The seventh dual-polarization radar of the Finnish Meteorological Institute became operational in mid-July. The radar is located on the Luosto hill in Sodankylä and it was supplied by Vaisala Oyj.
Photo: Ilpo Koskinen
Road users will be among the beneficiaries of the new technology because it helps to improve traffic safety by making precipitation observations and forecasts more accurate. With the new technology, the radar will be able to distinguish between different types of precipitation (such as rain, snow and hail). This additional information allows meteorologists to observe and forecast the intensity of precipitation more accurately. The Finnish Meteorological Institute also expects the new technology to improve the quality of the measurement data as, in addition to giving a more accurate view of different types of precipitation, the radar images are now also able to distinguish between birds and insects.
'The radar data is also used in many applications. It is used for such purposes as the assessment of the forest fire risk and monitoring of precipitation. In Lapland, where distances are long, the data produced by the radar is also particularly important during the winter months when the need for road maintenance depends on the amount of snowfall,' explains Harri Hohti, Senior Researcher at the Finnish Meteorological Institute. Precipitation also affects the availability of hydropower and flood forecasts. For these purposes, the Finnish Meteorological Institute also supplies radar data for the Finnish Environment Institute.
The weather radar network of the Finnish Meteorological Institute comprises eight radars of which the radars in Vantaa, Kouvola, Ikaalinen, Korppoo, Kuopio and Utajärvi also already use the dual-polarization technology.
The Finnish Meteorological Institute produces weather radar images for public use and for the use of its customers. One radar maps precipitation areas within a radius of about 250 kilometres. The publicly available images covering the whole of Finland are a combination of the information produced by several radars as this gives the best picture of the precipitation situation.
The new radars make use of dual-polarization technology in which the radar antenna emits horizontally and vertically polarised microwave pulses. Theses pulses provide information about the shape of the measured object, which allows the state of the object to be calculated. Using the horizontal and vertical pulses, the intensity of the precipitation can also be measured more accurately than with traditional radars.
Vaisala began the development of dual-polarization radars at the start of the 2000s in cooperation with such partners as the University of Helsinki and the University of Colorado. The Finnish Meteorological Institute has also been involved in the development work. Vaisala added the radars of the new generation to its product range in 2007. The entry into the market was made easier by the acquisition of the US company Sigmet, which gave Vaisala access to cutting-edge expertise in weather radar signal processors and application software. More than 50 Vaisala radars have been sold to 20 different countries.
Senior Researcher Harri Hohti, tel. +358 29 539 3629
Finnish Meteorological Institute's weather radar network: http://en.ilmatieteenlaitos.fi/fmi-radar-network
Dual-polarization radars: http://ilmatieteenlaitos.fi/uudet-tutkat
Vaisala weather radars: http://www.vaisala.fi/fi/meteorology/products/weatherradars/Pages/default.aspx
Vaisala is a global leader in environmental and industrial measurement. Building on 75 years of experience, Vaisala contributes to a better quality of life by providing a comprehensive range of innovative observation and measurement products and services for meteorology and chosen weather-related and industrial markets. Headquartered in Finland, Vaisala employs approximately 1400 professionals worldwide. www.vaisala.com