Meteosat Second Generation. System Overview EUM TD 07

Transcription

1 Meteosat Second Generation EUM TD 07

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3 METEOSAT SECOND GENERATION MSG EUM TD 07 Issue 1.1 EUM TD 07 Issue 1.1, 25 May 2001

4 Document Change Record Issue Date Change Issue April 2001 Initial Issue Issue May 2001 Update to Fig. 4.4 Page II EUM TD 07 - Issue 1.1, 25 May 2001

5 Table of Contents 1. PREFACE 1 2. INTRODUCTION Scope and Objectives EUMETSAT Satellite Programmes MSG Programme Objectives Document Hierarchy 5 3. MSG OPERATIONAL SERVICES Image Data Dissemination Service Data Collection and Retransmission Service Meteorological Data Dissemination Service Meteorological Product Extraction and Distribution Service Archived Data and Retrieval Service Geostationary Earth Radiation Budget Service User Support Service Operational Information User Service Helpdesk MSG SYSTEM DESCRIPTION MSG Space Segment The MSG Satellite The SEVIRI Radiometer Scanning Concept The MSG Ground Segment The Mission Control Centre The Central Facility Image Processing Facility Data Acquisition and Dissemination Facility Primary Ground Station Back-up Satellite Control Centre Back-up and Ranging Ground Station Foreign Satellite Data Support Application Ground Segment Meteorological Products Extraction Facility Unified Meteorological Archive and Retrieval Facility Satellite Application Facilities Support of Nowcasting and Very Short Range Forecasting SAF Ocean and Sea Ice SAF Ozone Monitoring SAF Climate Monitoring SAF Numerical Weather Prediction SAF Land Surface Analysis SAF ANNEX I COMPARISON BETWEEN MTP AND MSG Image Data Generation Image Data Dissemination Service Foreign Satellite Data Support Service Meteorological Data Dissemination Service Meteorological Product Extraction and Distribution Service Data Collection Service 33 EUM TD 07 - Issue 1.1, 25 May 2001 Page III

6 5.7. Archived Data and Retrieval Service User Transition Service ANNEX II EUMETSAT DATA POLICY LIST OF FIGURES LIST OF TABLES GLOSSARY OF TERMS GLOSSARY OF ACRONYMS 41 EUMETSAT wishes to thank those companies and institutes that have provided illustrations and photographs for this document but for which a specific acknowledgement has not been possible. Page IV EUM TD 07 - Issue 1.1, 25 May 2001

7 1. Preface This document presents a general introduction to the products, services and facilities provided by EUMETSAT through the Meteosat Second Generation (MSG) System. It provides an overview of the complete system, focusing on EUMETSAT services and including descriptions of the MSG space and ground segments. Like the first series of satellites, the primary service of Meteosat Second Generation is the provision to end-users of multi-spectral images of the earth. The acquisition area covers all of Europe, the Middle East, the entire continent of Africa, most of the North and South Atlantic oceans and some portions of South America (as illustrated in Figure 1.1). However, the Meteosat Second Generation system has many improvements over its predecessors and new features, which this document introduces. This document is complementary to a previous publication, EUM TD 05, that describes the Meteosat system for the Meteosat Transition Programme (MTP). It includes a comparison between the services offered by the MTP and the MSG systems. The transfer phase between the two programmes is also mentioned, albeit briefly, since EUMETSAT Newsletters and information on the EUMETSAT Web Site will address the necessary arrangements comprehensively. Figure 1.1 A colour-enhanced image of the full earth disk from the first generation Meteosat. Meteosat Second Generation will provide images with the same coverage, but with significantly improved spectral, temporal and spatial resolution. EUM TD 07 - Issue 1.1, 25 May 2001 Page 1

8 2. Introduction This chapter recalls the reasons why meteorology and climatology are so important to the global economy and the contribution of meteorological satellites to those disciplines. The EUMETSAT satellite programmes and the specific MSG objectives are described briefly. The document tree for user information is also included Scope and Objectives Meteorological satellites have become essential tools for both meteorology and climatology; they provide vital data for these disciplines at frequent intervals and over wide areas. They continue the two fundamental concepts of data exchange and international co-operation that have been traditional in these fields for more than 150 years. International co-operation exists at two levels: First at the European level through those countries which have come together to establish EUMETSAT. The continuity of the Meteosat system enabled through the Second Generation ensures the availability of data over nearly one quarter of the planet. The second level of co-operation is on a global scale, which ensures the availability of satellite data over the entire Earth. The Meteosat Second Generation system is the latest European contribution to the global observing system for meteorology and climatology. The primary objective of the Meteosat system is to provide cost-effective satellite data and related services that meet the requirements of the EUMETSAT Member States. To the greatest extent possible the system also addresses the requirements expressed by the World Meteorological Organization (WMO). The data and services are mainly focused on the requirements of operational meteorology, with the emphasis on support to operational weather forecasting. However, the data are of use for all areas of this discipline, including marine, agricultural and aviation meteorology, as well as, for example, climatology and the monitoring of planet Earth. Precise and accurate weather forecasts are of much greater importance than their use for merely predicting if it will rain or not during the next hours or days. They have become essential for the transport industry to ensure efficient and reliable operations, for the construction and agricultural industries to schedule activities that may be affected by weather, and by the retail industry to plan stocks of food and clothing for which the demand varies according to the weather. The energy industries also vary the available capacity of their plants according to weather-dependent predictions of demands. Accurate weather forecasts are therefore a strong contributor to the efficiency of the way in which many industries work and therefore a strong contributor to national economies. Page 2 EUM TD 07 - Issue 1.1, 25 May 2001

9 The need for climate data also has a strong economic justification. If weather patterns change, then agriculture will also change and this may have a profound effect, both on individuals and on the economies of nations. If sea levels change, expensive coastal defences may become necessary, or populations may have to migrate. Where changes are found to be due to human activity, major actions may have to be taken to reverse the trends. The variations in weather and climate have enormous economic consequences which are increasing as the world population grows and becomes more industrialised. The need to understand, monitor and predict the weather and the changing climate is becoming increasingly important EUMETSAT Satellite Programmes The initial development and early operation of Meteosat was covered by a series of ESA programmes. After EUMETSAT was defined in 1983, ESA initiated the Meteosat Operational Programme (MOP), and from 1987 this was conducted as a joint programme, under the overall authority of EUMETSAT. This programme provided the framework for the construction and launch of three satellites, Meteosat-4, -5 and -6, as well as the operation of the complete system from 1983 until the end of November In 1995 EUMETSAT took over the operations of the Meteosat system and implemented the Meteosat Transition Programme (MTP). This programme included provision and launch of a further satellite of the same design (Meteosat- 7), the development of a new ground system, and routine operations from December 1995 until the end of the year It has since been agreed to extend MTP Operations until at least the end of 2003 to provide an overlap with the Meteosat Second Generation of satellites (MSG). If technically feasible, it may be possible to further extend this period of parallel operations, however, this will require the approval of the EUMETSAT Council. Meteosat Second Generation is a significantly enhanced follow-on system to that operated under the MTP. It has been designed in response to user requirements and will serve the needs of nowcasting applications and short range weather forecasting as well as providing important data for climate monitoring and research. The development of Meteosat Second Generation continues the successful co-operation between EUMETSAT and ESA, with two thirds of the cost of the development of the first satellite being funded by ESA. The financial envelope already approved by the EUMETSAT Council covers the operation of three MSG satellites from the year 2002 for more than a decade. Consideration is being given to the manufacture of a fourth satellite in this series. The lack of observational coverage in parts of the globe, particularly at high latitudes (North & South), has increased the importance of polar-orbiting satellites for numerical weather prediction and climate monitoring. The EUM TD 07 - Issue 1.1, 25 May 2001 Page 3

10 EUMETSAT Polar System (EPS), now in preparation, is the European component of a joint European/US polar satellite system. The Metop-1 satellite, developed in co-operation with ESA and planned for launch at the end of 2005, will carry EUMETSAT and US provided instruments. Later satellites in the series will ensure earth observation well into the second decade of the 21 st century MSG Programme Objectives The MSG Programme objectives can be summarised by: 1) multi-spectral imaging of the cloud systems, the Earth surface and radiance emitted by the atmosphere, with improved radiometric, spectral, spatial and temporal resolution when compared with the first generation Meteosat; 2) data collection from data collection platforms (DCP); 3) dissemination of the satellite image data and meteorological information to the user community in a timely manner in support of nowcasting and very short range forecasting; 4) extraction of meteorological and geophysical fields from the satellite image data in support of general meteorological, climatological and environmental activities; 5) user support including the provision of user documents and information, the provision of a user helpdesk facility and of a service to enable access to archived MSG image data and products; 6) support to secondary payloads of scientific or pre-operational nature (GERB and Search & Rescue (GEOSAR)) which are not directly relevant to the MSG Programme. These payloads do not drive the system nor do they interfere with the primary objectives as laid out above under 1) to 5) above. EUMETSAT will provide the following services to achieve these objectives. Image Data Dissemination Service Data Collection and Retransmission Service Meteorological Data Dissemination Service Meteorological Product Extraction and Distribution Service Archived Data and Retrieval Service Geostationary Earth Radiation Budget Service EUMETSAT will provide a comprehensive document set for users wishing to learn more about the Meteosat Second Generation System and the services that EUMETSAT will operate to accomplish the mission objectives. Please see the following section for a document hierarchy. Page 4 EUM TD 07 - Issue 1.1, 25 May 2001

11 2.3. Document Hierarchy Figure 2.1 below shows the EUMETSAT technical document set. Documents EUM TD describe the services of the current Meteosat Transition Programme (MTP). The series will be extended to cover the entire range of services operating under Meteosat Second Generation (MSG). Whilst EUM TD 07 Meteosat Second Generation will provide an overview for all products and services available via the MSG system users are encouraged to refer to the documents EUM TD for a more detailed description of the services and how to access them. MTP EUM TD 05 The Meteosat System EUM TD 01 Meteorological Data Distribution EUM TD 02 Meteosat High Resolution Image Dissemination EUM TD 03 Meteosat WEFAX Dissemination EUM TD 04 Meteosat Data Collection and Retransmission System EUM TD 06 Meteosat Archive User Handbook MSG EUM TD 07 Meteosat Second Generation EUM TD 08 Image Data Dissemination Service EUM TD 09 Data Collection and Retransmission Service EUM TD 10 Meteorological Data Dissemination Service EUM TD 11 Meteorological Product Extraction and Distribution Service EUM TD 12 Archived Data Retrieval Service Figure 2.1 User Document Hierarchy EUM TD 07 - Issue 1.1, 25 May 2001 Page 5

12 3. MSG Operational Services The primary service provided by the Meteosat Second Generation system is the generation of multi-spectral images of the Earth and the transmission of these image data to users in the shortest practical time. In addition there are several other important services as follows: The Data Collection & Retransmission Service; The Meteorological Data Dissemination Service; The Meteorological Product Extraction and Distribution Service; The Archive Data and Retrieval Service; The GERB Service; The User Support Service. These services are briefly described in the following sections. They are also described in more detail in the publications EUM TD The operational Meteosat satellites are positioned in geostationary orbit, above the equator, normally at 0 longitude, i.e. the Greenwich Meridian. From this position the satellite is capable of providing images of all of Europe, the Middle East, the entire continent of Africa, most of the North and South Atlantic oceans and some portions of South America. Similarly the satellite is able to disseminate these data to users in an extensive area of the globe. The telecommunications coverage area for data dissemination and unrestricted access to the services operated by EUMETSAT is illustrated in Figure 3.1. Note that the 'nominal coverage area' shown includes all the EUMETSAT Member States, all of Africa and locations at which the elevation to the satellite is greater than or equal to 10. Page 6 EUM TD 07 - Issue 1.1, 25 May 2001

13 Figure 3.1 Meteosat Second Generation Telecommunications nominal coverage area 3.1. Image Data Dissemination Service The primary payload of the Meteosat Second Generation satellites is the Spinning Enhanced Visible and IR Imager (SEVIRI). The SEVIRI takes basic multi-spectral imagery with better spectral, spatial and temporal resolution than the previous Meteosat satellites. The SEVIRI takes images of the earth, measuring the radiance at 12 different wavebands of the electromagnetic spectrum. The various channels provide measurements of different physical characteristics of the atmosphere and the earth at a resolution of 3 km at the sub-satellite point. High resolution imagery is acquired by observing the Earth in the visible band and sampling at 1 km resolution. During normal operations the radiometers capture new images of the earth every 15 minutes. The earth images and other meteorological data are disseminated via the satellite so that information regarding the current meteorological conditions may be received by users in as short a time as practical. The MSG satellites are equipped with transponders to transmit information to user stations located anywhere within the field of view of Meteosat. MSG supports two channels of dissemination via the satellite, the Low Rate Information Transmission (LRIT) and the High Rate Information Transmission (HRIT). SEVIRI image data is included in both the LRIT and the HRIT transmissions, however, only HRIT provides the full set of data. The LRIT transmissions include image data from other geostationary satellites including the US satellites, GOES- E and GOES-W over the western Atlantic and eastern Pacific, Japan s GMS satellite over the western Pacific and the Russian GOMS satellite over the Indian Ocean. The LRIT transmission also delivers Meteorological Products from EUM TD 07 - Issue 1.1, 25 May 2001 Page 7

14 EUMETSAT and National Meteorological Services, Data Collection Reports, and administrative messages. In order to receive image data disseminated via MSG users must be equipped with suitable High Rate User Stations (HRUS) or Low Rate User Stations (LRUS) depending on their need. The capability to receive the complete set of disseminated may be achieved by using an HRUS with a built-in capability to receive the LRIT stream in addition to the HRIT stream. Generally MSG data will be encrypted so users will have to acquire decryption units from EUMETSAT in order to process the received data. For each user requesting one of these units an agreement will be concluded reflecting the user s requirements and in line with the EUMETSAT Data Policy (see Annex II). A detailed description of this service may be found in the publication EUM TD 08 Image Data and Product Dissemination Service. Further information can also be obtained by contacting the EUMETSAT User Support Service Helpdesk see section for details. In addition to the direct dissemination via satellite an MSG Internet image dissemination Service is planned which will provide some of the services formerly available to users from the WEFAX broadcast in MTP operations. Further information about the content of this service and conditions of access may be obtained from the EUMETSAT Web site Data Collection and Retransmission Service Data Collection Platforms (DCP) are automatic or semi-automatic environmental observing systems. Typical examples are automatic weather stations located at remote sites, automatic river or tide gauges, instrumented aircraft, ships, balloons or buoys. They transmit their environmental data to the MSG satellite, which relays the information to the Primary Ground Station (PGS). The Meteosat Second Generation system continues the support services for the collection and relay of Data Collection Platform Messages established with the first generation of Meteosat satellites. As a baseline, all basic operating characteristics will generally remain unchanged, however, there is a significant increase in the capacity of the MSG Data Collection System. DCP data will be retransmitted via the LRIT dissemination service, via the GTS and also made available via an Internet-based service. DCP operators wishing to have access to the Data Collection and Retransmission Service should communicate their requirements to EUMETSAT using the User Support Service Helpdesk as their initial point of contact (see section 3.7.2). Further detailed information about the service may be found in the publication EUM TD 09 Data Collection and Retransmission Service. Page 8 EUM TD 07 - Issue 1.1, 25 May 2001

15 3.3. Meteorological Data Dissemination Service The MDD Service operating under the MTP will have a similar equivalent in MSG Operations. The MDD data will be included in the LRIT data stream, thus ending the requirement for a separate user station for the reception of MDD data. The alphanumeric MDD messages are mainly meteorological reports in conventional numeric codes that are suitable for human interpretation but can also be used within computer systems. The binary MDD data are bit-level transmissions for use within user computer systems to generate charts; the pictorial MDD products are mainly charts for direct human interpretation. The MDD data relay is considered as a space-based extension of the Global Telecommunication System (GTS) of the WMO. Therefore access to these data follows the same conditions as for the conventional GTS systems, namely access rights are usually only granted to National Meteorological Services. This control is achieved through the means of encryption. Access to the MDD Service is controlled by the EUMETSAT User Support Service. Further detailed information about the service may be found in the publication EUM TD 10 Meteorological Data Dissemination Service Meteorological Product Extraction and Distribution Service The MSG system supports the derivation from imagery of meteorological and climatological products and their subsequent dissemination to users. This is accomplished within the Meteorological Products Extraction Facility (MPEF), located within the Mission Control Centre (MCC) in the EUMETSAT headquarters. The MPEF has been designed to allow new products to be added when user requirements have been determined and algorithm development is completed. Products are also generated at the Satellite Application Facilities (SAF), and other user facilities. The products are distributed to users via the GTS (restricted user community) and a subset of products also via the LRIT dissemination service (see section 3.1). In addition all products are archived and may be requested by users of the Archived Data Retrieval Service (see section 3.5). A detailed description of the products available may be found in the publication EUM TD 11 Meteorological Product Extraction and Distribution Service as well as on the EUMETSAT Web site Archived Data and Retrieval Service The EUMETSAT data archive is located at the EUMETSAT headquarters in Darmstadt, Germany, and is embodied in the Unified Meteorological Archive and EUM TD 07 - Issue 1.1, 25 May 2001 Page 9

16 Retrieval Facility (U-MARF). Its objective is to maintain a permanent archive containing all the imagery from the first and second generation Meteosat satellites as well as from the future EUMETSAT Polar System (EPS). In addition to the imagery, the archive stores all supporting information and centrally produced meteorological and climatological products, as well as the SAF product catalogue. The U-MARF has been designed to supersede the MARF, which was established to support the first generation satellites and has been in operation since The U-MARF will be available for user access at the start of MSG services in The U-MARF uses new technology to manage the increase in data volume from the MSG satellites and significantly enhances the services for data access available to users. A detailed description of the U-MARF and its products and services may be found in the publication EUM TD 12 Archived Data Retrieval Service. In addition, the following dedicated User Support Service Helpdesk point-of-contact exists for all enquires related to access to archived data: archive@eumetsat.de Geostationary Earth Radiation Budget Service The MSG system has been designed to support additional or research missions. ESA has, as a result of an Announcement of Opportunity, selected the Geostationary Earth Radiation Budget (GERB) instrument for flight on the MSG-1 satellite. The GERB instrument is being developed by a European consortium led by the Rutherford Appleton Laboratory (RAL), United Kingdom, under a co-operation between the UK, Italy and Belgium. The EUMETSAT Council decided in November 1998 to fund the flight of two additional GERB instruments on MSG-2 and MSG-3. The principle objective of the GERB mission is to measure the Earth radiation budget, in support of climate research and monitoring. A GERB International Science Team (GIST) has been established and tasked to define the science requirements, products and processing algorithms, and to implement science and validation activities. The GERB system comprises the GERB instrument and a de-centralised GERB ground segment. The GERB instrument is a scanning radiometer with two broadband channels, one covering the solar spectrum, the other covering the entire electromagnetic spectrum. Data will be calibrated on board in order to support the retrieval of radiative fluxes of reflected solar radiation and emitted thermal radiation at the top of the atmosphere with an accuracy of 1%. The GERB data are received at the EUMETSAT ground segment and passed on to the GERB ground segment for data processing. The data and products are then distributed by RAL. Page 10 EUM TD 07 - Issue 1.1, 25 May 2001

17 The GERB instruments, as part of the satellite, will be operated by EUMETSAT in co-ordination with the GERB specialists. Further details regarding access to the GERB service may be found on the EUMETSAT web site and, as always, enquiries may also be submitted to the User Support Service Helpdesk (see section 3.7.2) User Support Service The EUMETSAT User Support Service has been established to meet the growing demand for information from the users of EUMETSAT satellite data. This Service has key roles providing an effective interface to the services and a helpdesk facility for the user community, exchanging information with other satellite operators and providing key contact information for the various satellite services (e.g. image dissemination, DCP and MPEF products). In addition the User Support Service is providing the resources and information necessary to help the transition of many thousands of users of data from the Meteosat Transition Programme to the future satellite systems (MSG and EPS) and to coordinate and promote user training activities. Over the years, experience has shown that within the complex environment of the Meteosat Programme a considerable number and a wide variety of users needs have to be fulfilled. This requires a mechanism for effectively gathering and channelling requests of great variety from the user community as a whole and to satisfactorily respond to such requests within an acceptable time frame. The user community is, in fact, composed of many different user groups with differing needs (e.g. meteorologists, researchers, environmental services, educational establishments, press, media and many others). User enquiries might relate to reports of anomalous behaviour of the satellite or its services, more general observations about the system, requests for ancillary information, requests for access to the operational services and the provision of user documentation Operational Information Operational information is distributed to users in a variety of ways. The primary source of information is via the EUMETSAT web site. Administrative messages are also transmitted within the MSG LRIT and HRIT services to inform users about special operations or possible breaks in service, giving as much notice as possible. In addition, users will, from time to time, receive newsletters that give up-to-date information about the system and include the latest dissemination baseline. EUM TD 07 - Issue 1.1, 25 May 2001 Page 11

18 User Service Helpdesk The Helpdesk facility is open to all users to submit their enquiries concerning any EUMETSAT product or service. The Helpdesk staff is committed to responding to user enquiries within 3 working days wherever possible and, when internal investigations are involved, to fully respond within a maximum of 15 working days (with an interim response supplied within 3 working days). Alternative points of contact are provided (see below) for enquiries related to the Archived Data Retrieval Service. The accumulation of the many and varied user enquiries processed over several years of operations has resulted in the establishment of Frequently Asked Questions (FAQs) and a comprehensive list of these will be maintained on the EUMETSAT Web site. The points of contact for the Helpdesk are: Mail: EUMETSAT User Service Am Kavalleriesand 31 D Darmstadt Germany Telephone: +49 (0) or 377 Fax: +49 (0) or ops@eumetsat.de archive@eumetsat.de (general enquiries) (archive related enquiries) EUMETSAT Web Site: Page 12 EUM TD 07 - Issue 1.1, 25 May 2001

19 4. MSG System Description Figure 4.1 Illustration of the MSG System The Meteosat Second Generation System provides a comprehensive set of products and services involving the dissemination of information via the satellite and by other means. The MSG system consists of a space segment and a ground segment. It is designed to provide products and services over a lifetime of at least 12 years, based on a series of three satellites called MSG-1, -2 and -3. The MSG system will perform regular operations with one satellite at the nominal location at 0º degrees longitude over the equator, and foresees a stand-by satellite that would be used in case of emergencies or during major configuration changes MSG Space Segment The MSG Satellite The Meteosat Second Generation satellites have been designed to take advantage of new technology and to improve on the already successful and proven design of the original Meteosat satellites. The SEVIRI radiometer on- EUM TD 07 - Issue 1.1, 25 May 2001 Page 13

20 board the MSG satellite has a total of 12 channels that generate images by scanning the Earth every 15 minutes. The High Resolution Visible channel provides data at 1km sampling, the other channels sample at 3km. In addition to the main SEVIRI payload the satellite carries an instrument for the measurement of terrestrial radiation (GERB), telecommunications equipment for the dissemination of processed imagery and products, as well as components for the reception and relay of distress messages for search and rescue (GEOSAR). The Meteosat Second Generation Satellite is shown in an exploded view in Figure 4.3. The satellite is basically cylindrical with an overall size of 3.7 m in diameter and 2.4 m in height. The MSG spacecraft is composed of three main sections. The top section contains the mission communications payload including the antennas and transponders required for satellite monitoring and control, down-linking the raw data from the SEVIRI radiometer and GERB instrument, relay of DCP data, dissemination of LRIT and HRIT information, as well as the relay of distress signals. The middle section contains the SEVIRI instrument and it s associated electronics. The bottom section contains the satellite propulsion systems and components for the orbit and attitude control. Figure 4.2 Exploded view of the MSG Satellite Page 14 EUM TD 07 - Issue 1.1, 25 May 2001

21 The surface of the satellite is covered with solar cells that provide the electrical power for operating the satellite, although two rechargeable batteries are also available and are used during eclipse periods and for peak power demands. In orbit, viewed from above, the satellite spins at 100 rpm in a counter-clockwise direction around its main axis, which is aligned nearly parallel to the Earth's north-south axis. The spin is required to both stabilise the satellite and to assist in the scanning of the Earth by the SEVIRI radiometer The SEVIRI Radiometer The SEVIRI radiometer is the principal payload of the satellite. It provides the basic data of the Meteosat Second Generation system, namely 12 channels spanning the visible and infrared parts of the electromagnetic spectrum somewhat similar to those of the AVHRR instrument flown on the US NOAA satellites in polar orbits. There is one high resolution channel, imaging in the visible region of the spectrum, which can be used to support nowcasting and very short-range forecasting applications. There are also seven multi-spectral imaging channels providing, amongst other information, data about the temperatures of clouds, land and sea surfaces. Figure 4.3 Illustration of the SEVIRI instrument EUM TD 07 - Issue 1.1, 25 May 2001 Page 15

22 Scanning Concept A series of mirrors within the radiometer direct the radiation originating from the Earth surface, its atmosphere and cloud systems, received via an opening in the side of the satellite, onto an array of detectors. Readings are taken from the detectors approximately every 24 microseconds as the satellite spins, so that the spin is used to scan the earth in the East-West direction. After every scan line a mirror is stepped in the South-North direction in order to acquire subsequent scan lines. One complete revolution of the satellite lasts 0.6 seconds, of which only about 30 milliseconds are available over the Earth disk to acquire one scan. For each scan step several image lines are acquired (3 lines for nominal channels and 9 lines for the high resolution visible channel). Figure 4.4 Image acquisition by the SEVIRI radiometer The remaining 570 milliseconds are used mainly for scan mirror stepping, data transmission and measurements directed at deep space, used for removal of noise from the data. The nominal repeat cycle for a complete scan of the full Earth disk is 15 minutes, this includes measurement of on-board calibration sources and scan mirror retrace. The satellite can obtain shorter repeat cycles if a reduced area of the Earth is imaged. The nominal image size for all channels (Level 1.5 image) except for the High Resolution Visible (HRV) is 3712 by 3712 pixels (N-S by E-W), the sampling distance is defined to be exactly 3km by 3km at the sub-satellite point. For the HRV channel the image size is by 5568 pixels (N-S by E-W), the sampling distance defined to be exactly 1km by 1km at the sub-satellite point. Page 16 EUM TD 07 - Issue 1.1, 25 May 2001

23 Figure 4.5 HRV Detectors / IR & VNIR Detectors Pixel Acquisition The scans of data are taken at constant angular steps, and this together with the natural curvature of the earth means that as the satellite scans away from the sub-satellite point the area covered by the pixels is greater than that at the subsatellite point. This is illustrated for the multi-spectral channels in Figure 4.6 where the respective sizes of pixels are illustrated as a function of their position on the Earth. Figure 4.6 SEVIRI multi-spectral image ground resolution (equivalent surface). The bands show the decrease in pixel resolution away from the sub-satellite point. 3.1km pixel resolution (inner circle), 4km, 5km, 6km, 8km and 11km (outer band) EUM TD 07 - Issue 1.1, 25 May 2001 Page 17

24 4.2. The MSG Ground Segment The Meteosat Second Generation system has a dedicated ground segment, designed to support all MSG missions and operations over 12 years. The MSG Ground Segment is composed of: a set of central facilities located at EUMETSAT Headquarters in Darmstadt, Germany, forming the MSG Mission Control Centre (MCC); a Primary Ground Station (PGS), located in Usingen, Germany, hosting also the Back-up Satellite Control Centre (BSCC) and providing the primary interface between the satellite and the MCC, including all ranging functions and communications lines; a Back-up and Ranging Ground Station (BRGS), located in Maspalomas, Gran Canaria, Spain; Foreign Satellite Data Support (FSDS), located at Météo-France CMC Lannion. an Application Ground Segment, which extracts meteorological and geophysical products from the calibrated and geolocated image data generated by the MCC. The Applications Ground Segment is composed of the Meteorological Product Extraction Facility (MPEF) and the Unified Meteorological Archive and Retrieval Facility (U-MARF), both located at EUMETSAT Headquarters, as well as a distributed network of Satellite Application Facilities (SAF). EUMETSAT Overall Ground Infrastructure EUMETSAT HQ Central Facilities Acquisition and Control Station Back-up or Support Station Satellite Application Facility host site Lisboa Madrid FSDS Lannion Bracknell MDD-FDRS Toulouse MDD Usingen MSG PGS Roma MDD Copenhagen Offenbach EUMETSAT HQ Darmstadt MCC + MPEF Weilheim Meteosat BGS Fucino Meteosat PGS Helsinki Madrid (E) : Suppport tonowcasting and very Short Term Forecasting Lannion (F) : Ocean and Sea Ice Helsinki (FIN) : Ozone Monitoring Offenbach (D) : Climate Monitoring Bracknell (UK) : Numerical Weather Prediction Copenhagen (DK) : GRAS Meteorology Lisboa (P): Land Surface Analysis PGS Primary Ground Station MDD Meteorlogical Data Distribution BRGS Back-up and Ranging Station FSDS Foreign Satellite Data Support CDA Command and Data Acquisition MCC Mission Control Centre MPEF Met. Product Extraction Facility Canary Island MSG BRGS Figure 4.7 EUMETSAT Overall Ground Infrastructure Page 18 EUM TD 07 - Issue 1.1, 25 May 2001

25 The Mission Control Centre The Mission Control Centre (MCC) is the prime operations centre and is responsible for the monitoring and control of the main components of the MSG system, including the spacecraft, the telecommunication elements and most of the ground segment. It is located in the Operations wing of the EUMETSAT headquarters building in Darmstadt, Germany. The MCC is thus the core of the Meteosat ground segment. Dedicated communications links connect it to the Primary Ground Station. The MCC itself is composed of a number of facilities The Central Facility The Central Facility of the Mission Control Centre provides the essential control infrastructure for the satellite and the ground segment. This includes the planning, scheduling and execution of activities and the centralised monitoring and control of all components. The facility is highly automated in several areas to ease daily operations. The facility is responsible for the central configuration and control of software and databases that operate in the MCC. It is also responsible for local archiving and providing the means for the analysis of operational data (e.g. monitoring or housekeeping data from the ground segment and the satellite). The basis for all activity within the system is the operations plan. This governs the routine cycle of operations and is monitored using Central Facility consoles. Routine spacecraft commands are stored in the computer system and transmitted automatically in accordance with a pre-defined schedule. Nonroutine commands are transmitted in accordance with pre-defined procedures. The transmission of the command sequences and the telemetry from the spacecraft are all displayed on the consoles. Many hundreds of parameters are monitored for each spacecraft. The configuration of the spacecraft and the ground segment can also be shown on the consoles, with displays showing which of the redundant components are in active use and which are available in stand-by mode. The system permits reconfiguration of both the spacecraft and the ground station under software control from the consoles. This includes the facility for remote operation and control of the Primary Ground Station and the Back-up ground station Image Processing Facility Raw images are received from the Primary Ground Station and processed lineby-line in the Image Processing Facility (IMPF) to generate Level 1.5 image data. Re-sampling realigns the data from the various on-board sensors so that the image from each set of detectors coincides with the other images. At the same EUM TD 07 - Issue 1.1, 25 May 2001 Page 19

26 time, the sampling removes any slight perturbations caused by the movement of the spacecraft, thereby rectifying the image so that it appears to come from the nominal location of the spacecraft. The data are then adjusted according to certain calibration information. The IMPF is also responsible for the automatic radiometric and geometric quality assessment of the data. The image is passed in segments from the IMPF to the dissemination facility for immediate relay to users, to the Meteorological Product Extraction Facility (MPEF) for further processing and to the U-MARF for archiving Data Acquisition and Dissemination Facility The Data Acquisition and Dissemination Facility (DADF) collects together the various types of data required for dissemination through the satellite via the Low Rate Information Transmission (LRIT) and High Rate Information Transmission (HRIT) services. This includes the pre-processed imagery from the IMPF, meteorological products from the MPEF, DCP data, and foreign satellite data from the Support Ground Segment. The data are formatted and prioritised for transmission. Depending on the type of data the formatting may include compression and encryption. The facility also contains four user-monitoring stations for the reception of all LRIT and HRIT data transmissions from the satellites. These stations are used to implement a full end-to-end monitoring of the performance of the dissemination. Thus the system operators can, at any stage, be alerted to any problem in the complete system and take immediate action to rectify the situation. The Data Collection messages are also monitored within the DADF. Messages from DCPs are received in the Primary Ground Station from the Meteosat Second Generation satellite and transmitted immediately to the MCC in Darmstadt. There they are compared with the master list of expected DCP reports and processed and distributed as appropriate. This operation is performed entirely automatically Primary Ground Station The MSG Primary Ground Station (PGS) is located in Usingen, Germany. It is a facility fully owned by EUMETSAT, within a commercially operated site approximately 30 km north of Frankfurt. The PGS serves as the main channel of communications with the MSG satellites and is an essential component of the overall system. The prime transmission channel between the MCC and the PGS is a 34 Mbit Microwave link with a terrestrial based back-up link. These links support all the traffic to and from the PGS including image data, TT&C and disseminated data. Page 20 EUM TD 07 - Issue 1.1, 25 May 2001

27 To reliably accomplish these vital tasks a considerable amount of redundancy is incorporated in the station design which, to a great extent, can function completely automatically. Two fully steerable 13-metre diameter parabolic antennas are located at the PGS and used exclusively to support all communications with MSG. Each antenna is capable of supporting all the transmissions and data reception required for one spacecraft and is used for telemetry and telecommands, raw image reception, DCP report collection, LRIT and HRIT dissemination. Figure 4.8 A MSG 13 metre antenna at the PGS at Usingen, Germany. The control of the PGS is actually executed by a local monitoring and control system located in Usingen and interacting with the MCC in Darmstadt. The PGS can operate in two different modes: remotely, under the control of the MCC, or through the use of the local system consoles. This flexibility ensures maximum reliability in case of problems. EUM TD 07 - Issue 1.1, 25 May 2001 Page 21

28 Back-up Satellite Control Centre Also located at the PGS is a Back-up Satellite Control Centre (BSCC). This is established as a functional extension of the MCC in Darmstadt so that in an extreme emergency it could be used in a stand-alone mode to monitor and control the spacecraft and the PGS, as well as to perform all essential flight activities. It is not designed to support the user services but does ensure the safety of the spacecraft until any problem is solved Back-up and Ranging Ground Station The Back-up and Ranging Ground Station (BRGS) is located in Maspalomas, Gran Canaria, Spain. This location is sufficiently separated from the PGS to allow accurate ranging measurements to be made to determine the precise location and orbit of the MSG satellites. The BRGS also provides TT&C support to the Ground System so that in the unlikely event of a complete system failure at the PGS it would still be possible to safeguard the spacecraft in orbit. However, in this scenario mission control and user services would not be operable Foreign Satellite Data Support The satellite ground station facilities owned and operated by the French meteorological service in Lannion have been associated with the Meteosat system since the start of operations in EUMETSAT provides and maintains facilities at Lannion for the relay of image data from additional satellites, to complement the Meteosat images transmitted from the PGS. The primary requirement is to relay images covering the western part of the Atlantic and the Americas. These images are obtained from GOES-E, GOES-W, GOMS and GMS. MSG will continue to carry that mission through its data dissemination and aims at an expansion of the current service to meet the requirement of the Global Observing System (GOS) to provide a near global data coverage several times a day Application Ground Segment Meteorological Products Extraction Facility The Meteorological Products Extraction Facility (MPEF) is co-located with the Mission Control Centre and comprises another network of dedicated workstations, which receive pre-processed images from the IMPF and process Page 22 EUM TD 07 - Issue 1.1, 25 May 2001

29 them, together with ancillary data, to extract quantitative meteorological and climatological products. The MPEF also is responsible for monitoring the quality of the products (by comparison with independent observations) and of image data calibration. Image display and analysis tools allow the operators to monitor the progress of the automatic processing of the image data Unified Meteorological Archive and Retrieval Facility The Unified Meteorological Archive and Retrieval Facility (U-MARF) is also colocated at the MCC. The U-MARF provides the users with a non-real time retrieval capability for all of the imagery and meteorological products owned by EUMETSAT. This includes the data from the Meteosat Operation Programme, Meteosat Transition Programme, Meteosat Second Generation and the future EUMETSAT Polar System. The U-MARF uses modern tape recording technology to store the data in a robotic archive system. The retrieval will be possible either via a Web-based on-line interface to the system or off-line via the Helpdesk facility. Retrieved data may also be shipped on-line (via the Internet) or off-line (using electronic media) Satellite Application Facilities A network of Satellite Application Facilities (SAFs) is included in the MSG Ground Segment. These SAFs are under the overall co-ordination of EUMETSAT and have the remit to develop and deliver products (or software to derive products), extracting geophysical parameters primarily from MSG and EPS satellite data. The SAFs are generally located in National Meteorological Services or other approved institutes of a EUMETSAT Member State. By utilising the specialised expertise of the Member States the SAFs complement the production of standard meteorological products derived from satellite data at EUMETSAT s MCC. This will promote and ensure the optimum use of data from the MSG and EPS systems in their application domain. Seven SAFs have been approved and are under development. Each SAF concentrates on a different theme. Details of each SAF are outlined in the following text. Further information can be found by contact the SAFs through their web sites (URL provided at the end of each section). Information about SAF products is included in the U-MARF catalogue. Access to the products in non-real-time is supported by the U-MARF user interface. EUM TD 07 - Issue 1.1, 25 May 2001 Page 23

30 Support of Nowcasting and Very Short Range Forecasting SAF Nowcasting and very short range forecasting combine the continuous monitoring of meteorological conditions on a horizontal scale of tens to hundreds of kilometres, with the prediction of their development over the next two or three hours. This includes the monitoring of short-lived, but disruptive weather phenomena such as severe thunderstorms or fog. Under the leadership of the Spanish Meteorological Institute (INM), the NWC SAF is developed by a project team involving Météo-France and the Swedish and Austrian Meteorological Institutes. The list of products developed by the NWC SAF is as follows: Cloud mask and cloud amount Cloud type (including fog) Cloud top temperature / height Precipitating clouds Convective rainfall rate Total precipitable water Layer precipitable water Stability analysis imagery High resolution wind vectors from HRVIS Automatic satellite image interpretation Rapidly developing thunderstorms Air mass analysis The NWC SAF Web pages are located at: Ocean and Sea Ice SAF The Ocean and Sea Ice (OSI) SAF was established to develop a range of products relating to oceans and sea ice, using satellite data as the primary input. These products will provide information for a diverse set of users, including those in numerical weather prediction, climate monitoring, transport, the fishing industry, ecology, pollution monitoring, coastal engineering and the offshore oil and gas industry. Page 24 EUM TD 07 - Issue 1.1, 25 May 2001

31 The SAF is developed by a consortium, led by Météo-France, and involving the Meteorological Institutes from Norway, Denmark, Sweden and the Netherlands, as well as the French institute for Oceanography. The main objective of the OSI SAF will be the routine production and archive of a coherent set of information characterising the ocean surface and energy fluxes through it. Three scales of application will be considered: Atlantic Ocean and adjacent coastlines Regional (north-east and European seas) Polar seas The products to be produced by the OSI SAF include: Surface wind vectors (global) Atlantic sea surface temperatures Atlantic surface radiative fluxes Regional sea surface temperature Atlantic sea ice edge Atlantic sea ice cover Atlantic sea ice type The OSI SAF Web pages are located at: Ozone Monitoring SAF The Ozone monitoring (O3M) SAF has been developed to process data on ozone distribution, other trace gases, aerosols and ultraviolet data. The severe loss of stratospheric ozone in the high latitudes of the Northern Hemisphere and over the Antarctic and the subsequent increase of harmful ultraviolet radiation has been well established in various measurements. Ozone data are also important for climate research and as input to numerical weather prediction. Trace gas measurements are important for monitoring the long-term effects of, for example, freons and halons on the ozone layer. The O3M SAF involves nine institutes from seven countries (Finland, Netherlands, Germany, Greece, Denmark, France, and Belgium) and is led by the Finnish Meteorological Institute (FMI). The O3M SAF is responsible for research and development in radiative transfer calculation methods and other algorithms for obtaining ozone products from EUM TD 07 - Issue 1.1, 25 May 2001 Page 25

32 satellite data. Data from the EPS mission (GOME-2 instrument) will be the main input data for this SAF. The SAF will provide data for ultraviolet fields under real atmospheric conditions, total ozone, ozone profiles, aerosols and total amounts of chemically important gases such as: nitrogen dioxide, chlorine dioxide, bromine oxide, as well as stratospheric aerosols. The O3M SAF Web pages are located at: Climate Monitoring SAF The CLM SAF for climate monitoring has been established to generate and archive high quality data sets from satellite observations, essential for the monitoring of the global climate. These data sets will assist in the analysis and diagnosis of climate parameters to identify and understand changes in the climate system. The CLM SAF involves ten institutes from five countries: Belgium, Finland, The Netherlands, Sweden and Germany. The German Meteorological Institute (DWD) leads the project team. The deliverables of the SAF will be: Cloud data: fractional cloud cover, cloud classification, cloud top temperatures and height, cloud phase, optical thickness and cloud water path Components of the surface radiation budget: solar surface irradiance and albedo as core products Components of the radiation budget at the top of the atmosphere Homogeneous data sets of SST and sea ice cover Water Vapour layer information The CLM SAF Web pages are located at: Numerical Weather Prediction SAF Numerical Weather Prediction (NWP) involves the use of powerful computers to model the atmosphere and compute forecasts extending from a few hours up to ten days. NWP is a central facility of the National Meteorological Services, crucial to the quality of their forecasting services. Observational data are the basis of NWP, and satellite information is an important element. Page 26 EUM TD 07 - Issue 1.1, 25 May 2001

33 The NWP SAF consortium is led by the Meteorological Office (UK) and involves the National Meteorological Services from France and the Netherlands, as well as, the European Centre for Medium Range Weather Forecasts (ECMWF). The SAF will concentrate on developing techniques for more effective use of satellite data in NWP, in particular, exploiting the data and derived products from new satellite systems. This will involve the retrieval of geophysical parameters for integration as pseudo-observations by NWP. It will define the most effective interface between satellite data and NWP data assimilation systems. This will lead eventually to improved estimates of temperature, humidity, wind (both surface and upper air) and ozone. Concerning data from MSG, the SAF will work on improved observation operators for satellite winds, including radiative transfer models required for direct assimilation of time sequences of radiances from geostationary imagery. The NWP SAF Web pages are located at: Land Surface Analysis SAF Information about the land surface is essential for Numerical Weather Prediction, monitoring of the environment and climate change, agriculture and forestry. Many human activities benefit from increased information about the land surface. Examples are the monitoring and prediction of drought, crop yields and quality, forests and the mapping of vegetation. The LSA SAF involves thirteen institutes from eight countries (Portugal, France, Germany, Greece, Italy, Spain, Sweden, and Belgium) and is led by the Portuguese Meteorological Institute (IM). The LSA SAF will concentrate on developing techniques for deriving land surface parameters and radiation surface fluxes over the continents from the data provided by EUMETSAT s satellites. The land surface data will benefit other SAFs in addition to National Meteorological Services, and government and international agencies concerned with agriculture and forestry. The LSA SAF will produce the following products: Surface albedo Aerosols Scattered radiance field Down-welling surface short wave and long wave radiation fluxes EUM TD 07 - Issue 1.1, 25 May 2001 Page 27

34 Land surface temperature Soil moisture Snow cover and mapping Evapotranspiration rate Vegetation parameters (Normalised Differential Vegetation Index (NDVI), Fraction of Green Vegetation (FGV), fraction of Photosynthetic Radiation (fpar) and Leaf Area Index (LAI)) The LSA SAF Web pages are located at: Page 28 EUM TD 07 - Issue 1.1, 25 May 2001

35 5. Annex I Comparison between MTP and MSG The Meteosat Second Generation system will continue to provide the operational services required by National Meteorological Services and other users that were established with the so-called MOP and MTP satellite series. However, due to more demanding user requirements and improvements in technology there have been changes in the implementation of these services. It is important for existing users of the MTP system to understand the differences Image Data Generation The image rectification and dissemination service of the Meteosat Second Generation satellite significantly improves on the capabilities of the MTP. The radiometer on-board the MSG satellite has a total of 12 imaging channels instead of the three on the original Meteosat satellites. Images are generated every 15 minutes instead of every 30 minutes. The sampling distance of the infrared channels (at the sub-satellite point) is improved to 3km compared with 4.5km, while the new High Resolution Visible channel provides 1km instead of the previous 2.25km sampling distance. Figure 5.1 A side-by-side comparison of the Meteosat First and Second Generation satellites The MSG satellite is again spin-stabilised, rotating at 100 Revolutions Per Minute (RPM), and with an increased body weight of 2000kg in GTO orbit compared to the 720kg of the previous Meteosat satellites. The MSG satellite has a power demand three times that of the previous Meteosat satellites, 600Watts compared to 200Watts. In spite of this, the MSG satellite has been designed with a station- EUM TD 07 - Issue 1.1, 25 May 2001 Page 29