The estimation of wind turbine performance over complex terrain is very difficult because of the document of standard IEC61400-12 is adapted for flat or slightly complex topography.And the cost of constructing a meteo...The estimation of wind turbine performance over complex terrain is very difficult because of the document of standard IEC61400-12 is adapted for flat or slightly complex topography.And the cost of constructing a meteorological mast is higher with scaling wind turbine up.We have proposed a numerical site calibration(NSC) technique in order to estimate the inflow velocity at the position of wind turbine by using CFD tool to calculate the flow field around the site.The present paper shows the problems for the procedure of NSC in which a commercial nonlinear CFD tool and the improvement method are used to gain a more accurate result.It is clarified that the wind turbine performance which is estimated by using the wind speed on the meteorological mast has a good result for annual energy production.展开更多
A comprehensive field experiment was made with the support of the project of China Radiometric Calibration Site (CRCS) during June-July 1999.Ground reflectance spectra were measured at Dunhuang Calibration Test Site i...A comprehensive field experiment was made with the support of the project of China Radiometric Calibration Site (CRCS) during June-July 1999.Ground reflectance spectra were measured at Dunhuang Calibration Test Site in the experiment.More than two thousands of spectral curves were acquired in a 20km×20km area.The spectral coverage is from 350 nm to 2500 nm.The measurement values show that reflectance is between 10% and 33% at the VIS- SWIR spectral region.The standard deviation of reflectance is between 1.0% and 2.0% for the spectral range.Optical characteristics and ground reflectance measurements at the Dunhuang test site,result analysis and error source were described.In addition,a comparison of the reflectance obtained in 1999 with those measured in 1994 and 1996 was also made.展开更多
Satellite altimeter needs to be calibrated to evaluate the accuracy of sea surface height data.The dedicated altimeter calibration field needs to establish a special calibration strategy and needs to evaluate its cali...Satellite altimeter needs to be calibrated to evaluate the accuracy of sea surface height data.The dedicated altimeter calibration field needs to establish a special calibration strategy and needs to evaluate its calibration ability.This paper describes absolute calibration of HY-2 B altimeter SSH using the GPS calibration method at the newly Wanshan calibration site,located in the Wanshan Islands,China.There are two HY-2 B altimeter passes across the Wanshan calibration site.Pass No.362 is descending and the ground track passes the east of Dan’gan Island.Pass No.375 is ascending and crosses the Zhiwan Island.The GPS data processing strategy of Wanshan calibration site was established and the accuracy of GPS calibration method of Wanshan calibration site was evaluated.Meanwhile,the processing strategies of the HY-2 B altimeter for the Wanshan calibration site were established,and a dedicated geoid model data were used to benefit the calibration accuracy.The time-averaged HY-2 B altimeter bias was approximately 2.12 cm with a standard deviation of 2.08 cm.The performance of the HY-2 B correction microwave radiometer was also evaluated in terms of the wet troposphere path delay and showed a mean difference-0.2 cm with a 1.4 cm standard deviation with respect to the in situ GPS radiosonde.展开更多
文摘The estimation of wind turbine performance over complex terrain is very difficult because of the document of standard IEC61400-12 is adapted for flat or slightly complex topography.And the cost of constructing a meteorological mast is higher with scaling wind turbine up.We have proposed a numerical site calibration(NSC) technique in order to estimate the inflow velocity at the position of wind turbine by using CFD tool to calculate the flow field around the site.The present paper shows the problems for the procedure of NSC in which a commercial nonlinear CFD tool and the improvement method are used to gain a more accurate result.It is clarified that the wind turbine performance which is estimated by using the wind speed on the meteorological mast has a good result for annual energy production.
文摘A comprehensive field experiment was made with the support of the project of China Radiometric Calibration Site (CRCS) during June-July 1999.Ground reflectance spectra were measured at Dunhuang Calibration Test Site in the experiment.More than two thousands of spectral curves were acquired in a 20km×20km area.The spectral coverage is from 350 nm to 2500 nm.The measurement values show that reflectance is between 10% and 33% at the VIS- SWIR spectral region.The standard deviation of reflectance is between 1.0% and 2.0% for the spectral range.Optical characteristics and ground reflectance measurements at the Dunhuang test site,result analysis and error source were described.In addition,a comparison of the reflectance obtained in 1999 with those measured in 1994 and 1996 was also made.
基金The National Key R&D Program of China under contract Nos 2018YFB0504900 and 2018YFB0504904the National Natural Science Foundation of China under contract Nos 41406204 and 41501417the Operational Support Service System for Natural Resources Satellite Remote Sensing under contract No.180019。
文摘Satellite altimeter needs to be calibrated to evaluate the accuracy of sea surface height data.The dedicated altimeter calibration field needs to establish a special calibration strategy and needs to evaluate its calibration ability.This paper describes absolute calibration of HY-2 B altimeter SSH using the GPS calibration method at the newly Wanshan calibration site,located in the Wanshan Islands,China.There are two HY-2 B altimeter passes across the Wanshan calibration site.Pass No.362 is descending and the ground track passes the east of Dan’gan Island.Pass No.375 is ascending and crosses the Zhiwan Island.The GPS data processing strategy of Wanshan calibration site was established and the accuracy of GPS calibration method of Wanshan calibration site was evaluated.Meanwhile,the processing strategies of the HY-2 B altimeter for the Wanshan calibration site were established,and a dedicated geoid model data were used to benefit the calibration accuracy.The time-averaged HY-2 B altimeter bias was approximately 2.12 cm with a standard deviation of 2.08 cm.The performance of the HY-2 B correction microwave radiometer was also evaluated in terms of the wet troposphere path delay and showed a mean difference-0.2 cm with a 1.4 cm standard deviation with respect to the in situ GPS radiosonde.
