Simulation Study On Fine Analysis Of Low Layer Wind Field At Jiangsu Coastal Areas

Based on climatic statistical analysis of observational data of Jiangsu coastal areas, the fine simulation study on low layer wind field at this region has been accomplished by the mesoscale WRF model. The methods used in fine analysis consist of, numerical simulation, interpolations and computations. Finally, the main features of fine wind fields in low layer at Jiangsu coastal areas and wind resource distribution situation are obtained.The five-year mean wind fields show, northerly monsoon is prevalent in Jiangsu coastal areas during the whole winter. And10m/s wind speed isolines are along the coastal line as well as with big gradients there. It is shown by statistical results of seasonal wind fields that there are more low speed wind in summer and more large speed in winter. With the height increasing in the vertical direction, during winter the frequency of the same magenitude large speed is significant more than summer. Compared meteorological element field of2010winter with a five-year mean field, the mean pressure and temperatures are lower, while the wind speed is higher.The low layer wind fields of a typical cold wave event, March19,2010, was simulated by WRF model, after understanding the statistical characteristics of the element fields and wind fields of Jiangsu coastal areas in winter. The temperature drop rate was decreasing, when the cold wave invasion from north to south. Due to the affection of the main front and sub front on the ground there are three stages in the event,:initial temperature rapidly drop, then weak rebound and re-drop again.. The strong winds come with temperature drop, weakening of the wind speed lagged far behind temperature fast drop., and the next wind speed increase is with the rise of temperature. After investigating the effect of near surface and boundary layer schemes in the model, the near surface scheme MYJ Monin-Obukhov and boundary layer scheme Eta MYJ TKE are chosen. The scheme configuration has a better effect than others in low layer wind field simulation for the cold wave event,Two sensitivity tests:to Change sea surface temperature near shore and low-layer temperature field are designed for the purpose to investigate their influence on the low layer wind field features in the cold wave event. The simulation results showed that evolution of wind field features significantly response to the short period change of SST and low layer temperature. When the nearshore SST increased, the wind speed gradient decreases along coastal, and large value of wind speed at sea weakened. When increasing the temperature in low-layer warm area of the cold wave front, the strength of cold wave is increased, the wind strength increased overall wind field. Cold front moving faster, the maximum wind speed behind the shear line enhance.Finally, using a new method that at first to determine the weight coefficients by the probability distribution of wind speed classification, then to calculate the wind power density of wind speed by weighting average of wind speed. From this, it is obtained that the wind resource conditions of the annual average and of the average in cold wave event in Jiangsu coastal. Meantime, the characteristics of the wind power density in the special weather event is compared with the numerical simulation results, and is systematically analyzed.