Episodes of aerosol pollution and dust exported from East Asia to the Arctic: satellite observations

East Asia has emerged as an important source region of Arctic Haze in the last 20 years because of the remarkable industrial development it has undergone. In this study we present a detailed analysis of three case studies of aerosol export from East Asia to the Arctic making use of direct plume observation from lidar remote sensing (CALIPSO satellite), chemical transport model simulations (GEOS-Chem) and a lagrangian trajectory model. We investigate the composition and altitude of these Arctic haze layers, as well as the meteorological conditions that led to their export from Asia. Model and satellite observations are in good agreement on the altitude and location of the haze plumes. The model indicates that the composition of the plumes is predominantly sulfate with varying ratios of mineral dust. We find that in one episode CALIPSO classification algorithm misclassifies haze layers as clouds as a result of their relatively high depolarization ratio, caused by the presence of non-spherical dust particles. The three cases exhibit similar 500 hPa geopotential heights anomaly patterns suggesting that the Pacific North American oscillation (PNA) and the Western Pacific oscillation are related to the frequency of rapid export events from East Asia to the Arctic. In addition, a custom index is developed which effectively captures rapid export of Asian aerosols to the Arctic.