December 2007 Downloads & Links

WMO activities


Better protection against flash floods / La Niña is back—but different / WMO World Climate Applications and Services Programme and Climate Information and Prediction Services / Marine meteorology / Climate change and tourism /Aviation meteorology


Better protection against flash floods

WMO supports Members’ efforts to protect against flash flooding by improving early warning systems and strengthening local capacity to adequately respond to such extreme events.

Communities must be on the alert for flash floods, ensuring systems are in place to record rapidly rising water levels. This can provide the warning needed to start evacuating populations from areas where a flash flood is predicted to occur.

National Meteorological and Hydrological Services (NMHSs) face tough challenges in predicting when and where floods will hit. Crisis services face similar dilemmas in responding, because of the limited warning time available.

flash flood

In October 2007, WMO co-sponsored a workshop with officials from NMHSs, disaster response services and local communities in central and eastern Europe, a region which has suffered significant loss of life and economic damage in floods in the recent past. The aim was to reduce the vulnerability of communities which are prone to these phenomena.

A comprehensive national strategy can help coordinate various parties to minimize loss of life from flooding and reduce the vulnerability of local communities. Awareness must be raised through schools and the media. The private sector can contribute resources for emergency response and recovery.

Some countries in the region have upgraded their monitoring, forecasting and warning capabilities, while others are struggling to secure funding needed for such investments.

WMO runs the Associated Programme on Flood Management, supporting countries through its Integrated Flood Management policy. This concept integrates land and water-resources development in a river basin under an overall water resources management system. It aims to maximize the net benefit from floodplains and minimize loss of life from flooding.


La Niña is back—but different

The El Niño/La Niña update issued by WMO on 31 October indicated that a La Niña event was under-way across the central and eastern equatorial Pacific, with sea-surface temperatures as much as 1.5°C colder than normal. These conditions are expected to continue throughout the first quarter of 2008.

The magnitude of the current sea-surface temperature departures from normal in the central and eastern equatorial Pacific are in the middle range of La Niña events found in the historical record. It is, however, markedly different from most other such events in the past. This is due to the presence of colder-than-normal sea-surface waters across northern Australia, around the western Indonesian islands and extending to the Indian Ocean. Sea-surface temperatures in this region are typically warmer than normal during a basin-wide La Niña. In addition, the sequence leading up to the event has been unusual: La Niña conditions were established only after a break in movement to such conditions during April-June.

sky and sea


Some regional climate patterns atypical of La Niña impacts are expected to be experienced in the surrounding continental regions as long as this situation continues. For example, rains have been unusually heavy in parts of eastern Africa, while dry conditions have persisted in many areas of Australia.

Thus, this La Niña situation requires careful consideration of geographically specific climate outlooks such as those produced by the National Meteorological and Hydrological Services (NMHSs) for optimal management of climate related risks.

WMO will continue monitoring the emerging indications in conjunction with NMHSs.

The WMO El Niño/La Niña Update is a consensus report prepared in collaboration with the International Research Institute for Climate and Society, with contributions from NMHSs, regional and global prediction/research centres and individual experts.


La Niña and the Indian Ocean Dipole

The cooler-than-normal sea temperatures currently being observed between Australia and the western Indian Ocean are associated with a positive phase of the Indian Ocean Dipole, a recently identified mode of the climate system.

A positive phase of the Indian Ocean Dipole is charac-terized by the presence of cooler-than-normal sea-surface temperatures in the eastern equatorial Indian Ocean near Indonesia and Australia and warmer-than-normal sea- surface temperatures in the western equatorial Indian Ocean, near Madagascar. A negative phase of the Indian Ocean Dipole has the opposite features.



WMO World Climate Applications and Services Programme and Climate Information and Prediction Services

Sand- and duststorms

WMO and partners are in the process of establishing a risk-reduction tool to assist countries experiencing severe sand- and duststorms.

Windstorms generated in desert areas can transport thousands of tonnes of sand and dust particles across continents and deposit them in cities. These particles consist of mineral aerosols that aggravate cardiovascular and respiratory diseases in people and animals. They can also carry disease, including spores responsible for Valley Fever in the Americas, while dust events have been linked to meningitis in arid African regions. Areas affected by duststorms have high incidences of asthma.

Desertification, which can be linked to changing climate, as well as inappropriate forestry and farming techniques, can spur erosion by sand- and duststorms. This can result in long-range airborne transport and deposition of nutrients and toxic materials, including fertilizers, herbicides, pesticides and chemical wastes that accompany soil particles.

WMO ensures that all parts of the world affected by dust- and sandstorms have access to forecast and analysis products.


Many countries would therefore benefit from a global warning system to coordinate and deliver advanced forecasts produced by meteorological centres. These forecasts predict when and where plumes of sand and dust will be generated and provide governments, businesses and communities with information necessary to minimize impacts.

The warning system supported by WMO Members can inform users up to five days in advance of sand- and duststorm risks via national warning and assessment centres. Two regional coordinating centres are being established in China and Spain and another is being considered in the Americas.

The work involves three groups: modellers, who produce sand and dust forecasts using numerical prediction techniques; observation experts, who generate observations and information through satellites, surface-based networks and aircraft; and users, who apply the forecasts and information. Amongst these are government agencies involved in risk reduction, the media, health experts and researchers.

Through national, regional and global cooperation, sand and dust forecasts, warnings and assessments can be better tailored to user needs.

WMO Sand and Dust Storm Warning System



Marine meteorology

Forecasting storm surge

Storm surges constitute a significant marine hazard, with a potential for causing serious loss of life, damage and inundation of valuable low-lying coastal areas. Since they are closely associated with tropical cyclones and extra-tropical storms, National Meteorological Services are normally charged with implementing warning and forecast services for storm surges.

The need was identified to enhance storm surge forecasting capabilities and to complement other international efforts. These include a series of capacity- building workshops on storm surge and wave forecasting which assist the development of marine-related hazard warning systems.

WMO and the Intergovernmental Oceanographic Commission (UNESCO), through their Joint Commission for Marine Meteorology (JCOMM), organized a scientific/technical symposium for the exchange of ideas and information related to tropical and extra-tropical storm-surge modelling, fore-casting and hind casting. It also provided in-put to the development of products such as flood maps and Geographical Information System tools.

Areas for future research and development were pinpointed and input was developed for the dynamic part of the Guide to Storm Surge Forecasting that is currently being prepared by JCOMM, emphasizing new developments.

The Symposium provided guidance/technical support for National Meteorological Services and other national agencies providing storm surge forecasting and warning services.

Storm surge

Storm surge is an abnormal rise of water due to a tropical cyclone or an extra-tropical storm—an oceanic event driven by meteorological forces. Potentially disastrous surges occur along coasts with low-lying terrain that allows inland inundation, or across inland water bodies such as bays, estuaries, lakes and rivers. For riverine situations, the surge is sea water moving up the river.

For a typical storm, the surge affects some 150-200km of coastline for a period of several hours. Larger, slow moving storms may impact considerably longer stretches of coastline.

coastal damage

Damage from a coastal storm surge


See also feature article “Profiling float network reaches its goal

WMO Marine Meteorology and Oceanography Programme



Climate change and tourism

Tourism is one of the largest economic sectors and an integral part of modern societies in both developed and developing countries. It is a vital element in poverty-reduction efforts and for the achievement of the UN Millennium Development Goals. Tourism is, however, vulnerable to climate variability and change, with some activities known to have an impact on climate itself.

The Second International Conference on Climate Change and Tourism (Davos, Switzerland, October 2007) was a joint activity of the UN World Tourism Organization, the United Nations Environment Programme and WMO. It underscored the need for the tourism sector to respond rapidly to climate change if it is to develop in a sustainable manner. It was agreed that this would require action to: mitigate greenhouse-gas emissions arising especially from transport and accommodation activities; adapt tourism businesses and destinations to changing climate conditions; apply existing and new technologies to improve energy efficiency; and secure financial resources to assist regions and countries in need.

summer ski

A report entitled Climate Change and Tourism: Responding to Global Challenges, commissioned in the context of the Davos meeting, is being prepared. It will provide the basis for developing practical tools that can be used by tourism policy-makers and managers to foster the sustainable growth of the industry.

These activities are an integral part of the UN system effort to develop a common framework in responding to the climate change challenge to “deliver as one”.



Aviation meteorology

National Meteorological Ser-vices (NMSs) fulfil a large variety of tasks and functions and have a multitude of user groups with different needs and requirements, a major one being aviation.

They invest in meteorological observation systems, forecasting efforts and research programmes to improve and expand their services and the International Civil Aviation Organization (ICAO) stipulates the “user pays” principle. This allows for the recovery of costs for air navigation services from civil aviation by the service providers.

Aeronautical meteorological services form part of air navigation services and are, therefore, recover-able from users.


In order to assess whether NMSs are receiving an equitable contribution towards their cost, the aeronautical meteorological services to civil aviation need to be analysed. WMO has helped design an institutional framework for the East African Community (Burundi, Kenya, Rwanda, United Republic of Tanzania and Uganda), which will make appropriate cost recovery a reality.

In view of the question of national airspace and the international nature of civil aviation, there is a need to standardize and have in place a regional/national quality management framework. WMO and ICAO have developed guidance materials to assist NMSs in implementing such frameworks.

WMO Aeronautical Meteorology Programme



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