Impact of synoptic patterns on East Asia pollutant transport pathways observed from satellites
Tuesday, 16 December 2014: 2:55 PM
This study presents that wintertime pollutant transport patterns in East Asia are visible from multiple satellite observations when inspected with corresponding synoptic weather analysis. Transport pathways of pollutants and anthropogenic emissions are investigated using satellite images, surface weather chart, and chemical transport model simulation in the context of conceptual categorization of synoptic weather pattern. We combined daily distributions of MODIS AOD and CMAQ simulated PM to represent aerosol distribution; and GOME-2 and OMI NO2 column density as a proxy for fresh anthropogenic emission flux; and Korean Meteorological Administration surface weather analysis chart to understand synoptic weather pattern using GIS geo-referencing technique. We identified a periodic extension of the Siberian high to south China and its associated migratory systems are important to understand transport patterns in this region. Based on the relative location and strength of high pressure system over south China, we classified three types of synoptic patterns that might affect high surface PM events: (1) Expansion of Siberian high as a result of cold surge, (2) Cold front passage associated with migratory northern low pressure system, and (3) Stagnant high pressure system near Yellow Sea. In all cases, the development of high pressure system in south China is essential for development of pollutant event. We demonstrate that observed and simulated surface PM show good agreement, not only with MODIS AOD but also with NO2 column density, implying the possible contributions of transported anthropogenic emissions. We also demonstrate many of these PM plumes are originated from northeastern China, pushed southward by cold front passage, generating unique narrow-band-shape PM plumes. All 3 types of transport patterns are shown to be important, in terms of intensity, frequency, and vertical lifting. These transport pathways are crucial to understand not only local pollutant events but also mechanisms to lift and to transport East Asian anthropogenic emissions into Pacific.