Capabilities of Earth observation satellites


A variety of instruments are flown on space missions, employing various measurement technologies and techniques – both active and passive sensing, utilising a wide range of the electromagnetic spectrum.

CEOS agencies are operating or planning around 170 satellites with an Earth observation mission over the next 15 years. These satellites will carry over 340 different instruments.

This sustained investment by the space agencies will ensure the provision of information of unique value in both public and commercial spheres, derived from the measurements being undertaken of a diverse range of geophysical parameters and phenomena.

Public awareness of the applications of Earth observation satellites tends to focus on meteorology, and the knowledge that data from meteorological satellites is used on a daily basis for the Numerical Weather Prediction models which drive our weather forecasting capabilities.
Meteorology is certainly one of the most established disciplines for application of Earth Observation satellite data, with satellite-derived information being used operationally by weather services world-wide. Dedicated meteorological satellites have been in operation providing continuous coverage of much of the globe for many years.

In reality, only 60, or around a third of the missions planned for the next 15 years, could be described as having meteorology as a primary objective. The other 110 missions will be applied to a diverse range of research, operational and commercial activities. Given the significance of the issues, and the unique role of satellite Earth observations, many will be dedicated to different aspects of climate or environmental studies. Others will be employed to assist decision-making in strategic planning and management of industrial, economic, and natural resources, including the provision of information required for sustainable development strategies.

Increased frequency of satellite measurements, improved satellite and sensor technology, and easier access and interpretation of Earth observation data have all contributed to increased demand for satellite data, and to the reality of new operational services being established in the near future for several domains, including monitoring of key oceanic and atmospheric parameters.

Information on the various missions and instruments, their capabilities and their applications is given in sections 8 (missions) and 9 (instruments).

For ease of discussion, the different instruments listed in section 9 may be considered under the following categories:

Instrument categories
Atmospheric chemistry instruments
Atmospheric temperature and humidity sounders
Cloud profile and rain radars
Earth radiation budget radiometers
High resolution optical imagers
Imaging multi-spectral radiometers (vis/IR)
Imaging multi-spectral radiometers (passive microwave)
Imaging microwave radars
Multiple direction/polarisation instruments
Ocean colour instruments
Radar altimeters
Gravity, magnetic field, and geodynamic instruments

Plans for future missions and instruments include entirely new types of measurement technology, such as hyper-spectral sensors, cloud radars, lidars, and polarimetric sensors providing new insights into key parameters of soil moisture and ocean salinity. Several new gravity field missions aimed at more precise determination of the marine geoid are also planned. Importantly, every effort is being made to assure continuity of existing key measurements – for the generation of long-term datasets. Agency plans also reveal that future priorities will include: disaster management, studies of key Earth System processes, including the water cycle, carbon cycle, cryosphere, and the role of clouds and aerosols in global climate change.

The following section gives a brief discussion of the different types of instruments which feature on Earth observation satellite missions, including: a list of the relevant instruments for each type from the full catalogue in section 9; a description of the operational characteristics; and pointers to the key applications. Information on specific measurement parameters is given in section 7.