Optical characteristics of aerosol and its potential sources over Nam Co in the Tibetan Plateau during Asian summer monsoon period

Aerosols over the Tibetan Plateau (TP) play an important role in the regional and global climate change and ecological environment. The Second Tibetan Plateau Scientific Expedition and Research Program (STEP) carried out observation experiment at the Nam Co Station for Multisphere Observation and Research, Chinese Academy of Sciences (Nam Co Station, 30 degrees 46 ' N, 90 degrees 59 ' E, 4730 m) in the central TP from August 5 to September 11, 2020. This paper investigated the aerosol optical properties and its potential sources over Nam Co region. The main results are as follow: the average aerosol optical depth was 0.025 during the observation period; the average black carbon (BC) concentration and aerosol number concentration was 37 ng/m3 and 129 N/cm3, respectively; the diurnal variation and vertical distribution of aerosol were affected by the local meteorological elements. Frequent southerly winds during the summer monsoon led to a certain contribution of South Asia to the BC concentration in Nam Co region. And particles from the Taklimakan Desert led to dramatic increasing of aerosol number concentration over Nam Co region. The aerosol optical characteristics and influencing factors over the central TP were analyzed, which is beneficial to further study the influence of aerosols over the TP on regional and global weather and climate.

Automated summary

This study investigated the aerosol optical properties and potential sources over the Nam Co region. The results showed that the average aerosol optical depth during the observation period was 0.025, with an average black carbon concentration of 37 ng/m3 and an average aerosol number concentration of 129 N/cm3. The diurnal variation and vertical distribution of aerosols were influenced by local meteorological elements. The study found that the summer monsoon winds from South Asia contributed to the black carbon concentration in the Nam Co region, and particles from the Taklimakan Desert resulted in a significant increase in aerosol number concentration. These findings are important for understanding the influence of aerosols on the Tibetan Plateau and regional/global weather and climate.