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Info Note No.52

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New radiosonde to shed light on climate change

Geneva – 9 February 2009 (WMO)- Radiosondes are critically important to measure climate. The positive response of the private sector to a call by scientists to develop a new radiosonde will help promote the establishment by the Global Climate Observing System (GCOS) of a Reference Upper-air Network (GRUAN). This new generation of radiosondes will allow more accurate measurements of temperature and humidity trends in the atmosphere, leading to better understanding and prediction of climate change.

GCOS, sponsored by the World Meteorological Organization (WMO) jointly with the Intergovernmental Oceanographic Commission of UNESCO, the United Nations Environment Programme (UNEP) and the International Council for Science (ICSU), is establishing a reference network for upper-air climate observations (GRUAN). GRUAN is expected to provide long-term, highly accurate measurements of the atmospheric profiles, complemented by ground-based state of the art instrumentation.

In order to fully characterize the properties of the atmospheric column and their changes, GRUAN scientists defined stringent requirements of accuracy and recommended the development of a new radiosonde for that purpose. A radiosonde is a small, expendable measuring device for use on weather balloons that measures vertical profiles of key atmospheric parameters, such as air pressure, temperature, and humidity. The new generation of radiosondes will be reference high-quality instruments for climate information.

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WMO is the United Nations' authoritative voice on weather, climate and water

For more information please contact:

Ms Carine Richard-Van Maele, Chief, Communications and Public Affairs, WMO. Tel.: +41 (0)22 730 83 15; cpa[at]

Ms Gaëlle Sévenier, Press Officer, Tel. +41 (0) 22 730 8417.

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