1 / 14

Essential role of radio-frequencies for Earth observations and meteorology

Essential role of radio-frequencies for Earth observations and meteorology . Philippe TRISTANT Météo France Frequency Manager EUMETNET Frequency Manager (philippe.tristant@eumetnet.eu). Most people know that Meteorology and Earth observations are important …

hal
Download Presentation

Essential role of radio-frequencies for Earth observations and meteorology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Essential role of radio-frequencies for Earth observations and meteorology • Philippe TRISTANT • Météo France Frequency Manager • EUMETNET Frequency Manager • (philippe.tristant@eumetnet.eu) Accra, 7-8 June 2011

  2. Most people know that Meteorology and Earth observations are important … • … but much less are aware that these activities are fully dependent on radio-frequencies “No spectrum, no global observations!” (ITU Statement in a side event during Cancun UNFCCC) Accra, 7-8 June 2011

  3. WMO Global Observing System (GOS) Accra, 7-8 June 2011

  4. Radio applications for meteorology • Meteorological aids : • Radiosondes : about 900 stations worldwide in the 400 MHz band (core) and 1675 MHz band (roughly 1 000 000 launches per year) • Radiolocation : • Precipitation and Doppler radars : about 1000 radars worldwide in the 2.8, 5.6 and 9.4 GHz bands • Wind profiler radars (WPR) : about 200 radars in the 50, 900 and 1270 MHz bands • Miscellaneous : • Lightning detection • Terrestrial data collection • Satellites … Accra, 7-8 June 2011

  5. Constellation of METSAT Accra, 7-8 June 2011

  6. Satellite Applications • Space-Borne sensing (Earth Exploration Satellite Service (EESS)): • Passive sensors (radiometers) • Active sensors (scatterometers, altimeters, cloud and precipitation radars) • Data Transmissions, mainly in the 1.7, 2.2 and 7.8 GHz bands • Communication satellites, broadcasting data or forecasts • A number of METSAT receiving stations and several METSAT centers in a large number of countries Accra, 7-8 June 2011

  7. Importance of Satellite Applications • Space-borne sensing of the Earth’s surface and atmosphere has an essential and increasing importance for mitigating the impact of weather and climate-related disasters • Space-borne sensing allows for consistent observations all around the globe • The impressive progress made in the recent years in weather and climate analysis and forecasts, including warnings for dangerous weather phenomena (heavy rain, storms, cyclones) that affect all populations and economies, is to a great extent attributable to spaceborne observations and their assimilation in numerical models. • One key element : although the satellites are operated by a limited number of space agencies, the data, products and/or forecasts based on these data are shared among all countries (via WMO or GEO) • It is therefore a global and common responsibility to ensure protection and availability of the corresponding frequency bands Accra, 7-8 June 2011

  8. Activities in ITU-R on environmental satellite applications • Meteorological/Earth observations activities are considered in ITU-R Study Group 7 (science services) • All World Radiocommunication Conferences (WRC) include several related agenda items • Over long period of time, environmental and meteorological applications suffered from a lack of understanding and support • This was mainly under the fake argument, mainly economical, that it’s only science and hence represent less importance compared to telecommunication applications • The situation is improving but a lot is still to do through Radio Administrations to ensure relevant understanding of the importance of these activities. • WRC-07 adopted Resolution 673 to study possible means to improve the recognition of the essential role and global importance of Earth observation radiocommunications applications Accra, 7-8 June 2011

  9. Activities in ITU-R on environmental satellite applications • WRC-12 will have to consider the results of these studies to propose that this recognition be included in the Radio Regulations, and a broad support will be necessary. • In particular, during the preparation process, ITU-R adopted : • The Joint WMO/ITU Handbook on “Use of Radio Spectrum for Meteorology: Weather, Water and Climate Monitoring and Prediction” • Recommendation ITU-R RS.1859 on “disasters” • Recommendation ITU-R RS.1883 on “climate” • Report ITU-R RS.2178 on “The essential role and global importance of radio spectrum use for Earth observations and for related applications” Accra, 7-8 June 2011

  10. Activities in ITU-R on environmental satellite applications • All these documents stress the role of Earth Observations radio applications: • “The considerable societal value of Earth observation can directly be translated into terms of societal weight and economic value of the radio-spectrum which is used for these Earth observation activities” • “Most of the data retrieved from the use of this spectrum are directly dedicated to the benefit of every citizen” • “Most of this societal value is incommensurable in financial terms, as it relates to preventing large losses of lives or threats to socio-political stability and security” Accra, 7-8 June 2011

  11. Space-borne passive sensing • By far, space-borne passive sensing that involve the measurement of naturally-occurring terrestrial and atmospheric radiations is the most sensitive to interference • The radiations occur at very low power levels and contain essential information on the physical process under investigation • The relevant frequency bands are mainly determined by fixed physical properties (e.g., molecular resonance), so these bands cannot be changed • These “passive bands” are, therefore, an essential and unique natural resource Accra, 7-8 June 2011

  12. Space-borne passive sensing • the passive sensors are in general unable to discriminate between these natural radiations and man-made radiations • bands below 100 GHz are of particular importance, as they provide an “all-weather” observation capability • In this respect Provision No. 5.340 of the Radio Regulations (RR) states that “all emissions are prohibited”, meaning by principle that: • no in-band emissions are authorised • only unwanted emissions from adjacent bands can be experienced • Unfortunately, in may cases, such unwanted emissions can be high enough to interfere the sensors, in particular when aggregated from multiple sources of interference (Mobile phones, Short-Range devices, …) • the scientific community is working hard to convince Radio administrations to adopt limits in the RR to ensure protection of the “passive bands” • This is not always successful, in particular since we are said of being over-conservative and unduly constrain other radiocommunication service BUT … Accra, 7-8 June 2011

  13. Example of interference on passive sensors RFI at 1.4 GHz RFI at 10.6 GHz RFI at 6.8 GHz Accra, 7-8 June 2011

  14. “No spectrum, no global observations!”It is a global and common responsibility for worldwide countries to ensure protection and availability of essential frequency bands used for meteorology and Earth observationsThank you for your attention Accra, 7-8 June 2011

More Related