Spatiotemporal analysis of aerosol remote sensing in the northeastern Tibetan Plateau: Qinghai Lake region

The Tibetan Plateau (TP), located in western China, is the highest plateau in the world with an average elevation exceeding 4000 meters. Qinghai Lake (QHL), located in the northeastern TP, is China's largest inland saltwater lake. This study utilizes reanalysis data from the MERRA-2 and ERA5 datasets to investigate atmospheric aerosol characteristics. This study focuses on the spatiotemporal distribution characteristics of black carbon (BC) and dust aerosols (DU) in the QHL region from 2014 to 2023, as well as changes in related meteorological factors. BC concentration shows a declining trend, decreasing from 0.21 μg/m3 in 2014 to 0.16 μg/m3 in 2023. On a monthly scale, BC concentrations initially decrease and then increase, reaching the lowest levels in July and August. Winter contributes the most to BC concentrations throughout the year. In contrast to BC, DU concentrations have remained relatively stable over the past decade without any significant trends. The average DU concentration was 27.9 μg/m3 in 2014 and increased slightly to 29.0 μg/m3 in 2023. Monthly variations in DU concentrations exhibit a pronounced unimodal pattern, peaking in May with a concentration of 48.9 μg/m3. Higher wind speeds during spring and summer contribute to elevated DU concentrations due to the transport of dust from the northwestern Gobi Desert into the region. Summer, being the hottest season with the most precipitation in the QHL region, facilitates the dispersion and deposition of BC. Conversely, BC concentrations are highest in winter, likely associated with heating activities in nearby large cities.