Monitoring Weather and Climate from Space

Monitoring Weather and Climate from Space

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At a time when average global air temperatures are on the rise, ice and snow cover is disappearing fast and sea levels are rising, space-based solutions are needed to combat this change

Climate change is one of the greatest challenges facing mankind in the 21st century. To better understand this challenge and to be able to anticipate its future evolution requires reliable long-term information which only space-based observations by satellite can provide. This has been recognised by the United Nations Framework Convention on Climate Change (UNFCCC) and its subsidiary bodies.

An improved understanding of the earth system — of its weather, climate, oceans, land, natural resources, ecosystems, and natural and human-induced hazards — is essential to better predict and mitigate the expected global changes and their impacts on our civilisation.

artist-impression-of-EUMETSAT-Polar-System-Metop

An artist’s impression of EUMETSAT Polar System Metop

EUMETSAT, Europe’s meteorological satellite organisation, contributes to the global effort to meet the climate challenge. Its fleet of satellites already provides a wealth of environmental and climate data and products generated by EUMETSAT as well as its network of Satellite Application Facilities (SAFs) that are distributed rapidly to the global user community, 24 hours a day, 365 days a year. And equally importantly, the organisation possesses and reanalyses a unique archive of relevant long-term satellite data dating back to 1981, the year the second Meteosat weather satellite was launched. With this the organisation is in a position to generate Climate Data Records (CDR) covering more than 30 years of measurements.

EUMETSAT’s potential contribution to global climate monitoring was already recognised by its Member States in 2000, when they amended the organisation’s convention to affirm that its mandate is also “to contribute to the operational monitoring of the climate and the detection of global climatic changes.”

EUMETSAT does not pursue its goals in isolation but rather — together with other partners in the Coordination Group for Meteorological Satellites (CGMS), the Committee on Earth Observation Satellites and the World Meteorological Organization’s (WMO’s) space programme — is also spearheading the joint effort to define a comprehensive global design of a space-based climate monitoring system and resulting products.

Responding to global climate change
Two complementary approaches are being followed to respond to the challenges of climate change: mitigation and adaptation. Mitigation focuses on the reduction of greenhouse gases in order to reduce the rate magnitude of climate change. Adaptation, on the other hand, focuses on lessening the impact of climate change through appropriate planning measures, such as the introduction of coastal defences, general infrastructure and habitation planning. To support their respective decision processes, both the mitigation and adaptation approaches require access to reliable climate information that, in turn, relies heavily on the availability of sustained, homogeneous and high-quality earth observation data records. Earth observation data from space therefore play a crucial role in understanding the current state of the climate and how it may evolve.

The EUMETSAT contribution
EUMETSAT’s special capabilities in the area of long-term planning for future satellite programmes and their supporting ground structure provide a major contribution to future climate monitoring needs.

Given the immense nature of the global climate challenge, monitoring efforts will have to be increased in response. EUMETSAT is responsible for the planning, development and operation of operational European meteorological satellite systems. Taking into account the climate-specific requirements within these planning processes for future satellite programmes as well as their supporting ground structure — including the current and future activities of the SAF network — is indeed a unique responsibility of EUMETSAT. These tasks are a major contribution of EUMETSAT in support of climate monitoring as already reflected in the definition of the organisations’ forthcoming Meteosat Third Generation (MTG) and second generation EPS programmes.

Another major climate requirement concerns satellite sensors, where there is a need to ensure continuity of climate data records with similar, e.g., Meteosat imagery and advanced instruments such as the Infrared Atmospheric Sounding Interferometer (IASI)/ Advanced Microwave Sounding Unit (AMSU)-A and Microwave Humidity Sounder (MHS) combination that continues the traditional Advanced Television Infrared Observation Satellite (TIROS) Operational Vertical Sounder (ATOVS). Of high importance are the calibration of the sensors and a rigorous uncertainty characterisation including temporal stability of the measurements.

EUMETSAT activities related to climate monitoring, in particular, the generation of Climate Data Records (CDR) have evolved since 2010 in the context of an overall implementation plan that included the implementation of the second Continuous Development and Operations Phase (CDOP-2) of the SAF network. EUMETSAT and its SAF network have delivered several high quality CDRs at radiance and geophysical level that are used as input for weather prediction model-based reanalysis and climate analysis including climate model evaluation. In the near future these CDRs will also be delivered to the Copernicus Climate Change Service. The implementation plan foresees a sustainment of the activities which includes the preparation for an optimal use of MTG and EPS second generation data. EUMETSAT has also established close collaboration with European research institutions and universities in the field of climate research through participation in several EU-funded projects that for instance innovate the generation of CDRs, e.g., through new ways of uncertainty characterisation.

A further phase of implementation is expected to start after 2017, when the operational phase of new EUMETSAT mandatory programmes (MTG and second generation EPS) as well as the third CDOP of the SAF network begins. At this time, the objective is to have a portfolio of sustained climate-related activities in EUMETSAT with their corresponding funding arrangements.

An important component of EUMETSAT’s response to the global challenge of climate change will be to reinforce and further extend the dialogue with the end users of climate data. Recently, the 2014 Climate Symposium jointly organised by EUMETSAT and the World Climate Research Programme (WCRP) discussed how space-based observations could contribute to meet the requirements of the WCRP research Grand Challenges. This symposium also outlined observation requirements for the future development of an efficient and sustained international space-based Earth observing system, in line with the Global Architecture for Climate Monitoring from Space, developed under the auspices of CEOS, CGMS and WMO.

Existing EUMETSAT infrastructure
Meteosat satellites have been delivering climate-relevant measurements such as sea surface temperatures and surface albedo since 1981. EUMETSAT currently operates geostationary satellites of the Meteosat first and second generation. The second generation Meteosat satellites over the equator have much higher capabilities with temporal repeat cycles of 15 minutes and twelve spectral bands, compared to a 30 minute repeat cycle and only three spectral bands for the first generation Meteosat-satellites with the last one covering the Indian Ocean area.

A trio of storms captured by EUMETSAT satellites
A trio of storms captured by EUMETSAT satellites

Icelandic-fissures
Icelandic fissures

The newly designed instruments on board EUMETSAT’s Metop polar-orbiting satellites support climate monitoring and research activities through the continuation of observation series started in the late 1970s. Metop satellite-based measurements already provide a significant contribution to climate monitoring activities as they are used in the context of earlier research missions, e.g. the Advanced Scatterometer (ASCAT) continues earlier ERS Scatterometer (ESCAT) measurements and the Global Ozone Monitoring Experiment (GOME-2) continues GOME and Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) measurements that have started in the 1990s.

The Jason-2 Ocean Surface Topography Mission, launched in 2008, provides continuity in monitoring sea-level, a critical parameter of global climate change. Jason-2 and its follow-on satellites, starting with Jason-3, will continue the measurement of rising sea levels carried out by Jason-1 and TOPEX/Poseidon over the last 15 years.

Activities are already underway to ensure the future of climate-relevant satellite observations with Meteosat Third Generation (MTG) and the second generation EUMETSAT Polar System (EPS). EUMETSAT’s Application Ground Segment, which includes the organisation’s Central Application Facilities in Darmstadt and its network of Satellite Application Facilities (centres of expertise located in its Member States), continuously generates, on an operational basis, data and products of climate-relevant parameters which are stored by EUMETSAT’s Data Centre, dating back to 1981.

Global solutions though networks
The nature of climate change is such that no individual organisation or country has the capability and resources to fully respond to its challenges independently.

Monitoring global climate change is a priority on the political agenda and the issue is formally addressed through the UNFCCC, which in turn has placed responsibility for defining and specifying the requirements for observations relevant to climate change with GCOS.

GCOS was set up to ensure the availability of global climate observations for monitoring the climate system. It has identified a list of Essential Climate Variables (ECVs) that are feasible for implementation on a global scale and which are also highly relevant for the goals of the UNFCCC. GCOS has also published a plan that clearly defines the related satellite requirements as the need for global information on key indicators of climate change. This in turn implies that steps have to be taken to zharmonise and integrate the various observing systems in order to be able to provide the consistent information required.

In order to optimise its efforts within a global context, EUMETSAT coordinates its climate activities through the framework of the Committee on Earth Observation Satellites (CEOS) and of the Coordination Group for Meteorological Satellites (CGMS), whose climate-related activities generally focus on fulfilling the satellite requirements of GCOS.

In addition, EUMETSAT participates in a number of global and European initiatives to improve the generation of, and access to, timely and high-quality climate information: WMO’s Global Space-based Inter-Calibration System (GSICS) and Sustained Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM) initiative.

The overall objective of SCOPE-CM is the continuous and sustained provision of high-quality ECV CDRs on a global scale with GSICS providing the methodology to ensure that measurements from different satellite systems are inter-calibrated so that all the resulting products are comparable both at a global level and over the long time periods.