Sodankylä Geophysical Observatory

Although KAIRA will be built at Kilpisjärvi, the project is administered by the Sodankylä Geophysical Observatory (SGO). This world-class facility was established in 1913 by the Finnish Academy of Science and Letters to perform geophysical measurements and research. Now an independent research department of the University of Oulu, SGO maintains its continuous measurements of the Earth's magnetic field, cosmic radio noise, seismic activities, and cosmic rays.

Since the first measurements began on 1st January 1914, SGO has spread its range and location of sensors over multiple sites stretching from the south of Finland to Svalbard. KAIRA will be the latest in this proud tradition. However, the institute remains based near Sodankylä itself on the banks of the river Kitinen and this is where most of the KAIRA team are based.

The photograph (taken a few weeks ago) shows the main institute building in the dead of the Arctic night. It is one of many buildings scattered around the site. In actual fact, this building is shared with the Finnish Meteorological Institute. More on that later!

End-of-January status

We've now received the latest images from the winter testing! These photographs were taken on 31st January 2011. In the first picture, we see that the raised tile is managing quite well on its frame. There is some snow on the cover, of course, but it is not too thick


The ground tile, on the other hand, is completely covered with snow.



Both tiles remain vulnerable. The raised tile is subject to wind damage in its elevated position. The ground tile, while safe against wind, could suffer from the accumulation of the snow and the movement of the drift.

Photo credits: Th. Ulich

Mound Mesh Model

As reported in our piece on the site survey, we need to accurately model the region where we intend to put the KAIRA antennas. Unlike most LOFAR stations, KAIRA is located in pretty rugged terrain. This means that finding a suitable space is not as easy as it first appears. Especially when we are trying to avoid cutting down trees and keeping our impact on the Arctic wilderness to the barest minimum.

The site we have selected fits these requirements pretty well. The ground is mostly material from civil works, allowing us to re-use an existing development. However, the space is not easy to work in, especially when the main antenna array has an area of over 1200 m²., which needs to be levelled to an accuracy of ±3 cm. As a result, we need to consider well the exact location of the array and the amount of levelling required.

The plot shown here is from part of that analysis work. From the survey results, a topographic mesh is fitted to the data. That is then interpolated to derive a working model of the surface. From this, the detailed planning and layout can be completed.


The map is oriented with North at the top and the direction to the EISCAT VHF transmitter marked.

Amazing new images from LOFAR

There's been some major developments on the LOFAR project. As announced in a flurry of press-releases yesterday, LOFAR has managed to combine many of its international stations which, along with the core stations in the Netherlands, have resulted in some stunning images of the radio sky. These images demonstrate the enormous capabilities of this new generation of radio receiver technology and it provides a great encouragement for all of us here working on KAIRA and the EISCAT_3D projects.

A small portion of a wide field radio image (30-34 MHz), taken by the ASTRON/LOFAR commissioning teams led by Olaf Wucknitz (Bonn) and Reinout van Weeren (Leiden Observatory).

Not only do these images reveal the wide-field capabilities of the LOFAR system, but they are also at extremely high-resolution — especially at the higher frequencies — as fine as 0.2 arcseconds (close to 1/10000 of the diameter of the moon)!

As this resolution is a factor of the baseline (distance) between stations, the possibilities of linking KAIRA and LOFAR are even more exciting.

Press-releases:

• English
  
• French
• Dutch
  
• Swedish
  

LOFAR

LOFAR (LOw Frequency ARray) is a pan-European radio telescope designed to observe the radio universe at VHF frequencies. It is designed, built and operated by ASTRON, the Netherlands Foundation for Radio Astronomy. The LOFAR system is split across multiple sites — known as stations — each of which typically has two arrays of antennas.

The antennas in each of these two arrays are different in design. One design is a vertical 'aerial' which stands about 1.8 m tall, optimised for radio frequencies in the range 30 to 80 MHz. The other design is a large 'tile', with a square area of 5 × 5 m. It is for the higher frequency range of 120 to 240 MHz.

Did you note the gap from 80 to 120 MHz? LOFAR deliberately avoids these frequencies, as this is where commercial and public FM-radio stations broadcast. There is no point trying to listen for faint cosmic radio signals at the same frequency as a high-powered neighbouring radio station.

In addition to a large cluster of LOFAR stations in the Netherlands, there are additional participants in the main LOFAR project: Germany, France, Sweden and the United Kingdom. This map is a closer view than the one posted earlier, and shows the locations of the LOFAR stations (green = complete, yellow = under construction).


KAIRA makes use of the same antenna technology that is used in LOFAR, making it compatible with the LOFAR system. This opens up some exciting prospects of linking the two projects. We'll be looking at these antenna systems soon.

In addition, there have just been some important achievements by the LOFAR project. More on that in the next post!

Putting LOFAR, EISCAT and KAIRA on the map

As one might guess from the name, the Kilpisjärvi Atmospheric Imaging Receiver Array is located in Kilpisjärvi. For those of you who didn't already know, Kilpisjärvi is a small border town located in the top-left-hand corner of Finland. It is usually very easy to find on a map, as it is quite close to the corner of the three countries: Norway, Sweden and Finland.

But possibly less familiar are the related LOFAR and EISCAT projects associated with KAIRA.

This map marks the sites of these project with EISCAT in pale blue and LOFAR in magenta. KAIRA itself is marked in red. At a latitude of +69 degrees north, KAIRA is located well above the Arctic Circle (marked in white), making its association with LOFAR a most northerly one indeed.

There'll be more about LOFAR and EISCAT over the coming weeks, so be sure to visit this weblog again soon.

Twitter

@KairaProject

Did you know that the KAIRA project is now on Twitter? You can follow us there to keep in touch with the latest news. As the summer build commences, we'll use it as a way of keeping everyone informed with reports from the construction site. Short, sharp, to-the-point and very, very up-to-date!

http://twitter.com/KairaProject