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Yang S.,Datong Meteorological Bureau | Liang J.,Datong Meteorological Bureau | Zhang Y.,Datong Meteorological Bureau | Chen Z.,Datong Meteorological Bureau | And 2 more authors.
Journal of Natural Disasters | Year: 2014

Using Doppler radar products and surface observation data of Datong City in Northern part of Shanxi Province during 2006-2011 and selecting 20 hailing process with hail diameters greater than or equal to 4mm, the hail weathers were statistically analyzed. Results show that, Datongs new generation of Doppler radar can monitor the development and evolution of hail weather, and has a good indicative effect to responsibility area. Spring hail is more difficult to forecast, forecast should focus on the three-body scattering phenomena and the characteristics of velocity field, hail early monitoring should be started when the three-body scattering phenomenon appears and the speed convergence, wind velocity field and shear characteristics occur. Features of hail weather in summer include: three-body scattering phenomenon of hail leads about 40 minutes; velocity field displays convergence, adverse wind area, cyclone, gale area and shear characteristics, generally hail appears after 20-30 minutes.

Yang S.-H.,Datong Meteorological Bureau | Wang L.-L.,Datong Meteorological Bureau | Liang J.-Q.,Datong Meteorological Bureau | Jia L.-F.,Datong Meteorological Bureau | And 2 more authors.
Journal of Natural Disasters | Year: 2011

By using the basic reflectivity factor, the composite reflectivity factor, the speed profile map, the vertical liquid water content, the echo tops and the vad wind profile of Doppler radar products for Datong area of the north of Shanxi Province, and combined with circulation situation and automatic weather station data, this paper analyzes a squall line process happened in Datong area on June 16, 2010. The results show that the squall line process occurred at high, middle and lower layers cold vortex circulation situation; Atmospheric pressure, temperature and wind velocity alter sharply when squall go through. In studying the stations with maximize wind speed ≥16. 8 m · s -1, it is discovered that the time occurring maximum velocity in two stations is in accord with that of outflow boundary effect, the time of, maximum velocity value in four stations correspond to sink effect time of powerful echo; The cold air carried by cold eddy makes the air flowing into the tail of squall to be continuously added, but the warm moisture flow in front side continuously produce a new single body, and that is the main reason of maintenance and development of squall line.

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