3D structure of Asian dust transport revealed by CALIPSO lidar and a 4DVAR dust model

Abstract

We present detailed 3D structure of Asian dust outflow from a dust source region to the northwestern Pacific ocean retrieved by NASA/CALIOP onboard CALIPSO and results simulated by a four-dimensional variational (4DVAR) data assimilation version of a dust transport model (RC4) based on the NIES Lidar network. The modeled and CALIOP dust extinction showed good agreement, both for horizontal scale (600-1200 km) and vertical depth (1600-3600 m) near the dust source regions. Cross-section analyses of CALIOP and RC4 assisted by forward trajectory revealed that dust from the Gobi Desert on 5 May traveled approximately 1000-1500 km/day to the east and passed over Japan on 8 May. The elevated dust subsequently passed to the Pacific Ocean while maintaining the major dust layer height of 2500-4000 m MSL trapped within the potential temperature of 302-306 K. Results of our analyses demonstrate the importance of integration of CALIOP measurement and the dust model for clarifying the overall structure of an Asian dust event. Copyright 2008 by the American Geophysical Union.