AGENDA ITEM 8.2: NEXT WRC

Recommend[s] to the Council items for inclusion in the agenda for the next WRC, and to give its views on the preliminary agenda for the subsequent conference and on possible agenda items for future conferences, taking into account Resolution 806 (WRC 07).

Secondary Allocation to EESS (passive) of a 200 MHz Bandwidth Located Between 6.425 and 7.250 GHz

Recommendation ITU-R RS.1029 states that 200 MHz of bandwidth between 6.425 and 7.250 GHz is required for sea surface temperature and soil moisture remote sensing. Radio Regulations footnote 5.458 recognizes the current use of this frequency range for remote sensing of sea surface temperature and states, “Administrations should bear in mind the needs of the Earth exploration-satellite (passive) and space research (passive) services in their future planning of the bands 6.425-7.025 MHz and 7.075-7.250 MHz.”

Recommendation: A secondary allocation for Earth Exploration-Satellite Service (passive) between 6.425 and 7.250 GHz should be sought to normalize the radio regulations with the current and planned practical passive use of the spectrum for Earth observation.

Following the launch of NASA’s EOS Aqua in 2002 and Navy’s WindSat in 2003, radiometers have been passively using the spectrum near 7 GHz to measure soil moisture and sea surface temperature on a global basis. Table 2.11 lists current and future U.S. EESS passive sensors using this band. The satellites in Table 2.11 will have benefits that reach far beyond the countries that funded them.

Soil moisture is a key factor in evaporation and transpiration at the land-atmosphere boundary. Due to the large amount of energy required to vaporize water, soil moisture has a large influence on both surface energy and carbon fluxes at Earth’s land surface. Sea surface temperature provides critical information on the ocean surface thermal state, which plays an important role in the transpiration of gases at the air-sea boundary. Such air-sea interactions are important in climate studies. Furthermore, since the density of water is determined by its temperature and salinity, sea surface temperature is a key determinant of waves and currents in response to external forces. Passive microwave measurements of sea surface temperature in the 7-GHz band “see through” nearly all clouds and precipitation. Such all-weather coverage permits measurement of the ocean surface during and after hurricanes and tropical cyclones, which often spawn cirrus clouds that block geostationary weather satellites from viewing the surface at visible and infrared wavelengths from 1 day to about a week.

TABLE 2.11 EESS Passive Sensors Using the Spectrum Between 6.425 and 7.250 GHz

Sensor Satellites Minimum Frequency (GHz) Maximum Frequency (GHz)
WindSat Coriolis 6.737 6.863
AMSR-Ea EOS Aqua 6.750 7.100
MIS JPSS (under development) 6.450 6.800

aAMSR-2 on GCOM-W1, set for launch in early 2012, is a follow-on to AMSR-E and is planned to operate at two center frequencies of 6.925 and 7.3 GHz. See http://sharaku.eorc.jaxa.jp/AMSR/AMSR2_RA/documents/GCOM_RA1_E.pdf; accessed on June 18, 2010.



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