Workshop on Radio Frequencies for Meteorology March 20/21, 2006, Geneva

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

2. 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, Roberto IRA Baan, Willem Astron Cohen, Jim Jodrell Bank de La Noe, Jerome Obs. de Bordeaux Deschamps, Andre Obs. de Paris Feist, Dietrich Univ. Berne Fejes, Istvan FOMI Lazareff, Bernard IRAM Marelli, Edoardo ESA Martinelli, Massimo ESF Meens, Vincent CNES Millenaar, Rob Astron Mureddu, Leonardo INAF OAC Otter, Manfred ESA Porceddu, Ignazio INAF OAC Richner, Hans WMO Rochard, Guy † Meteo France Rommen, Bjorn ESA Ruf, Klaus DLR Spoelstra, Titus Astron/CRAF Struzak, Ryszard formerly ITU RRB Urban, Joachim Chalmers Univ. van Driel, Wim IUCAF vonDeak, Tom NASA Wheeler, Bill UK Met Office Wolf, Robert EUMETSAT The Workshop was organized by the European Science Foundation.

3. Overview 1. principle of molecular spectrum 2. interference mechanisms 3. future threats 4. what should be done

4. principle of molecular spectra

5. O3,CH3Cl, HOCl, ClO, HNO3, N2O, H2O2, HCN, BrO, SO2, ...

6. ASMUWARA, the All-Sky MUlti WAvelength RAdiometer Institute for Applied Physics, University of Bern (IAP)

9. Frequency bands and bandwidths used for passive sensing (1) Frequency BW (GHz) (MHz) main measurements 1.4-1.427 100 soil moisture, salinity, ocean surface temperature, vegetation index 2.69-2.70 60 salinity, soil moisture 4.2 - 4.4 200 ocean surface temperature 6.7 - 7.1 400 ocean surface temperature (no allocation) 10.6 - 10.7 100 rain, snow, ice, sea state, ocean wind,ocean surface temperature,soil moisture 15.35 - 15.40 200 water vapour, rain 18.6 - 18.8 200 rain, sea state, ocean ice, water vapour,snow 21.2-21.4 200 water vapour,cloud liquid water 22.21-22.50 300 water vapour,cloud liquid water 23.6 - 24.0 400 water vapour, cloud liquid water 31.3 - 31.8 500 window channel associated to temperature measurements 36-37 1000 rain, snow, ocean ice, water vapour,cloud liquid water,ocean wind,soil moisture

10. Frequency bands and bandwidths used for passive sensing (2) Frequency BW (GHz) (MHz) main measurements 50.2 - 50.4 200 O2 (temperature profiling) 52.6 - 59.3 6700 O2 (temperature profiling) 86 - 92 6000 Clouds, ice, snow, rain 100 - 102 2000 N2O 109.5 - 111.8 2300 O3 114.25 - 122.25 8000 O2 (temperature profiling), CO 148.5 - 151.5 3000 window channel 155.5 - 158.5 3000 window channel (to be terminated on 1 January 2018) 164 - 167 3000 window channel 174.8 - 191.8 17000 H2O (moisture profiling), N2O, O3 200 - 209 9000 H2O, O3, N2O 226 - 232 6000 clouds, CO 235 - 238 3000 O3 250 – 252 2000 N2O 275 – 277 2000 N2O

11. Frequency bands and bandwidths used for passive sensing (3) Frequency BW (GHz) (MHz) Main measurements 294 – 306 12000 N2O, O3, O2, HNO3, HOCl 316 – 334 10000 water vapour profiling, O3, HOCl 342 – 349 7000 CO, HNO3, CH3Cl, O3, O2, HOCl, H2O 363 – 365 2000 O3 371 – 389 18000 water vapour profiling 416 – 434 18000 temperature profiling 442 – 444 2000 water vapour 486 – 506 9000 O3, CH3Cl, N2O, BrO, ClO 546 – 568 22000 temperature profiling 624 – 629 5000 BrO, O3, HCl, SO2, H2O2, HOCl, HNO3 634 – 654 20000 CH3Cl, HOCl, ClO, H2O, N2O, BrO, O3, HO2, HNO3 659 – 661 2000 BrO 684 – 692 8000 ClO, CO, CH3Cl 730 – 732 2000 O2, HNO3 851 – 853 2000 NO 951 – 956 5000 O2, NO, H2O

12. 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

13. oxygen lines around 60 GHz

14. 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 O2 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

15. water vapor absorption around 24 GHz

16. Frequency hopping the basics of Ultras Wide Band (UWB) systems frequency

17. principle of UWB (Ultra Wide Band) systems

21. Jodrell Bank UK compared to radioastronomers, meteorologists are really modest:

22. normal with a UWB system active … but both have the same problems: Measurements in the 10.6 to 10.7 GHz band with the Effelsberg 100 m radio telescope

23. • Site control • Jodrell Bank Consultation Zone • Protection of particular frequency bands to agreed distances e.g. TV channel 38, 606-614 MHz

24. Greenbank Radio-Quiet Zone 1956 West Virginia state law puts zoning restrictions on the use of electrical equipment within 10 miles of any radio astronomy facility. 1958 National 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.)

25. Network for the detection of Stratospheric Change Measurements: ground-based but also balloon-borne airborne satellite-borne

26. Remote sensing of the atmosphere: ground-based used frequencies Range 10 to 280 GHz 22 GHz H2O 110 GHz O3 142 GHz O3 183 GHz H2O 200-210 GHz O3, ClO, HNO3, N2O, HO2 H218O, HO2 265-280 GHz O3, ClO, HCN, HNO3, N2O

27. Some ground-based microwave radiometers University of Bern MIAWARA: Middle Atmospheric Water Vapor Radiometer 22 GHz, H20 line

28. Some ground-based microwave radiometers University Bordeaux 1/OASU Floirac => Pic du Midi Ozone microwave radiometer 110.836 GHz, O3 line

29. Some ground-based microwave radiometers University of Bern GROMOS: Radiometer 142 GHz, O3 line

30. Some ground-based microwave radiometers 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 O3, ClO, HCN, HNO3, N2O

31. F. Briggs Mitigation methods - howadaptive cancellation using reference antennas

32. WSRT example, using neighboring telescopes as reference antennas observation at 355 MHz crosscorrelation RT 5 and 6 Resultsadaptive cancellation

33. GLONASS13 satellites in 3 orbits GALILEO30 satellites in 3 orbits

34. Low-Earth-Orbit Constellations • LEO satellites promised better solution + services in polar regions • Teledesic: 840 (1994) or 288 (1997) active satellites • suspended Oct. 2002 and died Picture from http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/teledesic.html

36. 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”)

37. 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

38. Japan’s project • Constellation (dozens) of stations • Operational in 2008 • Long. 250.0 m weight 32.0 t payload 1.0 tpower 10.0 kW

39. “Stratospheric satellites” StratoSatTM • 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 Model of Fully-Pressurized Balloons In Flight. Picture courtesy of NASA.

40. StratoSatTM • 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 http://www.gaerospace.com/ (06.2002) • Infrastructure: < $ 160 million • Operation: < $ 10 million per year • Life-cycle cost < $ 400,000 per unit

41. 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

42. Footnote to Radio Regulations: S5.340 All emissions are prohibited in the following bands:1 400 - 1 427 MHz2 690 - 2 700 MHz except those provided for by Nos. S5.421 an S5.42210.68 - 10.7 GHz except those provided for by No. S5.483 15.35 - 15.4 GHz except those provided for by No. S5.51123.6 - 24 GHz31.3-31.5 GHz31.5-31.8 GHz in Region 248.94-49.04 GHz from airborne stations51.4-54.25 GHz58.2-59 GHz64-65 GHz86-92 GHz105-116 GHz140.69-140.98 GHz from airborne stations and from space stations in the space-to-Earth direction182-185 GHz except those provided for by No. S5.563217-231 GHz.

43. particularly disturbing: Footnote to Radio Regulations: S5.340 All emissions are prohibited in the following bands:1 400 - 1 427 MHz2 690 - 2 700 MHz except those provided for by Nos. S5.421 an S5.42210.68 - 10.7 GHz except those provided for by No. S5.48315.35 - 15.4 GHz except those provided for by No. S5.51123.6 - 24 GHz…..….. we all know: there are unwanted emissions! unwanted emissions: consist of spurious emissions and out-of-band emissions

44. 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.

45. Footnote to Radio Regulations: S5.340 All emissions are prohibited in the following bands:1 400 - 1 427 MHz2 690 - 2 700 MHz except those provided for by Nos. S5.421 an S5.42210.68 - 10.7 GHz except those provided for by No. S5.48315.35 - 15.4 GHz except those provided for by No. S5.51123.6 - 24 GHz particularly disturbing: intentional

46. HAPS Re-radiation • Terrestrial radiations reflected by the HAPS • Threat of nullifying terrain shadowing and direction selectivity • Not treated in the Radio Regulations

48. absorption lines between 275 GHz and 1 THz -- tomorrows resources!?

49. Satellite versus conventional: NH height Forecast skill Sat data largest impact ~10 hr gain Roger Saunders, SFCG24

50. Sat data largest impact ~ 48 hr gain Satellite versus conventional: SH height Forecast skill Roger Saunders, SFCG24