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A crescent‐shaped low‐level jet as observed by a Doppler radar
Author(s) -
Lau S. Y.,
Chan S. T.
Publication year - 2003
Publication title -
weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.467
H-Index - 40
eISSN - 1477-8696
pISSN - 0043-1656
DOI - 10.1256/wea.234.02
Subject(s) - observatory , citation , history , library science , physics , computer science , astrophysics
Background Encountered in many parts of the world, low- level jets (LLJs) have attracted considerable attention because of their relation to thunder- storm development, cyclogenesis, air pollution and aviation safety. In south China, studies of LLJs have mostly focused on their role in con- nection with summer monsoon rain (Tao and Chen 1987; Chen et al. 1994; Chen and Chen 1995; Yeung 1998). In winter, the LLJ is usually associated with the passage of a cold front. The pool of cold air becomes shallower as it moves south, creating an elevated temperature inversion which is usually located near the 900 mbar level over the south China coastal areas (Wong and Yu 1998). LLJs are sometimes observed around the inversion. While wintertime LLJs may not be associated with heavy rain, their existence warrants atten- tion as LLJs aligned in the direction of an air- port runway can cause wind shear during aircraft take-off and landing. Wind shear is a sudden change in the wind direction and/or wind speed resulting in a change in the lift to the aircraft. This short note reports the observation of an LLJ in winter in south China by means of a Terminal Doppler Weather Radar (TDWR). During the episode, wind shear was reported by several pilots using Hong Kong Interna- tional Airport.