Regionally Different Precipitation Trends Over the Tibetan Plateau in the Warming Context: A Perspective of the Tibetan Plateau Vortices

Precipitation over the Tibetan Plateau (TP) significantly affects both the local ecology and the downstream water resources. In this study, it is found that there exists an increasing precipitation trend over the northern TP but not in the southern TP, which is interpreted from the perspective of the activities of Tibetan Plateau vortices (TPVs). In the context of recent warming over the TP, the increasing rate of genesis frequency of TPVs over the northern TP is remarkably larger than that over the southern TP, which is responsible for different precipitation trends in the northern and southern TP, respectively. That is, the most significant warming over the TP appears in the upper troposphere, which intensifies the 200 hPa westerly jet north of the TP, hereby produces more favorable conditions for the genesis of TPVs over the northern TP than over southern TP, and contributes to regional difference in precipitation trends. Plain Language Summary Precipitation over the Tibetan Plateau (TP) significantly affects the local ecology and the downstream water resources. In recent decades, significant warming trend is observed over the TP. It is found that the precipitation trends over the TP show robust regional differences in the warming context, with the causal physical process being not yet clear. Given the Tibetan Plateau vortices (TPVs) are important rainfall triggers over the TP, the regionally different precipitation trends over the TP are interpreted from the perspective of TPVs. Here, we show that warming over the TP causes regionally different increases in the genesis frequency of TPVs by modulating the upper-level westerly jet, and hereby contributes to the regional difference in precipitation trends over the TP.

Automated summary

The Tibetan Plateau (TP) experiences increasing precipitation trends in the northern region but not in the southern region, which is attributed to the activities of Tibetan Plateau vortices (TPVs). The significant warming over the TP influences the genesis frequency of TPVs differently in the north and south, leading to distinct precipitation trends in the two regions.