Assessing Ocean Wind Energy Resources Integrated Multiple Satellite And Groundbased Data

It is therefore of utmost necessity to evaluate ocean wind energy resources for wind electricity generation.Ocean wind information around the globe can be obtained from multiple satellite data to compensate for limitation in situ measurements.However,there are still some problems remain to be researched for previous studies in ocean wind energy resources assessment using multiple satellite data,which are as follows:(1)what a large influence that the number of satellite data would have on the accuracy for ocean wind resources assessment;(2)what a large influence that crossing time of different satellite data and their combinations would have on the precision for ocean wind resources assessment;(3)considering the phenomenon of distortion or lacking of offshore wind information from satellite observations due to the land contamination,if it is possible to assess offshore wind energy resources based on the integration of multiple satellite and ground-based data by spatial interpolation methods.The main research contents and conclusions of this paper are as follows:(1)Verification of the accuracy of wind data derived from different satellite.Comparison between Quik SCAT(1999?2009),ASCAT(2007?2015),Wind SAT(2003?2015)and 39 NDBC buoy hourly wind measurements(1999?2015)at a height of 10 m are carried out.The results show that wind speeds from ASCAT have the lowest RMSE(1.19 m/s)and than Quik SCAT(1.23 m/s)and Wind SAT(1.45 m/s)compared with wind speeds from NDBC buoys.For the impact of the offshore distance on the accuracy of satellite-derived wind,when the offshore distance to the coastline is less than 50 km,the wind speeds(or wind directions)show higher errors due to the land contamination,the accuracy of satellite-derived wind in the offshore areas is lower.(2)Estimating the uncertainty associated with the number of satellite observations and its impact on the accuracy of ocean wind resources assessment derived from multiple satellite data.The current study compares wind energy parameters(mean wind speeds,mean wind power densities,Weibull parameters)retrieved from Quik SCAT,ASCAT,Wind SAT and their different combinations with39 NDBC buoy measurements(1999?2015)at heights of 10 m and 100 m above sea level.The results show that a better accuracy of wind energy parameters may be derived from multiple satellite data than from single satellite data.Meanwhile,Quik SCAT+ASCAT+Wind SAT-derived wind energy parameters at heights of 10 m and 100 m show the lowest RMSE.Furthermore,we quantified the impacts of data sampling density(number of satellite observations)on the accuracy of satellite-derived wind energy parameters at 10 m and 100 m above sea level.The results show an increase in the accuracy of wind energy parameters calculation with more satellite observations at 10 m and 100 m above sea level.The wind energy parameters estimated by the satellite data basically stay within a relatively stable error range(eg.RMSE of mean wind power densities are 29?30 W/m~2 and 56?58 W/m~2 at heights of 10 m and 100 m,respectively)when the overlaping number of satellite data is more than 8000(Which is consistent with the minimum wind sample requirement for wind resources assessment based on NREL/SR-440-22223 and GB/T18710-2002).(3)Estimating the uncertainty associated with the crossing time of satellite observations and its impact on the accuracy of ocean wind resources assessment derived from multiple satellite data.The current study compares wind energy parameters retrieved from the 39 NDBC buoy data(1999?2015)of simulated different satellite crossing time and their different combinations with 39 NDBC buoy hourly wind measurements at a height of 10 m.The results show that a better accuracy of wind energy parameters may be derived from multiple crossing time of satellite data than from single crossing time.(4)Assessment of China's offshore wind resources based on the integration of multiple satellite data and ground-based data.Wind energy parameters were estimated with the synergetic use of Quik SCAT+ASCAT+Wind SAT data(1999?2017)and meteorological data(2016?2017)from coastal stations by spatial interpolation methods,including inverse distance weighted(IDW),ordinary kriging(OK)and ordinary co-kriging(OCK).The spatial distribution of offshore wind energy parameters over China Sea is assessed at heights of 10 m and 100 m.Then 8 Chinese buoy measurements at a height of 10 m were used to evaluate the accuracy of offshore wind resources assessment.The results show that combining multiple satellite data and meteorological data from coastal stations improves the accuracy of wind resources assessment in the offshore areas than those from multiple satellite data or meteorological data only,and the OCK method show the best performance of accuracy in most cases.The statistical results show that interpolated mean wind speeds and mean wind power densities derived from multiple satellite data+270meteorological data by OCK method show lowest errors at a height of 10 m,the RMSE of them are 0.17 m/s and 23.38 W/m~2,respectively.Based on the spatial distribution of wind energy parameters obtained,the highest wind resources are mainly found in the Taiwan Strait and offshore regions along the Fujian Province.