The response of warm-season precipitation extremes in China to global warming: an observational perspective from radiosonde measurements

Abstract

Consensus has been reached that precipitation extremes vary proportionally with global warming. Nevertheless, the underlying cause and magnitude of these factors affecting their relationships remain highly debated. To elucidate the complex relationship between precipitation extremes and temperature in China during the warm seasons (May through September), a 60-year (1958–2017) record of hourly rain gauge measurements, in combination with surface air temperature, RH, precipitable water (PW), and convective available potential energy (CAPE) collected from 120 radiosonde stations were examined. Spatially, the scaling relationship between precipitation extremes and temperature exhibits a large geographic difference across China. In particular, the Clausius–Clapeyron (CC) and sub-CC relationships tend to occur in northwest (ROI-N) and southeast China (ROI-S), whereas the super-CC relationship is found to mainly concentrates in central China (ROI-C). Additionally, the response of precipitation extremes to temperature becomes more sensitive as precipitation intensity increases, shifting from CC to super-CC at a certain point of inflection that varies by geographic regions. This shift occurs at approximately 15 °C in ROI-C and ROI-N, but at around 20 °C in ROI-S. Within the temperature range of the super-CC slope, the PW rises with the increases in temperature, whereas the CAPE decreases with rising temperature, which is contrary to the monotonic scaling of precipitation with temperature. From the perspective of interannual variation, the precipitation extremes correlate positively with temperature. This further confirms the notion that global warming, through jointly affecting PW and CAPE, is able to considerably regulate precipitation extremes.