0.75 +/- 0.44), Kanpur (similar to 0.69 +/- 0.7) and Chandigarh (similar to 0.55 +/- 0.16), whereas low annual average AOD values (<0.5) are found at Raipur (similar to 0.38 +/- 0.046), Jaipur (similar to 0.38 +/- 0.096), Bhopal (similar to 0.33 +/- 0.087), Nainital (similar to 0.19 +/- 0.097) and Shimla (similar to 0.19 +/- 0.11). Highest annual mean increase in AOD (similar to 75 %) has been found over Jaipur, whereas lowest over Chandigarh (similar to 21 %) across Central North region of India during the study period of 2003-2012. We have investigated the relationship between Terra AOD values at 550 nm and other cloud parameters, namely cloud fraction, water vapor, cloud top temperature, cloud top pressure, cloud optical depth and cloud effective radius over this urban tropical zone of India so as to have a better understanding of aerosol-cloud interaction. A one-tailed distribution single paired Student's t test has also been applied to the Terra AOD values and cloud parameters.