Future Projection of Extreme Precipitation Indices over the Qilian Mountains under Global Warming

Abstract

The Qilian Mountains are a climate-sensitive area in northwest China, and extreme precipitation events have an important impact on its ecological environment. Therefore, considering the global warming scenario, it is highly important to project the extreme precipitation indices over the Qilian Mountains in the future. This study is based on three CMIP6 models (CESM2, EC-Earth3, and KACE-1-0-G). A bias correction algorithm (QDM) was used to correct the precipitation outputs of the models. The eight extreme precipitation indices over the Qilian Mountains during the historical period and in the future were calculated using meteorological software (ClimPACT2), and the performance of the CMIP6 models to simulate the extreme precipitation indices of the Qilian Mountains in the historical period was evaluated. Results revealed that: (1) The corrected CMIP6 models could simulate the changes in extreme precipitation indices over the Qilian Mountains in the historical period relatively well, and the corrected CESM2 displayed better simulation as compared to the other two CMIP6 models. The CMIP6 models performed well while simulating R10mm (CC is higher than 0.71) and PRCPTOT (CC is higher than 0.84). (2) The changes in the eight extreme precipitation indices were greater with the enhancement of the SSP scenario. The growth rate of precipitation in the Qilian Mountains during the 21st century under SSP585 is significantly higher than the other two SSP scenarios. The increment of precipitation in the Qilian Mountains mainly comes from the increase in heavy precipitation. (3) The Qilian Mountains will become wetter in the 21st century, especially in the central and eastern regions. The largest increase in precipitation intensity will be observed in the western Qilian Mountains. Additionally, total precipitation will also increase in the middle and end of the 21st century under SSP585. Furthermore, the precipitation increment of the Qilian Mountains will increase with the altitude in the middle and end of the 21st century. This study aims to provide a reference for the changes in extreme precipitation events, glacier mass balance, and water resources in the Qilian Mountains during the 21st century.

Evaluation and Projection of Precipitation in CMIP6 Models over the Qilian Mountains, China

“…Another possible factor for the wet bias was the sparse distribution of stations in the QMs. Most of these stations are located in the valleys of the QMs, and there are elevation errors between them and the grid points of the model, which may lead to an underestimation of precipitation [50]. Especially in the western region, precipitation decreases gradually with increasing altitude, and the whole layer of atmospheric water vapor is mainly concentrated below 5000 m.…”

“…Another possible factor for the wet bias was the sparse distribution of stations in the QMs. Most of these stations are located in the valleys of the QMs, and there are elevation errors between them and the grid points of the model, which may lead to an underestimation of precipitation [50]. Especially in the western region, precipitation decreases gradually with increasing altitude, and the whole layer of atmospheric water vapor is mainly concentrated below 5000 m. From the data we have analyzed, we found that (Figure 4) MME simulated the spatial distribution characteristics of decreasing precipitation from the southeast to northwest QM, which is in agreement with Qiang Fang's research [51].…”

“…At the same precipitation is an important factor affecting the change in the mass balance of gla Some studies have shown that warming and increased precipitation will lead to g retreat [61,62]. So, in the context of the climate warming, by the middle and late 21s tury, the glaciers of the QMs will undergo significant changes [50]. This conclusion is in line with Deng's research [60], which suggests that rising temperatures in places that are already near freezing mean that snow will turn to rain and snowfall will rapidly diminish [60].…”

“…Some studies have shown that warming and increased precipitation will lead to glacier retreat [61,62]. So, in the context of the climate warming, by the middle and late 21st century, the glaciers of the QMs will undergo significant changes [50].…”

“…The interpolation method has been inadequate for precipitation applications in alpine regions. Therefore, improving the precipitation observation accuracy in the QM region is an important basis for future studies of precipitation and extreme precipitation [50].…”