Ten-year global particulate mass concentration derived from space-borne CALIPSO lidar observations

Abstract

Passive remote sensing has been widely used in recent decades to obtain global particulate matter (PM) mass concentration at daytime and under cloud-free condition. In this study, a retrieval method was developed for providing PM (PM10 and PM2.5) mass concentration both at daytime and nighttime using the latest data version (V4.10) from space-borne Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) lidar measurements. The advantage of the method is that PM10 & PM2.5 mass concentrations were obtained for seven aerosol types respectively base on active remote sensing observation at daytime and nighttime, even under cloudy condition. The results show that satellite-based PM mass concentrations are in good agreement with in-situ observations from 1602 ground monitoring sites throughout the world. Moreover, global distributions of PM10 and PM2.5 mass concentration during 2007–2016 were investigated, showing that for Beijing the annual mean PM2.5 mass concentration at nighttime is 11.31% less than those at daytime, however for London is 36.62%. It is suggested that diurnal variations in PM2.5 mass concentration are closely related to human activities. This work provides a reliable high-resolution database for long-term particulate mass concentrations on the global scale, which is of importance to evaluate aerosol impacts on climate, environment as well as ecosystem.