Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree c...Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree classification rules through multi-source and multi-temporal feature fusion, classified groundobjects before the disaster and extracted flood information in the disaster area based on optical imagesduring the disaster, so as to achieve rapid acquisition of the disaster situation of each disaster bearing object.In the case of Qianliang Lake, which suffered from flooding in 2020, the results show that decision treeclassification algorithms based on multi-temporal features can effectively integrate multi-temporal and multispectralinformation to overcome the shortcomings of single-temporal image classification and achieveground-truth object classification.展开更多
Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation...Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation over several decades,thereby overlooking the movement of slopes and failing to capture landslide dynamics.The long-term ground deformation map(GDM)derived from multi-temporal interferometric synthetic aperture radar(MT-InSAR)can effectively address the shortcomings.Fengjie County is an important area for geohazard management in the Three Gorges Reservoir Area(TGRA),China.Landslides in this area,however,cause significant socio-economic loss due to geological,tectonic,climatic,and anthropological factors.This research aims to integrate random forest(RF)with MT-InSAR to generate a landslide dynamic susceptibility map(LDSM)for Fengjie County,enhancing the reliability of landslide risk management.First,the RF model was employed to generate a static LSM,whereas MT-InSAR was utilized to obtain the GDM of the study area from January 2020 to June 2023.The static LSM and the GDM were subsequently integrated using a dynamic weight matrix to derive the LDSM.Our analysis covered a temporal framework spanning three years,focusing on spatiotemporal changes in landslide susceptibility levels and the influence of climate factors.Compared with the static LSM,the LDSM can promptly identify moving landslide areas,reduce high landslide susceptibility areas,and achieve greater accuracy.Moreover,the spatiotemporal changes in landslide susceptibility are regulated by the total annual rainfall,with wet years being more conducive to landslides than dry years.The proposed LDSM offers useful insights for the dynamic prevention and refined management of landslide hazards in the TGRA,significantly enhancing the resilience in this region.展开更多
Glacier area changes in the Qangtang Plateau are analyzed during 1970-2000 using air photos,relevant photogrammetric maps and satellite images based on the multi-temporal grid method.The results indicate that the melt...Glacier area changes in the Qangtang Plateau are analyzed during 1970-2000 using air photos,relevant photogrammetric maps and satellite images based on the multi-temporal grid method.The results indicate that the melting of glaciers accelerated,only a few of glaciers in an advancing state during 1970-2000 in the whole Qangtang Plateau.However,the glaciers seemed still more stable in the study area than in most areas of western China.We estimate that glacier retreat was likely due to air temperature warming during 1970-2000 in the Qangtang Plateau.Furthermore,the functional model of glacier system is applied to study climate sensitivity of glacier area changes,which indicates that glacier lifespan mainly depends on the heating rate,secondly the precipitation,and precipitation increasing can slow down glacier retreat and make glacier lifespan prolonged.展开更多
Pre-harvest yield prediction of ratoon rice is critical for guiding crop interventions in precision agriculture.However,the unique agronomic practice(i.e.,varied stubble height treatment)in rice ratooning could lead t...Pre-harvest yield prediction of ratoon rice is critical for guiding crop interventions in precision agriculture.However,the unique agronomic practice(i.e.,varied stubble height treatment)in rice ratooning could lead to inconsistent rice phenology,which had a significant impact on yield prediction of ratoon rice.Multi-temporal unmanned aerial vehicle(UAV)-based remote sensing can likely monitor ratoon rice productivity and reflect maximum yield potential across growing seasons for improving the yield prediction compared with previous methods.Thus,in this study,we explored the performance of combination of agronomic practice information(API)and single-phase,multi-spectral features[vegetation indices(VIs)and texture(Tex)features]in predicting ratoon rice yield,and developed a new UAV-based method to retrieve yield formation process by using multi-temporal features which were effective in improving yield forecasting accuracy of ratoon rice.The results showed that the integrated use of VIs,Tex and API(VIs&Tex+API)improved the accuracy of yield prediction than single-phase UAV imagery-based feature,with the panicle initiation stage being the best period for yield prediction(R^(2) as 0.732,RMSE as 0.406,RRMSE as 0.101).More importantly,compared with previous multi-temporal UAV-based methods,our proposed multi-temporal method(multi-temporal model VIs&Tex:R^(2) as 0.795,RMSE as 0.298,RRMSE as 0.072)can increase R^(2) by 0.020-0.111 and decrease RMSE by 0.020-0.080 in crop yield forecasting.This study provides an effective method for accurate pre-harvest yield prediction of ratoon rice in precision agriculture,which is of great significance to take timely means for ensuring ratoon rice production and food security.展开更多
Estimating wheat grain protein content by remote sensing is important for assessing wheat quality at maturity and making grains harvest and purchase policies. However, spatial variability of soil condition, temperatur...Estimating wheat grain protein content by remote sensing is important for assessing wheat quality at maturity and making grains harvest and purchase policies. However, spatial variability of soil condition, temperature, and precipitation will affect grain protein contents and these factors usually cannot be monitored accurately by remote sensing data from single image. In this research, the relationships between wheat protein content at maturity and wheat agronomic parameters at different growing stages were analyzed and multi-temporal images of Landsat TM were used to estimate grain protein content by partial least squares regression. Experiment data were acquired in the suburb of Beijing during a 2-yr experiment in the period from 2003 to 2004. Determination coefficient, average deviation of self-modeling, and deviation of cross- validation were employed to assess the estimation accuracy of wheat grain protein content. Their values were 0.88, 1.30%, 3.81% and 0.72, 5.22%, 12.36% for 2003 and 2004, respectively. The research laid an agronomic foundation for GPC （grain protein content） estimation by multi-temporal remote sensing. The results showed that it is feasible to estimate GPC of wheat from multi-temporal remote sensing data in large area.展开更多
Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR) is one of the most powerful Earth observation techniques, especially useful for measuring highly detailed ground deformation over large ground areas. M...Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR) is one of the most powerful Earth observation techniques, especially useful for measuring highly detailed ground deformation over large ground areas. Much research has been carried out to apply MT-InSAR to monitor ground and infrastructure deformation in urban areas related to land reclamation, underground construction and groundwater extraction.This paper reviews the progress in the research and identifies challenges in applying the technology, including the inconsistency in coherent point identification when different approaches are used, the reliability issue in parameter estimation, difficulty in accurate geolocation of measured points, the one-dimensional line-of-sight nature of InSAR measurements, the inability of making complete measurements over an area due to geometric distortions, especially the shadowing effects, the challenges in processing large SAR datasets, the decrease of the number of coherent points with the increase of the length of SAR time series, and the difficulty in quality control of MT-InSAR results.展开更多
目的对脑梗死伴大脑中动脉狭窄患者进行CT血管成像(computed tomography angiography,CTA)联合CT灌注成像(computed tomography perfusion imaging,CTP)检查,拟从侧支循环及脑血管储备能力方面探讨头穴透刺对脑梗死伴大脑中动脉狭窄患...目的对脑梗死伴大脑中动脉狭窄患者进行CT血管成像(computed tomography angiography,CTA)联合CT灌注成像(computed tomography perfusion imaging,CTP)检查,拟从侧支循环及脑血管储备能力方面探讨头穴透刺对脑梗死伴大脑中动脉狭窄患者的治疗效果。方法收集该院神经内科在2022年1月—2023年12月住院治疗的80例脑梗死伴大脑中动脉狭窄患者纳入研究,通过随机数字表法分为观察组与对照组,各40例。对照组给予西医常规基础用药,观察组在对照组治疗基础上给予头穴透刺干预,每次治疗30 min,每周连续治疗5 d,暂停2 d,共治疗4周。CTP测量并获得局部脑血流量(regional cerebral blood flow,rCBF)、局部脑血容量(regional cerebral blood volume,rCBV)、局部达峰时间(regional time to peak,rTTP)及局部平均通过时间(regional mean transittime,rMTT)相对灌注值;CTA观察并进行侧支循环评分,以判断侧支循环情况。治疗前后所有患者行头颅多普勒超声检查,获得双侧大脑中动脉的血流平均速度(mean velocity,Vm)及搏动指数(pulsatility index,PI),计算脑血管储备功能(cerebrovascular reserve,CVR)水平。比较两组患者治疗前后美国国立卫生研究院卒中量表(National Institute of Health stroke scale,NIHSS)评分、改良Barthel指数(modified Barthel index,MBI)评分、脑卒中专用生活质量量表(stroke-specific quality of life scale,SS-QOL)评分;测定并比较治疗前后血清神经功能指标水平,包含神经元特异性烯醇化酶(neuron specific enolase,NSE)、神经纤维丝轻链(neurofilament light chain,NFL)及脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)。结果两组患者CTP参数比较,治疗后rCBF、rCBV显著高于治疗前(P<0.05),rTTP、rMTT显著低于治疗前(P<0.05);治疗后观察组rCBF、rCBV显著高于对照组(P<0.05),rTTP、rMTT显著低于对照组(P<0.05)。两组患者侧支循环情况比较,治疗后侧支循环评分均显著高于治疗前(P<0.05),观察组显著高于对照组(P<0.05);治疗后观察组侧支循环不良比例(3/40)显著低于对照组(10/40)(χ^(2)=4.501,P<0.05)。两组患者脑血管储备能力比较,治疗后Vm、CVR水平显著高于治疗前(P<0.05),PI显著低于治疗前(P<0.05);治疗后观察组Vm、CVR水平显著高于对照组(P<0.05),PI显著低于对照组(P<0.05)。两组患者治疗后MBI评分、SS-QOL评分及BDNF水平显著高于治疗前(P<0.05),NIHSS评分及NSE、NFL水平显著低于治疗前(P<0.05);治疗后观察组MBI评分、SS-QOL评分及BDNF水平显著高于对照组(P<0.05),NIHSS评分及NSE、NFL水平显著低于对照组(P<0.05)。结论头穴透刺治疗脑梗死伴大脑中动脉狭窄患者,能显著改善患者神经功能缺损情况,提高患者的日常生活能力及生活质量,CTA联合CTP评估提示头穴透刺能够明显改善脑梗死伴大脑中动脉狭窄患者侧支循环及脑血管储备能力。展开更多
文摘Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree classification rules through multi-source and multi-temporal feature fusion, classified groundobjects before the disaster and extracted flood information in the disaster area based on optical imagesduring the disaster, so as to achieve rapid acquisition of the disaster situation of each disaster bearing object.In the case of Qianliang Lake, which suffered from flooding in 2020, the results show that decision treeclassification algorithms based on multi-temporal features can effectively integrate multi-temporal and multispectralinformation to overcome the shortcomings of single-temporal image classification and achieveground-truth object classification.
基金supported by the National Science Fund for Distinguished Young Scholars(Grant No.42225702)the Maria Skłodowska-Curie Action(MSCA)-UPGRADE(mUltiscale IoT equipPed lonG linear infRastructure resilience built and sustAinable DevelopmEnt)project-HORIZON-MSCA-2022-SE-01(Grant No.101131146)。
文摘Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation over several decades,thereby overlooking the movement of slopes and failing to capture landslide dynamics.The long-term ground deformation map(GDM)derived from multi-temporal interferometric synthetic aperture radar(MT-InSAR)can effectively address the shortcomings.Fengjie County is an important area for geohazard management in the Three Gorges Reservoir Area(TGRA),China.Landslides in this area,however,cause significant socio-economic loss due to geological,tectonic,climatic,and anthropological factors.This research aims to integrate random forest(RF)with MT-InSAR to generate a landslide dynamic susceptibility map(LDSM)for Fengjie County,enhancing the reliability of landslide risk management.First,the RF model was employed to generate a static LSM,whereas MT-InSAR was utilized to obtain the GDM of the study area from January 2020 to June 2023.The static LSM and the GDM were subsequently integrated using a dynamic weight matrix to derive the LDSM.Our analysis covered a temporal framework spanning three years,focusing on spatiotemporal changes in landslide susceptibility levels and the influence of climate factors.Compared with the static LSM,the LDSM can promptly identify moving landslide areas,reduce high landslide susceptibility areas,and achieve greater accuracy.Moreover,the spatiotemporal changes in landslide susceptibility are regulated by the total annual rainfall,with wet years being more conducive to landslides than dry years.The proposed LDSM offers useful insights for the dynamic prevention and refined management of landslide hazards in the TGRA,significantly enhancing the resilience in this region.
基金supported by the National Natural Science Foundation of China (Nos.40871043,40801025)the Project of National Scientific Basic Special Fund on the Ministry of Science and Technology of China (No.2006FY110200)the Key Construction Disciplines of Hunan Province (No.40652001)
文摘Glacier area changes in the Qangtang Plateau are analyzed during 1970-2000 using air photos,relevant photogrammetric maps and satellite images based on the multi-temporal grid method.The results indicate that the melting of glaciers accelerated,only a few of glaciers in an advancing state during 1970-2000 in the whole Qangtang Plateau.However,the glaciers seemed still more stable in the study area than in most areas of western China.We estimate that glacier retreat was likely due to air temperature warming during 1970-2000 in the Qangtang Plateau.Furthermore,the functional model of glacier system is applied to study climate sensitivity of glacier area changes,which indicates that glacier lifespan mainly depends on the heating rate,secondly the precipitation,and precipitation increasing can slow down glacier retreat and make glacier lifespan prolonged.
基金supported by the Key Research and Development Program of Heilongjiang,China(Grant No.2022ZX01A25)Cooperative Funding between Huazhong Agricultural University and Shenzhen Institute of Agricultural Genomics(Grant No.SZYJY2022014)+2 种基金Fundamental Research Funds for the Central Universities,Beijing,China(Grant Nos.2662022JC006 and 2662022ZHYJ002)National Natural Science Foundation of China(Grant No.32101819)Huazhong Agriculture University Research Startup Fund,China(Grant Nos.11041810340 and 11041810341).
文摘Pre-harvest yield prediction of ratoon rice is critical for guiding crop interventions in precision agriculture.However,the unique agronomic practice(i.e.,varied stubble height treatment)in rice ratooning could lead to inconsistent rice phenology,which had a significant impact on yield prediction of ratoon rice.Multi-temporal unmanned aerial vehicle(UAV)-based remote sensing can likely monitor ratoon rice productivity and reflect maximum yield potential across growing seasons for improving the yield prediction compared with previous methods.Thus,in this study,we explored the performance of combination of agronomic practice information(API)and single-phase,multi-spectral features[vegetation indices(VIs)and texture(Tex)features]in predicting ratoon rice yield,and developed a new UAV-based method to retrieve yield formation process by using multi-temporal features which were effective in improving yield forecasting accuracy of ratoon rice.The results showed that the integrated use of VIs,Tex and API(VIs&Tex+API)improved the accuracy of yield prediction than single-phase UAV imagery-based feature,with the panicle initiation stage being the best period for yield prediction(R^(2) as 0.732,RMSE as 0.406,RRMSE as 0.101).More importantly,compared with previous multi-temporal UAV-based methods,our proposed multi-temporal method(multi-temporal model VIs&Tex:R^(2) as 0.795,RMSE as 0.298,RRMSE as 0.072)can increase R^(2) by 0.020-0.111 and decrease RMSE by 0.020-0.080 in crop yield forecasting.This study provides an effective method for accurate pre-harvest yield prediction of ratoon rice in precision agriculture,which is of great significance to take timely means for ensuring ratoon rice production and food security.
基金the National Natural Science Foundation of China (41171281, 40701120)the Beijing Nova Program, China (2008B33)
文摘Estimating wheat grain protein content by remote sensing is important for assessing wheat quality at maturity and making grains harvest and purchase policies. However, spatial variability of soil condition, temperature, and precipitation will affect grain protein contents and these factors usually cannot be monitored accurately by remote sensing data from single image. In this research, the relationships between wheat protein content at maturity and wheat agronomic parameters at different growing stages were analyzed and multi-temporal images of Landsat TM were used to estimate grain protein content by partial least squares regression. Experiment data were acquired in the suburb of Beijing during a 2-yr experiment in the period from 2003 to 2004. Determination coefficient, average deviation of self-modeling, and deviation of cross- validation were employed to assess the estimation accuracy of wheat grain protein content. Their values were 0.88, 1.30%, 3.81% and 0.72, 5.22%, 12.36% for 2003 and 2004, respectively. The research laid an agronomic foundation for GPC （grain protein content） estimation by multi-temporal remote sensing. The results showed that it is feasible to estimate GPC of wheat from multi-temporal remote sensing data in large area.
基金The National Natural Science Foundation of China(41774023)The Research Grants Council(RGC)of Hong Kong(PolyU152232/17E,PolyU152164/18E),The Faculty of Construction and Environment(ZZGD)+1 种基金The Research Institute for Sustainable Urban Development(RISUD)(1-BBWB)The TerraSAR-X Science plan(GEO3603)。
文摘Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR) is one of the most powerful Earth observation techniques, especially useful for measuring highly detailed ground deformation over large ground areas. Much research has been carried out to apply MT-InSAR to monitor ground and infrastructure deformation in urban areas related to land reclamation, underground construction and groundwater extraction.This paper reviews the progress in the research and identifies challenges in applying the technology, including the inconsistency in coherent point identification when different approaches are used, the reliability issue in parameter estimation, difficulty in accurate geolocation of measured points, the one-dimensional line-of-sight nature of InSAR measurements, the inability of making complete measurements over an area due to geometric distortions, especially the shadowing effects, the challenges in processing large SAR datasets, the decrease of the number of coherent points with the increase of the length of SAR time series, and the difficulty in quality control of MT-InSAR results.
文摘目的对脑梗死伴大脑中动脉狭窄患者进行CT血管成像(computed tomography angiography,CTA)联合CT灌注成像(computed tomography perfusion imaging,CTP)检查,拟从侧支循环及脑血管储备能力方面探讨头穴透刺对脑梗死伴大脑中动脉狭窄患者的治疗效果。方法收集该院神经内科在2022年1月—2023年12月住院治疗的80例脑梗死伴大脑中动脉狭窄患者纳入研究,通过随机数字表法分为观察组与对照组,各40例。对照组给予西医常规基础用药,观察组在对照组治疗基础上给予头穴透刺干预,每次治疗30 min,每周连续治疗5 d,暂停2 d,共治疗4周。CTP测量并获得局部脑血流量(regional cerebral blood flow,rCBF)、局部脑血容量(regional cerebral blood volume,rCBV)、局部达峰时间(regional time to peak,rTTP)及局部平均通过时间(regional mean transittime,rMTT)相对灌注值;CTA观察并进行侧支循环评分,以判断侧支循环情况。治疗前后所有患者行头颅多普勒超声检查,获得双侧大脑中动脉的血流平均速度(mean velocity,Vm)及搏动指数(pulsatility index,PI),计算脑血管储备功能(cerebrovascular reserve,CVR)水平。比较两组患者治疗前后美国国立卫生研究院卒中量表(National Institute of Health stroke scale,NIHSS)评分、改良Barthel指数(modified Barthel index,MBI)评分、脑卒中专用生活质量量表(stroke-specific quality of life scale,SS-QOL)评分;测定并比较治疗前后血清神经功能指标水平,包含神经元特异性烯醇化酶(neuron specific enolase,NSE)、神经纤维丝轻链(neurofilament light chain,NFL)及脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)。结果两组患者CTP参数比较,治疗后rCBF、rCBV显著高于治疗前(P<0.05),rTTP、rMTT显著低于治疗前(P<0.05);治疗后观察组rCBF、rCBV显著高于对照组(P<0.05),rTTP、rMTT显著低于对照组(P<0.05)。两组患者侧支循环情况比较,治疗后侧支循环评分均显著高于治疗前(P<0.05),观察组显著高于对照组(P<0.05);治疗后观察组侧支循环不良比例(3/40)显著低于对照组(10/40)(χ^(2)=4.501,P<0.05)。两组患者脑血管储备能力比较,治疗后Vm、CVR水平显著高于治疗前(P<0.05),PI显著低于治疗前(P<0.05);治疗后观察组Vm、CVR水平显著高于对照组(P<0.05),PI显著低于对照组(P<0.05)。两组患者治疗后MBI评分、SS-QOL评分及BDNF水平显著高于治疗前(P<0.05),NIHSS评分及NSE、NFL水平显著低于治疗前(P<0.05);治疗后观察组MBI评分、SS-QOL评分及BDNF水平显著高于对照组(P<0.05),NIHSS评分及NSE、NFL水平显著低于对照组(P<0.05)。结论头穴透刺治疗脑梗死伴大脑中动脉狭窄患者,能显著改善患者神经功能缺损情况,提高患者的日常生活能力及生活质量,CTA联合CTP评估提示头穴透刺能够明显改善脑梗死伴大脑中动脉狭窄患者侧支循环及脑血管储备能力。
