Impacts of the irrigation area on extreme rainstorm in the western Tarim Basin
[Objective]The irrigation area in the Tarim Basin is imperative to supporting the local economy and social development;however,frequent and extreme rainstorm events in the basin have posed serious danger to human lives and property.Irrigation areas alter the local near-surface climatic conditions,and irrigation has cooling and humidifying effects and affects local climate.Thus,analyzing the impact of irrigation areas on extreme rainstorm events could improve our understanding of its mechanism and provide reference for irrigation development and flood management.[Methods]This study analyzed the impact of the irrigation area on the extreme rainfall process.The weather research and forecast(WRF)model was used,and the research object was the extreme rainstorm event that occurred in the western Tarim Basin from June 15 to 17,2021("6·15"rainstorm).Furthermore,to explore the mechanism of the irrigation area,a high-resolution comparative simulation experiment was performed using two simulation scenarios set up in WRF,one with irrigation and one without irrigation,to study the impact of the irrigation area on various meteorological elements,and water vapor transport process and formation process in this extreme rainstorm event and reveal the impact mechanism of the irrigation area on the extreme rainstorm.[Results](1)The Tarim Basin's eastward flow caused by the north-south high pressure brought a substantial amount of water vapor to the basin.Before the precipitation,water vapor was transported along the northern part of the basin to the west and then turned southward to the southwest of the basin,thus forming an extreme rainstorm.(2)The existence of the irrigation area obstructed wind in both the northern and western parts of the basin.The irrigation area caused wind speed to rise in front of the irrigation area,with a decline in water vapor behind the irrigation area leading to a decrease in water vapor transported to the north,and an increase to the southwest providing more water vapor for the extreme rainstorm event.(3)In the main precipitation area,the combined action of the irrigation and mountainous areas enhanced the uplifting effect of the terrain on the wind,forming vertical circulation in front of the mountains,and the precipitation increased due to the high amount of water vapor brought by the eastward flow.[Conclusions]A large amount of water vapor transport is found to be the main cause of the extreme rainstorm event.The obstruction effect of the irrigation area on water vapor transport process results in more water vapor being transported to the extreme rainstorm area.However,the enhanced uplifting effect of the terrain from the combination of the irrigation and mountainous areas causes water vapor to accumulate in the rainstorm area,leading to increased extreme rainstorm.Thus,these results further elucidate the significance of exploring flood management in irrigation areas.
Tarim Basinirrigation areaextreme rainstormwater vapor transport
万方数据
维普
