The Himalayas and Tibetan Plateau (the HTP), referred to as “the third pole” with an excessive warming rate, exerts strong impacts on the global environment. As one of warming contributors, atmospheric brown carbon (BrC) remains limited scientific understanding in the HTP due to a scarcity of observations. In this study, we present a study of the light-absorbing properties of methanol-soluble brown carbon (MeS-BrC) and water-soluble brown carbon (WS-BrC) during 2018–2021. Highly spatiotemporal variations of BrC light absorptions were observed. In the HTP marginal area, elevated BrC absorption coefficients at 365 nm (b_abs,365) and levoglucosan concentrations were obtained, and MeS-BrC exhibits approximately 1.3–1.8 times higher absorption compared to WS-BrC. We determined that BrC light absorptions was largely attributed to biomass burning (29%–35%). BrC can act as a potent warming agent in the HTP marginal area, with high direct solar absorption (25%–47% relative to black carbon).

中文翻译：

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生物质燃烧产生的棕色碳加剧了喜马拉雅山和青藏高原的变暖

喜马拉雅山和青藏高原被称为“第三极”，气候变暖速度过快，对全球环境造成严重影响。作为变暖的原因之一，由于观测的缺乏，大气棕色碳（BrC）在高温TP中的科学认识仍然有限。在这项研究中，我们对 2018 年至 2021 年期间甲醇溶性棕碳 (MeS-BrC) 和水溶性棕碳 (WS-BrC) 的光吸收特性进行了研究。观察到 BrC 光吸收的高度时空变化。在 HTP 边缘区域，获得了 365 nm ( b _abs,365 )处的 BrC 吸收系数和左旋葡聚糖浓度的升高，并且 MeS-BrC 的吸收率比 WS-BrC 大约高 1.3–1.8 倍。我们确定 BrC 光吸收很大程度上归因于生物质燃烧 (29%–35%)。 BrC 可以作为 HTP 边缘区域的有效增温剂，具有较高的直接太阳吸收率（相对于黑碳为 25%–47%）。