The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR ...The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR data archive and provide new control point data for large-scale topographic mapping and geodetic surveying.However,the accuracy of the ATL 08 terrain estimates has not been fully evaluated on a large scale and in complex terrain conditions.This article aims to quantitatively assess the accuracy of ICESat-2 ATL 08 terrain estimates.Firstly,the ICESat-2 ATL 08 terrain estimates were compared with the high-precision airborne LiDAR digital terrain model(DTM),and impacts of acquisition time,vegetation cover type,terrain slope,and season change on the terrain estimation accuracy were analyzed.We get the following conclusions from the analysis:1)the mean and RMSE of the terrain estimates of day acquisitions are 0.22 m and 0.59 m higher than that of night acquisitions;2)the accuracy of the ATL 08 terrain estimates acquired in vegetated areas is lower than those in non-vegetated areas;3)the accuracy of the ATL 08 terrain estimates is inversely proportional to the slope,and the elevation error increases significantly when the terrain slope is larger than 30°;4)in the non-vegetation covered area,the accuracy of the ATL 08 terrain estimates of summer and winter acquisitions has no obvious discrepancy,but in vegetated area,the accuracy of winter acquisitions is significantly better than that of summer acquisitions.This research provides references for the selection and application of ICESat-2 data.展开更多
The quality factor Q is an important parameter because it can refl ect the reservoir attenuated features and can be used for inverse-Q filtering to compensate for the seismic wave energy.The accuracy of the Q estimati...The quality factor Q is an important parameter because it can refl ect the reservoir attenuated features and can be used for inverse-Q filtering to compensate for the seismic wave energy.The accuracy of the Q estimation is greatly significant for improving the precision of the reservoir prediction and the resolution of seismic data.In this paper,the Q estimation formulas of the single-frequency point are derived on the basis of a diff erent-order Taylor series expansion of the amplitude attenuated factor.Moreover,the multifrequency point average(MFPA)method is introduced to obtain a stable Q estimation.The model tests demonstrate that the MFPA method is less aff ected by the frequency band,travel time diff erence,time window width,and noise interference than the logical spectrum ratio(LSR)method and the energy ratio(ER)method and has a higher Q estimation accuracy.In addition,the proposed method can be applied to post-stack seismic data and obtain eff ective Q values of complex models.When the MFPA method was applied to real marine seismic data,the Q values estimated by the MFPA method with the 1st–4th order showed good consistency with each other.In contrast,the Q values obtained by the ER method were larger than those of the proposed method,while those estimated by the LSR method signifi cantly deviated from the average values.In conclusion,the MFPA method has superior stability and practicability for the Q estimation.展开更多
The small hydropower(SHP) will be less competitive in the absence of environmental value.The lack of information has become an important obstacle challenging decision-makers in resource-use choices.This paper is an ap...The small hydropower(SHP) will be less competitive in the absence of environmental value.The lack of information has become an important obstacle challenging decision-makers in resource-use choices.This paper is an application of contingent valuation method(CVM) in rural China to estimate the willingness-to-pay(WTP) for environmental services provided by exiting hydropower station.Using the single-bounded and dichotomouschoice CVM,the ecological value of Tongjiqiao Reservoir(TJQR) is estimated,and the annual mean WTPs of single-bounded and double-bounded CVM estimation are 141.05 and 219.52 Yuan(RMB)/a,respectively.The 95% confidence interval of annual WTP on an average is 118.47,166.79 Yuan(RMB)/a and 204.41,236.22(Yuan RMB)/a,respectively.In contrast,double-bounded model could obtain much more information of WTP of the investigated,thus reducing the confidence interval of estimation,and enhancing the estimation accuracy of the WTP.According to the estimated mean WTP of the double-bounded CVM,the total ecosystem service value of the TJQR is 15.54 million Yuan(RMB).Compared with the conventional electricity of fossil power and large hydropower,the SHP will be less competitive in the absence of non-market value,ignoring that the environmental impacts of existing SHP will undermine the healthy development of clean energy sector.展开更多
基金Projects(41820104005,41904004,42030112)supported by the National Natural Science Foundation of China。
文摘The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR data archive and provide new control point data for large-scale topographic mapping and geodetic surveying.However,the accuracy of the ATL 08 terrain estimates has not been fully evaluated on a large scale and in complex terrain conditions.This article aims to quantitatively assess the accuracy of ICESat-2 ATL 08 terrain estimates.Firstly,the ICESat-2 ATL 08 terrain estimates were compared with the high-precision airborne LiDAR digital terrain model(DTM),and impacts of acquisition time,vegetation cover type,terrain slope,and season change on the terrain estimation accuracy were analyzed.We get the following conclusions from the analysis:1)the mean and RMSE of the terrain estimates of day acquisitions are 0.22 m and 0.59 m higher than that of night acquisitions;2)the accuracy of the ATL 08 terrain estimates acquired in vegetated areas is lower than those in non-vegetated areas;3)the accuracy of the ATL 08 terrain estimates is inversely proportional to the slope,and the elevation error increases significantly when the terrain slope is larger than 30°;4)in the non-vegetation covered area,the accuracy of the ATL 08 terrain estimates of summer and winter acquisitions has no obvious discrepancy,but in vegetated area,the accuracy of winter acquisitions is significantly better than that of summer acquisitions.This research provides references for the selection and application of ICESat-2 data.
基金supported by The National Natural Science Foundation (Grant Nos.41874126, 42004114)the Key Research and development project of Jiangxi Province in China (Grant No.20192ACB80006)+1 种基金the Natural Science Foundation of Jiangxi Province (Grant Nos. 20202BAB211010, 20212BAB203005)Open Foundation of State Key Laboratory of Nuclear Resources and Environment (2020NRE25)
文摘The quality factor Q is an important parameter because it can refl ect the reservoir attenuated features and can be used for inverse-Q filtering to compensate for the seismic wave energy.The accuracy of the Q estimation is greatly significant for improving the precision of the reservoir prediction and the resolution of seismic data.In this paper,the Q estimation formulas of the single-frequency point are derived on the basis of a diff erent-order Taylor series expansion of the amplitude attenuated factor.Moreover,the multifrequency point average(MFPA)method is introduced to obtain a stable Q estimation.The model tests demonstrate that the MFPA method is less aff ected by the frequency band,travel time diff erence,time window width,and noise interference than the logical spectrum ratio(LSR)method and the energy ratio(ER)method and has a higher Q estimation accuracy.In addition,the proposed method can be applied to post-stack seismic data and obtain eff ective Q values of complex models.When the MFPA method was applied to real marine seismic data,the Q values estimated by the MFPA method with the 1st–4th order showed good consistency with each other.In contrast,the Q values obtained by the ER method were larger than those of the proposed method,while those estimated by the LSR method signifi cantly deviated from the average values.In conclusion,the MFPA method has superior stability and practicability for the Q estimation.
基金supported by National Natural Science Foundation of China in 2008 (Grant No. 70873108)Zhejiang Provincial Natural Scien8ce Foundation of China (Grant No. Z607126)+1 种基金the key research project funded by a national key research base for humanities and social sciences under the guidance of the Ministry of Education (Grant No. 2007JJD630014)Programfor New Century Excellent Talents in University in 2008
文摘The small hydropower(SHP) will be less competitive in the absence of environmental value.The lack of information has become an important obstacle challenging decision-makers in resource-use choices.This paper is an application of contingent valuation method(CVM) in rural China to estimate the willingness-to-pay(WTP) for environmental services provided by exiting hydropower station.Using the single-bounded and dichotomouschoice CVM,the ecological value of Tongjiqiao Reservoir(TJQR) is estimated,and the annual mean WTPs of single-bounded and double-bounded CVM estimation are 141.05 and 219.52 Yuan(RMB)/a,respectively.The 95% confidence interval of annual WTP on an average is 118.47,166.79 Yuan(RMB)/a and 204.41,236.22(Yuan RMB)/a,respectively.In contrast,double-bounded model could obtain much more information of WTP of the investigated,thus reducing the confidence interval of estimation,and enhancing the estimation accuracy of the WTP.According to the estimated mean WTP of the double-bounded CVM,the total ecosystem service value of the TJQR is 15.54 million Yuan(RMB).Compared with the conventional electricity of fossil power and large hydropower,the SHP will be less competitive in the absence of non-market value,ignoring that the environmental impacts of existing SHP will undermine the healthy development of clean energy sector.
