Increased absorption by coarse aerosol particles over the Gangetic–Himalayan region

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Atmospheric Chemistry and Physics (Online)

DOI:https://doi.org/10.5194/acp-14-1159-2014· OSTI ID:1393991

Manoharan, V. S.; Kotamarthi, R.; Feng, Y.; Cadeddu, M. P.

Each atmospheric aerosol type has distinctive light-absorption characteristics related to its physical/ chemical properties. Climate models treat black carbon as the main light-absorbing component of carbonaceous atmospheric aerosols, while absorption by some organic aerosols is also considered, particularly at ultraviolet wavelengths. Most absorbing aerosols are assumed to be < 1 μm in diameter (sub-micron). Here we present results from a recent field study in India, primarily during the post-monsoon season (October–November), suggesting the presence of absorbing aerosols sized 1–10 μm. Absorption due to supermicron- sized particles was nearly 30% greater than that due to smaller particles. Periods of increased absorption by larger particles ranged from a week to a month. Radiative forcing calculations under clear-sky conditions show that supermicron particles account for nearly 44% of the total aerosol forcing. The origin of the large aerosols is unknown, but meteorological conditions indicate that they are of local origin. Such economic and habitation conditions exist throughout much of the developing world. Hence, large absorbing particles could be an important component of the regional-scale atmospheric energy balance.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science - Office of Biological and Environmental Research
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1393991
• Journal Information: Atmospheric Chemistry and Physics (Online), Vol. 14, Issue 3; ISSN 1680-7324
• Publisher: European Geosciences Union
• Country of Publication: United States
• Language: English