With Meteosat Third Generation (MTG) the user community can look forward to continued visible observations from geostationary orbit, as well as the use of observations from infrared and ultraviolet/visible sounding instruments. In addition to improved imagery at 10-minute full disc repeat cycles, the provision of data from the MTG infrared and ultraviolet/visible sounding missions will be crucial for the derivation of quantitative products in future.
The EUMETSAT Application Ground Segment will be upgraded to accommodate the future processing requirements of MTG imager and sounder data. The Satellite Application Facility (SAF) enhancements are being considered in the current planning for phase two of the SAF Continuous Development and Operations Phase (CDOP-2). Likewise, the Central Facility will be upgraded in the coming years to accommodate the central processing of MTG data.
The measurements derived from the Flexible Combined Imager (FCI) will provide improved meteorological information about the rapid processes of the atmospheric water cycle. Operational meteorologists expect that this new advanced information, delivered by FCI, will beneficially support Nowcasting, as well as regional numerical modelling activities, resulting in improved severe weather forecasts and early warnings. The additional channels within the solar domain will surpass current aerosol retrievals, including volcanic ash, thereby providing an important contribution to future air quality monitoring. The increased spatial resolution and range of channels will offer improved fire detection products and an increase in the quality of climate relevant products, such as fire radiative energy and power, which are directly related to carbon dioxide production.
Infrared Sounder Service
The new geostationary sounder service is based upon requests from the Numerical Weather Prediction (NWP) community to deliver spectral information and/or retrieved products as horizontal and vertical gradients of humidity and temperature. The deduced information on atmospheric dynamics (e.g. vertically resolved ~2 km Atmospheric Motion Vectors (AMVs) surpassing present height assignment) will be invaluable to numerical models used in operational forecasting in the future. In particular, a breakthrough regarding a better precipitation forecast is expected by using this new information within these advanced models, coupled with advanced data assimilation capabilities.
Making available 3-dimensional information on humidity, temperature, and wind will support Nowcasting applications, particularly in situations of water vapour convergence and convective instability, giving improved warnings on location and intensity of convective storms. In addition, the MTG-IRS is expected to provide information on ozone, carbon monoxide and volcanic ash compositions within the atmosphere.
The user community has already identified the crucial role of infrared instruments for future volcanic-ash monitoring. At an expert workshop addressing future opportunities for volcanic ash detection, following the eruption of Iceland’s Eyjafjälla volcano in April 2010, Fred Prata, Senior Scientist for Atmosphere and Climate Change at the Norwegian Institute for Air Research, stated:
“Satellite data are extremely important for volcanic eruptions because these events can occur anywhere at any time, so you need a measurement system that can see the entire globe, all of the time. Infrared instruments are absolutely vital. Firstly, infrared does not require sunlight, so we can see volcanic emissions equally well day or night. Secondly, and perhaps most importantly, the infrared radiation that we use is in a band between eight and twelve micrometers, and it turns out that the particles that cause problems for aviation are micron sized — so they look in just the right wavelength region.”
The improved MTG capabilities of the imagery mission will provide further details on the extent of the ash plume, whereas the capabilities of the MTG sounding mission will be essential for the derivation of quantitative products with additional information on the composition and density of the ash cloud.
Ultraviolet Sounder Service
The Sentinel 4 mission is one component of the joint GMES Sentinel 4 and 5 concept for climate protocol monitoring (lower troposphere) and air quality applications. The primary objective of the Sentinel 4 mission is to support air quality monitoring, and forecast over Europe with a high revisit time (~1 hour or better). The primary data products will be ozone, nitrogen dioxide, sulphur dioxide, formaldehyde and aerosol optical depth.
In support of services like air traffic routing and safety, it is expected that the Lightning service will combine complementary information on total lightning, measured by the Lightning Image (LI), and the global distribution of cloud-to-ground lightning, measured by the surface based Arrival Time Difference network (ATDnet). This combination should greatly improve the quality of information essential for air flight safety.
Each lightning stroke initiated by an electrical discharge in, or below, clouds, causes radiation in the visible spectrum, via the photons which are emitted from the hot lightning channel. The pulse width in time of such a stroke is about 50 µs and the photons released are scattered to the cloud top, delayed and visible as an optical pulse widened in time and space. These optical pulses at cloud tops do have durations of about 600 µs and cover areas of about 10x10 km2. A flash itself consists of a series of such strokes; 11 on average, happening in time sequences of about 50 ms. Flash duration itself is around one second up to one and a half seconds. Lightning Imager on board MTG-I will measure at a wave-length of 777.4 nm, with a spatial resolution of 10 km continuously, triggered by a threshold — optical pulses initiated by strokes emitting energy of larger than 4-7 µJm-2sr-1. The information delivered to the users will be time, position and intensity of detected optical pulses.
Lightning observations will also be of benefit to climate monitoring. One approach to assess the impact of climate change on thunderstorm activity is to globally monitor and long-term analyse the lightning characteristics, which would require a long-term stable and spatially homogeneous lightning observing system.
Lightning is a major source of harmful nitrogen oxides (NOx) in the atmosphere. NOx does play a key role in the ozone conversion process and acid rain generation. A detailed knowledge of the global distribution of the total lightning (CG + IC) is a prerequisite for studying and monitoring the physical and chemical processes in the atmosphere regarding NOx.
Lightning observations from the geostationary orbit, delivered with spatially homogenous and well-characterised quality, are specifically suited to support these climate and atmospheric chemistry applications. The LI on MTG will compliment the NOAA Geostationary Lightning Mapper (GLM) placed on the GOES-R and the GOES-S satellites.
Data Collection and Retransmission
Following on from its predecessors, MTG will also provide a Data Collection and Retransmission service to collect and relay environmental data from automated data collection platforms. The requirements for the future service have been raised and consolidated with users and application experts at a Workshop on DCPs for MTG held on 26–27 May 2004.
Geostationary Search and Rescue (GEOSAR) relay
As with previous Meteosat satellite series, MTG will carry a small communications payload (GEOSAR) to relay distress signals of 406 MHz beacons to a central reception station in Europe, which passes the signals on for quick organisation of rescue activities. The geostationary relay allows a continuous monitoring of the earth disc and immediate alerting.
The MTG data and products generated within the EUMETSAT Application Ground Segment will be made available in near real-time through future evolutions of today’s delivery mechanisms like EUMETCast and the Global Telecommunication System (GTS). Some of the high data rate near-real-time dissemination may also be based on a terrestrial high-speed communication network. The offline and time series data and products will be available through the EUMETSAT Data Centre.
Future services will be described on these pages as the programme develops.