Abstract
Precipitable water vapor (PWV) and convective available potential energy (CAPE) are two key variables affecting the formation and persistence of rainfall. Most previous studies only independently and qualitatively analyzed the long-term relationship between PWV/CAPE and extreme precipitation, but their synergistic contribution of PWV and CAPE to extreme precipitation (EP) was rarely investigated. Therefore, a novel model named PCEP (comprising PWV, CAPE, and EP), that integrates Global Navigation Satellite System (GNSS)-derived PWV and the fifth-generation ECMWF reanalysis (ERA5)-derived CAPE, is proposed in this study, where the joint contribution of PWV and CAPE on EP was investigated. Precipitation data is derived from the China Meteorological Administration (CMA). The daily PWV, CAPE and precipitation from 219 GNSS collocated meteorological stations in China from 2011 to 2018 were collected to perform the PCEP model. The tendency and periodic information of the three variables were revealed based on the multichannel singular spectral analysis and Lomb-scale methods. Moreover, the power-law relationships of PWV to loge(EP) varied with the seasons in China, while the linear relationships existed between loge(CAPE) and loge(EP). Finally, to solve the collinearity issue among PWV, CAPE and EP that occurred on the regional scale, the partial least square (PLS) method was first introduced to investigate their relationships on the seasonal scale. The PLS method found that PWV and CAPE also complement each other to EP on the seasonal scale, on the basis of regional complementarity. Additionally, the qualitative relationship between PWV, CAPE and the frequency of EP was elucidated. These results showed that the close relationships between high PWV and CAPE and the intensity and frequency of EP events on the annual and seasonal scales throughout China.
Published Version
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