Local Climate Change Induced by Urbanization on a South China Sea Island

Abstract

: The South China Sea is a hotspot for regional climate research. Over the past 40 years, considerable improvement has been made in the development and utilization of the islands in the South China Sea, leading to a substantial change in the land-use of the islands. However, research on the impact of human development on the local climate of these islands is lacking. This study analyzed the characteristics of local climate changes on the islands in the South China Sea based on data from the Yongxing Island Observation Station and ERA5 re-analysis. Furthermore, the influence of urbanization on the local climate of the South China Sea islands was explored in this study. The findings revealed that the 10-year average temperature in Yongxing Island increased by approximately 1.11 °C from 1961 to 2020, and the contribution of island development and urbanization to the local warming rate over 60 years was approximately 36.2%. The linear increasing trend of the annual hot days from 1961–2020 was approximately 14.84 days per decade. The diurnal temperature range exhibited an increasing trend of 0.05 °C per decade, whereas the number of cold days decreased by 1.06 days per decade. The rapid increase in construction on Yongxing Island from 2005 to 2021 led to a decrease in observed surface wind speed by 0.32 m s –1 per decade. Consequently, the number of days with strong winds decreased, whereas the number of days with weak winds increased. Additionally, relative humidity exhibited a rapid decline from 2001 to 2016 and then rebounded. The study also found substantial differences between the ERA5 re-analysis and observation data, particularly in wind speed and relative humidity, indicating that the use of re-analysis data for climate resource assessment and climate change evaluation on island areas may not be feasible.