World Meteorological Organisation Use of Radio Frequency spectrum for weather, water and climate sciences and operations Jean-Michel Rainer

Weather, Water and Climate Prime importance of specific radiocommunication services for meteorological and related environmental activities required for: prevention, detection, early warning and mitigation of natural and technological (man-made) disasters safety of life and property protection of the environment climate change studies and scientific research,

Weather, Water and Climate Importance of information provided by Earth-exploration systems including meteorological systems for a wide range of economic activities such as agriculture, transportation, construction, tourism, etc,

Weather, Water and Climate Crucial importance of the allocation of suitable radio-frequency bands for: the operation of surface-based meteorological and related observing systems, including in particular radiosondes, weather radars, wind profiler radars the operation of Meteorological and R&D satellites, including remote sensing (passive & active), data collection and data distribution links

Importance of radiocommunications for weather, water and climate operation and research

XV World Meteorological Congress, 2007 (188 WMO Members) By Resolution 3: Re-affirmed the crucial importance of RF bands for meteorological and related environmental operations and research, and for disaster risk reduction Stressed that some RF bands are a unique natural resource for passive sensing that deserve absolute protection Urged all Members to do their utmost at national, regional and international levels to ensure the availability and protection of suitable RF bands Appealed ITU and its Administrations to ensure the absolute protection of the passive sensing RF bands, and to give due consideration to the WMO requirements for RF allocations and regulatory provisions

Radiocommunication Services used for weather, water and climate sciences and operations Specific radiocommunication services: Meteorological Aids Service Meteorological-Satellite Service Earth Exploration-Satellite Service (passive) Earth Exploration-Satellite Service (active)

Radiocommunication Services for weather, water and climate sciences and operations As special systems of generic radiocommunication services: Meteorological weather radars and Wind-profiler radars of the Radiolocation Service As users of Radiocommunication Services: Fixed Service, Mobile Service, etc.

Meteorological Aids Service The radio service of meteorological aids (Metaids) includes radiosondes, dropsondes and rocketsondes, used for in-situ upper-air measurements ITU Working Party 7C (WP 7C) is responsible for Metaids Metaids allocations: 400.15 – 406 MHz, 1668.4 – 1700 MHz and 35.2 – 36 GHz Metaids stations are licensed or provided frequency assignments by the country in which they operate

History- Metaids Spectrum Issues The bands 400.15-406 MHz and 1668.4-1700 MHz were identified as potential sources of spectrum for the mobile-satellite service (MSS) in 1992; WARC-92 decided some MSS allocations Studies within the ITU showed that MSS would cause interference to Metaids Proposals were made to WRC-95, WRC-97 and WRC-2000 for additional MSS allocations, but no action was taken WRC-2003 decided MSS allocations in 400.15-401 MHz and 1668.4-1675 MHz only

Meteorological Satellite Service

Typical use of Frequency Bands allocated to the MetSat service (1) 137 – 138 MHz (s-E) 401 – 403 MHz (E-s) 1670 – 1710 MHz (s-E) 2025 – 2110 MHz (E-s) 2200 – 2290 MHz (s-E) Dissemination of low rate data from NGSO MetSat to user stations Data uplink from DCPs to GSO MetSat. The band is divided into regional and international channels The band is divided into several parts and is used for downlink of raw data, DCP data, dissemination Telecommand and ranging from main Earth and uplink of processes data for dissemination Telemetry and downlink of raw data to main station

Typical use of Frequency Bands allocated to the MetSat service (2) 7450 – 7550 MHz (s-E) 7750 – 7850 MHz (s-E) 8025 – 8400 MHz (s-E) 18.1 – 18.3 GHz (s-E) 25.5 – 27 GHz (s-E) Downlink of medium rate raw data from GSO MetSat to main Earth station (not used on current generation MetSat systems) Downlink of raw data from NGSO MetSat to main Earth station, but also dissemination Downlink of sensor data from GSO and NGSO MetSat to main Earth station Downlink of high rate raw data to main Earth station Downlink of high rate raw data to main Earth station (currently no plans for next generation MetSat)

Earth Exploration Satellite Service passive Passive microwave remote sensing of the Earth operates spaceborne passive sensors to measure natural emissions produced by the Earth’s surface and atmosphere, that, after processing, measure with a global coverage:   Earth surface parameters such as soil moisture, sea surface temperature, ocean wind stress, ice extension and age, snow cover;    Three-dimensional atmospheric parameters such as temperature profiles, water vapour content. The relevant frequency bands are determined by fixed physical properties (e.g. molecular resonance) of atmospheric components and are, therefore, an important natural resource. The frequencies below 100 GHz enable « All-weather" observing capability (clouds are almost transparent at these frequencies)

Earth Exploration Satellite Service passive

Earth Exploration Satellite Service passive Spaceborne passive sensors measure very low energy levels and are highly sensitive to interference. They cannot discriminate between natural radiations and man-made radiations. Corrupted measurements from one or more areas may affect global measurements. measurements in several frequencies bands must be made simultaneously in order to extract each parameters' value Data provided is critical for weather, water and climate and related environmental analysis, forecasting and warnings.

Earth Exploration Satellite Service passive Two types of passive bands: P= primary exclusive (RR 5.340 « All emissions are prohibited»), which enables the passive services to deploy and operate their systems p = primary passive bands shared with other active services, in general terrestrial services (FS, MS) Typical bands and their main application: 1400-1427 MHz: salinity (ocean), soil moisture (ground) 10.6-10.7 MHz: rain, snow, ice, sea state, ocean wind 23.6-24 GHz: total content of water vapour 31.3-31.5 GHz: the lowest cumulated effects due to oxygen and water vapour in the vicinity of the 50 GHz band. Optimum window channel to see the Earth’s surface: reference for the other channels. 36-37 GHz: cloud liquid water, vegetation structure, surface roughness 50.2-50.4 GHz: temperature profile

Earth Exploration Satellite Service active Active Sensors of the Earth Exploration-Satellite Service are spaceborne instruments measuring information relating to the characteristics of the Earth and its natural phenomena by transmission and reception of radio waves  

Earth Exploration Satellite Service active Active Sensor Types SYNTHETIC APERTURE RADARS - Sensors looking to one side of nadir track, collecting phase and time history of coherent radar echo from which typically can be produced a radar image or topographical map of the Earth surface ALTIMETERS - Sensors looking at nadir, measuring the precise time between a transmit event and receive event to extract the precise altitude of ocean surface SCATTEROMETERS - Sensors looking to the sides of the nadir track, using the measurement of the return echo power variation with aspect angle to determine wind direction and speed on Earth ocean surface

Earth Exploration Satellite Service active Active Sensor Types (contd) PRECIPITATION RADARS - Sensors scanning perpendicular to nadir track, measuring the radar echo from rainfall to determine the rainfall rate over Earth surface, usually concentrating on the tropics CLOUD PROFILE RADARS - Sensors looking at nadir, measuring the radar echo return from clouds, to determine cloud reflectivity profile over Earth surface

Meteorological weather radars Radiolocation Service Meteorological radars worldwide perform precipitation and wind measurements and play a crucial role in the immediate meteorological and hydrological alert processes. Meteorological radar networks represent the last line of defence against loss of life and property in flash flood or severe storms and heavy rain events. Radar data are also input to Numerical Weather Prediction models for nowcasting, short-term and medium-term forecasting.

Meteorological weather radars Radiolocation Service Three allocations exist in the Radio Regulations specifically identified for meteorological radars 2700-2900 MHz- ground based radars 5600-5650 MHz- ground based radars 9300-9500 MHz- ground based and airborne radars The three bands provide different services and performance: System Cost : Highest- 2700-2900 MHz & Complexity Lowest- 9300-9500 MHz Operating Range: ~450 km- 2700-2900 MHz ~200 km- 5600-5650 MHz <75 km- 9300-9500 MHz Severe Weather Highest- 2700-2900 MHz Performance: Lowest- 9300-9500 MHz

Meteorological weather radars Radiolocation Service Interferences (in 5600-5650 MHz, RLAN devices not fulfilling mandatory Dynamic Frequency Selection - DFS) have a serious impact on the detection and warning of severe weather (e.g. heavy rain and flash flood)

Wind-profiler radars Radiolocation Service Wind profiler radars are vertically‑directed Doppler radars used to measure wind direction and speed as a function of altitude. About one hundred Wind Profilers are operational worldwide and are providing valuable information for both operational (e.g. wind shear at airports) and research applications In order to conduct measurements up to a height of 30 km, frequency bands for these radars are required in the general vicinity of 50 MHz (3 to 30 km), 400 MHz (500 m to about 10 km) and 1000 MHz (100 m to 3 km). WRC-97 identified the following bands for implementation of wind profiler radars as radiolocation service systems: 46 - 68 MHz 440 - 450 MHz 470 - 494 MHz 904 - 928 MHz in Region 2 only 1270 - 1 295 MHz 1 300 - 1 375 MHz;

WMO’s position on the WRC-07 agenda Issues of prime interest for meteorology: Agenda item 1.2: Extension of the 18 GHz MetSat allocation and protection of the 10.7 and 36 GHz EESS (passive) bands Agenda item 1.3: Upgrading and protection of radiolocation in the 9 GHz range, and 200 MHz extension of the Earth exploration-satellite service (EESS) allocation at 9 500-9 800 MHz Agenda item 1.4: Impact on meteorological radars and satellite C-band related to future frequency bands for IMT-2000 Agenda item 1.12: Coordination and notification procedures for Earth exploration-satellite service (EESS) (active and passive) sensors Agenda item 1.17: Protection of the 1.4 GHz EESS (passive) band Agenda item 1.20: Unwanted emissions in EESS (passive) bands Agenda item 7.2: WRC-11 agenda WMO’s position is available as WRC-07 Doc.20 (WMO Information paper), including WMO Congress Resolution «Radio-frequencies for meteorological and related environmental activities» All 188 WMO Members (National Meteorological Services) have been urged to address the matter with their national radiocommunication administration

WMO’s position on the WRC-07 agenda Issues of prime interest for meteorology: Agenda item 1.2: Extension of the 18 GHz MetSat allocation and protection of the 10.7 and 36 GHz EESS (passive) bands WMO favours a worldwide allocation in either 18-18.1 GHz band or 18.3-18.4 GHz band. WMO strongly encourages the identification of the maximum power and eirp for fixed and mobile services that would protect EESS (passive) in the 10.6-10.68 GHz and the 36-37 GHz passive bands Agenda item 1.3: Upgrading and protection of radiolocation in the 9 GHz range, and 200 MHz extension of the Earth exploration-satellite service (EESS) allocation at 9 500-9 800 MHz WMO supports the upgrade to primary of Radiolocation Service in the band 9 300-9 500 MHz on an equal footing with Radionavigation Service retaining the provisions that address meteorological radars. Expecting no potential interference impact to meteorological radar operations, WMO supports extension to the band 9 300-9 500 MHz of the EESS (active) and the space research service (active) allocations.

WMO’s position on the WRC-07 agenda Issues of prime interest for meteorology: Agenda item 1.4: Impact on meteorological radars and satellite C-band related to future frequency bands for IMT-2000 Studies prior to WRC-2000 already concluded on the non-compatibility between IMT-2000 and radars; WMO is strongly opposed to any IMT‑2000 and IM66-Advanced identification in the 2700-2900 MHz and 5250-5650 MHz bands. Agenda item 1.12: Coordination and notification procedures for Earth exploration-satellite service (EESS) (active and passive) sensors WMO supports modifications to Radio Regulations to permit recording and publication of appropriate data pertaining to EESS and SRS active and passive sensors in the International Master Frequency Register Agenda item 1.17: Protection of the 1.4 GHz EESS (passive) band This band is a vital resource for measuring salinity and other aspects of the Earth. WMO is of the view that such a secondary FSS allocation should not be confirmed at WRC‑07

WMO’s position on the WRC-07 agenda Issues of prime interest for meteorology: Agenda item 1.20: Unwanted emissions in EESS (passive) bands WMO supports appropriate regulatory measures in the Radio Regulations (power limits for unwanted emissions) to ensure the protection of the Earth exploration satellite service service (passive) from unwanted emissions. Agenda item 7.2: WRC-11 agenda WMO supports the retention in WRC-10 agenda of the review of the uses of the spectrum from 275 to 3 000 GHz by the Earth exploration-satellite (passive), radio astronomy, and space research (passive) services.

Thank You!