Effects of urbanization on the land sea breeze circulation over the Pearl River Delta region in winter

In this study, the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Model (MM5) was used to investigate the effects of urbanization on land sea breezes (LSBs) in the Pearl River Delta (PRD) region, which is a rapidly developing area located in southern China. LSBs in the 2003/2004 winter were simulated utilizing an approach in which the NCEP Final Analysis data averaged in the 2003/2004 winter is used as initial and lateral boundary conditions for the model. The simulated surface winds are shown to be capable of reproducing the basic features and diurnal variation of the LSBs. Sensitivity experiments with changes in land uses were performed with this model. Results of these experiments show that urbanization in the PRD region can have significant effects on the patterns of the LSBs and circulation in the region. In particular, it has been shown that the urbanization of Shenzhen (a major city located in the eastern coast of the PRD and neighbouring to the north of Hong Kong) may significantly enhance the sea breeze to the west of Hong Kong in the early afternoon. This may enhance the low-level convergence in Hong Kong and may worsen the air pollution problem there. On the other hand, the effects of urbanization in the western coast of the PRD region are relatively local and LSBs on the eastern PRD are generally not affected. Copyright (C) 2009 Royal Meteorological Society