Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Unique weather radar to investigate snowfall

20.03.2006


The Department of Physical Sciences at the University of Helsinki has acquired a state-of-the-art polarimetric weather radar. The new radar is reserved exclusively for research. Its most important meteorological research target is the physics of rain clouds, and scientists intend to focus on snow and sleet in particular. Snowfall and its polarimetric measurements have hardly been studied anywhere else in the world, although in the Finnish conditions, for instance, snowfall is one of the key weather elements.



The first test measurements of the prototype radar built for the University’s radar laboratory provided good evidence for the potential of a polarisation weather radar. The largest road traffic catastrophe in the Helsinki metropolitan area took place on 17 March 2005, with several multiple pile-ups on all Helsinki. The new radar was just undergoing test runs and it immediately revealed the meteorological factors which led to the accidents.

Radar images showed that the road conditions before the accident were dry and cold with only slight snowfall. There was, however, supercooled water in the air, which made the road surfaces slippery immediately prior to the accidents. At the time of the accidents, a narrow zone of heavy snowfall arrived from the south, suddenly reducing visibility. In places, this was followed by a larger area of snowfall with a high content of supercooled water.


Radar signals distinguish rain from snow

As the above example shows, the polarisation weather radar can reveal meteorological factors behind accidents. There is no radar as efficient in every aspect anywhere else in the world. Its exceptional features include an antenna with top-class properties, a versatile and powerful transmitter and an ability to measure two perpendicular polarisations.

The radar works by simultaneously transmitting two differently polarised microwaves to the atmosphere and receiving their reflected signals from the rain. The slight differences in the weak reflected signals with different polarisations enable scientists to deduce whether the precipitation falls as water, snow, hail or sleet, and gives information on the quantity and quality of the various precipitation particles (water drops, ice crystals, snow flakes or hailstones) over distances up to 200 km at all levels of the atmosphere. This is not possible using conventional weather radars, which only show where there is precipitation without being able to distinguish between rain or snow.

The radar’s transmitter is designed so that it can transmit either ordinary microwave pulses or what is called coded pulses. This makes it possible to further improve the radar’s measuring capacity with the help of new mathematical processing methods of radar signals. Indeed, research at the University is also being carried out to develop radar technology and further improve its measuring capacity.

The University’s radar was manufactured in Finland. The properties required from the radar were defined by Timo Puhakka, PhD, radar laboratory manager, and the radar was designed and built by Vaisala Oyj in co-operation with the radar laboratory.

The radar is located at the University’s Kumpula campus, on top of the Physicum building under a round dome, which acts as a landmark for the campus.

Radar meteorology has been one of the focal areas of meteorological research at the University of Helsinki for more than 35 years. The University’s radar laboratory boasts radar meteorological expertise of the highest level and it is widely known internationally.

Minna Meriläinen | alfa
Further information:
http://www.helsinki.fi

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>