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Abstract: Rate of aerosol production/loss over the globe is estimated employing aerosol flux continuity equation by introducing multi-year satellite measurements on aerosols and reanalyzed winds. The estimation is done for the four different seasons averaged over a period of four years, 2007–2010. Prominent aerosol production with a source strength ∼0.2 AOD day−1 is observed over east Asia in all the seasons. There are regions of significant production in central Asia and north western Africa in DJF (December–February) and MAM (March–May) seasons and over eastern mid Atlantic in MAM and JJAS (June–September) seasons. Aerosol production is found the largest with rate >0.5 AOD day−1 over north western Indian Ocean during JJAS season, in association with summer monsoon circulation. Role of atmospheric dynamics in aerosol distribution through transport, accumulation and dispersion is made evident through the mismatch observed between the regions of aerosol production and aerosol abundance. [Copyright &y& Elsevier]

Abstract: This study explores the inevitable role of wind parameters such as wind speed, wind convergence and wind vorticity in the long range transport and distribution of aerosols in the winter time atmosphere over the Bay of Bengal (BoB) during the campaign Winter ICARB. MODIS observed aerosol optical depth (AOD), with an excellent agreement with ship borne Microtops AOD, was found to increase over the BoB particularly, in the eastern parts during the course of the campaign. The influence of atmospheric circulation on this increase is examined using the wind field from NCEP reanalysis and computed wind convergence and vorticity for first and second halves (FH and SH) of the campaign along with a back trajectory analysis using HYSPLIT transport and dispersion model. While surface winds over the BoB remained nearly the same throughout the campaign denying the possibility of enhancement in marine aerosol generation, the higher altitude winds altered significantly in SH providing a channel for aerosol transport from the Indian landmass to the BoB in addition to the increased forest fire contribution from south Asia. This suggested mechanism is supported by CALIPSO aerosol extinction profiles over the eastern BoB and the surrounding land masses. Fine particle dominance in MODIS AOD and diminished correlation between ship borne AOD and surface aerosol mass measurements during SH corroborate this inference by indicating the presence of elevated aerosol layers, which can contribute substantially to the radiative effects of the earth–atmosphere system. This study throws light on the importance of wind convergence and vorticity in the investigations on the long range transport and spatial distribution of aerosols. [Copyright &y& Elsevier]