Nº 1 2012 > Earth observation
Natural disasters and climate monitoring
World Meteorological Organization
Trends in natural disasters
The number of natural disasters reported globally has increased considerably over the past three decades (Figure 1). Every year, disasters related to meteorological, hydrological and climate hazards cause significant loss of life, and set back economic and social development by years, if not decades. Between 1980 and 2005, nearly 7500 natural disasters worldwide took the lives of more than 2 million people and produced economic losses estimated at over USD 1.2 trillion. Hazards related to weather, climate or water — such as droughts, floods, windstorms, tropical cyclones, storm surges, extreme temperatures, landslides and wildfires — or health epidemics and insect infestations directly linked to meteorological and hydrological conditions caused 90 per cent of these natural disasters, around 73 per cent of the casualties and 75 per cent of the economic losses.
Disasters and climate monitoring
Progress in monitoring, forecasting and warnings of climate-related hazards, linked to effective emergency preparedness and response on the ground, saves lives. In the past five decades, globally, while the numbers of disasters and related economic losses have increased between 10 and 50 times, the reported loss of life has been reduced by a factor of 10. Climate forecasting and information allow us to plan our communities better so as to reduce the risk of disaster when extreme weather strikes. Better planning in health, agriculture, insurance and water resource management can help save livelihoods.
Nowadays radio-based remote sensors (active and passive) are the main tools for environment and climate monitoring, disaster prediction and detection, and for mitigating the negative effects of disasters. These sensors obtain environmental data by measuring the level and parameters of natural and artificial radio waves, which inherently contain information about the environment with which they have been in contact. Terrestrial and space-borne remote sensing applications form the backbone of the Global Climate Observing System (GCOS) of the World Meteorological Organization (WMO).
Global Climate Observing System
The relevant frequency bands for remote sensing applications are determined by fixed physical properties (molecular resonance) that cannot be changed and cannot be duplicated in other bands (see Figure 2 for an example). Therefore, these frequency bands are an important natural resource. Even low levels of interference received by a passive sensor may degrade its data.
Effective and prudent management of frequency bands allocated to different meteorological and Earth exploration-satellite services is paramount in maintaining and enhancing the quality and accuracy of environment and climate monitoring systems.
Importance of WRC‑12 for the development and operation of monitoring systems
Successive ITU world radiocommunication conferences have taken into account the needs of the meteorological community to ensure the availability and protection of radio-frequency bands for observation tools such as radiosondes, weather and wind profiler radars and space-borne infrared and microwave sounders.
On the agenda of World Radiocommunication Conference 2012 (WRC‑12), several items concern frequency bands or matters of prime interest for meteorology. These items may be divided into two groups:
- items devoted to the further development of observation systems or applications;
- items that may have some effects on the operation of monitoring systems or applications.
Topics related to the environment and to the further development of climate monitoring systems include agenda items 1.6, 1.15, 1.16, 1.24 and 8.1.1.
One of the main directions for the future of Earth observation applications is the development of passive sensors flying on meteorological and environmental satellites that will operate in frequency bands between 275 and 3 000 GHz. These bands, to be discussed under agenda item 1.6, correspond in particular to water vapour and oxygen spectral lines that are important for ice cloud and precipitation measurements. Such measurements are needed for storm monitoring and climate studies, so it is crucial for WRC‑12 to update No.5.565 of the Radio Regulations on the basis of the conclusions reached by the Study Groups concerned.
Possible allocations in the range 3–50 MHz to the radiolocation service for oceanographic radar applications, to be discussed under agenda item 1.15, could be used for monitoring the sea surface for wave heights and currents, and for the tracking of large objects. Oceanographic radars have been successfully operating in the 3–50 MHz frequency range since the 1970s in some countries. The need for additional data to mitigate the effects of disasters (including tsunamis), understand climate change and ensure safe maritime travel calls for a global network. Such a network will support environmental, oceanographic, meteorological, climatological, maritime and disaster mitigation activities. WMO believes that WRC‑12 will include the relevant allocations in the Radio Regulations.
Agenda item 1.16 will consider the needs of passive systems for lightning detection. Data provided by the lightning detection system contribute towards safety of life, both in terms of forecasting for public safety and for the safety of aviation operations, especially over the oceans and large areas of land where national lightning detection systems do not exist. As well as the dangers of the lightning strike itself, thunderstorms can result in intense precipitation with consequent flooding, severe icing, wind shear, turbulence and gusting winds. Recently, it has been shown that this system can also monitor volcanic ash cloud activity. Based on the successful results of studies carried out by the ITU Radiocommunication Sector, WMO expects that a new allocation for these applications will be included in the Radio Regulations.
Non-geostationary orbit (non-GSO) satellites are an important part of the space-based Global Observing System. The mission requirements for next-generation non-GSO meteorological satellites in terms of observations, instruments and user-services clearly show a need to transmit higher data rates compared to current systems. Extension of the existing allocation to the meteorological-satellite service in the band 7 750–7 850 MHz to the band 7 850–7 900 MHz will be discussed under agenda item 1.24. Technical studies have demonstrated compatibility in these frequency bands with systems of other services, and the proposed extension is viable without undue limitations on other services
ITU and WMO both recognize the crucial importance of radio-frequency spectrum and radio-based remote sensing systems and applications for meteorological and environmental observations for climate monitoring, disaster risk reduction, and adaptation to and mitigation of the negative effects of climate change. In the context of agenda item 8.1.1, WMO stresses the importance of Resolution 673 (WRC‑07) in relation to Earth observation activities and the need to secure a long-term WRC Resolution on the subject.
From WMO’s point of view, special attention also needs to be paid to agenda items 1.2, 1.5, 1.8, 1.19, 1.20, 1.22 and 1.25, because they may have some effects on the operation of meteorological monitoring systems or applications. These items relate to enhancing the international regulatory framework, electronic news gathering, the fixed-service systems in the frequency bands 71–238 GHz, use of software-defined radio and cognitive radio systems, emissions from short-range devices, and allocations to the mobile-satellite service. In discussing and taking decisions on these items, WRC‑12 should bear in mind that:
- the protection of frequencies used for meteorological purposes is of direct and vital interest to the international meteorological community;
- timely warning of impending natural and environmental disasters, accurate climate prediction and detailed understanding of the status of global water resources, which are all provided by meteorological applications, are critically important for the global community every day.
WMO considers that it is especially important to introduce mandatory limits for unwanted emissions of fixed-service systems operating in the 81–86 GHz and 92–94 GHz bands for the protection of the 86–92 GHz Earth-exploration satellite services (passive) frequency band (under agenda item 1.8). This band is one of the most important passive bands for current and future sensors measuring clouds, ice, rain and snow.