Trends in autumn rain of West China from 1961 to 2014

Self Cite

Autumn rainfall in West China, the last rainy season of China, exerts profound impacts on the economic society, therefore, researches on its changes in the context of a warmer world are crucial for better adaptation to climate change. Using the dynamical downscaling performed by the regional climate model RegCM4 from four global climate models, this study firstly evaluated the fidelity of the RegCM4 simulations on the mean and extreme aspects of autumn rainfall in West China, and then projected their changes during the middle and the end of the 21st century under the RCP4.5 scenario. The evaluations indicate a good performance of the RegCM4 downscaling simulations in reproducing the observed spatial distribution of autumn rainfall amount, wet days, maximum consecutive 5‐day precipitation (RX5day), total extremely wet‐day precipitation (R95p), and consecutive dry days (CDD). Under the RCP4.5 scenario, relative to 1986–2005, the amount of autumn rainfall and the frequency of wet days are projected to increase in the northwestern part of West China and to decrease in its southeastern flank, concurrent with greater changes by the end of the 21st century than by the middle of the 21st century. Such an increase is closely associated with the enhancement of zonal water vapour transport and atmospheric unstable stratification, while the projected decrease is largely related to the reduction of moisture supply. Similar changes are also projected for the precipitation extremes Rx5day and R95p. Corresponding to the changing pattern of autumn rainfall, the CDD is projected to decrease in the northwestern part and to increase in the southeastern part of West China.

Section: Introductionmentioning

confidence: 99%

Projected changes in autumn rainfall over West China: Results from an ensemble of dynamical downscaling simulations

Zhou

et al. 2019

Self Cite

“…This rainfall amount sub‐peak is associated with the autumn rain of west China (ARWC), which usually occurs in September–October and is similar to the post‐Changma period in Korea (Wang et al ., 2007). During this period, AHREs are characterized by their long durations (Figure 6c), reflecting the feature of continuous rainy days during the ARWC (Zhang et al ., 2019). Furthermore, on the seasonal scale, we find negative correlations between variations of mean intensity and those of rainfall amount and mean duration, implying that over SWC the changes in AHRE rainfall amounts are driven mainly by changes in their duration.…”

Section: Resultsmentioning

confidence: 99%

Spatial and temporal characteristics of abrupt heavy rainfall events over Southwest China during 1981–2017

Chen

Wang

Huang

et al. 2021

The spatial and temporal characteristics of abrupt heavy rainfall events (AHRE: defined as 3‐hr rainfall amount ≥50 mm and at least one 1‐hr rainfall amount ≥20 mm during the 3 hr) over southwest China (SWC) between 1981 and 2017, including their occurrence frequency, intensity, and duration, were investigated based on hourly rainfall data collected from 468 rain gauge stations. The occurrence frequency of these AHREs exhibited large spatial variability among different regions. We distinguished three regions with high occurrence rates of AHREs: the Sichuan Basin (subregion A, SR‐A), South Guizhou–North Guangxi (subregion B, SR‐B), and West Hunan (subregion C, SR‐C). Overall, the amount of rainfall generated by the AHREs was more closely related to event duration than event intensity. Analysis of the monthly variations showed that the frequency of AHREs over SWC mostly (ca., 86.8%) appeared in the warm season (May–August) and peaked in July. But the peak month exhibited distinct regional features, with it occurring in midsummer over SR‐A, late spring or early summer over SR‐B, and early summer over SR‐C. With regards to diurnal variations, AHREs over areas with higher (lower) topography were initiated mostly in the afternoon (around midnight). In addition, short‐duration (1–3 hr) AHREs began most frequently in the late afternoon, whereas the long‐duration events (>6 hr) tended to begin around midnight. Composite analysis of the anomalies of moisture, equivalent potential temperature, and wind during extreme AHRE days revealed that AHRE occurrence coincided with an abnormal low‐level cyclonic circulation, which enhanced wind convergence and the transport of moist and warm air, providing favourable thermodynamic conditions for AHRE formation. These results advance our understanding of rainfall characteristics over SWC and provide observation‐based metrics for the evaluation of numerical simulations.

“…(Bai & Dong, 2004; Jiang, Ma, Liu, & Li, 2014). In addition, the occurrence of significant inter‐decadal changes of ARWC is also a consensus among most researchers (Bai & Dong, 2004; Feng & Guo, 1983; Jiang et al, 2014; Luo, Li, & Wang, 2013; Wang & Zhou, 2019; Zhang et al, 2019).…”

Section: Introductionmentioning

confidence: 94%

Inter‐decadal variation of autumn rain of west China and its relationship with atmospheric circulation and sea surface temperature anomalies

Zhi

Zhao

Zhou³

et al. 2020

The inter‐decadal variation of autumn rain of west China (ARWC) and its relationship with atmospheric circulation and sea surface temperature anomalies (SSTAs) was analysed. The intensity of ARWC shows significant inter‐decadal variability. The year 1990 is one of the abrupt change points of ARWC in both the southern and northern zone, and the year 2000 is another one in the northern zone. The inter‐annual correlation between the intensity of ARWC in the northern (southern) zone and the El Niño–Southern Oscillation continuously weakens (strengthens) from 1961. The relationship between the intensity of ARWC in the northern zone and atmospheric circulation of September–October mean significantly weakens after 2000, so does the relationship with the SSTAs in the equatorial central Pacific. On the contrary, the relationship between the intensity of ARWC in the southern zone and atmospheric circulation of September–October mean significantly strengthens after 1990, so does the relationship with the east–west contrast pattern of SSTAs in the equatorial central–western Pacific. The positive phase of the east–west contrast pattern of SSTAs in the equatorial central–western Pacific (i.e., when the tropical central [western] Pacific is colder [warmer] than normal) gradually strengthening and maintaining from the preceding spring to September–October is favourable for a stronger western Pacific subtropical high, which further facilitates northwards transportation of water vapour and provides better dynamic conditions for ARWC in the southern zone by strengthening the local Hadley circulation.