Finnish Meteorological Institute Vaisala

Accurate weather information benefits athletes in Helsinki

August 2, 2005

The Finnish Meteorological Institute, Vaisala, and partners have launched the first measurement campaign in the Helsinki Testbed project. Helsinki Testbed is a dense weather measurement network suitable for forecasting mesoscale weather phenomena - within a relatively small area and short period of time. The first measurement campaign will benefit the organizers, competitors, audience and meteorologists of the World Championships in Athletics, commencing in Helsinki on August 6th. In cooperation with the Finnish Athletics federation and the City of Helsinki, several additional weather observation sites have been installed e.g. along the marathon route and at the Olympic Stadium. Helsinki Testbed observation data will be available at http://testbed.fmi.fi through August.

Data gathered during the five forthcoming Helsinki Testbed measurement campaigns will benefit worldwide research for years to come. A similar research project was carried out in conjunction with the Sydney Olympics in 2000.

A dense observation network enables gathering a large amount of data for meteorological research. This data will help in comparing different models for predicting weather phenomena. Another point of interest is how the quantity of observations will affect forecasts made using computer calculation models. Different architectures and methods can be compared and the most suitable methods for each atmospheric phenomenon can be identified. Results from a restricted geographical area can be generalized to wider national and international levels in a cost-effective way.

Shortest forecasts - a matter of minutes

Mesoscale phenomena typically cover an area ranging 1-10 km and last less than three hours. The existing observation network has been supplemented with new observation equipment in a 150 x 150 km area around the Greater Helsinki. Cellphone network masts are used extensively as measurement equipment installation sites. This way tremendous amount of new meteorologically important information can be obtained from the 2-100 m thick surface layer of the atmosphere. In addition to automatic weather stations, new network equipment includes remote sensing methods such as laser radars for cloud detection, a dual-polarization radar, and a wind profiler.

Shortest weather forecasts indicate the weather as it is at present. A forecast this short becomes inaccurate very quickly, for example if a cloud drifts to cover the sun. The next step is to forecast that atmospheric phenomena - such as clouds, rain, and low pressure areas - continue their movement to their current direction. This kind of forecast is accurate for some 30 minutes, and the accuracy of the forecast deteriorates more slowly than in the first case. There are typical lifecycles for many phenomena, and by understating these we can reach forecasts up to a few hours. For example, we know that cumulus clouds grow to thunder clouds, and that radiation fog dissipates approximately two hours after sunrise. Forecasts for longer periods are based on mathematical equations computed with computers.

Accurate short-term weather data for a wider audience

Short-term forecasts have been available for decades to special target groups, such as aviation weather authorities. Other professional uses include road maintenance authorities, construction sites, harbors, and sports events.

The first channels to provide accurate short-term weather data to the public were local radio stations, morning TV shows, and some recorded payphone services. The next generation information sources are the likes of cellphones, digital TV, and broadband internet.

Further information:

Finnish Meteorological Institute, Project Manager Jani Poutiainen, tel +358 (9) 1929 4140
Vaisala Oyj, Project Manager Heikki Turtiainen, tel +358 (9) 8949 2261
Helsinki Testbed homepage, http://testbed.fmi.fi

August climate information on FMI main site
Some more climate data for August in Helsinki