Thunderstorm Climatologies and Their Relationships to Total and Extreme Precipitation in China
Weixin Xu
Abstract
Abstract This study investigates climatologies of lightning and thunderstorms in China and their relationships to total rainfall and extreme (hourly) precipitation (95th percentile) using spaceborne lightning, microwave, and radar measurements. Annually, total and extreme precipitation only weakly collocate or correlate with flash density (FLD) and thunderstorm. Also, none of these variables show significant trends during 1995–2014. FLD and precipitation are generally in phase on the monthly time scale, except over southern China (SCH), where FLD leads precipitation by 2 months. Thunderstorms contribute 40–50% of total rainfall and 70–80% of extreme precipitation over lower‐elevation regions. While correlation coefficients between extreme precipitation and flash rate are decent during April–May (AM, r = 0.75), they are significantly lower in June–July–August (JJA, r = 0.55), possibly due to larger warm cloud depth and thus greater rainfall contribution by warm‐rain process during JJA. JJA thunderstorms have markedly higher radar echo tops (MAXHT30) and induce stronger microwave ice scattering than AM thunderstorms, related to larger convective available potential energy in JJA, whereas AM thunderstorms have larger precipitation area in association with stronger vertical wind shear. Conversely, AM thunderstorms show markedly greater number/frequency of high flash rates than JJA thunderstorms (especially over SCH), consistent with their larger volumes of intense radar echo in the mixed‐phase region (VOL35). Compared to MAXHT30 ( r = 0.38), VOL35 is far better correlated to flash rate ( r = 0.88), as VOL35 represents the total amount of precipitation‐sized ice particles and/or supercooled liquid water in the mixed‐phase region essential for cloud electrification.