ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 46 Issue 4 > 2020,46(4):478-489. DOI:10.7519/j.issn.1000-0526.2020.04.003 Prev Next
Mechanism of a Rare Night Sudden Intense Warming Event in Beijing and Surrounding Area
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Abstract:
Surface temperature normally decreases after sunset, but a great many night sudden intense warming events were observed in winter in Beijing and the surrounding area, and the intense rise in temperature could be higher than 10 ℃ per hour. Such sudden warming events are aften 〖JP2〗followed by rapid tempera〖JP〗ture dropping, which would cause great difficulty in forecasting. This paper detailedly analyzes a rare intense night warming event with the increase range of 12 ℃·h-1, which was caused by a cold front passing through Beijing and surrounding area over the night of 26 November 2010. Compared with the statistical climatological results, the heating intensity and affected area this time are extreme rarely seen. The analysis is based on the data of automatic weather stations, conventional surface stations and rawinsonde, meteorological observation tower, stationary meteorological satellite, and wind profiler, as well as the reanalysis data of NCEP. The results show that, during the event, there was significant cold advection in the lower troposphere, and significantly strong downward motion in the middle and lower troposphere illustrated by diagnosed vertical velocity and the data from the satellite and the wind profiler. The temporal evolution of both the meteorological tower observations and soundings in Beijing indicates that strong turbulence existed in the boundary layer. Therefore, this rare warming event was caused by the significant surface potential temperature differences between the plateau and the plain, the strong downward adiabatic warming and the intense turbulent mixing with strong boundary layer jet. The estimation shows that the turbulent mechanical mixing associated with the lowlevel jet could cause about 8℃ increase in temperature. Finally, the conceptual model of this event is presented.
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