Tiwary Priyanshu, Kukreti Saurabh, Shridhar Vijay, Abhinav Akash, Rana Shakuntala, Arunachalam Kusum, Singh Vimal
School of Environment and Natural Resources, Doon University, Dehradun 248001, India.
School of Environment and Natural Resources, Doon University, Dehradun 248001, India.
Sci Total Environ. 2024 Jul 10;933:173050. doi: 10.1016/j.scitotenv.2024.173050. Epub 2024 May 9.
The study aimed to understand the optical properties of Black Carbon (BC) and radiative forcing over a data deficient Himalayan region focusing on critical zone observatory employing ground-based measurements by Aethalometer for BC and satellite retrieval techniques for optical properties during mid-May-June 2022 and January-May 2023. BC mass concentration ranged from 0.18 to 4.43 μgm, exhibit a mean of 1.47 ± 0.83 μgm with higher summer concentration (1.51 ± 0.94 μgm) than winter (1.39 ± 0.61 μgm). The average Absorption Ångström Exponent observed to be significantly higher than unity (1.77 ± 0.31) over the studied high-altitude Himalayan region, suggesting the dominance of biomass-burning aerosol. Higher aethalometer derived compensation parameter (K) in winter suggesting locally originated BC while, lower K value in summer suggesting aged BC transported from Indo-Gangetic Plains. Optical properties calculated from "Optical Properties of Aerosol and Cloud" (OPAC) model are used in the "Santa Barbara DISORT Atmospheric Radiative Transfer" (SBDART) model to calculate the aerosol Direct Radiative Force (DRF). The entire studied period is characterized by the predominance of absorbing aerosols, particularly BC, increasing Aerosol Optical Depth, Asymmetric Parameters and decreasing Single Scattering Albedo, leading to a considerable increase in atmospheric radiative forcing (+0.9 Wm, top of atmosphere) and Heating Rate (0.36 KDay). The mean radiative forcing within atmosphere during summer was higher (+14.29 Wm) relative to the winter (+12.00 Wm), emphasizing the impact of absorbing aerosols on regional warming and potential glacier melting in the Himalayas at a faster rate. Urgent policy consideration for the reduction of absorbing aerosols is highlighted, recognizing the critical roles of Black Carbon in the changing behaviour of Critical Zone observatory. The study's data serve as a valuable resource to understanding and addressing uncertainties in climate models, aiding effective policy implementation for Black Carbon reduction.
该研究旨在通过2022年5月中旬至6月以及2023年1月至5月期间，利用黑碳（BC）的黑碳仪地面测量数据和光学特性的卫星反演技术，了解数据匮乏的喜马拉雅地区的黑碳光学特性和辐射强迫，重点关注关键带观测站。BC质量浓度范围为0.18至4.43μg/m³，平均为1.47±0.83μg/m³，夏季浓度（1.51±0.94μg/m³）高于冬季（1.39±0.61μg/m³）。在所研究的高海拔喜马拉雅地区，观测到的平均吸收埃指数明显高于1（1.77±0.31），这表明生物质燃烧气溶胶占主导地位。冬季黑碳仪得出的补偿参数（K）较高，表明BC是本地产生的，而夏季K值较低，表明是从印度-恒河平原输送来的老化BC。由“气溶胶和云的光学特性”（OPAC）模型计算出的光学特性被用于“圣巴巴拉离散纵标大气辐射传输”（SBDART）模型中，以计算气溶胶直接辐射强迫（DRF）。整个研究期间的特点是吸收性气溶胶占主导，特别是BC，气溶胶光学厚度、不对称参数增加，单次散射反照率降低，导致大气辐射强迫（大气顶层为+0.9W/m²）和加热率（0.36K/天）显著增加。夏季大气中的平均辐射强迫（+14.29W/m²）相对于冬季（+12.00W/m²）更高，这突出了吸收性气溶胶对喜马拉雅地区区域变暖以及潜在冰川快速融化的影响。强调了减少吸收性气溶胶的紧急政策考量，认识到黑碳在关键带观测站变化行为中的关键作用。该研究的数据是理解和解决气候模型不确定性的宝贵资源，有助于有效实施减少黑碳的政策。
