Estimation Of Directional Distribution Of Offshore Wind Energy From Satellite Observations

Satellite remote sensing with irreplaceable advantages is one of effective methods to estimate a specific offshore region’s wind energy.Currently,the wind energy parameters retrieved by remote sensing do not include directional parameters.Thus,they cannot meet the real engineering needs in the selection of wind farm.To address this problem,this thesis built a retrieval method of directional wind energy parameters using satellite remote sensing data,which consists of the parameters system of directional characteristics of wind energy,retrieval and data process schemes,methods to limit the impacts of uncertainty and error factors and precision evaluation methods of retrieval results.This thesis built the system of directional characteristics parameters of wind energy,which includes wind direction frequency,directional distribution of wind energy density,circular mean of wind direction,circular mean of wind energy direction,circular standard deviation of wind direction and circular standard deviation of wind energy direction.This thesis built difference estimate method with total difference and Wasserstein metric for the precision evaluation of retrieval results.By using Fisher discriminate analysis and Kuiper test,the consistent criteria for total difference and Wasserstein are found,which are 16.32% for total difference and 0.74 for Wasserstein metric.By analyzing the retrieval process,this thesis showed that the retrieval error of wind speed and direction,the data density,the integral time,the representative of observation time and the range of wind speed are main uncertainty factors in this retrieval method.With the sensitivity analysis results,this thesis stated that the retrieval error of wind speed and direction,the data density and the representative of observation time are sensitive factors.With theoretical analysis and simulation experiment,we found that at least 350 records and 800 records are needed to retrieve wind direction frequency and directional distribution of wind energy density accurately with remote sensing observation time rule,and retrieval error of wind speed and direction will enlarge the retrieval results of circular standard deviation of wind direction and circular standard deviation of wind energy direction.This thesis retrieves the global directional wind energy parameters using 9 years’ ASCAT wind vectors products,and analyzes the retrieval results.At the same time,the effectiveness and accuracy of these retrieval outputs are tested with the help of 54 buoys’ data provided by National Data Buoy Center of National Oceanic and Atmospheric Administration.