Mechanism of moisture transport associated with summer precipitation of the Hanjiang River Basin
In order to cope with the increasingly frequent and intense droughts under climate change,and to guarantee the water safety of water transfer projects and local water use,it is urgent to reveal the mechanisms of the changes in precipitation of the Hanjiang River Basin(HRB),which is a national strategic water source.Sum-mer precipitation in the HRB accounts for 40-50％of the annual precipitation.In this study,the Hybrid Single-Particle Lagrangian Integrated Trajectory model was used to analyze the moisture transport of summer precipitation in the HRB and its atmospheric circulation background during 1959-2022.It was found that precipitation lasting over 72 hours accounted for 44.6％of the total summer rainfall,and both frequency and amount have shown sig-nificant downward trends,which is the main reason for the decrease in precipitation of the HRB.Simulation of the moisture transport process shows that the South China Sea(SCS),Western Pacific(WP),and Eastern China(EC)are the main sources of water vapor for summer precipitation in the basin,with contributions of 34.7％,28.7％,and 27.2％,respectively.Comparison of moisture transport processes for precipitation of different durations shows that the longer the precipitation duration,the higher the contribution of water vapor from SCS and WP.Although the moisture from WP shows a significant increase,the moisture from SCS decreases significantly so the precipitation over 72 hours still shows a decreasing trend.The negative correlation between the West Pacific Subtropical High index and the contribution of SCS to the precipitation in HRB partially confirms the contribution of the enhance-ment and expansion of the WPSH on the reduction of summer precipitation of HRB in recent years.
Hanjiang River Basinprecipitation variabilityHYSPLITmoisture transportlarge-scale climate pattern
万方数据
维普
