The light scattering and absorption of atmospheric aerosols have important radiation effects on the Earth atmosphere system through aerosol radiation and aerosol cloud interactions. The single scattering albedo of aerosols (the ratio of scattering to scattering and absorption) not only affects the magnitude of radiative forcing, but may also determine the heating or cooling effects of aerosols at the top of the atmosphere. The Himalayan region is an important channel for the transport of anthropogenic pollutants from South Asia to the Qinghai Tibet Plateau. The strong absorbing aerosols such as black carbon emitted by humans in South Asia result in low single scattering albedo in the South Asia and Himalaya regions. Previous observational and numerical simulation studies conducted in the Himalayas and South Asia only used aerosol absorption to explain changes in single scattering albedo. The results and conclusions were contradictory and incorrect, bringing significant uncertainty to the evaluation of aerosol radiation effects in the region.

       To clarify the above issues, the research team of atmospheric dust aerosols on the Qinghai Tibet Plateau of Lanzhou University conducted a comprehensive scientific investigation of dust aerosols at Yadong Station and Everest Base Camp Station in the Himalaya region in 2020 and 2021, respectively (Figure 1), obtaining first-hand observation data and gaining new understanding of aerosol radiation effects in the Himalaya region. The relevant research results have recently been published in the journal npjClimate and Atmospheric Science, titled 'Atmospheric aerosol size distribution impacts radial effects over the Himalayas via modulating aerosol single catching aldo'. The authors of the paper are all from the research team of atmospheric dust aerosols on the Qinghai Tibet Plateau at Lanzhou University. The first author is Tian Pengfei, a young researcher at the College of Atmospheric Sciences, the second and third authors are master's students Yu Zeren and Cui Chen, respectively. The corresponding authors are Academician Huang Jianping and Professor Zhang Lei.

       Research has found that the particle size distribution of aerosols in the Himalayan region determines the scattering efficiency of aerosols, thereby determining the change in single scattering albedo, which in turn affects the direct radiative forcing efficiency of aerosols (Figure 2). Therefore, the particle size distribution of atmospheric aerosols affects the radiation effect of aerosols in the Himalayan region by adjusting the single scattering albedo. This new understanding will be of great significance for understanding the radiation effects of aerosols on a global scale.

       This research achievement has been supported by projects such as the Second Qinghai Tibet Plateau Comprehensive Scientific Expedition Research Project (2019QZKK0602).
       Paper link: https://www.nature.com/articles/s41612-023-00368-5

 

 

       Figure 1. The research team of atmospheric dust aerosols on the Qinghai Tibet Plateau of Lanzhou University conducted comprehensive scientific investigations on atmospheric dust aerosols at Yadong Station and Everest Dabenying Station from June 11 to August 31, 2020 and May 20 to June 13, 2021, respectively.

 

 

       Figure 2. The effect of aerosol particle size distribution at Yadong Station on radiative forcing efficiency: (a) The relationship between single scattering albedo and particle size distribution; (b) The variation of scattering coefficient and (c) scattering efficiency factor with particle size; (d) The relationship between the forcing efficiency of atmospheric top, (e) atmosphere, and (f) ground radiation and the single scattering albedo.