Vertical variation and temporal trends of extreme precipitation indices in a complex topographical watershed in the Hengduan Mountain Region, China

Abstract

Spatial-temporal trends of extreme precipitation have great impacts on disaster risks, and relevant studies usually receive much attention. In China, spatial-temporal trends have been analysed in numerous studies based on daily rainfall data; however, the densities of rain gauges in many studies were relatively low, and the effects of complex topography on extreme precipitation were usually not considered, which have lowered the reliability and accuracy of the reported results. In this study, several widely used extreme precipitation indices were chosen, and the spatial-temporal trends of a typical watershed in the Hengduan Mountain Region in Southwest China, the Longchuanjiang watershed, were analysed using the Mann-Kendall trend analysis based on daily rainfall data. The effect of elevation on the extreme precipitation indices based on the high-intensity rain gauges and the effect of elevation on the temporal trends of extreme precipitation indices were analysed, which have rarely been reported. The results indicated that: (a) significant positive correlations with elevation were reported for annual precipitation and most of the extreme precipitation indices, including PRCPTOT, Rx5day, R95P, R99P, RD, SDII, and CWD, while significant negative correlations were reported for CDD; the relationships between SDII and Rx1day were not significant with elevation; (b) the density of rain gauges in the regions with complex topography can have great impacts on the results; and (c) no significant correlation between the elevation and the temporal trends of extreme precipitation indices were reported. This study highlights the effects of the density of rain gauges and elevation, or topographical factors on the spatial distribution and temporal trends of extreme precipitation indices, which has rarely been reported in previous studies, implying that such effects should be fully taken into consideration in the relevant studies in the future. K E Y W O R D Selevation, extreme precipitation, spatial-temporal trend, the Hengduan Mountain Region

Elevation gradient dependence of extreme climate indices on Yunnan Plateau, China

“…The three extreme precipitation indices (CWD, R10mm, and Rx5day) did not significantly go down, and the three extreme precipitation indices (CDD, R95p, and Rx1day) did not significantly increase. However, extreme precipitation presents apparent regional differentiation on the spatial scale, consistent with Guo's research (Guo et al ., 2020).…”

“…Deng et al found that the spatial distribution pattern of climate changes in Qinling Mountains showed significant elevation sensitivity based on the long‐term analysis of climate during 1964–2015, the location of the temperate zone had an apparent vertical upward migration along with the elevation, and the range of migration was more extensive after the abrupt temperature change (mainly in the 1990s) (Deng, ). Guo et al analysed the influence of elevation on extreme climate indices in the Longchuan River basin based on high‐density meteorological stations and they found that with the rise of temperature, the drought trend in high‐elevation areas becomes more apparent and the intensity of single precipitation becomes prominent (Guo et al ., 2020).…”

Analysis of Spatiotemporal Variability in Extreme Climate and Potential Driving Factors on the Yunnan Plateau (Southwest China) during 1960–2019

“…Compared with longitude and latitude, altitude plays a leading role in the process of extreme climate change in regions with complex topography [60]. Studies have pointed out that extreme weather and extreme hydrological events in plateau and mountainous areas are susceptible to altitude [61]. The trend coefficients of FD0 and ID0 were significantly different above and below the 2112 m elevation boundary, although there was no positive or negative change trend.…”

Contributions of natural climate variability on the trends of seasonal precipitation extremes over China

“…In addition to the effects of climate variability modes, such as ENSO and PDO, the intense rainfall events over China are also modulated by local forcing factors, for example topography (Shi et al ., 2008; Guo et al ., 2020), and the extreme events over central‐east China are also influenced by tropical cyclones (Zhang et al ., 2018; Cao et al ., 2019a; 2019b). Moreover, the strengthened greenhouse gas emissions derived from human activities during last decades also alter regional rainfall features across China (Ma et al ., 2017; Li et al ., 2017a; 2017b).…”