Global Observing System (GOS)
Programmes > WWW > GOS > Evolution > Vision for the GOS


The Vision for the Global Observing System (GOS) in 2025 was approved by EC-LXI (Geneva, 2009) and provides high-level goals to guide the evolution of the GOS in the coming decades.

The fifth Session of the Expert Team on the Evolution of the Global Observing System (ET-EGOS), Geneva, December 2009, has noted a couple of issues which should be considered by the Team and monitored, as well as other observing capabilities that might have been omitted in the Vision for the GOS in 2025. This web page provides for a simple mechanism of recording proposed additions to the Vision.

The following elements are proposed for addition in a future revised version of the Vision for the GOS:


Station type

Geophysical variables



Cloud Radars

Cloud structure (top, bottom), vertical velocities of cloud constituents, aerosol


Including surface-based cloud radar (as opposed to precipitation radars); and cloud/aerosol lidars satellite missions.

Note that the 2025 vision already includes Doppler wind lidar on LEO for measuring Wind, aerosol, and cloud-top height [and base]

ET-EGOS-5, para 6.2.5

Cloud Radars


In addition to Precipitation Radars that are well addressed, CBS has suggested to include Cloud Radars into the Operational pathfinders and technology demonstrators


CBS-XIV, 2009, Section 6.1.14 of the General summary


Clouds, aerosols

CBS suggested including Cloud and aerosol lidars in the Operational pathfinders and technology demonstrators. The Vision mentions Doppler lidar , which is too restrictive.

CBS-XIV, 2009, Section 6.1.14 of the General summary

Radio-occultation constellation

Temperature, humidity, electron density

The current Vision calls for at least 8 GNSS RO receivers; it would be more appropriate to specify a minimum number of occultations per day.


ET-SAT-7 Final report Section 6.3

Multi-angle, multi-polarization visible/infrared imagery

Albedo, aerosols

The current Vision only calls for an “IR dual angle view imager”; the potential of multi-angle and multi-polarization sensors should be recognized for proper monitoring of albedo and aerosols.

ET-SAT-7 Final report Section 6.3

Limb sounders for atmospheric composition

Stratospheric ozone and GHG

The current Vision only calls for “including high spectral resolution UV sounder on geostationary orbit and at least a UV sounder on am + pm orbit”. This does not provide a precise enough reference for planning. Distinction should at least be made between nadir and limb sounders. More detailed requirements should be expressed by the relevant scientific community,

ET-SAT-7 Final report Section 6.3

Geostationary constellation, maximum longitude separation

Many variables, including cloud products, atmospheric motion vectors, stability, lightning, etc.

The maximum separation of 70 degrees will not be achieved under current plans. Suggestion to consider 70 ° as a desirable target instead of a strict maximum, unless the 70 ° value can be justified by quantitative impact studies. Such justification is presently not available.

ET-SAT-7 Final report Section 6.3

Ocean acoustic tomography

Ocean temperature, Currents


ET-EGOS-5, para 6.2.5




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