A long-term study of aerosol modulation of atmospheric and surface solar heating over Pune, India

作者：Kumar Sumit; Devara P C S^*

来源：Tellus Series B-Chemical and Physical Meteorology, 2012, 64: 18420.

DOI：10.3402/tellusb.v64i0.18420

• aerosol optical properties
• direct radiative effect
• surface albedo
• sun/sky radiometer
• heating rates

Implications of aerosol characteristics, observed during a five-year (2004-2009) period over Pune (a tropical urban location), to short-wave radiation budget are reported. A discrete ordinate radiative transfer (DISORT) model with a code, namely, Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART), has been used to carry out the radiative transfer computations. The validity of the method is demonstrated using independent ground-based remote sensing observations. Uncertainties in the estimates are also quantified. Clear-sky forcing reveals the points that include (1) Large negative bottom-of-the-atmosphere (BOA) forcing (more than -30 Wm(-2)) in all the months with peaks during October, December and March when the surface forcing exceeds similar to -40 Wm(-2), and (2) Surface forcing values are higher for pre-monsoon months, while they are comparable for winter and post-monsoon months. The top-of-the-atmosphere (TOA) forcing is found to be negative during all the seasons. Large differences between TOA and BOA forcing during pre-monsoon, winter and post-monsoon indicate large absorption of radiant energy (similar to 30 Wm(-2)) within the atmosphere during these seasons, thus increasing atmospheric heating by similar to 1 K/d. These values imply that aerosols have considerable impact on the atmosphere-surface system by causing substantial warming/cooling at the atmosphere/surface. This persistent trend in strong atmospheric absorption is likely to alter atmospheric thermodynamic conditions and thus affects circulation considerably.

• 出版日期2012