WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Workshop on Radio Frequencies for Meteorology March 20/21, 2006, Geneva Hans Richner, IAC ETH, Zurich WMO World Weather Watch Commission on Basic Systems Steering Group Radiofrequency Coordination Ground-based passive sensors

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Sources and Acknowledgments: This presentation is primarily based in information which is freely available on the internet. Some of the figures were presented at the Workshop "Active Protection of Passive Radio Services: towards a concerted strategy." Contributors were: Ambrosini, RobertoIRA Baan, WillemAstron Cohen, JimJodrell Bank de La Noe, JeromeObs. de Bordeaux Deschamps, AndreObs. de Paris Feist, DietrichUniv. Berne Fejes, IstvanFOMI Lazareff, BernardIRAM Marelli, EdoardoESA Martinelli, MassimoESF Meens, VincentCNES Millenaar, RobAstron Mureddu, LeonardoINAF OAC Otter, ManfredESA Porceddu, IgnazioINAF OAC Richner, HansWMO Rochard, Guy †Meteo France Rommen, BjornESA Ruf, KlausDLR Spoelstra, TitusAstron/CRAF Struzak, Ryszardformerly ITU RRB Urban, JoachimChalmers Univ. van Driel, WimIUCAF vonDeak, TomNASA Wheeler, BillUK Met Office Wolf, RobertEUMETSAT The Workshop was organized by the European Science Foundation.

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva 1. principle of molecular spectrum 2. interference mechanisms 3. future threats 4. what should be done Overview

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva principle of molecular spectra

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva O 3,CH 3 Cl, HOCl, ClO, HNO 3, N 2 O, H 2 O 2, HCN, BrO, SO 2,...

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Institute for Applied Physics, University of Bern (IAP) ASMUWARA, the All-Sky MUlti WAvelength RAdiometer

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Frequency bands and bandwidths used for passive sensing (1) Frequency BW (GHz)(MHz)main measurements soil moisture, salinity, ocean surface temperature, vegetation index salinity, soil moisture ocean surface temperature ocean surface temperature (no allocation) rain, snow, ice, sea state, ocean wind, ocean surface temperature, soil moisture water vapour, rain rain, sea state, ocean ice, water vapour, snow water vapour, cloud liquid water water vapour, cloud liquid water water vapour, cloud liquid water window channel associated to temperature measurements rain, snow, ocean ice, water vapour, cloud liquid water, ocean wind, soil moisture

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Frequency bands and bandwidths used for passive sensing (2) Frequency BW (GHz)(MHz)main measurements O2 (temperature profiling) O2 (temperature profiling) Clouds, ice, snow, rain N2O O O2 (temperature profiling), CO window channel window channel (to be terminated on 1 January 2018) window channel H2O (moisture profiling), N2O, O H2O, O3, N2O clouds, CO O3 250 – N2O 275 – N2O

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Frequency bands and bandwidths used for passive sensing (3) Frequency BW (GHz)(MHz)Main measurements 294 – N2O, O3, O2, HNO3, HOCl 316 – water vapour profiling, O3, HOCl 342 – CO, HNO3, CH3Cl, O3, O2, HOCl, H2O 363 – O3 371 – water vapour profiling 416 – temperature profiling 442 – water vapour 486 – O3, CH3Cl, N2O, BrO, ClO 546 – temperature profiling 624 – BrO, O3, HCl, SO2, H2O2, HOCl, HNO3 634 – CH3Cl, HOCl, ClO, H2O, N2O, BrO, O3, HO2, HNO3 659 – BrO 684 – ClO, CO, CH3Cl 730 – O2, HNO3 851 – NO 951 – O2, NO, H2O

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva intermediate conclusion: evidently, the electro- magnetic spectrum is a very precious natural resource!!! it must be protected, on the other hand reasonable use has to accepted

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva oxygen lines around 60 GHz

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Weighting function for MSU at nadir Weighting function has a peak at specific altitude Each channel had different sensitivity to altitudes by measuring at several channels within the steep slope of the O 2 absorption spectrum and correcting for several factors (for which information is obtainable in the 31 GHz and 24 GHz frequency bands), an accurate temperature profile of the atmosphere results

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva water vapor absorption around 24 GHz

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Frequency hopping the basics of Ultras Wide Band (UWB) systems frequency

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva principle of UWB (Ultra Wide Band) systems

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Jodrell Bank UK compared to radioastronomers, meteorologists are really modest:

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Measurements in the 10.6 to 10.7 GHz band with the Effelsberg 100 m radio telescope … but both have the same problems: normal with a UWB system active

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Site control Jodrell Bank Consultation Zone Protection of particular frequency bands to agreed distances e.g. TV channel 38, MHz

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Greenbank Radio-Quiet Zone 1956West Virginia state law puts zoning restrictions on the use of electrical equipment within 10 miles of any radio astronomy facility. 1958National Radio Quiet Zone established by FCC: 13,000 square miles of Virginia and West Virginia. (The laws were set up before the radio telescopes were built and before any frequency bands were allocated to the RAS.)

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Network for the detection of Stratospheric Change Measurements: ground-based but also balloon-borne airborne satellite-borne

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Remote sensing of the atmosphere: ground-based used frequencies Range 10 to 280 GHz 22 GHzH 2 O 110 GHzO GHzO GHzH 2 O GHz O 3, ClO, HNO 3, N 2 O, HO 2 H 2 18 O, HO GHz O 3, ClO, HCN, HNO 3, N 2 O

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Some ground-based microwave radiometers University of Bern MIAWARA: Middle Atmospheric Water Vapor Radiometer 22 GHz, H 2 0 line

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva University Bordeaux 1/OASU Floirac => Pic du Midi Ozone microwave radiometer GHz, O 3 line Some ground-based microwave radiometers

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva University of Bern GROMOS: Radiometer 142 GHz, O 3 line Some ground-based microwave radiometers

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva University of Bremen Univ. Bordeaux Danish Meteorology Institute, University of Leeds Radiometer at Summit: RAMAS SIS junction, cooled to 4 K 265 to 281 GHz O 3, ClO, HCN, HNO 3, N 2 O Some ground-based microwave radiometers

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Mitigation methods - how adaptive cancellation using reference antennas F. Briggs

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Results adaptive cancellation WSRT example, using neighboring telescopes as reference antennas –observation at 355 MHz –crosscorrelation RT 5 and 6

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva GALILEO 30 satellites in 3 orbits GLONASS 13 satellites in 3 orbits

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Picture from LEO satellites promised better solution + services in polar regions Teledesic: 840 (1994) or 288 (1997) active satellites –suspended Oct and died Low-Earth-Orbit Constellations

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Stratospheric radio Radio station at stratospheric heights, or constellations of such stations HAPS = High-Altitude Platform Station The concept similar to that of LEO satellites but reduced to stratospheric heights Cheaper than terrestrial or satellite radio Satisfy “business” needs (profit), military needs, “humanitarian” needs (“digital gap”)

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Helios On June 26, 2003, the Helios aircraft was lost in the Pacific Ocean (Hawaii) during tests of a new fuel cell system for overnight flight operations in the stratosphere

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Japan’s project Constellation (dozens) of stations Operational in 2008 Long m weight32.0 t payload1.0 t power10.0 kW

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva “Stratospheric satellites” StratoSat TM Model of Fully-Pressurized Balloons In Flight. Picture courtesy of NASA. Constellation of stratospheric balloons powered by solar array Could be steered/ directed to fly over specific areas Payloads up to 2 tons at ~35 km

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva StratoSat TM 400 stations/hemisphere Projected life: 3 to 10 years. Costs: 10 to 100 times less than present space satellite or aircraft communications platforms according to ( ) –Infrastructure: < $ 160 million –Operation: < $ 10 million per year –Life-cycle cost < $ 400,000 per unit

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Space Data “Swarm” - millions (?) of low-cost “weather-type” balloons moving freely with the wind Reusable payload Built from “of-the-shelf” low-cost components

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Footnote to Radio Regulations: S5.340All emissions are prohibited in the following bands: MHz MHz except those provided for by Nos. S5.421 an S GHz except those provided for by No. S GHz except those provided for by No. S GHz GHz GHz in Region GHz from airborne stations GHz GHz GHz GHz GHz GHz from airborne stations and from space stations in the space-to-Earth direction GHz except those provided for by No. S GHz.

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Footnote to Radio Regulations: S5.340All emissions are prohibited in the following bands: MHz MHz except those provided for by Nos. S5.421 an S GHz except those provided for by No. S GHz except those provided for by No. S GHz ….. ….. particularly disturbing: unwanted emissions: consist of spurious emissions and out-of-band emissions we all know: there are unwanted emissions!

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva out-of-band emissions: Emissions on a frequency or frequencies immediately outside the necessary band- width which results from the modulation process, but excluding spurious emissions spurious emissions: Emissions on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmission of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products and frequencies and frequency conversion products, but exclude out-of-band emissions.

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Footnote to Radio Regulations: S5.340All emissions are prohibited in the following bands: MHz MHz except those provided for by Nos. S5.421 an S GHz except those provided for by No. S GHz except those provided for by No. S GHz intentional particularly disturbing:

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Re-radiation Terrestrial radiations reflected by the HAPS Threat of nullifying terrain shadowing and direction selectivity Not treated in the Radio Regulations HAPS

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva absorption lines between 275 GHz and 1 THz -- tomorrows resources!?

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Satellite versus conventional: NH height Sat data largest impact ~10 hr gain Forecast skill Roger Saunders, SFCG24

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Sat data largest impact ~ 48 hr gain Satellite versus conventional: SH height Forecast skill Roger Saunders, SFCG24

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Conclusions and recommendations (1) Radiofrequency issues for ground-based passive systems are basically the same as for other, say, space-based passive systems. Potential interference of active systems depends much on the siting. Topographic shielding might prove to be not effective due to re-radiation (reflection). Air and/or space-borne emissions are generally more problematic for ground- based passive systems than terrestrial sources. The biggest threat for any passive sensor are ultra wide band (UWB) systems; even if they do not cause direct interference, they increase the noise level. The number of interference sources is ever increasing; ground-based, satellites, high altitude platforms.

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Conclusions and recommendations (2) To a limited extent, mitigation techniques will allow observations in contami- nated bands. Mitigation is the second choice, primarily interference must be avoided. The dialog with the telecommunication community must be improved. Bands currently protected by Radio Regulations must not be used by UWB systems! The scientific community should carefully select those bands which must be protected; it will not be possible to protect all bands. The scientific community should take all steps necessary for keeping some frequency bands free on any intentional emission - including ultra wide band.

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva Conclusions and recommendations (3) Protection requirements in the not yet regulated frequency bands (>275 GHz) should be formulated before this band is used by active systems. The operators of ground-based passive systems are poorly organized. The operators of ground-based systems should compile an inventory of their instruments. All operators of passive systems should combine their protection efforts. As technology progresses, higher frequencies are used. In many countries, the cooperation between telecom administrations and the scientific and meteorological community should be intensified.

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva (thanks to Guy Rochard, † Dec 05) Mr. Telecom some unknown scientist

WMO SG RFC: Radio Frequencies for Meteorology: Ground-based passive sensors Hans Richner, IAC ETH, March 20/21, 2006, Geneva T h e E n d