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ABSOLUTE CALIBRATION OF EUROPEAN AND CHINESE SATELLITE ALTIMETERS ATTAINING FIDUCIAL REFERENCE MEASUREMENTS STANDARDS
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This research and collaboration project aims at the calibration and validation (Cal/Val) of the European Sentinel-3 and Sentinel-6 and the Chinese HY-2 satellite altimeters based upon two permanent Cal/Val facilities: (1) the Permanent Altimetry [...] |
Prof.. Stelios Mertikas, Technical University of Crete, GREECE |
Prof.. Mingsen LIN, National Satellite Ocean Application Service (NSOAS), CHINA |
Calibration and Validation |
This research and collaboration project aims at the calibration and validation (Cal/Val) of the European Sentinel-3 and Sentinel-6 and the Chinese HY-2 satellite altimeters based upon two permanent Cal/Val facilities: (1) the Permanent Altimetry Calibration Facility (PFAC) established by ESA in Crete, Greece and (2) the National Cal/Val facility at the Wanshan islands, South China Sea. Other satellites, such as Guanlan, CryoSat-2, CFOSAT, CRISTAL, etc., may be also supported by these Cal/Val services. Satellites will be calibrated and monitored using uniform, standardized procedures, protocols and best practices and also built upon trusted and undisputable reference standards at both Cal/Val infrastructures in Europe and China. Altimeters will be thus monitored in a coordinated, absolute, homogeneous, long-term and worldwide manner.Calibration of altimeters is accomplished by examining satellite observations in open seas against reference measurements. Comparisons are established through precise satellite positioning, water level observations, GPS buoys and reference models (geoid, mean dynamic topography, earth tides, troposphere and ionosphere) all defined by Cal/Val sites. In this work, final uncertainty for altimeter bias will be attributed to several individual error sources, coming from observations in water level, atmosphere, absolute positioning, reference surface models, transfer of heights from Cal/Val sites to satellite observations, etc. Absolute calibration of altimeters has also been carried out on land with microwave transponders. This is a unique technique that calibrates the altimeter range directly with the transponder. At the moment, the PFAC in Crete hosts the only operational transponder. A second transponder is currently under construction to be installed at the Gavdos Cal/Val facility and will support Sentinel-6 and Sentinel-3 calibrations. If future HY-2 Chinese missions, such as HY-2C, overpass this European Cal/Val facility, and when operationally supported. The project will implement the action plan established by ESA for Fiducial Reference Measurements for Altimetry (FRM4ALT) calibration. At present, the PFAC is the only facility in the world that reports its Cal/Val results along with their FRM uncertainty. Through this project, the procedures, protocols and best practices, developed in the course of the ESAÔÇÖs FRM4ALT project, will be updated, upgraded and followed at both Cal/Val facilities in Europe and China. This proposed collaborative project will contribute to an FRM4ALT calibration of Sentinel-3 and HY-2B missions during their operational phase, but also to upcoming Sentinel-6 and HY-2C and possibly to the Quanlan satellite of China. As such, it will promote the FRM4ALT strategy of ESA to Chinese stakeholders and scientists. The main outcomes of the proposed project will be (1) the standardization of operations and data processing followed at both Cal/Val infrastructures in Europe and China, (2) the exchange of knowledge and training on properly implementing FRM4ALT in practice, (3) the absolute calibration of European and Chinese satellite altimeters along with unified reporting of FRM uncertainty for the produced Cal/Val results, and (4) inter-comparison of the Cal/Val results obtained at the two main Cal/Val facilities and investigation of any of deviations. Calibration and validation activities at the PFAC in Greece are currently supported by two ESA projects namely SeRAC and FRM4S6. Further funding is provided by international space agencies (i.e., CNES, France) and institutional funds (TUC and Space Geomatica). Similar support has been provided by the Chinese government for the Wanshan Cal/Val facility in South China Sea.
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ALL-WEATHER LAND SURFACE TEMPERATURE AT HIGH SPATIAL RESOLUTION: VALIDATION AND APPLICATIONS
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Problem statement: Land Surface Temperature (LST) is one of the main quantities governing the energy exchange between surface and atmosphere. On the extensive Tibetan Plateau (TP), where in-situ observations are usually extremely sparse, [...] |
Dr. Frank Goettsche, Karlsruhe Institute of Technology, GERMANY |
Prof.. Ji Zhou, University of Electronic Science and Technology of China, CHINA |
Calibration and Validation |
Problem statement: Land Surface Temperature (LST) is one of the main quantities governing the energy exchange between surface and atmosphere. On the extensive Tibetan Plateau (TP), where in-situ observations are usually extremely sparse, accurate knowledge of the land surface energy balance is crucial for understanding and simulating regional processes of meteorology, hydrology and ecology. More specifically, all-weather LST products are required for accurately simulating soil heat transfer, which provides insights into changes in TP permafrost / seasonally frozen ground and regional climate change. However, LST products based on thermal infrared (TIR) remote sensing are limited to clear sky conditions. Recently two all-weather satellite LST products became available, but they still require more extensive validation and assessment of their uncertainty. Objectives: The main objective is to inter-compare and validate the two new LST products, which provide (nearly) gap-free all-weather LST at high spatial resolution. The two all-weather LST products utilise different retrieval approaches, namely the method by – Zhang et al. (2019): temporal component decomposition and merging of TIR LST with passive microwave (PMW) LST. – Martins et al. (2019): merging of clear-sky MSG/SEVIRI LST with LST generated by a Soil-Vegetation-Atmosphere (SVAT) model under cloudy conditions. Further objectives: – Generation of long term (global) all-weather LST data set – Setting up an LST validation station in China to provide Fiducial Reference Measurements (FRM) – Employing all-weather LST data to simulate and study freeze / thaw on the TP Method: The two new all-weather LST products and LST extracted from ERA5-Land data, which are provided by Copernicus Climate Change Service (C3S), will be inter-compared over selected regions in China, Europe, and Southern Africa. All inter-comparisons will utilise ESA GlobTemperature (GT) harmonised data format (netCDF) and their relative performance will be assessed to provide insights into their respective strengths and limitations. The three LST products will be validated against in-situ measurements from the following station networks: 1) Karlsruhe Institute of Technology (KIT), 2) Baseline Surface Radiation Network (BSRN), 3) European Fluxes Database Cluster (EFDC) initiative, 4) Heihe Watershed Allied Telemetry Experimental Research (HiWATER) and Watershed Allied Telemetry Experimental Research (WATER) in the Heihe River basin, and 5) networks operated by other Chinese groups on the TP. Based on experience and an instrument package provided by KIT, the Chinese partners will set up a new LST validation station in China. Since the thermal sampling depth correction (TSDC) between TIR LST and PMW LST is larger for dry soil, all-weather LST determined over the arid validation site Gobabeb (Namibia) will be compared with results from the Zhou et al. (2017) method, which explicitly models soil heat conduction. The main causes of differences between the three LST products will be identified and used to improve the estimates of LSA SAF all-weather LST uncertainty. The all-weather LST retrieved from merged TIR and PWM data will serve as input for model simulations of freeze / thaw on the TP. Deliverables: – Inter-comparison and validation results for the two all-weather LST products – Assessment of all-weather LST product uncertainties – Results from simulating freeze / thaw on TP Source of funding: Frank-M. Göttsche is funded by Karlsruhe Institute of Technology (KIT). João P.A. Martins is funded by Instituto Português do Mar e da Atmosfera /Portuguese Institute for the Sea and the Atmosphere (IPMA). Ji Zhou is funded by the National Natural Science Foundation of China under Grant 41871241 and the University of Electronic Science and Technology of China (UESTC). Wenjiang Zhang is funded by the National Natural Science Foundation of China under Grant 41771112.
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CALIBRATION AND VALIDATION OF THE FIRST CHINESE GNSS-R MISSION—BUFENG-1 A/B
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1 Objectives On June 5 2019, following the UK TechDemoSat-1 mission and the US Cyclone GNSS (CYGNSS) constellation, BuFeng-1 A/B in-orbit demonstration satellites were successfully deployed in orbit by Chinese first-time sea platform launch. [...] |
Dr. Weiqiang Li, Institute of Space Sciences, CSIC, SPAIN |
Dr. Cheng Jing, China Academy of Space Technology (CAST)-XIAN, CHINA |
Calibration and Validation |
1 Objectives On June 5 2019, following the UK TechDemoSat-1 mission and the US Cyclone GNSS (CYGNSS) constellation, BuFeng-1 A/B in-orbit demonstration satellites were successfully deployed in orbit by Chinese first-time sea platform launch. Now, it is one of the only two in-orbit operational GNSS-R mission (NASA CYGNSS and BuFeng-1 A/B). After months of full-time operation, the preliminary results reveal that the derived sea surface wind speed is impressively reliable at low-to-moderate wind speed range under fully developed seas condition. As a result, the GNSS-R technique have become a key component for China meteorological satellite observation system for the future numerical weather forecast and typhoon monitoring. The calibration of scattering coefficients for high sea surface wind speeds under heavy precipitation and the validations of the performances for the other GNSS-R applications (such as soil moisture and ocean altimetry) should be further studied, which can guide the design of future ESA and China GNSS-R satellite missions, such as BuFeng constellations, FFScat, G-TERN, Cookie, ORORO and HydroGNSS. The products of ESA SMOS mission, for soil moisture and ocean salinity, can also provide high ocean wind products, and are especially suitable for the calibration and validation of spaceborne GNSS-R measurements. It is noted that the Dragon 5 project can fully cover the life span of the BuFeng-1 A/B satellites. Regarding these requirements, the objectives are summarized as follows: 1) Collocation of integrated ESA-CHINA EO data products and BuFeng-1 data preprocessing 2) Calibration of the BuFeng-1 A/B main observables, including NBRCS, power DDM, and SNR 3) Validation of the calibrated results from BuFeng-1 A/B; 4) Optimization and improvements of future spaceborne GNSS-R instruments. 2 Methods With respect to the objectives, the accumulated first handed BuFeng-1 data from CMA are collected and collocated with other products from ESA and China EO missions, including SMOS, CRYOSAT-2, HY-1/2, and FY series. After that, spaceborne GNSS-R observations and auxiliary data will be analyzed to check the sensitivities of the GNSS-R observables (such as NBRCS, SNR, calibrated power DDM) to different spaceborne GNSS-R applications, such as sea surface winds, inland soil moisture, and sea surface height. Besides EO data, the validation methods also comprise the ECMWF reanalysis products on wind speed, soil moisture content, sea surface height, etc. Based on the preparation of the matchup datasets, the calibration and validation of objectives 2) and 3) will be carried on with the state-of-the-art big data analysis approaches, including Artificial Intelligence and Machine Learning to optimize the models of each application. In order to achieve the objective 4), the error budget of different geophysical measurements will be developed as the functions of different mission and instrumental parameters, which can guide the design of future GNSS-R instruments, such as the data acquisition methods, antennas design, and power calibration algorithms. 3 Deliverables The major deliverables expected from this project include the following: 1) New models, methods, and documents for instrument calibration and performance validation of BuFeng-1 GNSS-R satellite mission are developed and made available to the scientific community. 2) Peer-reviewed journal papers in Remote Sensing of Environment, IEEE TGRS, Remote Sensing, IEEE J-STAR, Geophysical Research Letters, IJRS, etc. 3) Presentations at major international symposium, such as Dragon 5 symposium, ESA Live Planet Symposium and IGARSS. 4) Interim project reports and final project report 5) Ph.D. thesis and M.Sc. thesis 4 Funding Chinese fund: National Major Projects of High-Resolution Earth Observation Systems;European fund: Sensing with Pioneering Opportunistic Techniques, Spanish Ministry of Economy and Competitiveness (RTI2018-099008-B-C22)
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CROSS-CALIBRATION OF HIGH-RESOLUTION OPTICAL SATELLITE WITH SI-TRACEABLE INSTRUMENTS OVER RADCALNET SITES
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Various global scientific issues (like climate change, environment monitoring, and ecological security) are making more and more strict requirements on the accuracy of remote sensing information products, which put forward very high accuracy and [...] |
Dr. Philippe Goryl, ESA-Esrin, ITALY |
Prof.. Chuanrong LI, Chinese Academy of Sciences, CHINA |
Calibration and Validation |
Various global scientific issues (like climate change, environment monitoring, and ecological security) are making more and more strict requirements on the accuracy of remote sensing information products, which put forward very high accuracy and stability demands on the on-orbit calibration of remote sensors. Nowadays, on-board calibration for spaceborne sensors cannot reach the level of actually traceable to the ground-based radiometric primary standard, whereas field vicarious calibration can only obtain limited calibration accuracy since it is likely to be influenced by scaling effect, atmospheric condition, environment variation, etc. In recent years, ESA, USA, and China have successively proposed the essential concept of spaceborne radiometric benchmark sensors. The main idea of radiometric calibration based on this benchmark sensor is: upload the SI-traceable radiometric benchmark instrument in a small number of radiation benchmark satellites, then transfer the traceable radiation values from the benchmark satellite to other satellites to be calibrated. However, as the high-resolution spaceborne sensor is concerned, the cross-points (between the benchmark satellite and monitored satellite) can hardly be found under the strict matching condition when performing cross-calibration, because of high-resolution satellite’s narrow swath. So, this project will propose a new method of benchmark transfer calibration for the high-resolution space-borne sensor, which uses RadCalNet site measurement as the ground reference value. The new method is to solve the problem of increasing of cross-calibration error due to unavoidable relaxation of matching constraints to improve cross-point opportunities between high-resolution satellites. In this project, Chinese and European researchers dedicated to radiometric calibration will collaborate in the transfer calibration technologies based on RadCalNet and the SI-traceable spaceborne reference instrument. On one side, new method of radiometric benchmark transfer calibration which adopts RadCalNet measurement as ground reference value will be cooperatively developed to break through important technical problems existed in the benchmark transfer chain (benchmark satellite -> standard TOA spectral reflectance provided by RadCalNet -> satellite to be calibrated (i.e., the monitored satellite)). On the other side, based on previous cooperative research on RadCalNet, both parties will make effort to further improve the accuracy of RadCalNet standard product and the inter-site product consistency, and incorporate more Chinese automated calibration sites into the RadCalNet framework if possible, to carry out demonstration applications of automated calibration & benchmark transfer calibration for Chinese and European high-resolution satellites. The main research contents of this project include constraint mechanism analysis of the radiometric benchmark transfer calibration; a new method of the radiometric benchmark transfer calibration; demonstration of radiometric calibration for Chinese and European high-resolution satellites. The expected achievements of this project include (1) constraint mechanism of the radiometric benchmark transfer calibration based on RadCalNet; (2) new method of the radiometric benchmark transfer calibration; (3) technical report on the demonstration of transfer calibration for high-resolution satellites; (4) academic papers and talent training. In the project executing process, a series of external projects can be available to effectively support the operation of this project. Relevant supporting projects include: (a) Spaceborne radiometric benchmark transfer calibration and its ground-based validation; (b) Global automated radiometric calibration network; (c) Land satellite calibration network; (d) Radiometric re-calibration of thermal infrared band of land satellite and surface temperature retrieval.
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EXPLOITING UAVS FOR VALIDATING DECAMETRIC EARTH OBSERVATION DATA FROM SENTINEL-2 AND GAOFEN-6 (UAV4VAL)
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Surface reflectance is the fundamental quantity required in the majority of optical earth observation analyses, and as an essential input to biophysical variable retrieval algorithms, it forms the basis of many higher level products. These [...] |
Prof.. Jadu Dash, University of Southampton, UK |
Prof.. Yongjun Zhang, Wuhan University, CHINA |
Calibration and Validation |
Surface reflectance is the fundamental quantity required in the majority of optical earth observation analyses, and as an essential input to biophysical variable retrieval algorithms, it forms the basis of many higher level products. These products, which include essential climate variables (ECVs) such as leaf area index (LAI) and the fraction of absorbed photo synthetically active radiation (FAPAR), in addition to parameters such as the fraction of vegetation cover (FCOVER), provide insight into the evolution of the terrestrial environment. In turn, they are crucial in understanding vegetation productivity/yield, biogeochemical cycles, and the weather and climate systems. In the context of an increasing global population, the need to ensure food security, and environmental change, accurate estimates of these parameters are required to enable sustainable management of natural resources. To ensure their accuracy, validation of decametric surface reflectance and vegetation products is required, using independent ground reference measurements to verify product performance. However, the collection of ground reference measurements is time-consuming and resource intensive, limiting the extent of validation efforts in both space and time. Recently, the potential of unmanned aerial vehicles (UAVs) to reduce required resources and increase spatial and temporal coverage has been recognised. The aim of this project is to evaluate the capability of UAVs as a source of reference data for validating decametric surface reflectance and vegetation products, with a specific focus on the European Sentinel-2 and Chinese Gaofen-6 missions. The project will provide an opportunity to transfer knowledge gained from existing ESA-funded projects on fiducial reference measurements (FRM), which focus on traceability and uncertainty evaluation in earth observation validation efforts. The aim of the project will be achieved by the collection, processing, and analysis of ground measurements over a number of European and Chinese sites, coinciding with UAV acquisitions. The project will investigate the feasibility of using UAV data as an alternative to traditional ground measurements for validating Sentinel-2 and Gaofen-6 products.
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LIDAR OBSERVATIONS FROM ESA´S AEOLUS (WIND, AEROSOL) AND CHINESE ACDL (AEROSOL, CO2) MISSIONS: VALIDATION AND ALGORITHM REFINEMENT FOR DATA QUALITY IMPROVEMENTS.
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n August 2018, ESA’s Earth Explorer mission Aeolus has been successfully launched to space. Since then Aeolus has been demonstrating its capability to accurately measure atmospheric wind Prof.iles from the ground to the lower stratosphere on a [...] |
Dr. Oliver Reitebuch, DLR-German Aerospace Center, GERMANY |
Prof.. Songhua Wu, Ocean University of China OUC - Ocean Remote Sensing Institute OSRI, CHINA |
Calibration and Validation |
n August 2018, ESA’s Earth Explorer mission Aeolus has been successfully launched to space. Since then Aeolus has been demonstrating its capability to accurately measure atmospheric wind Prof.iles from the ground to the lower stratosphere on a global scale deploying the first ever satellite-borne wind lidar system ALADIN. In order to validate Aeolus wind products several airborne campaigns were performed over Central Europa and the North Atlantic region (most recently in autumn 2019 in Iceland), employing the ALADIN Airborne Demonstrator (A2D) developed by DLR (Deutsches Zentrum für Luft- und Raumfahrt). Ground-based direct-detection and heterodyne Doppler wind lidar and ocean lidar are developed by the Ocean University of China (OUC) and deployed during several field campaigns, including the sailing competition within the Olympic Games in 2008 in Qingdao and the atmospheric explorer in Tibetan Plateau Experiment of Atmospheric Sciences (TIPEX III). The Shanghai Institute of Optics and Fine Mechanics (SIOM) of the Chinese Academy of Sciences (CAS) developed a ground based direct-detection wind lidar in 355nm and a airborne coherent Doppler wind lidar. SIOM is responsible for several ground validation stations for future spaceborne atmospheric lidar in China, which may provide useful aerosol and wind Prof.iles data for Aeolus validation. The National Satellite Meteorological Center (NSMC), China Meteorological Administration (CMA) is responsible for receiving, processing the data of Chinese FY meteorological satellites, and distributing the data and information products to users for application. Apart from that, it is envisaged to investigate the capability of measuring the marine boundary layer with Aeolus and to measure marine optical properties with co-located shipborne ocean lidar systems during overpasses of Aeolus. The first part of this proposal covers the validation of Aeolus wind and aerosol data products by means of ground and airborne observations with the objective to improve the quality of Aeolus operational data products. Global observations of column carbon dioxide concentrations and aerosol extinction Prof.iles are important for climate study and environment monitoring which is why China decided to implement the lidar mission ACDL (Aerosol and Carbon dioxide Detection Lidar) to measure CO2 and aerosol from space – currently scheduled for 2021. Within this framework a spaceborne engineering prototype of the ACDL lidar is being developed and an airborne lidar prototype for column carbon dioxide concentration measurements was developed by Shanghai Institute of Optics and Fine Mechanics (SIOM) of the Chinese Academy of Sciences (CAS). The second part of the proposal covers the preparation of the ACDL mission with the objectives to analyse requirements for column carbon dioxide concentration and aerosol extinction Prof.ile measurements of the ACDL lidar for science applications and to validate the retrieval algorithms for carbon dioxide and aerosol parameters for the future space mission.
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THE CROSS-CALIBRATION AND VALIDATION OF CSES/SWARM MAGNETIC FIELD AND PLASMA DATA
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China Seismo-Electromagnetic Satellite (CSES) has been launched successfully on Feb. 2, 2018 in a sunsynchronous polar orbit at an altitude around 507 km, measuring the electromagnetic field, the energetic particles and the ionospheric plasma [...] |
Dr. Claudia Stolle, Deutsche GeoForschungsZentrum - GFZ Potsdam, GERMANY |
Prof.. Xuhui Shen, Institute of Crustal Dynamics, China Earthquake Administration, CHINA |
Calibration and Validation |
China Seismo-Electromagnetic Satellite (CSES) has been launched successfully on Feb. 2, 2018 in a sunsynchronous polar orbit at an altitude around 507 km, measuring the electromagnetic field, the energetic particles and the ionospheric plasma parameters. At present ESA’s Swarm mission is the only in-orbit satellite which has payloads comparable with CSES, allowing a direct cross-validation between the two platforms. The Swarm mission was launched on 22 Nov 2013, with three spacecraft at altitudes from 460 to 530 km. For CSES and Swarm, the comparable payloads include: CSES high precision magnetometer (HPM, for the total magnetic field observations), search-coil magnetometer (for the magnetic field variations) and the Langmuir probe (LAP, for in-situ plasma parameters); Swarm VFM and ASM the magnetic field), EFI (in-situ plasma). The two missions will operate in parallel in the next years, providing a good opportunity for cross-calibration and validation on similar types of payloads at same time intervals. The cooperation is aimed to take full advantages of the simultaneous observations of CSES and Swarm satellite in order to calibrate and validate the geomagnetic field and plasma parameters, to improve electromagnetism satellite data processing methods. Besides data validation, both sides share and exchange data and other related resources in order to achieve high-level scientific applications. Additionally, the cooperation will build a long-term stable international team able to drive and train young scientists for Low Earth Orbit (LEO) satellites data processing and analysis in the frame of geophysical observations, such as ionospheric electromagnetic field and gravity field. Such activity is expected to extend to the Chinese future missions, e.g., CSES-2, Zhangheng 02 gravity satellites. The validation of the magnetic field will be done through the direct comparison between the residual fields of CSES and Swarm during similar geomagnetic conditions. This technique will be done for each orbit and, from a statistical point of view, for the entire CSES/Swarm dataset. Concerning the plasma data, the validation will be realized via the direct comparison of the different plasma parameters (i.e. density, temperature, floating potential, and so on), after the calibration of the I-V curve fitting algorithms. From the scientific point of view, the use of both CSES and Swarm data will allow to study the possible Lithosphere-Atmosphere-Ionosphere (LAIC) effects at the satellite orbits on the occasion of significant earthquakes, the FACs dynamics, the ULF wave property and generation mechanisms, the solar activity and seasonal dependences of plasma density and temperature, and the magnetic perturbations in ionosphere. The deliverables include the comprehensive validation results of the magnetic field and plasma data of CSES and Swarm; a set of well-calibrated and high quality magnetic field and plasma density data; the joint academic activities and scientific publications. Related Funding supports: Besides the limited funding provided by Dragon 5 project, both sides will fund the research activities by themselves, to well organize their own team, to execute the joint cooperation tasks with support of other related funding. For the Chinese side, the activities involved in this proposal will be supported by CSES 01 mission operation budgets, the National Key R&D Program of China (No.2018YFC1503500) and other national science foundation of China. For the German side, these are the DFG SPP 1788 “Dynamic Earth”, ESA’s Swarm ESL/DISC under grant no 4000109587/13/I-NB, and Helmholtz institutional support. For the Italian side, the activities will be supported by Italian Space Agency under the contract ASI ”LIMADOU scienza” n° 2016-16-H0 and INGV national funds.
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VALIDATION OF CHINESE CO2-MEASURING SENSORS AND EUROPEAN TROPOMI/SENTINEL-5 PRECURSOR USING FTIR AND MAX-DOAS DATA AT XIANGHE (VCEX)
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The project aims at applying FTIR and MAX-DOAS measurements for the validation of air quality and greenhouse gas measurements from the European Copernicus Sentinel-5 Precursor (S5P) and Chinese TanSat satellites. The focus will be on monitoring [...] |
Dr. Bart Dils, Royal Belgian Institute for Space Aeronomy, BELGIUM |
Prof.. Pucai Wang, Institute of Atmospheric Physics, Chinese Academy of Sciences, CHINA |
Calibration and Validation |
The project aims at applying FTIR and MAX-DOAS measurements for the validation of air quality and greenhouse gas measurements from the European Copernicus Sentinel-5 Precursor (S5P) and Chinese TanSat satellites. The focus will be on monitoring NO2, O3, HCHO, SO2, CHOCHO, CO, CH4 and CO2 columns and Prof.iles using standardised operation protocols and retrieval methods at the Xianghe site, in Northern China. The FTIR instrument allows measurements of O3, HCHO, CO, CH4 and stratospheric NO2 columns, while the MAX-DOAS instruments can measure NO2, O3, HCHO, SO2 and CHOCHO columns as well as aerosol extinction. The differences between the FTIR and MAX-DOAS common targets, in particular regarding their vertical sensitivity, need to be well understood before combining them together to validate satellite measurements. As FTIR and MAX-DOAS instruments are operated from the same building in Xianghe, we have a good opportunity to compare the FTIR and MAX-DOAS NO2, O3 and HCHO measurements and to combine them together for satellite validation. A strong focus of this project will be the implementation of standardized operation and retrieval protocols for the Xianghe FTIR and MAX-DOAS measurements in order to obtain reliable ground-based measurements that are harmonized with the wider scientific community. To reach this target, we will take full advantage of the ongoing activities in projects such as the European ACTRIS-IMP and ECMWF Copernicus Atmospheric Monitoring Service-related CAMS-27 and the Copernicus Climate Change Service-related C3S_311a_Lot3 (C3S-Baron), which concentrate on the establishment of standards for FTIR and MAX-DOAS operation and data processing. Exchange of knowledge, tools and retrieval software will take place, and access to facilities such as the VCEX processing system will be offered.Validation methodologies will be developed and applied, making use of all available sources of information such as the averaging kernels of the satellite products, cloud information, and the vertical Prof.iles of the various trace gases complemented by aerosol data (which will be derived from MAX-DOAS measurements and AERONET measurements). Comprehensive uncertainty budgets will be derived, addressing accuracy, precision and long-term stability. Based on the obtained validation results, recommendations for satellite product quality improvement can eventually be formulated. The project will contribute to validate the S5P and Chinese CO2 sensors (FY-3H/GAS and TanSat) and its successor measurements during the full duration of the project (2020-2023). In this period, the progressive accumulation of data will allow for improved statistics and refinement of the validation results. This will include analysis of, e.g., seasonal cycle effects and longer-term stability. As Xianghe is located in a sub-urban polluted region with a high and variable aerosol concentration, the ground-based MAX-DOAS and FTIR measurements, together with AERONET aerosol optical depth measurements, are valuable to understand the performance of the satellite measurements under different aerosol conditions. In addition, as Xianghe is about 50 km away from the capital Beijing, representativeness effects will also be investigated especially.The main outcomes of the project will be (1) the collection of the ground-based measurements of standardised FTIR and MAX-DOAS column and Prof.ile measurements of NO2, O3, HCHO, SO2, CHOCHO, CO, CH4 and CO2 columns at Xianghe, Northern China, and (2) an assessment of the corresponding quality of the S5P, FY-3H/GAS and TanSat sensors.
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VALIDATION OF OLCI AND COCTS/CZI PRODUCTS AND THEIR POTENTIAL UTILIZATION IN MONITORING OF THE DYNAMIC AND QUALITY OF THE CHINESE AND EUROPEAN COASTAL WATERS
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Objectives: (1) Characterization of the error budgets of officially distributed products of OLCI onboard Sentinel 3 satellites and COCTS/CZI onboard HY-1 satellites in coastal waters around China and Europe, e.g., Yellow Sea in China, English [...] |
Dr. Cédric Jamet , Laboratoire d'Océanologie et de Géosciences UMR 8187 CNRS/ULCO, FRANCE |
Dr.Bing HAN, National Ocean Technology Center, CHINA |
Calibration and Validation |
Objectives: (1) Characterization of the error budgets of officially distributed products of OLCI onboard Sentinel 3 satellites and COCTS/CZI onboard HY-1 satellites in coastal waters around China and Europe, e.g., Yellow Sea in China, English Channel in Europe, French Guiana in South America. (2) Examination of the consistency between OLCI and COCTS/CZI, and among other ocean color sensors in these waters. (3) Development and refinement regional algorithms to accurately retrieve marine environment parameters (optical and biogeochemical) in these regions of interest. (4) Utilization of OLCI and COCTS/CZI products to monitor the dynamic and quality of the Chinese and European coastal waters. Methods: In-situ data acquisition Bio-optical, biogeochemical and atmospheric data will be collected and processed following community widely accepted protocols in the areas of interest. Spatial-temporal match-up methodology The in-situ measurements are considered as the reference or ‘true’ values and will be compared with satellite data (pixels) both temporally and spatially over a given pixel-box. Both spatial box and temporal differences during match-up procedure should be selected with care in coastal waters. Moreover, product flags should also be selected appropriately to avoid suspicious or bad retrievals. (3) Satellite-satellite consistency examination Differences in wavelength/spectral response, spatial resolution as well as temporal difference should be thoroughly considered and corrected properly. Effect of adopting various atmospheric correction and retrieval algorithm may also impact product inconsistency. (4) Relationship analysis between reflectance and water constituents Refinement of existing or development of novel algorithms will be investigated, to improve the accuracy of the products (e.g., Chlorophyll a, suspended particulate matter) in local ecosystems. Deliverables: Annual Summary Report Report includes datasets, use of EO data from multiple sources, and outcomes. (2) Peer viewed publications 4~5 peer viewed papers will be planned under this proposal’s framework. (3) Novel EO dataset Novel EO products processed with refined and/or newly developed algorithms. Funding: Chinese partner: (1) National Key Research and Development Program of China – Real-time Validation and Correction of Ocean Color Products (2016YFC1400906) (2) National Satellite Engineering program of China – Field campaign and product evaluation of COCTS/CZI onboard HY-1C/1D(since 2018). French partner: (1) Centre National d’Etudes Spatiales (CNES) – Evaluation and improvement of OLCI atmospheric correction and bio-optical products over French coastal waters (Funding for sea campaigns) (2) Partenariat Hubert Curien (French ministry of Research, French ministry of Foreign Affairs) Monitoring the quality of French and Chinese coastal waters using OLCI and COCTS/CZI satellite images (Funding for travel in 2020)
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