Institute of International Rivers and Eco-security, Yunnan University, Kunming, Yunnan 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Yunnan University, Kunming 650091, China.
State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2021 Oct 1;789:147746. doi: 10.1016/j.scitotenv.2021.147746. Epub 2021 May 21.
In snow and ice, light-absorbing particles (LAPs), such as black carbon (BC) and dust, accelerate the melting of Third Pole glaciers (TPGs). In this study, we revaluated LAP concentrations in the snow pits of TPGs (SP-TPGs), measured LAP mass absorption cross-sections (MACs), and simulated their effects on glacier darkening and melting based on the Spectral Albedo Model for Dirty Snow and a surface energy and mass balance model. The results indicated that because of their short distances to emission sources, the average BC concentrations measured in snow pits in the periphery of Third Pole were much higher than those measured in the inland Tibetan Plateau, and the average dust concentrations generally decreased from north to south. The average MACs of BC in the SP-TPGs varied from 3.1 to 7.7 m g at 550 nm, most of the average spectral values were comparable in the visible and near-infrared bands to those calculated by Mie theory, except those in Urumqi Glacier No. 1 (UR), Syek Zapadniy Glacier (SZ), and Laohugou Glacier No.12 (LH), while the average spectral MACs of dust in the SP-TPGs were considerably smaller in magnitude than most of the variations measured in other regions. Compared with the pure snow surfaces, BC and dust played comparable roles in reducing albedo in UR, SZ, LH, and Renlongba Glacier, whereas BC was the most prominent absorber in the other glaciers. The combined effect of BC and dust accelerated melting by 30.4-345.9 mm w.e. (19.7-45.3% of the total mass balance) through surface albedo darkening (0.06-0.17) and increased radiation absorption (25.8-65.7 W m) within one month of the ablation season. This study provides a new data set of LAP concentrations and MACs and helps to clarify the roles of these factors in the cryospheric environment of the Third Pole.
在冰雪中，吸光粒子（LAP），如黑碳（BC）和灰尘，会加速第三极冰川（TPG）的融化。在这项研究中，我们重新评估了 TPG 雪坑（SP-TPG）中的 LAP 浓度，测量了 LAP 质量吸收截面（MAC），并根据脏雪光谱反照率模型和表面能量和质量平衡模型模拟了它们对冰川变暗和融化的影响。结果表明，由于距离排放源较近，第三极周边雪坑中测量到的 BC 平均浓度远高于内陆青藏高原的浓度，而平均灰尘浓度通常从北到南逐渐降低。SP-TPG 中 BC 的平均 MAC 从 550nm 的 3.1 到 7.7m g 不等，大多数平均光谱值在可见和近红外波段与 Mie 理论计算的值相当，除了 Urumqi Glacier No.1 (UR)、Syek Zapadniy Glacier (SZ) 和 Laohugou Glacier No.12 (LH) 以外，而 SP-TPG 中灰尘的平均光谱 MAC 要小得多。与纯净雪面相比，BC 和灰尘在 UR、SZ、LH 和仁龙巴冰川减少反照率方面发挥了相当的作用，而在其他冰川中，BC 是最显著的吸收体。BC 和灰尘的综合作用通过表面反照率变暗（消融季节内一个月内的总质量平衡的 0.06-0.17）和增加辐射吸收（25.8-65.7W m），加速了 30.4-345.9mm w.e.（总质量平衡的 19.7-45.3%）的融化。本研究提供了一个新的 LAP 浓度和 MAC 数据集，并有助于澄清这些因素在第三极冰雪环境中的作用。
