Indian Institute of Tropical Meteorology, MoES, Govt. of India, Pune, India; Savitribai Phule Pune University, Pune, India.
Indian Institute of Tropical Meteorology, MoES, Govt. of India, Pune, India; Savitribai Phule Pune University, Pune, India.
Sci Total Environ. 2021 Apr 20;766:144242. doi: 10.1016/j.scitotenv.2020.144242. Epub 2020 Dec 24.
Continuous measurement of Black Carbon (BC) concentration was carried out during May-October 2018 periods over Satopanth Glacier in the central Himalayas. BC concentrations varied between 28 and 287 ngm on different days during the observational period. High concentration of BC was observed in the month of May (monthly mean of 221 ± 79 ngm), and a lower concentration was observed in August (monthly mean of 92 ± 58 ngm). Biomass burning was found to contribute up to 58% of BC mass over the region, with lower contribution during June and higher during the month of May. Compensation parameter (K) values were found to vary between -0.005 and 0.005 in different months, asserting the presence of aged BC in June to October months and relatively fresh BC in the month of May. Concentration weighted trajectory (CWT) analysis showed that the air mass from Indo Gangetic Plains (IGP) was responsible for the majority of transported BC in July & August months (up to 65%) and partially in September (up to 40%). However, the transport from Middle East and far north-western regions was found to be the major contributor to BC concentrations in other months. The estimated BC direct radiative forcing was found to induce 4.5 to 7.6 Wm reduction of radiation at the surface (SFC) and the forcing was +2.3 to +3.5 Wm at the Top of the Atmosphere (TOA). The BC induced atmospheric heating rates were found to be up to 0.35 k day over the region. The sensitivity of snow albedo to radiative forcing was studied, and it is found that BC albedo changes tend to decrease albedo with an increase in BC-snow deposition, leading to a decrease in atmospheric absorption.
2018 年 5 月至 10 月期间，在喜马拉雅山脉中部的萨托潘恩冰川上进行了黑碳（BC）浓度的连续测量。在观测期间的不同日子里，BC 浓度在 28 到 287ngm 之间变化。5 月份观测到的 BC 浓度较高（月平均值为 221±79ngm），8 月份观测到的浓度较低（月平均值为 92±58ngm）。研究发现，生物质燃烧对该地区 BC 质量的贡献高达 58%，6 月和 5 月的贡献较低。补偿参数（K）值在不同月份变化在-0.005 到 0.005 之间，表明 6 月至 10 月存在老化的 BC，而 5 月存在相对新鲜的 BC。浓度加权轨迹（CWT）分析表明，来自印度恒河平原（IGP）的气团是 7 月和 8 月（高达 65%）以及部分 9 月（高达 40%）输送的大部分 BC 的原因。然而，从中东和远西北地区的输送被发现是其他月份 BC 浓度的主要贡献者。估计的 BC 直接辐射强迫导致地面（SFC）辐射减少 4.5 至 7.6 Wm，在大气层顶（TOA）的强迫为+2.3 至+3.5 Wm。在该地区，BC 引起的大气加热率高达 0.35 k day。研究了雪反照率对辐射强迫的敏感性，发现 BC 反照率的变化趋势是随着 BC-雪沉积的增加而降低反照率，从而导致大气吸收减少。
