Characterization of aerosol optical and radiative properties at Leh, located over the climate sensitive Hindu Kush Himalayan region using sky radiometer observation

IF 4.2 2区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Atmospheric Environment Pub Date : 2025-04-20 DOI:10.1016/j.atmosenv.2025.121234

Shantikumar S. Ningombam , Swagata Mukhopadhyay , B.L. Madhavan , A.K. Srivastava , Som K. Sharma , Amarendra Singh , Sonam Jorphel , Dorje Angchuk , Tashi Thsering Mahay

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Abstract

Aerosol optical and radiative properties over the Leh Ladakh, located in the climate sensitive Hindu Kush Himalayan region are examined using one year measurements from a newly installed sky radiometer from July 2023 to June 2024. Columnar aerosol optical depth (AOD), at 500 nm exhibits a distinct seasonal variation with peak during spring (0.104 ± 0.041) and minimum in autumn (0.077 ± 0.031), while Extinction Angstrom Exponent (EAE) is found to be maximum in winter (1.041 ± 0.205) and minimum (0.658 ± 0.225) in spring. The highest EAE in winter is complemented with the highest AOD_Fine-mode (0.071 ± 0.034) among the seasons which may be associated with the combustion of firewood, charcoal, kerosene or other fuels used to burn to bear the cold winter months, when temperature varied between −15 and −25 °C. Seasonal variation of Single Scattering Albedo (SSA) at 500 nm varied from 0.905 ± 0.055 (winter) to 0.942 ± 0.061 (summer), while the lowest value of SSA during winter is complemented with more absorbing aerosols during winter season. The dominance of fine mode aerosols during the winter seasons is also complemented by the bi-modal volume size distribution. However, the station is experiencing a negligible contribution of dust-aerosols (1%), followed by 18% mixed aerosols and 16% non-absorbing aerosols. The current observing site is dominated by absorbing aerosols which contributed by highly absorbing (49%), moderately absorbing (9%) and slightly absorbing (6%) during the one year of study period. The absorbing aerosols are characterized by high values of AOD_Fine-mode (0.061 ± 0.028), imaginary refractive-index (0.014 ± 0.009), EAE (0.932 ± 0.240) and low value of SSA_Total (0.872 ± 0.070). On the other hand, the non-absorbing aerosols are characterized by high values of AOD_Total (0.088 ± 0.040), SSA_Total (0.991 ± 0.016), SSA_Coarse-mode (0.978 ± 0.038), and low value of imaginary refractive-index (

\sim

0.001). The estimated aerosol radiative forcing (ARF) reveals the high heating rates during spring (0.09 K day⁻¹) among the seasons, while the heating rate is found to be highest by absorbing aerosols (0.08 K day⁻¹) among the aerosol types.

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利用天空辐射计观测气候敏感的兴都库什喜马拉雅地区列城气溶胶光学和辐射特性

列拉达克位于气候敏感的兴都库什喜马拉雅地区，利用新安装的天空辐射计从2023年7月到2024年6月的一年测量数据，研究了列拉达克气溶胶的光学和辐射特性。500 nm处柱状气溶胶光学深度（AOD）季节性变化明显，春季峰值（0.104±0.041），秋季最小（0.077±0.031）；消光埃指数（EAE）冬季最大值（1.041±0.205），春季最小（0.658±0.225）。冬季EAE最高，AOD_Fine-mode最高（0.071±0.034），这可能与燃烧木柴、木炭、煤油或其他燃料以承受寒冷的冬季有关，当温度在- 15至- 25°C之间变化。500 nm单次散射反照率（SSA）的季节变化范围为0.905±0.055（冬季）~ 0.942±0.061（夏季），冬季最低的SSA被冬季吸收较多的气溶胶所补充。细态气溶胶在冬季的优势也由双峰态体积大小分布补充。然而，该站所经历的粉尘气溶胶的贡献可以忽略不计（1%），其次是18%的混合气溶胶和16%的非吸附性气溶胶。目前观测点以吸收气溶胶为主，在一年的研究期间，气溶胶的吸收分别为高吸收（49%）、中等吸收（9%）和轻微吸收（6%）。吸波气溶胶具有高AOD_Fine-mode（0.061±0.028）、高虚折射率（0.014±0.009）、高EAE（0.932±0.240）和低SSA_Total（0.872±0.070）的特征。非吸收气溶胶具有高的AOD_Total（0.088±0.040）、SSA_Total（0.991±0.016）、ssa_粗模（0.978±0.038）和低的虚折射率（~ 0.001）。气溶胶辐射强迫（ARF）估算结果表明，春季（0.09 K d−1）的升温速率在各季节中较高，而气溶胶类型中吸收气溶胶（0.08 K d−1）的升温速率最高。

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来源期刊

Atmospheric Environment 环境科学-环境科学

CiteScore

9.40

自引率

8.00%

发文量

458

审稿时长

53 days

期刊介绍： Atmospheric Environment has an open access mirror journal Atmospheric Environment: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review. Atmospheric Environment is the international journal for scientists in different disciplines related to atmospheric composition and its impacts. The journal publishes scientific articles with atmospheric relevance of emissions and depositions of gaseous and particulate compounds, chemical processes and physical effects in the atmosphere, as well as impacts of the changing atmospheric composition on human health, air quality, climate change, and ecosystems.