A Numerical Study of a Low-level Jet and Its Accompanying Secondary Circulation in a Mei-Yu System
| Autor: | Wu-Ron Hsu, Wen-Yih Sun |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Monthly Weather Review. 122:324-340 |
| ISSN: | 1520-0493 0027-0644 |
| Popis: | A primitive equation numerical model has been used to study the Mei-Yu system that occurred in the middle of May 1987. Although cumulus heating was not included in one of the experiments, all of the major features of a Mei-Yu system other than deep convection are reproduced in that experiment. These features are a cloud band along the coastline in southern China; a weak temperature gradient, a strong moisture gradient, and a strong wind shear across the cloud band; and a supergeostrophic low-level jet (LLJ) with an accompanying secondary circulation. When the moist air coming from the south encounters the migrating high pressure system in the north, it turns to the east-northeast and becomes saturated. The resulting stratiform cloud covers all of southern China and the pressure trough at the 850-hPa level deepens by 1.5 hPa due to the latent heat released. It induces convergent motion in the lower level and generates a direct, cross-frontal secondary circulation that helps keep the low-level wind... |
| Databáze: | OpenAIRE |
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