Nº 9 2011 > Climate change
Using radiocommunication to monitor climate
The climate is changing, but what are the trends at the global scale? And how can we monitor the processes that are causing the changes? This article outlines some of the ways that radiocommunication can be used to monitor the Earth's climate. In fact, using radiocommunication networks is often the only way to observe and measure the various factors involved.
Understanding what is going on
We need to improve our knowledge and understanding of how electromagnetic radiation from the sun influences the Earth’s environment, including the climate. This requires continuous and long-term monitoring of solar spectral irradiation, coupled with continuous observations to characterize changes in the atmosphere, oceans and land surface. All this information then has to be put together to improve climate change modelling. An area of particular concern relates to changes in the ozone layer, and continuous observations are needed to determine the effects not only on the environment, but also on human health.
Sustainable management of natural resources also requires knowledge and an understanding of the dynamics of changes in land cover. An ability to assess global conditions and see how they might alter is essential if we are to have a solid basis for programmes to protect the environment, ensure food security, and mitigate the humanitarian consequences of climate change.
Satellites as remote-sensing tools
Satellites, as part of the global array of radiocommunication systems, now provide a vital means of gathering global data on the climate and on climate change. Satellites are now being used to monitor carbon emissions, the changes occurring in the ice stored in polar caps and glaciers, and the way atmospheric temperatures vary. Remote sensing provides accurate and up-to-date information on land cover and any changes that are happening over wide areas, providing data from remote areas that are otherwise difficult to reach. Repeated measurements have made it possible to create archives of remote sensing data spanning several decades, which can be used to construct time-series data on land cover and land use.
ITU’s Radiocommunication Sector (ITU–R) has done important work in the field of climate change. In particular, ITU–R studies have formed the basis for several timely resolutions addressing urgent matters related to climate change.
For example, Resolution 673 (WRC‑07) entitled “Radiocommunications use for Earth observation applications” notes that more than 90 per cent of natural disasters are related to climate or weather. According to the resolution, the availability of Earth observation data will increase the understanding of climate change, making it easier to model and verify various aspects of climate change. This understanding will obviously be of benefit in policy-making.
Resolution 672 (WRC‑07) “Extension of the allocation to the meteorological-satellite service in the band 7 750–7 850 MHz” recognizes that the data obtained by meteorological satellites are essential for global weather forecasting, and for predicting climate changes and climate-related hazards.
Regulatory and technical standards
ITU–R creates the regulatory and technical bases for the development and effective operation of satellite and terrestrial climate monitoring and data dissemination systems (see box). It does so by: allocating the necessary radio-frequency spectrum and satellite orbit resources; analysing compatibility between new and existing satellite systems; carrying out studies and developing international standards for space-based and other radiocommunication systems and networks; and providing guidance and support on the use of satellite and terrestrial systems for environmental monitoring, and for prediction and mitigation of the negative effects of disasters caused by climate change.
The standards that are embodied in the Radio Regulations have treaty status and are obligatory. Other standards take the form of ITU Recommendations and are voluntary. Various standards cover the activities of systems such as:
- Earth observation satellites that monitor fluctuating land, sea and atmospheric parameters (such as vegetation biomass, ocean salinity, subterranean reserves of fresh water and cloud relief), track the progress of hurricanes and typhoons and the effluent from volcanoes and major forest fires.
- Weather radars that track tsunamis, tornadoes and thunderstorms.
- Radio-based meteorological aid systems that collect and process weather data.
- Various radiocommunication systems (satellite and terrestrial) that are used to disseminate information concerning natural and man-made disasters.
Helping administrations implement climate monitoring
Radiocommunication technologies are needed for environmental observation, climate control, weather forecasting, and to help in predicting, detecting and mitigating natural and man-made disasters. Where do administrations look for help with implementing these technologies, bearing in mind the need for spectrum planning, and for the engineering and deployment of both satellite and terrestrial technologies? The answer lies in ITU–R Recommendations, Reports and Handbooks on radiocommunication systems and radio-based applications operating in the Space research, Earth-exploration satellite, meteorological-aids, meteorological satellite and radiolocation services.
The upcoming debate at WRC‑12
The 2nd Session of the Conference Preparatory Meeting (CPM11‑2) to the World Radiocommunication Conference to be held in Geneva from 23 January to 17 February 2012 (WRC‑12) considered some topics concerning climate change. In particular, it proposed a change to the Radio Regulations in order to protect the operation and development of long-range lightning detection systems in frequencies below 20 kHz. Based on the discussions at CPM11‑2, WRC‑12 will also consider:
- Making a new allocation of the band 7750–7850 MHz for meteorological satellite systems to improve operational meteorology, in particular with respect to numerical weather prediction.
- Allocating additional spectrum between 275 GHz and 3000 GHz for use by the Earth-exploration satellite service to improve measurement of the components of the hydrological cycle.
- Modifying Resolution 673 (WRC‑07), which calls for studies by ITU–R “on possible means to improve the recognition of the essential role and global importance of Earth observation radiocommunication applications”, and including a new provision in the Radio Regulations urging administrations to recognize the importance of Earth observation.
- Making radiolocation allocations in the range 3–50 MHz that could be used for the operation of oceanographic radars to monitor the sea surface for wave heights and currents, and to track large objects, bearing in mind the increased reliance on the data from these systems for disaster response, as well as for oceanographic, climatological and meteorological operations. This has increased the need to improve the regulatory status of the spectrum used by oceanographic radars.
Some administrations have proposed that ITU–R Study Groups should identify energy-saving measures that could be built into radiocommunication devices without prejudice to their quality of service. Where such measures are likely to result in non-negligible reductions of greenhouse gas emissions, their use should obviously be generalized. A draft new ITU–R Resolution to this end will be presented for consideration at the upcoming Radiocommunication Assembly, to be held in Geneva on 16–20 January 2012.
Environmental monitoring: recent work by ITU–R Study Groups
- New Recommendation ITU–R RS.1883 “Use of remote sensing systems in the study of climate change and the effects thereof”, which provides guidelines on the use of satellites for remote sensing to obtain data for studying climate change.
- ITU–R Study Group 7 has published the new Report ITU–R RS.2178 “The essential role and global importance of radio spectrum use for Earth observations and for related applications”.
- ITU–R Study Group 7 delivered in June 2011 the new ITU–R Handbook “Earth-exploration satellite system”, which describes the technical characteristics, applications, spectrum requirements and benefits of the Earth-exploration satellite service.
- ITU–R Study Group 7 in cooperation with the World Meteorological Organization (WMO) has produced the WMO/ITU Handbook “Use of Radio Spectrum for Meteorology”, which provides information on the development and use of radiocommunication systems and radio-based technologies for environmental observation, climate control, weather forecasting and natural and man-made disaster prediction, detection and mitigation.
- ITU–R Study Group 5 has developed the new Recommendation ITU–R M.1874 “Technical and operational characteristics of oceanographic radars operating in sub-bands within the frequency range 3–50 MHz”.
- ITU–R Study Group 5 has developed the ITU–R “Intelligent Transport System” — Handbook on Land Mobile (including wireless), Volume 4, which describes different uses of radio technologies in regard to transport. One use is to minimize transport distances and cost, resulting in a positive effect on the environment. Another use is to take advantage of cars as an environmental monitoring tool to measure air temperature, humidity and precipitation. In this case, data can be sent through wireless links, to support weather forecasting and climate monitoring.
*Contributed by Vadim Nozdrin, Counsellor, ITU–R Study Group 7.