Abstract: The analysis of the response structure of extreme precipitation to temperature (P-T relationship) under urbanization is helpful to develop measures to reduce the risk associated with extreme weather in urban areas. Based on the site observation data of temperature and precipitation in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) from 1970 to 2019, the long-term evolution structure of extreme temperature and precipitation in GBA was analyzed, and the response structure of extreme precipitation with different thresholds to the temperature of the previous 1-day (T1) and the temperature of the previous 9-day (T1-9) was constructed by using the binning scaling function. The influence of urbanization on the P-T relationship was also explored. The results show that the P-T relationship of GBA generally shows a peak-like structure with the increase of temperature, and the extreme precipitation intensity increases first and then decreases. The breaking temperature is about 25 ℃. This structure is formed by the limited influence of water vapor at high temperature. The P-T1 relationship in urban areas is affected by typhoons, which the extreme precipitation intensity increases again when T1 is higher than 30 ℃. Urban areas of extreme precipitation intensity average scaling rate (8.0%/℃ ~ 12.5%/℃) not only higher than the suburbs (6.3%/℃ ~ 8.7%/℃), and also more than the theory scaling rate (7%/℃).

Key words: urbanization, Clausius-Clapeyron equation, extreme precipitation, temperature, GBA