Key Laboratory of Remote Sensing of Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou, 730000, China.
State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou, 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Pollut. 2021 Feb 1;270:116234. doi: 10.1016/j.envpol.2020.116234. Epub 2020 Dec 7.
The deposition of light absorbing impurities (LAIs) (e.g., black carbon (BC), organic carbon (OC), mineral dust (MD)) on snow is an important attribution to accelerate snowmelt across the northern Xinjiang, China. At present, there is still a lack of understanding of the LAIs concentration, elution and enrichment process in snow cover over Xinjiang. Based on these, continuously sampling during two years carried out to investigate the concentrations, impacts and potential sources of LAIs in snow at Kuwei Station in the southern Altai Mountains. The average concentrations of BC, OC and MD in the surface snow were 2787 ± 2334 ng g, 6130 ± 6127 ng g, and 70.03 ± 62.59 μg g, respectively, which dramatically increased along with snowmelt intensified, reflecting a significant enrichment process of LAIs at the snow surface. Besides, high LAIs concentrations also found in the subsurface and melting layers of the snowpit, reflecting the elution and redistribution of LAIs. With the simulation of the SNow ICe Aerosol Radiative model, BC was the main dominant factor in reducing snow albedo and radiative forcing (RF), its impact was more remarkable in the snowmelt period. The average contribution rates of BC, MD and BC + MD to snow albedo reduction increased by 20.0 ± 1.9%, 13.0 ± 0.2%, and 20.5 ± 2.3% in spring compared with that in winter; meanwhile, the corresponding average RFs increased by 15.8 ± 3.4 W m, 4.7 ± 0.3 W m and 16.4 ± 3.2 W m, respectively. Changes in the number of snowmelt days caused by BC and MD decreased by 3.0 ± 0.4 d to 8.3 ± 1.3 d. It indicated that surface enrichment of LAIs during snow melting might accelerate snowmelt further. Weather Research and Forecasting Chemistry model showed that the resident emission was the main potential source of BC and OC in snow. This implied that the mitigation of intensive snowmelt needs to mainly reduce resident emission of LAIs in the future.
光吸收杂质（LAIs）（例如黑碳（BC）、有机碳（OC）、矿物粉尘（MD））在雪上的沉积是加速中国新疆北部积雪融化的一个重要因素。目前，人们对新疆积雪覆盖层中 LAIs 的浓度、洗脱和富集过程仍缺乏了解。基于此，在阿尔泰山南麓的库威站连续两年进行了采样，以调查雪层中 LAIs 的浓度、影响和潜在来源。在地表雪中，BC、OC 和 MD 的平均浓度分别为 2787±2334ng g、6130±6127ng g 和 70.03±62.59μg g，随着积雪的融化，这些浓度显著增加，反映出雪表面 LAIs 的显著富集过程。此外，在雪坑的次表层和融化层中也发现了高浓度的 LAIs，反映出 LAIs 的洗脱和再分布。通过 SNow ICe 气溶胶辐射模型的模拟，BC 是降低雪反照率和辐射强迫（RF）的主要主导因素，在积雪融化期的影响更为显著。与冬季相比，BC、MD 和 BC+MD 对雪反照率降低的平均贡献率在春季分别增加了 20.0±1.9%、13.0±0.2%和 20.5±2.3%；同时，相应的平均 RF 分别增加了 15.8±3.4 W m、4.7±0.3 W m 和 16.4±3.2 W m。BC 和 MD 引起的积雪融化天数减少了 3.0±0.4 天至 8.3±1.3 天。这表明，积雪融化过程中 LAIs 的表面富集可能会进一步加速积雪融化。天气研究与预报化学模型表明，驻留排放是雪层中 BC 和 OC 的主要潜在来源。这意味着，未来减缓强烈的积雪融化需要主要减少 LAIs 的驻留排放。
