Cause analysis of the extreme hourly precipitation and its relationship with the urban heat island intensity in Shenyang, China

Based on the hourly temperature and precipitation data from China national meteorological stations regional automatic weather in Shenyang, relationship between extreme (ExHP) urban heat island Intensity (UHII) is analyzed. Results show that UHII higher at night early morning. The ExHP events mostly occur summer when relatively high. spatial distribution of Shenyang consistent with economic development transportation density. Denser population transportation, high-rise buildings center contribute to UHII. There are three types ExHP, namely abrupt-type growing-type continuous-type ExHP. overall variation characteristics consistent. Their values positive stable 6–12 h before start begins increase dramatically about 6 but decreases obviously turn negative after begins. Before abrupt high can rapidly return ending remarkably larger than differs greatly. low both ends, high-value areas mainly located area. After EXHP, drops whole increasing urbanization. diurnal enormous, which during daytime. cause abnormal air pressure cities villages. lower atmospheric layer city be heated expanded, hence resulting local pressure. Then, promote convergence upward movement air, facilitating establishment circulation. This phenomenon particularly distinct night, conducive occurrence events.