Figure 1.
Monthly mean columnar AODs at five different wavelengths (nm).
Figure 2.
Seasonal variations in a) AOD at 500 nm and Angstrom exponent and b) derivative of Angstrom exponent.
Figure 3.
Seasonal variations in fine and coarse mode aerosol concentrations.
Figure 4.
Seasonal variations in concentrations of several aerosol components.
Figure 5.
Comparisons of aerosol components between Darjeeling (2200 m) and other Himalayan sites.
(Jiri, Nepal at 1900 m; Nagarkot, Nepal at 2150 m; Langtang, Nepal at 3920 m; Phortse, Nepal at 4450 m; NCO-P, Nepal at 5079 m). Data have been taken from Decesari et al. [20]. It is seen that dust component (Ca2+) over Darjeeling does not significantly differ from other locations during premonsoon. This vertical homogeneity of dust aerosol could be attributed to a common transport mechanism i.e. long-range transport from distant sources. Black Carbon and Sulphate aerosols over Darjeeling show significant differences from other locations. This vertical inhomogeneity could be attributed to the local anthropogenic sources.
Figure 6.
Contour plots of Aerosol Index (AI) showing dust transport over Himalaya during a) April 2008 and b) May 2008.
Figure 7.
Percentage changes in aerosol component concentrations and AOD (at 500 nm) from respective annual means.
Figure 8.
Correlations between increase in AOD (500 nm) and a) increase in dust loading during pre-monsoon and b) increase in anthropogenic aerosol loading during winter.