A Study On The Spatial And Temporal Characteristics Of Wave And Wind In The East China Sea

At present, lack of measured data was the problem of wave energy and offshore wind energy development. With the help of meteorological model, reanalysis data and satellite data, the analysis of spatial and temporal characteristics of the wave and offshore wind energy was done in the East China Sea region, to provide a reference for offshore energy macro and micro planning. Main contents and findings as follows:(1) Wind speed field of20years from1991to2010in the East China Sea area were decomposed to the first space typical field (only space-related) and the time factor by empirical orthogonal function (EOF). The first space field represented the average wind speed in the study area, and the time factor indicated the time trend of wind speed. The results showed that the shape of wind speed contour is similar to the coastline, and the wind speed increased rapidly near the coastline; the East China Sea area was significantly affected by the northeast monsoon, and there was a high-velocity zone and two low-speed zones; wind speed in the past20years had growth trend, and wind speed showed a annual cycle fluctuations. The wind speed spatial distribution of the first space typical field is same as the Fourth of wind energy resources detailed investigation, and this confirmed that empirical orthogonal method was feasible to macro-planning of wind energy resources in the East China Sea.(2) Four nested grid WRF model was used to simulate the wind field, the mode of the fourth layer was compared to the observed wind data, with the second layer to the ECMWF re-analysis data. The correlation coefficient between WRF model simulated wind speed and measured was closed to0.8; the main wind direction could be expressed by the simulated data; the simulated average wind speed and average wind power density were closed to the measured. There was strong consistency between the spatial and temporal distribution of simulated wind field and reanalysis wind field; and the ECMWF reanalysis data had a good applicability for the East China Sea region.(3) The maximum entropy principle and weibull distribution were used to fit the wind speed measured at the offshore towers with different heights. The results showed that the maximum entropy distribution had obvious advantages, and the difference value between the maximum entropy distribution error and the weibull distribution had a tendency to increase with height; as the height increased, the maximum entropy of wind speed had increased trends; the difference between the four-parameter maximum entropy distribution and the five-parameter maximum entropy at higher place was less than the lower. These showed that the wind speed distribution more conformed with the law revealed by the maximum entropy principle, within the information system.(4) The global scale and ocean-scale wave field were forecasted day ahead by WAVEWATCH Ⅲ numerical model, WAVEWATCH Ⅲ model has a good performance on forecasting the global wave height distribution, wave propagation and growth. But the significant wave height values were significantly influenced by the input wind data; and the forecasted direction of waves was not accurate enough. Using the WRF output as the input of WAVEWATCHⅢ model could improve forecast accuracy.