Characteristics Analysis Of High Winds Over The Bohai And North Yellow Seas And Numerical Study Of A High Wind Event

With the continuous development and use of marine resources, research of strongwinds at sea is put forward higher requirements, and more and more scholars haveconducted in-depth research in this area. The research for the spatial and temporaldistribution of strong winds at sea and short-term local windy forecast and genesis isthe emphasis. Firstly, based on the United States NCEP (National Centers forEnvironmental Prediction) CSFR that are kept (Climate Forecast System Reanalysis)reanalysis data (1991-2010), the spatial and temporal distribution of strong winds ofBohai and northern Yellow Sea are count in order to find the distribution regularity ofthe strong winds at sea. And then with the new generation of atmospheric mesoscalemode WRF (Weather Research and Forecasting) and its cycle3DVAR (3-DimensionalVariational) assimilation, conventional observational data, satellite radiation andDopplar radar data are used to assimilated. One case of sea short-term severeconvective windy has detailed numerical simulations. The genetic mechanism of theshort-term of strong convection and strong wind is studied. The main conclusions asfollows:1) The20-years averaged wind days of strong breeze and gale were100and4days, The interannual variation of wind days of strong breeze and gale were-0.16day/year and0.11day/year. The interannual variation of wind days of gale in differentseas are increased, the Bohai Bay and middle Bohai sea are only domain which windspeed and wind days are increased. The maximum of wind days of gale lies in winterand the minimum lies in summer, while the extreme windy weather is more likely tooccur in the latter season.2) Observational facts analysis shows that the sea short-term severe convectivewinds case is influenced by eastward shift of500hPa westerly jet stream and thelower troposphere shear line southward caused by cold air. The occurrence of strong convective is lead to the low-level Rapids momentum, resulting in a severe windyweather. The high-resolution output of the WRF model results further reveal thedynamic action of low-level wind shear, and ocean thermal effects are the specificgenetic mechanism of the short-term windy, the strong convective are made thedevelopment of the short-term windy. The thermal factors such as ocean adequatemoisture and unstable stratification play a key role on the development of strongwinds at sea.