Spatiotemporal distribution of dust aerosol optical properties from CALIPSO and CATS observations in Xinjiang, China

Abstract

In the current study, the spatiotemporal distribution of optical properties of desert dust aerosols (DD) are investigated in Xinjiang Basin located in Northwest China, using Cloud-Aerosol Transport System (CATS) lidar onboard International Space Station (ISS) during 2015–2017, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar level 3 product during 2007–2021. CALIPSO and CATS are in good agreement to capture the high aerosol loading in this dust-dominant region. From the horizontal scale, the dust aerosol optical depth (DAOD) presents the seasonal variations (Spring > Summer > Autumn > Winter) observed by CALIPSO. Moreover, DAOD suggests the south-to-north with the declined gradient, likely due to the different scale of dust sources and climate conditions between Southern Xinjiang (SXJ) and Northern Xinjiang (NXJ). From the vertical scale, the dust extinction coefficient (DEC) is gradually decreased with the height in the four seasons, possibly attributed to the larger and heavier dust particles near the low-level contributing to the larger DEC. Compared with SXJ, the DEC has the slighter decreased gradient with height, and the optically thin DD occupies the higher ratio in NXJ observed by CALIPSO. In addition, the diurnal cycle of DD is insignificant in SXJ obtained from CATS, which is likely associated with the dust emission from Taklimakan Desert mainly driven by frontal passage, further causing the high wind and deep convection activities. Meantime, the insignificant diurnal variation of DD is also found in NXJ based on CATS.