Investigation of the meteorological effects of urbanization in recent decades: A case study of major cities in Pearl River Delta

This paper investigates the evolution of the climatological effects of urbanization in the major cities of the Pearl River Delta region of China during the summer season. Land use data representing the 1990s, 2000s, and 2010s are obtained by classifying the land use from collected Landsat images. This classification standard follows the guidelines of land use classification from the World Urban Database and Access Portal Tools (WUDAPT). Before the model simulation, the WUDAPT land use categorization was remapped according to the United States Geological Survey (USGS) land use classification. The Weather Research and Forecasting (WRF) model was then applied under the same initial and boundary conditions with respect to different land use data. Spatial comparison and statistical analysis reveal a general increase in temperature (approximately 1 °C) and heat index (2 °C at night) and a deceleration of wind speed over time (around 0.5 ms−1) when compared with the 1990s. These impacts are due to urbanization. Moreover, simulation shows that the sensible heat flux is increased, whereas the latent heat flux is decreased because there was less vegetation and more impervious surfaces. These findings can let planners and governors have a quantitative understanding about the impact of urbanization on local climatic conditions.