Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India.
Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India; Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India.
Sci Total Environ. 2022 Mar 1;810:151299. doi: 10.1016/j.scitotenv.2021.151299. Epub 2021 Oct 29.
Recent increases in surface temperature and snow melt acceleration in the Himalayan region are influenced by many factors. Here we investigate the influence of absorbing aerosols, including black carbon and dust, on surface temperature and snow melt in western, central, and eastern parts of the India-Nepal Himalayan region (INHR). We compare 40-y simulations (1971-2010) one with all evolving forcing agents representative of a present-day aerosol scenario, compared to a low aerosol forcing scenario. The difference between these scenarios shows a significant increase in surface air temperature, with higher warming in parts of Western and Central Himalaya (~0.2-2 °C) in the months of April and May. Higher absorbing aerosol (BC and dust abundance) both at the surface and in the atmospheric column, in the present-day aerosol simulations, led to increases in atmospheric radiative forcing and surface shortwave heating rate forcing (SWHRF), compared to the low aerosol forcing case. Therefore, the absorbing aerosols cause anomalous atmospheric heat energy transfer to land due to high surface SWHRF and changes in surface energy flux, leading to snow melt. The present model version did not parameterize snow albedo feedback, which would increase the magnitudes of the changes simulated here.
喜马拉雅地区地表温度和冰雪融化加速的最近增加受到许多因素的影响。在这里，我们研究了包括黑碳和灰尘在内的吸收性气溶胶对印度-尼泊尔喜马拉雅地区（INHR）西部、中部和东部地表温度和冰雪融化的影响。我们将 40 年的模拟（1971-2010 年）与一个代表当前气溶胶情景的所有演化强迫因素的模拟进行了比较，与一个低气溶胶强迫情景进行了比较。这些情景之间的差异表明，地表空气温度显著升高，在 4 月和 5 月，喜马拉雅西部和中部的部分地区变暖幅度更高（约 0.2-2°C）。在当前气溶胶模拟中，地表和大气柱中更高的吸收性气溶胶（BC 和灰尘丰度）导致大气辐射强迫和地表短波加热率强迫（SWHRF）增加，与低气溶胶强迫情况相比。因此，由于高地表 SWHRF 和地表能量通量的变化，吸收性气溶胶导致异常的大气热能向陆地转移，导致冰雪融化。本模型版本没有参数化冰雪反照率反馈，这将增加这里模拟的变化幅度。
