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 Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

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: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

How gut bacteria can make us ill

18.01.2017 | Life Sciences

On track to heal leukaemia

18.01.2017 | Health and Medicine

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>