|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|6343190||1620511||2015||8 صفحه PDF||سفارش دهید||دانلود رایگان|
- Aerosol radiative forcing estimated from dust, anthropogenic, and clean conditions
- Dust advection is more pronounced than the anthropogenic cases at the station.
- Dust aerosols exhibit stronger radiative forcing than the anthropogenic aerosols.
- Atmospheric perturbation was enhanced by surface cooling and atmospheric warming.
Estimation of aerosol radiative forcing (ARF) was performed using a radiative transfer model (Rstar6b) along with physical and optical parameters of aerosols obtained from sky radiometer observation over Indian Astronomical Observatory (IAO), Hanle, Ladakh, during 2008-2010 from dust, anthropogenic, and aged background observing conditions. ARF was estimated at the top of the atmosphere (TOA), in the atmosphere, and at the surface during the three observing conditions. During dust and anthropogenic events, average aerosol optical depth (AOD at 500Â nm) went up to 0.24 from the aged background observing condition 0.04. Such enhancement of AOD is associated by the combination of desert-dust and anthropogenic aerosols transported from distant sources as noticed from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Such three types of aerosols are also identified from the observed properties of single scattering albedo (SSA), aerosol asymmetry (AS) parameter, and aerosol size distribution. The estimated ARFs at TOA, at the surface, and in atmosphere are âÂ 3.73, âÂ 6.82, and 3.40Â WmâÂ 2, respectively during the dust advection period. On the contrary, the respective ARFs during the aged background observing condition are âÂ 1.50, âÂ 2.22, and 0.70Â WmâÂ 2, respectively. A significant difference of spectral AOD is observed during dust, anthropogenic, and aged background observing conditions. Ã ngström exponent (AE) decreases from 1.05 in the aged background observing condition to 0.40 in the dust event. A significant difference of coarse-fine mode volume distribution is also observed between the dust and the anthropogenic cases. Further, the study reveals high aerosols induced during the dust and the anthropogenic episodes caused warming at atmosphere and cooling at surface which collectively may affect the local atmospheric circulation.
Journal: Atmospheric Research - Volumes 164â165, 1 Octoberâ1 November 2015, Pages 76-83