| dc.description.abstract |
Anthropogenic aerosol induced declining trends in indian region precipitation are now acknowledged, however, the role of rapid adjustments to aerosol forcing needs further understanding. An atmospheric general circulation model with dynamic aerosol fields, echam6-ham2, is used to investigate changes in stratiform and convective precipitation through simulations using different levels of aerosol emissions over india. The spatial pattern of precipitation change, with increased aerosol levels, increases over the northern indian region, decreasing over peninsular south india. This is driven by the spatial heterogeneity of stratiform precipitation changes, while simultaneous convective precipitation changes are negative throughout the subcontinent, from absorbing aerosol induced stabilization. Stratiform response to the rapid adjustments includes dynamic changes to the divergence of the dry static energy, cloud microphysics and rainfall formation processes. Positive divergence in dry static energy, consistent with moisture convergence, leads to increased water vapour mixing ratios, thus significantly increasing cloud liquid water and cloud fraction in north india. The increases in rainfall formation processes like the autoconversion rate result from those in the liquid water path, which overcome decreases due to increased droplet number concentration. Overall, aerosol induced changes in dynamic dry static energy divergence, rather than on cloud microphysics, play a dominant role in driving the spatial heterogeneity in stratiform and total precipitation change in the indian region. © 2021, the author(s), under exclusive licence to springer-verlag gmbh germany, part of springer nature. |
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