查看更多>>摘要：Optical and Synthetic Aperture Radar(SAR)remote sensing has a long history of use and reached a good level of maturity in archaeological and cultural heritage applications,yet further advances are viable through the exploitation of novel sensor data and imaging modes,big data and high-performance computing,advanced and automated analysis meth-ods.This paper showcases the main research avenues in this field,with a focus on archae-ological prospection and heritage site protection.Six demonstration use-cases with a wealth of heritage asset types(e.g.excavated and still buried archaeological features,standing monu-ments,natural reserves,burial mounds,paleo-channels)and respective scientific research objectives are presented:the Ostia-Portus area and the wider Province of Rome(Italy),the city of Wuhan and the Jiuzhaigou National Park(China),and the Siberian"Valley of the Kings"(Russia).Input data encompass both archive and newly tasked medium to very high-resolution imagery acquired over the last decade from satellite(e.g.Copernicus Sentinels and ESA Third Party Missions)and aerial(e.g.Unmanned Aerial Vehicles,UAV)platforms,as well as field-based evidence and ground truth,auxiliary topographic data,Digital Elevation Models(DEM),and monitoring data from geodetic campaigns and networks.The novel results achieved for the use-cases contribute to the discussion on the advantages and limitations of optical and SAR-based archaeological and heritage applications aimed to detect buried and sub-surface archaeological assets across rural and semi-vegetated landscapes,identify threats to cultural heritage assets due to ground instability and urban development in large metropolises,and monitor post-disaster impacts in natural reserves.
查看更多>>摘要：Remote sensing,particularly satellite-based,can play a valuable role in monitoring areas prone to geohazards.The high spatial and temporal coverage provided by satellite data can be used to reconstruct past events and continuously monitor sensitive areas for potential hazards.This paper presents a range of techniques and methods that were applied for in-depth analysis and utilization of Earth observation data,with a particular emphasis on:(1)detecting mining sub-sidence,where a novel approach is proposed by combining an improved U-Net model and Interferometry Synthetic Aperture Radar(InSAR)technology.The results showed that the Efficient Channel Attention(ECA)U-Net model performed better than the U-Net(baseline)model in terms of Mean Intersection over Union(MIoU)and Intersection over Union(loU)indicators;(2)monitor-ing water conservancy and hydropower engineering.The Xiaolangdi multipurpose dam complex was monitored using Small BAsline Subsets(SBAS)InSAR method on Sentinel-1 time series data and four small regions with high deformation rates were identified on the slope of the reservoir bank on the north side.The dam body also showed obvious deformation with a velocity exceeding 60 mm/a;(3)the evaluation of the potential of InSAR results to integrate monitoring and warning systems for valuable heritage and architectural preservation.The overall outcome of these methods showed that the use of Artificial Intelligence(AI)techniques in combination with InSAR data leads to more efficient analysis and interpretation,resulting in improved accuracy and prompt identification of potential hazards;and(4)finally,this study also presents a method for detecting landslides in mountainous regions,using optical imagery.The new temporal landslide detection method is evaluated over a 7-year analysis period and unlike conventional bi-temporal change detection methods,this approach does not depend on any prior-knowledge and can potentially detect landslides over extended periods of time such as decades.
查看更多>>摘要：The Greenhouse Gas Monitoring Instrument(GMI)onboard the Chinese hyperspectral satellite GF5-02 can provide abundant observations of global atmospheric CO2,which plays an impor-tant role in climate research.CO2 retrieval precision is the key to determining the application value of the GMI.To reduce the influence of atmospheric scattering on retrieval,we combined the Directional Polarimetric Camera(DPC)data on the same satellite to improve the anti-interference ability of GMI CO2 retrieval and ensure its retrieval precision.To realize the reliability and feasibility of the collaborative use of the GMI and DPC,this paper designs the pointing registration method of the GMI based on coastline observations,the spatial resolution matching method and the collaborative cloud screening method of the GMI and DPC observa-tions.Combined with the DPC,which supplied the spectral data and aerosol product,the retrieval ability of the coupled bidirectional reflectance distribution function CO2 retrieval(CBCR)method developed for GMI CO2 retrieval was improved,with the retrieval efficiency of CO2 products increasing by 27％,and the CO2 retrieval precision increasing from 3.3 ppm to 2.7 ppm.Moreover,collaborative use not only guaranteed the GMI's ability to detect global and area CO2 concentration distribution characteristics,such as significant concentration differ-ences between the Northern and Southern Hemispheres in winter and high CO2 concentra-tions in urban agglomeration areas caused by human activities,but also extended the GMI's potential for monitoring anomalous events,such as the Tonga volcanic eruption.
查看更多>>摘要：In this paper,the Multi-Temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technol-ogy is adopted to monitor the Line of Sight(LOS)displacement of Fushun West Opencast Coal Mine(FWOCM)and its surrounding areas in northeast China using Sentinel-1 Synthetic Aperture Radar(SAR)images acquired from 2018 to 2022.The spatial-temporal evolution of urban subsidence and the south-slope landslide are both analyzed in detail.Comparison with ground measurements and cross-correlation analysis via cross wavelet transform with monthly precipitation data are also conducted,to analyze the influence factors of displacements in FWOCM.The monitoring results show that a subsidence basin appeared in the urban area near the eastern part of the north slope in 2018,with settlement center located at the intersection of E3000 and fault F1.The Qian Tai Shan(QTS)landslide on the south slope,which experienced rapid sliding during 2014 to 2016,presents seasonal deceleration and acceleration with precipitation,with the maximum displacement in vicinity of the Liushan paleochannel.The results of this paper have fully taken in account for the complications of large topographic relief,geological conditions,spatial distribution and temporal evolution characteristics of surface displacements in opencast mining area.The wide range and long time series dynamic monitoring of opencast mine are of great significance to ensure mine safety production and geological disaster prevention in the investigated mining area.
查看更多>>摘要：Landslides are destructive geohazards to people and infrastructure,resulting in hundreds of deaths and billions of dollars of damage every year.Therefore,mapping the rate of deforma-tion of such geohazards and understanding their mechanics is of paramount importance to mitigate the resulting impacts and properly manage the associated risks.In this paper,the main outcomes relevant to the joint European Space Agency(ESA)and the Chinese Ministry of Science and Technology(MOST)Dragon-5 initiative cooperation project ID 59,339"Earth observation for seismic hazard assessment and landslide early warning system"are reported.The primary goals of the project are to further develop advanced SAR/InSAR and optical techniques to investigate seismic hazards and risks,detect potential landslides in wide regions,and demonstrate EO-based landslide early warning system over selected landslides.This work only focuses on the landslide hazard content of the project,and thus,in order to achieve these objectives,the following tasks were developed up to now:a)a procedure for phase unwrap-ping errors and tropospheric delay correction;b)an improvement of a cross-platform SAR offset tracking method for the retrieval of long-term ground displacements;c)the application of polarimetric SAR interferometry(PolInSAR)to increase the number and quality of monitoring points in landslide-prone areas;d)the semiautomatic mapping and preliminary classification of active displacement areas on wide regions;e)the modeling and identification of landslides in order to identify triggering factors or predict future displacements;and f)the application of an InSAR-based landslide early warning system on a selected site.The achieved results,which mainly focus on specific sensitive regions,provide essential assets for planning present and future scientific activities devoted to identifying,mapping,characterizing,monitoring and predicting landslides,as well as for the implementation of early warning systems.
Marco ManzoniNaomi PetrushevskyChuanjun WuStefano Tebaldini...
624-637页
查看更多>>摘要：This paper is intended to summarize the research conducted during the first 2 years of the Dragon 5 project 59,332(geophysical and atmospheric retrieval from Synthetic Aperture Radar(SAR)data stacks over natural scenarios).Monitoring atmospheric phenomena,encompassing both tropospheric and ionospheric conditions,holds pivotal significance for various scientific and practical applications.In this paper,we present an exploration of advanced techniques for estimating tropospheric and ionospheric phase screens using stacks of Synthetic Aperture Radar(SAR)images.Our study delves into the current state-of-the-art in atmospheric monitor-ing with a focus on spaceborne SAR systems,shedding light on their evolving capabilities.For tropospheric phase screen estimation,we propose a novel approach that jointly estimates the tropospheric component from all the images.We discuss the methodology in detail,high-lighting its ability to recover accurate tropospheric maps.Through a series of quantitative case studies using real Sentinel-1 satellite data,we demonstrate the effectiveness of our technique in capturing tropospheric variability over different geographical regions.Concurrently,we delve into the estimation of ionospheric phase screens utilizing SAR image stacks.The intri-cacies of ionospheric disturbances pose unique challenges,necessitating specialized techni-ques.We dissect our approach,showcasing its capacity to mitigate ionospheric noise and recover precise phase information.Real data from the Sentinel-1 satellite are employed to showcase the efficacy of our method,unraveling ionospheric perturbations with improved accuracy.The integration of our techniques,though presented separately for clarity,collec-tively contributes to a comprehensive framework for atmospheric monitoring.Our findings emphasize the potential of SAR-based approaches in advancing our knowledge of atmospheric processes,thus fostering advancements in weather prediction,geophysics,and environmental management.
查看更多>>摘要：In this paper,we will conclude the results of Bufeng-1(BF-1)A/B data processing,calibration workflow,and validation of the calibrated sea surface winds,land surface soil moisture,and sea surface height measurements.Since 2019,the BF-1 mission has operated in-orbit for over 4 years.The Earth reflected delay Doppler maps(DDMs)are continuously collected to perform global sea surface and land observations.At the same time,the intermediate frequency(IF)raw data are also obtained for 12 seconds every pass in diagnostic mode.To begin with,a brief description of the spaceborne Global Navigation Satellite System Reflectometry(GNSS-R)technique will be provided in the introduction.Next,we will present the overview of Chinese BF-1 mission and the data specifications used in our research.In the next section,the BF-1 mission-related spaceborne power calibration and validation are presented to show the sup-port to power DDM observable production for sea surface and land surface applications.Then,the status of Chinese Beidou System(BDS)Equivalent Isotropic Radiated Power(EIRP)acquisi-tion programme is then introduced.Furthermore,the latest sea surface height(SSH)measure-ments results including two modes(group delay and carrier phase)and wind speed derivation based on machine learning(ML)method will be spatial-temporal aligned and validated with auxiliary datasets including Denmark Technology University(DTU)mean sea surface(MSS)products and European Centre for Medium-Range Weather Forecasts(ECMWF)ERA5 reanalysis.The previous published results of sea surface winds retrieval under Hurricane conditions and soil moisture retrieval are also reviewed for the BF-1 mission applications.Finally,the conclu-sion of BF-1 derived results will be discussed to draw out ongoing/future works.
查看更多>>摘要：The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,the underlying homogeneity assumption of the typical wind retrieval methods,such as Doppler Beam Swinging(DBS)and Velocity Azimuth Display(VAD)based on a single-lidar,will introduce the measurement uncertainty in complex terrain.In this paper,a new design of a wind measurement campaign involving seven lidars was carried out,which contained the three-lidar-based Virtual Tower(VT)using a time-space synchroniza-tion technique and four single-lidars with different elevation angles.This study investigates the performance of VT and VAD measurements under various conditions and evaluates the sensitivity of wind measurement uncertainty of VAD to the horizontal spatial-and probe volume-average effects associated with elevation angles of the laser beam.The inter-comparison results between VT and four VADs show consistent trends with small relative errors under neutral atmospheric conditions with weak wind velocity.Under convective or high Turbulence Intensity(TI)conditions,the relative errors between VT and VAD become larger and more fluctuant.Moreover,it is found that the measurement uncertainty of VAD increases at a given elevation angle with the increasing measurement heights,which is caused by the horizontal homogeneity associated with the conical scanning area.Additionally,the simulated and measured results of four VADs indicate that a larger elevation angle corresponds to a lower measurement uncertainty for a given height.
查看更多>>摘要：The need for cross-comparison and validation of all-weather Land Surface Temperature(LST)products has arisen due to the release of multiple such products aimed at providing compre-hensive all-weather monitoring capabilities.In this study,we focus on validating two well-established all-weather LST products(i.e.MLST-AS and TRIMS LST)against in-situ measure-ments obtained from four high-quality LST validation sites:Evora,Gobabeb,KIT-Forest,and Lake Constance.For the land sites,MLST-AS exhibits better accuracy,with RMSEs ranging from 1.6 K to 2.1 K,than TRIMS LST,the RMSEs of which range from 1.9 K to 3.1 K.Because MLST-AS pixels classified as"inland water"are masked out,the validation over Lake Constance is limited to TRIMS LST:it yields a RMSE of 1.6 K.Furthermore,the validation results show that MLST-AS and TRIMS LST exhibit better accuracy under clear-sky conditions than unclear-sky conditions across all sites.Since the accuracy of the all-weather LST products is considerably affected by the input clear-sky LST products,we further compare the all-weather LST with the correspond-ing input clear-sky LST to conduct an error source analysis.Considering the clear-sky pixels on MLST-AS directly using the estimates from MLST,the error source analysis is limited to examining TRIMS LST and its input(i.e.MODIS LST).The findings indicate that TRIMS LST is highly correlated with MODIS LST.The investigation and validation of the two selected all-weather LST products objectively evaluate their accuracy and stability,which provides impor-tant information for applications of these all-weather LST products.
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