The MetOp-SG Programme is the follow-on to the current, first generation series of Meteorological Operational (MetOp) satellites, which is now established as a cornerstone of the global network of meteorological satellites. MetOp-SG is required to ensure the continuity of these essential meteorological observations, improve the accuracy / resolution of the measurements, and also to add new measurements and missions.

MetOp-SG is being implemented in collaboration with EUMETSAT. ESA will develop the prototype MetOp-SG satellites (including associated instruments) and procure, on behalf of EUMETSAT, the recurrent satellites (and associated instruments).

The ESA MetOp Second Generation (MetOp-SG) Programme has completed the CDRs for the Satellite A Instruments and Satellite A System. The CDRs for the Satellite B Instruments and System will be held in 2019. The Industrial contract is led by Airbus Defence and Space SAS, France as Prime contractor for the Satellite A series, and with Airbus Space and Defence GmbH, Germany as Prime contractor for the Satellite B series. The EUMETSAT Polar System – Second Generation (EPS-SG) Programme plans its CDR in 2019.

The MetOp-SG satellites accommodate a total of ten instruments. Six of these are procured with the satellites, namely MicroWave Sounder (MWS), SCAtterometer (SCA), Radio Occultation (RO) sounder, MicroWave Imager (MWI), Ice Cloud Imager (ICI), and Multi-viewing, Multi-channel, Multi-polarisation Imager (3MI). Four other instruments complete the payload: METImage from DLR, the Infrared Atmospheric Sounder Instrument Next Generation (IASI-NG) from CNES, Sentinel-5 from ESA under the Copernicus Programme and Argos-4 from CNES.

This paper will present an overview of each of first six instruments (MWS, SCA, RO, MWI, ICI, 3MI), including the key design features, together with the associated industrial progress.

Area D - Board 388

The Multiviewing, Multichannel and Multipolarisation Imaging mission (3MI) has been selected by EUMETSAT as part of the European Polar System – Second generation (EPS-SG) and is currently under development by ESA. This new generation imaging polarimeter will provide, for the first time from an operational mission, unique measurements for characterization for aerosols and clouds. Leveraging on the POLDER instrumental concept previously developed by CNES, 3MI will bring observation at an enhanced spatial resolution and over an extended spectral range (from 410 nm to 2130 nm).

Although primarily dedicated to aerosol monitoring, the multiangle and polarisation 3MI observation will provide advanced capabilities for monitoring of cloud properties and water vapour from an operational meteorological mission. In particular, 3MI will allow for detailed observation of cloud parameters that are crucial in understanding the complex interactions between aerosols and clouds, sources of large discrepancies among climate models.

Among other objectives, 3MI will enable better characterisation of cloud microphysics (phase, particle size distribution) and provide access to cloud vertical extent (geometrical thickness, multilayer detection). These parameters are key for many meteorological and nowcasting applications. New developments also suggest that information on vertical profile of cloud properties (LWC, extinction coefficient) might be obtained from the high information content of 3MI observations.

In this presentation, we will provide an overview of the instrument characteristics and of various preparatory studies being conducted in anticipation of 3MI launch at the 2021 horizon. Synthetic observations of 3MI, obtained using a highly realistic simulator developed for different sensors of the EPS-SG, are used to assess the performances of cloud retrieval algorithms under preparation for operational NRT processing. Expected accuracy and current limitations of derived products will be presented and discussed.

Finally, we will briefly outline the potential of the 3MI mission to enhance the operational capabilities of the EPS-SG for clouds and water vapour monitoring through synergistic use with other instruments of the METOP-SG A platform (METImage, IASI-NG or UV-NS). In particular, the potential of 3MI and METImage synergy for multilayer cloud situation description will be illustrated.

Area D - Board 389

The EUMETSAT Polar System (EPS) products and services and their contribution for weather monitoring and forecast

Dieter Klaes, Manfred Lugert, Bojan Bojkov, Jörg Ackermann, Régis Borde, Dorothée Coppens, Thomas August, Christian Marquardt, Stefanie Linow, Craig Anderson, Rüdiger Lang, Rosemary Munro

EUMETSAT

This Paper provides an overview on the products and services of the EUMETSAT Polar System (EPS), highlighting the aspects related to observing and forecasting the weather. EPS is the European contribution to the Polar Meteorological Satellite Observing System. It forms a part of the Initial Joint Polar System (IJPS), formed with NOAA (National Oceanic and Atmospheric Administration). EUMETSAT is assuring the mid-morning service (9:30 AM LST, descending node), whereas the US partners are assuring the afternoon service (13:30 PM LST, ascending node). Eight meteorological instruments (among 11) are embarked on the Metop satellites (seven on Metop-C). The Metop satellites developed in co-operation with the European Space Agency (ESA) form the space segment of EPS. Metop instrument data – in particular the sounding instruments - provide an essential contribution to global operational Numerical Weather Prediction (NWP). Climate monitoring and atmospheric composition monitoring and ocean and cryosphere observations are further application areas supported by Metop instrument data. There are three Metop satellites in the programme and fly in a sun-synchronous mid morning polar orbit with equator crossing time of 9:30 Local Solar Time (LST) for the descending node. At least 15 years of operations are foreseen to provide measurements from space. All three Metop satellites are in orbit (Metop-A launched 2006 and Metop-B in 2012), with the third, Metop-C successfully launched on the 7 November 2018 (UTC time) from Kourou. After its successful commissioning, there will be three Metop-satellites in orbit for about three years. The paper will also highlight commissioning results of Metop-C and impact already visible from the data on the quality of weather forecasts.

Area D - Board 390

EUMETSAT has provided the user community with more than four decades worth of satellite data, starting with the mandatory geostationary missions of the Meteosat First Generation, and since 2002 the Meteosat Second Generation (MSG) series satellites.

EUMETSAT is currently developing the future geostationary program, the Meteosat Third Generation (MTG). The MTG system will host a more advanced 16-channel VIS/IR Flexible Combined Imager (FCI) as well as a Lightning Imager (LI) on its geostationary imaging platform (MTG-I), whereas the sounding platform (MTG-S) will host the MTG InfraRed Sounder (IRS) and the Copernicus Sentinel-4 ultraviolet/near-infrared (UVN) sounding mission. The launch of the first two satellites MTG-I1 and MTG-S1 hosting the imaging and sounding instruments, respectively, is foreseen in the early 2020s.

MTG products are developed either centrally at the EUMETSAT Headquarters or at the Satellite Application Facilities (SAF) distributed among the Member States. With the range of new instruments becoming operational in the next decade it will be during the development phase a challenge firstly for EUMETSAT to assess the impacts of possible non-conformances on future products and secondly to prepare the users to make early use of the data from these instruments. This is particularly the case for instruments with limited geostationary heritage such as the LI or the IRS, which are at the same time expected to bring a significant added value to both Nowcasting and Numerical Weather Prediction needs. To mitigate this EUMETSAT is developing end-to-end reference processor chains for all instruments to support performance assessments, facility acceptance testing and provide example data for user familiarisation. EUMETSAT is supported in many aspects of these overall product development activities by Mission Advisory Groups (MAGs), which draw on external expertise. In addition, the MAGs support the preparation of the commissioning and Cal/Val activities that will lead to the development of new tools and techniques to analyse the instrument data.

The presentation will give an overview of the MTG system, its observations missions and the status of the EUMETSAT internal product development activities in preparation for the first MTG-I and -S launches.

Area D - Board 391

The Meteosat Third Generation (MTG) Programme is being realised through the well-established and successful Cooperation between EUMETSAT and ESA. It will ensure the continuity with, and enhancement of, operational meteorological (and climate) data from Geostationary Orbit as currently provided by the Meteosat Second Generation (MSG) system, the last of which MSG4/MET11 has been successfully launched, commissioned in 2015 and put in orbit storage as a back-up.

The industrial Prime Contractor for the Space segment is Thales Alenia Space France (TAS-F) with a core team consortium including OHB-Bremen (Germany) and OHB-Munich (Germany). This contract includes the provision of six satellites, four Imaging satellites (MTG-I) and two sounding satellites (MTG-S), which will ensure a total operational life of the MTG system in excess of 20 years. TAS-F is also responsible for the MTG Imager development, namely the Flexible Combined Imager or FCI

The FCI is an improved successor of the SEVIRI on board MSG. It is designed to provide images of the Earth every 2.5 to 10 minutes in 16 spectral channels between 0.44 and 13.3 μm, with a ground resolution ranging from 0.5 km to 2 km. Following the closure of the CDR’s of all its units and equipment’s, the FCI has gone through its testing phases (Structural and Thermal Models – STM and Engineering Models – EM tests are completed). The FCI CDR has been run successfully through the Q4/2018 to Q1/2019. The FCI Proto-Flight Model (PFM) units/equipments have been delivered and the integration and testing at FCI level has started. The end to end radiometric, spectral and image quality performance evaluation indicates that the FCI confidently meets most of its stringent mission requirements.

This paper will briefly recall the overall FCI instrument design and its calibration concept covering VIS/NIR and IR domains. The presentation will then provide a complete overview of the end-to-end performance predictions for the FCI in the geometrical, spectral and radiometric domains. The performance prediction include all the available test results obtained from the STM, EM and/or PFM units.

Area D - Board 392

Meteosat Third Generation (MTG) is the next generation of European meteorological geostationary satellites, set to be launched in 2021. Besides ensuring continuity with
Meteosat Second Generation imagery mission, the new series will feature new instruments, such as the Lightning Imager (LI), a high-speed optical detector providing near real-time lightning detection capabilities over Europe and Africa.

The LI instrument is built by Leonardo (I) under the industrial Prime contractor Thales Alenia Space (F).
The LI instrument will detect lightning on a global scale on a 24/7 timeline. The LI products will be used to provide near real-time monitoring and short range forecast of severe weather phenomena as well as for long term climate observations.

The fundamental working principle behind the lightning detection consists in triggering events on pixels where and when a sudden increase of energy is measured over the background radiance image. These events, also called detected transients (DTs) can result from real lightning pulses or from a number of unwanted sources, e.g. acquisition noise or jitter movement.
The main design trade-off to be performed is to use an optimum detection scheme which is sensitive enough to detect small real lightning pulses while at the same time trying to limit the amount of events generated by noise sources. This involves a succession of on-board and on-ground filters, implemented in hardware and software to discard the false events.

To achieve a high detection probability for real lightning events, the LI instrument design makes use of several novel technologies, including back-thinned CMOS detectors with a large pixel size of 24 um, real time processing implemented in multiple ASICs and FPGAs, high speed data interfaces, narrow bandwidth optical filters, as well as a PowerPC for on-board data processing.

The instrument will enter its CDR from Q4/2018 to Q1/2019.

This paper will briefly recall the overall LI instrument design and development status. The presentation will then provide an overview of the end-to-end performance predictions also based on the latest development model test results. The results of the various tests (STM and EM) will be presented.

Area D - Board 393

The Meteosat Third Generation (MTG) Programme is being realised through the well-established and successful Cooperation between EUMETSAT and ESA. It will ensure continuity with, and enhancement of, operational meteorological (and climate) data from Geostationary Orbit as currently provided by the Meteosat Second Generation (MSG) system. The MTG-S mission with its IRS and Sentinel-4 missions will complement the traditional horizontal imaging system with vertical profiling of wind, temperature, and air quality, thanks to its sounding capability. Flight Acceptance Review (FAR) of the MTG-S1 spacecraft is planned for 2022.

The IRS is a Fourier Transform infrared spectrometer. It is designed to provide soundings of the Earth every hour in 2 bands; LWIR, 700 to 1210 cm-1, and MWIR, 1600 to 2175 cm-1. Spectral and spatial resolutions are respectively 0.754 cm-1 and 4 km (at sub-satellite point) using stares of 600x600 km2. The IRS has entered manufacturing and testing phases. The Structural and Thermal Model (STM) and the Core Spectrometer Model (CS) of the instrument are being integrated while Engineering Model (EM), and in several cases Proto Flight Model (PFM) equipment, are being manufactured and tested. With results from development model testing, at all levels, the IRS Critical Design Review (CDR) is scheduled to take place in mid 2019. Radiometric, spectral and image quality performance evaluation indicates that the IRS will closely meet its mission requirements.

This paper will briefly recall the overall IRS instrument design and calibration concept. The presentation will provide an overview of performance predictions for the IRS in the geometrical, spectral and radiometric domains. As far as available, it will take into account the latest test results at unit, sub-system and instrument level. Furthermore, the paper will provide an overview of the resulting mission performances up to Level 1b and highlight some of the many challenges and design solutions.

Area D - Board 394

Sentinel 4 is an imaging UVN (UV-VIS-NIR) spectrometer, developed by Airbus DS under ESA contract in the frame of the joint EU/ESA COPERNICUS program. The mission objective is the operational monitoring of trace gas concentrations for atmospheric chemistry and climate applications.
The Sentinel-4 UVN instrument model philosophy consists of the following models: STM, Flat EM, e-EM, PFM and FM2.
Amongst those, the enhanced Engineering Model (e-EM) is fully representative for the two flight models from Structural, Thermal and Electrical perspective except for what concerns redundancy. From the optical and performance point of view, the e-EM has a simplified built standard with respect to the PFM/FM2, having in the optical path no spectrometers (neither UVVIS, nor NIR) but a QM telescope as well as the two focal plane assemblies, containing the two detectors and front-end-electronics. However only the NIR detector is be in the nominal light path. With such built standard, the e-EM is optically speaking an imager, operating in the NIR band.
After its assembly and integration, completed since April 2018, the e-EM encompassed a complete test programme in ambient conditions, consisting of microvibration and EMC tests at IABG (GER). After completion of this first test campaign by end of spring 2018, the instrument has been brought to the new test facility at RAL (UK), where the instrument is being further tested in thermo-vacuum conditions. Specifically the e-EM will experience a thermal balance test and a performance risk mitigation test. The whole campaign should be completed by Q1 2019.

Due to its built standard limitation, the e-EM does not allow to perform any check of the performance of the instrument prior to the PFM campaign. However, aspects as critical interfaces between the instrument and the vacuum facility or between instrument and its EGSE, MGSE and OGSE (including the evaluation of the straylight generated by the OGSE), the run of test procedures, and the generation of a preliminary set of Calibration Key Data will be done with the e-EM. For all these aspects the e-EM is considered as a unique tool to de-risk the PFM test campaign.

This paper gives an overview of the Sentinel-4 UVN instrument performances and development status after successful completion of the Critical design review. Furthermore the S4 instrument e-EM AIT phase, its preparation, implementation and test results will be presented.

Area D - Board 395

With the move towards integrated modelling of the Earth system, Numerical Weather Prediction Centres are increasingly including atmospheric composition variables in their data assimilation and forecast systems. With its long history of providing operational meteorological satellite data products, and more recently operational atmospheric composition data products, EUMETSAT is in a unique position to provide data to support these developments.

In addition to provision of operational meteorological data products and services from its fleet of satellites, EUMETSAT will, as part of the Copernicus tasks entrusted by the European Commission under the Delegation Agreement, Building Block 2, ATSE Atmospheric Services, deliver operational Near Real Time (NRT) data and support services for the Copernicus Sentinel-4 mission to be hosted on the MTG-S platform, the Copernicus Sentinel-5 mission to be hosted on the EPS-SG A platform. EUMETSAT’s demonstrated expertise in the provision of operational data products and services, and the availability of data and products from EUMETSAT’s own missions brings a wealth of opportunities, in particular related to the potential for the development of synergistic products.

In this presentation we provide an overview of the full suite of instruments relevant to atmospheric composition on the EPS-SG and MTG platforms and highlight the additional value that this brings in addition to the extensive suite of meteorological data and products. Particular attention will be paid to the synergy between data products.

Area D - Board 396

Atmospheric Motion Vectors (AMVs) are derived from satellites by tracking clouds or water vapour features in consecutive satellite images. Currently, AMVs constitute the only upper-level wind observations with good coverage of the tropics, the mid-latitudes, the polar areas, and especially over the large oceanic areas where there is a lack of ground-based measurements. The satellite AMVs are assimilated in the Numerical Weather Prediction (NWP) models and contribute to the improvement of the forecast scores.
At EUMETSAT, AMVs are derived operationally from the Meteosat geostationary (GEO) satellites and from the Low Earth Orbit (LEO) Metop satellites. The current EUMETSAT contribution to the global AMV production covers Meteosat disks at 0 and 41 deg longitudes, the northern and southern high latitude (Poleward 50 deg.) areas with Metop A and Metop B single AVHRR product, and a global coverage using the Global AVHRR wind product. In the upcoming years, the transition from current EUMETSAT operational programs Meteosat Second Generation (MSG) and Earth Polar System (EPS) to new generation programs Meteosat Third Generation (MTG) and Earth Polar System Second Generation (EPS-SG) creates some scientific and technical challenges. The strategy adopted for AMV development considers several critical aspects such as the continuity of current operation capabilities, and the development of new capabilities to fulfil increasing user needs. These last ones mainly concern algorithms under development for EPS-SG/METImage and Sentinel 3 Sea and Land Surface Temperature Radiometer (SLSTR) instruments, but also the recent investigation in the extraction of 3D wind profiles from Infrared sounders level 2 products like Metop Infrared Atmospheric Sounding Interferometer (IASI) or the future MTG Infrared Sounder (MTG-IRS) instruments.
This paper will give an overview of the current status of AMV products at EUMETSAT together with information on mid-term perspectives and developments. Emphasis will be given on the expected benefits of the new MTG and EPS-SG instruments capabilities on AMV production.

Area D - Board 397

The EPS/Metop satellite programme operates three satellites: Metop-A was launched in 2006, followed by Metop-B in 2012, and the most recent contribution, Metop-C, was launched in 2018. The Metop satellite series provides data on the atmospheric state, land and ocean surface, cryosphere and atmospheric composition. The ASCAT instrument on board of the Metop satellites is a C-band fan beam scatterometer. It is used to measure wind speed and direction over the ocean, and to retrieve soil moisture over land surfaces. The data provided by ASCAT is also used to monitor sea ice motion, extent and type.
Following the recent launch of Metop-C in November 2018, this paper provides an introduction into the status of the commissioning of the ASCAT instrument on board the new satellite. Similar to the previous ASCAT instruments, the calibration and validation of the Level-1 data includes different activities, such as a cross-validation with the other ASCAT instruments and the validation of the measurements using natural targets such as the tropical rainforest or the ocean. Of particular importance is the absolute calibration of the instrument using active transponders. As part of the ASCAT-C commissioning activities, new transponders have been installed at the calibration sites and we will present an initial analysis of the new data. In summary, we will provide an overview of the calibration and validation activities and present a preliminary analysis of the ASCAT-C data quality.

Area D - Board 398

Several interdisciplinary studies had been already carried on and published as predictive dengue risk models based on environmental conditions (Estallo et al., 2008; Espinosa et al., 2016) and operational tools (Porcasi et al., 2012). As the current approach for dengue prevention is mainly based on vector control (Guzmán and Kouri, 2002; Guzmán et al., 2004), models based on geophysical and climate remotely sensed data integrated with urban demography and socioeconomic data would allow prediction of spatio-temporal variation of vector population abundance. Nevertheless, until now, they are not considering the soil moisture conditions.

Thus, the main objective of this work is analyzing the impact of the soil moisture and other parameters in the dengue episodes in Brazil. As the ESA SMOS mission was launch in November the 2nd 2009, nowadays, soil moisture products are regularly available at global scale (around 30 km spatial resolution). In this study we are using the Soil Moisture (SM) level 3 data product from the Barcelona Expert Center (BEC). The SM is combined with other climatological data (e.g. temperature and rain fall), and demographic and socioeconomic data over the Brazilian territory for the 2010-2018 period, when the SM is available. Meteorological information such as temperature (maximum, minimum and mean) and precipitation, are obtained from Center for Weather Forecasting and Climate Studies (CPTEC)/National Institute for Space Research (INPE). Moreover, demographic density of population is also considered. The dengue episodes distribution during this period has been obtained from http://www2.datasus.gov.br/DATASUS/index.php?area=0203&id=29878153.

In summary, the applied method uses both sensibility data (such as population, urban and rural areas) and susceptibility data (soil moisture, temperature, precipitation and others) for the analysis and development of the potential vulnerability of dengue’s occurrence for each region in Brazil. Detailed results of this study will be presented at the conference.

References

- Lowe, R. Barcellos, C., Coelho, C. A., Bailey, T. C., Coelho, G. E., Graham, R. Jupp, T., Ramalho, W. M. Carvalho, M. S., Stephenson, D. B., Rodó, X. Dengue outlook for the World Cup in Brazil: an early warning model framework driven by real-time seasonal climate forecasts. Lancet Infect Dis. 2014 Jul;14(7):552-3. doi: 10.1016/S1473-3099(14)70807-2.
- Scavuzzo, J. M., Trucco, F., Espinosa, M., Tauro, C. B. M., C. M Abril, Scavuzzo, A. C. Frer. Modeling Dengue Vector Population Using Remotely Sensed Data and Machine Learning, Acta Tropica May 8, 2018.
- Kesetyaningsih, T. W., Sudarto, S. A., Pramoedyo, H. Determination of environmental factors affecting dengue incidence in Sleman district, Yogyakarta, Indonesia. Afr., J. Infect. Dis. (2018) 12(S): 13-25.
- Sanna, M., Wu, J., Zhu, Y., Zhicong Y., Jiahai Lu, Ying-Hen Hsieh. Spatial and Temporal Characteristics of 2014 Dengue Outbreak in Guangdong, China. Scientific Reports, (2018) 8:2344, DOI:10.1038/s41598-018-19168-6.
- Estallo E. L., Lamfri, M. S., Scavuzzo, C. M., Ludueña-Almeida F. F., Introini, M. V., Zaidenberg, M. et al. (2008) Models for predicting Aedes aegypti larval indices based on satellite images and climatic variables. J Am Mosq Control Assoc 24: 368–376.
- Espinosa, M, Weinberg, D, Rotela, CH, Polop, F,Abril, M,Scavuzzo, CM(2016). Temporal Dynamics and Spatial Patterns of Aedes aegypti Breeding Sites, in the Context of a Dengue Control Program in Tartagal (Salta Province, Argentina). PLoS Negl Trop Dis10(5):e0004621.doi:10.1371/journal. pntd.0004621.
- Porcasi X, Rotela CH, Introini MV, Frutos N, Lanfri S, et al. (2012) An operative dengue risk stratification system in Argentina based on geospatial technology. Geospat Health 6: S31–42.
- Guzmán M. G., Kourí G. Dengue diagnosis, advances and challenges, Int J Infect Dis. 2004 Mar;8(2):69-80.

Area D - Board 399

The BF-1 constellation is composed of two observatories. Each observatory contains an instrument that consists of a multichannel GNSS-R receiver, a low-gain zenith antenna for reception of the direct signals, and two high-gain nadir antennas for reception of the surface scattered signals. The measurements made by BF-1 satellites GNSS-R bistatic radar are referred to as delay-Doppler maps (DDMs). Both delay and Doppler are varied in the DDM across a range that includes the delay and Doppler coordinates of the nominal specular reflection point on the surface with respect to mean sea level.
The highest power occurs at the specular reflection point, diffuse scattered power, away from the specular point, increases as the ocean surface roughness increases due to strengthening winds. Based on this principle, wind speed retrieval research based on DDM data was carried. Some wind retrieval schemes for detecting ocean surface wind speed from BF-1 satellites DDMs were presented, such as an empirically derived geophysical model function, Support Vector Machines and convolutional neural network based on deep learning algorithm. The results of each algorithm were compared and analyzed also. In order to improve the accuracy of the wind speed extraction model, calibration and validation were also performed. The primary objectives of the calibration and validation effort are to characterize the model function, evaluate the retrieval algorithm, and evaluate the retrieved wind speeds.
Various truth data with the BF-1 data were collocated. These truth data include Marine meteorological observatory data, other satellite data, and Marine buoy-based measurements. We have established an observation site at the Bohe Marine-meteorological observatory station in Guangdong Province to collect tropical cyclones truth data. A large population of DDMs, covering a wide dynamic range of wind speeds that from the lower wind speed regime to the much higher winds, were collected and used to training the retrieval model. The RMS wind speed retrieval error is expected to meet or exceed the mission requirement of 2 ms-1 (for winds less than 20 ms-1) or 10% (for winds greater than 20 ms–1) of the wind speed, whichever is greater. We hope that these results could be used in assimilation studies to assess their impact on hurricane intensity and track forecasts in future, and an effort will be made to integrate these data into the China Meteorological Administration (CMA) workstation environment so that they can be utilized and evaluated in near-real time.

Area D - Board 400

Observation of sea surface wind condition is among the most important factors in both improving our understanding of tropical cyclones and predicting them operationally. However, Observations of the inner core of tropical cyclones by the current suite of space-borne remote sensing instruments tend to be obscured by the intense precipitation found in the eye-wall and inner rain-bands. Because of inadequate observations and modeling of the inner core of the tropical cyclones, the improvements in its intensity forecasting have been relatively modest in recent years.
The micro-satellite mission is a constellation of two small satellites, scheduled to launch in 2019, designed to measure ocean surface wind speed with high temporal-spatial resolution and extensive spatial coverage, under all precipitating conditions and over the full dynamic range of wind speeds experienced in a tropical cyclone. Each satellite carries a Global Navigation Satellite System reflectometry (GNSS-R) radar receiver that measures GPS L1 channel at 1575 MHz and Beidou B1 channel at 1561 MHz, which are reflected from the Earth surface. These L-bands suffers no appreciable attenuation at even severe rainfall rates. The mission uses a bistatic radar method for measuring winds. The measurements made by bistatic radar are referred to as delay Doppler maps (DDMs). These are maps of the power in the Global Navigation Satellite System (GNSS) signal scattered by the ocean surface after the signals are selectively filtered by time delay and Doppler shift.
Due to the large number of GPS and BD navigation satellites were used, there are typically many specular reflections from the surface available at any given time. Each micro-satellite selects the four specular reflections located in the highest sensitivity region of its nadir antenna pattern and simultaneously computes DDMs centered on each of them. Then these DDM data were preprocessed by image power calibration and BRCS calculation to generate L1A-level products and L1B-level products through ground data processing system, respectively. Being the China's first space-based GNSS-R constellation system, that will systematically provide wind speed retrievals over much of the world's oceans and improving human understanding of tropical cyclones and predicting them effectively during operation.

Area D - Board 401

The past GRACE (Gravity Recovery And Climate Experiment) mission has clearly demonstrated its value for monitoring global mass redistribution and has allowed us to better understand the complex feedback mechanisms of the components of the Earth system. Nonetheless, GRACE observations are limited by their relatively low spatial (~300 km) and temporal resolutions (30 days) as well as by the precision and accuracy of the background models (e.g., atmospheric and oceanic de-aliasing products) used in the processing.

An on-going ESA-funded ADDCON (Additional Constellation & Scientific Analysis Studies of the Next Generation Gravity Mission Concept) project was supported to investigate multi-pair GRACE-like satellite constellations and their potential applications in the Earth science. The ADDCON project aims to establish a future satellite gravimetric constellation as a mass sensor for the atmosphere as well, which is a paradigm change relative to GRACE and GRACE-FO, where the atmosphere is simply treated as a nuisance in terms of dealiasing models. Within the project, all mass changes in the Earth system components will be recovered during the data processing, the implication being that no de-aliasing products will be needed in the data processing. To achieve this goal, it will be important to investigate the potential of extracting atmospheric mass signals from the recovered gravity signals. Based on ESA’s Earth System Models developed for gravity mission simulation studies, we first analyze atmospheric signal characteristics from the simulated AOHIS (Atmosphere, Ocean, Hydrology, Ice and Solid Earth) gravity signals. In this poster, we report on our experiments using different statistical approaches to separate the atmospheric signals from the recovered signals of the selected satellite constellations. Possible applications of the extracted atmospheric grids will also be discussed.

Area D - Board 402