Journal
JOURNAL OF CLIMATE
Volume 34, Issue 21, Pages 8481-8501Publisher
AMER METEOROLOGICAL SOC
DOI: 10.1175/JCLI-D-20-0646.1
Keywords
Mei-yu fronts; Monsoons; Topographic effects; Eddies; Jets
Categories
Funding
- National Natural Science Foundation of China [41690123, 41690120, 42088101, 91637208]
- Guangdong Major Project of Basic and Applied Basic Research [2020B0301030004]
- Second Tibetan Plateau Scientific Expedition and Research program [2019QZKK0106]
- Strategic Priority Research Program of Chinese Academy of Sciences [XDA20000000]
- Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies [2020B1212060025]
- PearlRiver S&TNova Programof Guangzhou [201906010054]
- Jiangsu Collaborative Innovation Center for Climate Change
Ask authors/readers for more resources
This study finds that the persistent suppression of transient eddies by the Tibetan Plateau weakens the East Asian westerly jet stream, leading to changes in precipitation patterns over East Asia, particularly in early summer. This suppression causes a southward shift of the East Asian rain belt, promoting increased rainfall in the southern region.
It is known that the Tibetan Plateau (TP) can weaken the transient eddies (TEs) transported along the westerly jet stream. This study investigates the effects of the persistently suppressed TEs by the TP on the East Asian summer monsoon and the associated mechanisms using the NCAR Community Earth System Model. A nudging method is used to modify the suppression of the TEs without changing the steady dynamic and thermodynamic effects of the TP. The suppressed TEs by the TP weaken the East Asian westerly jet stream through the weakened poleward TE vorticity flux. On the one hand, the weakened jet stream leads to less (more) rainfall in northern (southern) East Asia by inducing anomalous moisture convergence, midtropospheric warm advection, and upper-level divergence, particularly in early summer when the eastward propagation of TE suppression by the TP is strong. On the other hand, the precipitation anomalies can shift the East Asian westerly jet stream southward and promote the moisture convergence in southern East Asia through latent heat release. Therefore, the persistent suppression of the TEs leads to a southward shift of the East Asian rain belt by a convective feedback, as it was previously found that the steady thermodynamic and dynamic forcings of the TP favored a northward shift of the rain belt. This study suggests that the anomalously weak TEs can lead to a rainfall change (more in the south, less in the north) over East Asia.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available