LAUSR

With the development of urbanization, whether precipitation characteristics in Guangdong Province, China, from 1981 to 2015 have changed are investigated using rain gauge data from 76 stations. These characteristics include annual precipitation, rainfall frequency, intense rainfall (defined as hourly precipitation ⩾ 20 mm), light precipitation (defined as hourly precipitation ⩽ 2.5 mm), and extreme rainfall (defined as hourly rainfall exceeding the 99.9th percentile of the hourly rainfall distribution). During these 35 years, the annual precipitation shows an increasing trend in the urban areas. While rainfall frequency and light precipitation have a decreasing trend, intense rainfall frequency shows an increasing trend. The heavy and extreme rainfall frequency both exhibit an increasing trend in the Pearl River Delta region, where urbanization is the most significant. These trends in both the warm seasons (May−October) and during the pre-flood season (April−June) appear to be more significant. On the contrary, the annual precipitation amount in rural areas has a decreasing trend. Although the heavy and extreme precipitation also show an increasing trend, it is not as strong and significant as that in the urban areas. During periods in which a tropical cyclone makes landfall along the South China Coast, the rainfall in urban areas has been consistently more than that in surrounding areas. The precipitation in the urban areas and to their west is higher after 1995, when the urbanization accelerated. These results suggest that urbanization has a significant impact on the precipitation characteristics of Guangdong Province. 本文利用 1981–2015 年中国广东省的 76 个自动观测站资料, 分析了中国广东省的降水特征随城市化的变化. 这些降水特征包括年降水量、 降水频次、 强降水 (小时降雨量≥ 20 mm)、 弱降水 (小时降水量≤ 2.5mm) 和极端降水 (总降水样本中降水强度最大的0.1%) 频次. 结果表明: 近 35 年来, 广东城市区域降水量和强降水频次呈增加趋势, 而降水频次和弱降水频次呈减少趋势. 这种降水变化的趋势在暖季 (5-10 月) 和华南前汛期 (4-6 月) 最显著. 在城市化最强的珠三角区域, 强降水和极端降水均明显增强. 同城市区相比, 郊区的年降水量呈下降趋势. 尽管郊区的强降水和极端降水也呈增加趋势, 但没有珠三角城市区域显著. 在台风登陆华南沿海, 城市区域的降水也显著多于郊区. 随着 1995 年后城市化进程加快, 在城市区及其西边的台风降水也呈增加趋势. 这些结果表明城市化对广东省的降水特征有重要影响.