Gaoyuan qixiang (Jun 2024)
Characteristics of Qinghai-Xizang Plateau Vortex Activities and Identification of Sensitive Areas： A Study on Its Correlation with the Land Surface
Abstract
The Qinghai-Xizang Plateau Vortex is a mesoscale low-pressure vortex system generated within the boundary layer of the Qinghai-Xizang plateau in summer， which not only has an important influence on the weather patterns and precipitation dynamics across the plateau， but also profoundly impacts the surrounding regions.In this study， the database of the plateau vortex obtained from an objective analysis method， along with ERA5-land reanalysis data， was utilized to conduct a comprehensive statistical and analytical investigation of the vortex's activity from 1950 to 2021.Various analytical methods， including correlation analysis， regression analysis， Bayesian time series analysis algorithm， and probability statistics were used.Furthermore， the intensity and path of the plateau vortex during the years 1950 and 2021 were specifically examined to identify the areas most sensitive to its activity during this time span.Results reveal a noteworthy increasing trend （at a 95% confidence level） in both the annual number and duration of the plateau vortex， with climate tendency rates of 0.16·a-1 and 1.25 h·a-1， respectively.However， the growing trend for the total number and duration of the plateau vortex during the active period （May to August） is not statistically significant.The sensitive areas that affect the activity of the plateau vortex are located on the north side of the northern Qinghai-Xizang Plateau and near the Hoh Xil Mountains， corresponding to the main mountains in the central and western Qinghai-Xizang Plateau.Furthermore， the study investigates the relationship between land surface parameters and the vortex's characteristics， showing positive correlations between latent heat， surface longwave radiation， and surface soil moisture （0~7 cm） with the number and duration of the plateau vortex.Conversely， sensible heat exhibits a negative correlation， it is further found that the plateau vortex is relatively consistent with precipitation when the time scale of the study is inter-annual， while on the daily scale， the sensible heat is positively correlated with the number， duration， and intensity of the plateau vortex mainly in the sensitive areas and to the east of the sensitive areas， with the most significant correlation being in the months of May and June.In conclusion， the results derived from this study provide a solid theoretical foundation for further exploration of the land-atmosphere interaction mechanism in the identified sensitive area.Moreover， these findings lay a critical foundation for enhancing numerical simulations and data assimilation studies of the Qinghai-Xizang Plateau Vortex.
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