Monitoring of dust aerosol properties in a source region of southern Tajikistan-Ayvaj station

Abstract

To advance our understanding of the interactions among dust aerosol, cloud, and radiation budget and relevant climate influences over Central Asia, the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) and the Academy of Sciences of Tajikistan jointly established a permanent site at Shaartuz-Ayvaj in southern Tajikistan since 8 June 2023. This study mainly introduces the scientific objective, measurements, and analyses the aerosol optical properties, mass concentrations, size distributions, and radiative balances under two heavy dust events during summer of 2023. A set of state-of-the-art instruments was deployed at Ayvaj, and we could capture several heavy dust events during the summer of 2023. The maximum mass concentrations of surface PM2.5 and PM10 increased sharply to 1500 and 8000 µg/m3, respectively on 9 June for the heaviest dust event, and the aerosol optical depth at 500 nm (AOD500) increased from 0.20 to 3.2, and the corresponding Angstrom Exponent (AE440–870) decreased to about 0.01. The maximum mass concentrations are located in the coarse-mode of 2.5–32 µm, suggesting that dust aerosol is the dominant aerosol type at Ayvaj. These findings are of great importance to investigate the environmental health and climate effects of desert dust aerosols in Central Asia.