Testing the Role of Westerly Jet in Triggering and Terminating Mei-Yu
Abstract
Mei-Yu is characterized by a tilted elongated quasi-stationary subtropical frontal rainband over East Asia. This study tests the hypothesis that the positioning of the westerly jet relative to the Tibet plays deterministic role in triggering, sustaining, and terminating Mei-Yu. We argue that the modification of orographic forced stationary waves during the northward jet transition is key to the timing and position of Mei-Yu. Toward this end, we firstly test the sensitivity of Mei-Yu to changes in the latitudinal position and meridional extension of the Tibetan Plateau in a general circulation model (CAM5). We employ the self-organizing maps (SOMs) to extract the timing and spatial pattern of Mei-Yu. The responses of Mei-Yu to different configurations of the Tibet will be discussed. To understand the evolution of the stationary waves during the jet transition, we also embed a Gaussian-shaped mountain with similar dimension to the Tibet in a dry dynamical core with the `Held-Suarez' configuration, and mimic the seasonal transition of the jet via shifting the mountain latitudinally.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A23J0366K
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 3344 Paleoclimatology;
- ATMOSPHERIC PROCESSESDE: 4901 Abrupt/rapid climate change;
- PALEOCEANOGRAPHY