It is vital for the space-based observing system to carefully manage the use of electromagnetic spectrum frequency allocations and to protect the frequency bands used for remote-sensing.
Specific objectives of these activities are:
- to prevent any artificial emission in those natural atmospheric radiation bands that are used for passive radiometry, in particular in the microwave region
- to secure the allocation of frequencies needed for active measurements, in particular in the microwave spectrum
- to secure the allocation of frequencies needed for safe spacecraft operations and data download, and prevent any interference among the various satellite systems comprising the space-based observing system
Frequency allocations are part of the International Radio Regulations that are developed and negotiated among national telecommunications authorities and eventually agreed at the World Radio Conference, which is organized on a regular basis by the International Telecommunications Union (ITU). Preparations for the World Radio Conference involve detailed studies and assessments by the various communities involved.
For the meteorological community, these issues are addressed within WMO by the Steering Group on Radio-Frequency Coordination (WMO SG-RFC). Within Europe, more than 20 National Meteorological Services and other relevant organizations have established the EUMETFREQ programme in order to coordinate their frequency protection activities.
Frequency management and protection are particularly important for satellite activities in general, and Space Agencies have established the Space Frequency Coordination Group (SFCG) to coordinate their activities in this respect.
Current threat on L-Band (1675-1710 Mhz)
An enquiry was released by the Federal Communications Commission (FCC) of the USA on 4 June 2010 regarding the possible use of the 1675-1710 MHz band for mobile broadband use. (ET Docket No. 10-123).
The WMO Executive Council expressed concern regarding this emerging threat to the L-band allocated on a co-primary basis for Meteorological Aids Service (including radiosondes) and Meteorological Satellite Service space-to-Earth (including Direct Broadcast dissemination to users).
WMO submitted on 24 June a response to this enquiry recalling the essential use of this band for meteorological operations and urging the FCCto withdraw this band from any plan for mobile broadband telecommunications. (Click here to see the WMO response)