高度城镇化背景下珠三角地区降雨结构时空演变特征分析

Analysis of temporal and spatial evolution characteristics of rainfall structure in the Pearl River Delta area under background of high urbanization

针对全球气候变化和城镇化快速发展的背景下,极端气候事件频发,高度城镇化地区的洪涝灾害问题,考虑频繁的人类活动对区域水循环产生重要影响,人口、财富的高度集中使得承灾体的易损性日益凸显,以城镇化发展快、经济要素集中度高的珠三角地区为研究区域,梳理了区域城镇化发展进程和特点,分析了降雨结构时空变化特征及其与城镇化发展的关系。结果表明,从降雨历时角度来看,降雨事件主要以6 h以内的短历时降雨为主,但降水量的贡献主体是6 h以上的长历时降雨,降雨结构并未发生显著变化;从降雨等级角度来看,降雨事件主要以弱降雨为主,但降水量的主要贡献则取决于发生次数较少的强降雨事件,降雨结构发生了显著变化,中、大雨发生率显著增加,小雨发生率显著减少;高度城镇化地区的降雨结构变化最为明显,中、大、暴雨发生率显著增加,小雨发生率明显下降。

Under the background of global climate change and rapid urbanization, extreme climate events occur frequently and flood disasters occur in highly urbanized areas. Considering that frequent human activities have an important impact on regional water cycle and the high concentration of population and wealth makes the vulnerability of disaster bearing bodies increasingly prominent. Taking the Pearl River Delta with rapid urbanization and high concentration of economic factors as the research area, this paper combed the development process and characteristics of regional urbanization, and analyzed the temporal and spatial evolution characteristics of rainfall structure and its relationship with urbanization development. The results show that from the perspective of rainfall duration, the rainfall events are mainly short duration rainfall within 6 h, but the main contribution of precipitation is long duration rainfall more than 6 h, and the rainfall structure has not changed significantly. From the perspective of rainfall grade, rainfall events are mainly weak rainfall, but the main contribution of precipitation depends on the less frequent heavy rainfall events. The rainfall structure has changed significantly, the incidence of medium and heavy rain has increased significantly, and the incidence of light rain has decreased significantly. The change of rainfall structure in highly urbanized areas is the most obvious, the incidence of medium, heavy rain and storm increases significantly, and the incidence of light rain decreases significantly.