Calibration of the All-Sky Cameras

As nights are getting dark enough to observe the northern light, it is time to perform the yearly absolute calibration of the cameras and imagers which monitor the aurora. This week, scientists from the Finnish Meteorological Institute, EISCAT, the University of Southampton and the University Centre in Svalbard (UNIS) are calibrating their instruments in Tähtelä.

Four all-sky imagers are being calibrated: two ICCDs (Sodankylä and Longyearbyen) and two EMCCDs (Kilpisjärvi and Abisko). The calibration of each instrument takes a couple of hours. It consists in measuring the response curve of the sensor to a known source of light obtained from three lamps illuminating an integrating sphere. The purpose is to be able to convert the number of counts received in each pixel of the sensor into photon flux in rayleigh (1 R = 795,774,716 photons.m^-2.s^-1.sr^-1).

Integrating sphere used to produce the calibrating light source.
Photo: M. Grandin

Since the instruments measure the auroral emission in three wave lenghts (427.8 nm "blue", 557.7 nm "green" and 630.0 nm "red"), the calibration must be done for each of these three channels. In practice, the green and red channels are calibrated during a same procedure, and the blue channel calibration takes place separately. The whole calibration procedure is of course done in a dark room and is controlled remotely.

The Sodankylä ICCD imager set up for calibration.
Photo: M. Grandin

May this auroral season be rich in substorms with clear-sky conditions!

Midnight Sun on Svalbard

As summer is on its way, here on Svalbard we have had the midnight sun for several weeks already. Last "night" turned out to be optimal to try a photomontage with the sun slowly approaching the northern horizon and being only hidden by the mountains.

The picture below is based on images taken between 22:00 yesterday evening and 03:15 today (local time), from the third floor exterior stairs of the Sjøskrenten student housing, in Longyearbyen.

Picture: M. Grandin.

An EISCAT cake at the Northernmost Baking Competition

Last Sunday, a group of students at the University Centre in Svalbard (UNIS) organised a baking competition – which they assumed to be the northernmost one, with rather high chances of being right. Fifteen teams came up with their masterpieces, competing in three different categories: best taste, best design/creativity and unexpected ingredient.

It must be said that the level was pretty high, and the event attracted about seventy students to the third-floor kitchen of the Sjøskrenten student housing to be judges and vote for their favourite cakes after conscientious tasting.

The ESR cake, by the Collisional Quenchers

The Arctic Geophysics Master and PhD students, aka the Collisional Quenchers, proudly managed to get to the third place in the best design/creativity category! Their EISCAT Svalbard Radar (ESR) cake indeed made a great impression on the audience, although this could not compete with the very professional-looking Russian Mine Cake, by far ranking first. Had there been a nerdy category in the competition, though, they would surely have won!

The Russian Mine Cake, winner in the best design/creativity category

Successful ICI-4 rocket launch during fieldwork at ESR

Lucky again! The Master and PhD students in Arctic Geophysics at the University Centre in Svalbard (UNIS) are this time spending the week at the EISCAT on Svalbard Radar (ESR). They are allocated two hours of radar time per pair of students to run the experiments they designed during the previous weeks to study substorms, polar cap patches, auroral structures and ion outflows. If Tuesday night was the opportunity to take group pictures in front of the ESR dishes with the aurora in the background, last night was a really special one.

It reads "UNIS" (of course).
Photo: M. Grandin

Indeed, as the weather conditions were quite promising, we were informed upon our arrival at ESR that the ICI-4 rocket was likely to be launched from Andøya (mainland Norway) that very night. The ICI-4 mission, led by Pr Jøran Moen from the University of Oslo, is aimed at studying the interaction of an electron cloud with an auroral arc. The electron cloud in question is the result of the drifting of a polar cap patch to auroral latitudes. Since such a configuration generates high disturbances on radio signals, it is a topic of great interest, and in-situ measurements of the physical phenomena occurring within this structure therefore prove extremely valuable.

There was a lot of suspense regarding the possibility to have at the same time favourable weather and geophysical conditions, and both from Andøya and ESR we were all monitoring in real time the ionospheric measurements made by EISCAT and the Norwegian magnetometer chain. Finally, as the optimal conditions appeared, it was decided to launch ICI-4. The final countdown ended at 23:06 local time (22:06 UT), and we all followed the mission elapsed time count for about ten minutes after the take-off.

Happiness at ESR after the successful launch.
Photo: A. Hall

After such a thrilling fieldwork evening, let us wish to Jøran Moen and all the people involved in ICI-4 that the rocket recorded great data for them to study what happens when an electron cloud encounters an auroral arc!

Field work at the Kjell Henriksen Observatory

This week, the Master and PhD students in Arctic Geophysics at the University Centre on Svalbard (UNIS) are going up to the Kjell Henriksen Observatory (KHO) every evening to do some field work.  To get up to the observatory, we first need to drive to Mine 7 on Adventdalen and then have a ten-minute drive to KHO in a so-called bandwagon. Quite an experience...

The bandwagon.
Photo: M. Grandin

Many optical instruments make auroral observations at KHO and monitor the geomagnetic activity. First, there are several UNIS cameras to record the auroral emission above KHO, among which: a DSLR all-sky camera, taking colour images with a resolution ranging between 5–30 s, an all-sky video camera with 25 ms time resolution and a narrow-field monochromatic imager enabling to study fine structures within the auroral arc when it fills the field of view. Imagers owned by other institutes (University of Oslo, Finnish Meteorological Institute, University College London...) are also set up at KHO.

The meridian scanning photometer at KHO (owned by UNIS).
Photo: M. Grandin

The instrument on which we focus the most is the meridian scanning photometer (MSP). It measures the number of photons reaching the detector in order to provide the intensity of the auroral emission. Thanks to a rotating mirror, a scan of the sky along the geomagnetic north-south direction is made every 4 s. When an auroral arc is present, since it is generally oriented along the east-west direction, its elevation as seen from the observatory is recorded. By making a keogram out of the data, it is therefore possible to track the movement of the aurora across the sky. We made an absolute calibration of the MSP last night. This operation is generally performed about three times in the aurora season.
Tonight, we will do some bigger work: we need to make the absolute calibration of three spectrometers. We will mostly work outside, keeping two people to watch for polar bears and getting some others climb onto the roof of KHO. It should be quite chilly (around -30°C) but fortunately without too much wind...

A photomultiplier similar to the one used by the meridian scanning photometer.
Photo: M. Grandin

As a bonus, it turns out that we have been very lucky weather-wise, as we were granted clear skies for our first two nights onsite. Cherry on the top, we even got some aurora (i.e. good data to analyse later)! Although it was quite cold outside – around -25°C –, we of course found enough motivation to go out to take some pictures.

Group picture under the aurora!
Photo: D. Billett

The History of Svalbard course (and its unexpected Royal visitor)

This week and the previous one, an excellent twenty-hour course on the history of Svalbard is being given at UNIS by Dr Thor B. Arlov, who is also the Pro-Rector for Research at NTNU (Norges Teknisk-Naturvitenskapelige Universitet) in Trondheim, Norway. The lectures take place every evening and are open to the Longyearbyen public as well.

During these two weeks, the Svalbard Museum allows the students who take this course to visit the expositions for free. It provides very interesting illustration of the different activities which brought people to Svalbard after its discovery by Willem Barentsz in 1596: whaling, hunting, coal mining, and ultimately research and tourism. One session focused on the development of scientific research on Svalbard, from Chichagov's expedition in 1764–1766 until the establishment of UNIS in 1993 and the installation of the first antenna of the EISCAT Svalbard Radar in 1996.

The (cosy) interior of a Russian trapper's house

The course also describes the expeditions to(wards) the North Pole which departed from Svalbard during the 19th and early 20th centuries, and it discusses the specific administration and status of the archipelago within the kingdom of Norway.

By the way, this week, Queen Sonja of Norway is in Longyearbyen and has been visiting many of the local facilities, including UNIS, the Kjell Henriksen Observatory and the Svalbard Museum. She even attended about half an hour of yesterday's course! And – mere coincidence – that part of the lecture dealt with... the process by which Svalbard was integrated into the kingdom of Norway, and how its local administration has been evolving, until the creation of the local council (lokalstyret) in 2002.

Hilsen fra Longyearbyen

78°13'N. This is the geographic latitude of Longyearbyen, the main human settlement on Spitsbergen, where the University Centre on Svalbard (aka UNIS) provides first-class teaching for Bachelor, Master and PhD students in Arctic-related topics. The teaching and research carried out at UNIS are divided into four departments: Arctic Biology, Arctic Geology, Arctic Geophysics and Arctic Technology. Each year, a few hundred students from all around the world come to take part of their degree in this very peculiar environment, where unique opportunities to carry out field work in the extreme Arctic are provided.

I am presently enrolled as a student at UNIS in Arctic Geophysics to take two courses (The Upper Polar Atmosphere; Radar Diagnostics of Space Plasma). The courses include practical sessions at the Kjell Henriksen Observatory (KHO, auroral station) and in the EISCAT on Svalbard Radar (ESR) next month. 

Eventually, the sun will rise. Someday. Or so we hope.

The whole last week was dedicated to the Arctic Survival and Safety course, mandatory for all the spring semester students and aimed at providing them with the necessary knowledge and skills to carry out field work safely on Svalbard.

The extreme Arctic is full of hazards due to weather conditions and the remoteness of most of the regions of the archipelago. The students who are part of an expedition outside Longyearbyen must therefore be aware of the risks they may face and be able to act efficiently if in a difficult situation. Besides the polar bears — which although dangerous do not represent the most serious threat —, the deadly hazards awaiting for human beings are numerous: crevasses in glaciers, weak sea ice, avalanches, fragile ice caves, walruses... without mentioning the cold, the wind and the absence of resources.

The lessons included a lot of practical training, especially to rescue victims of an avalanche or fallen in a sea ice hole or in a crevasse, including first aid techniques and building of an emergency camp. Another session was dedicated to telecommunication and navigation, as in most cases the only way to call for help is to use an emergency beacon and/or a satellite phone.

On Saturday, the students were taken to Longyearbreen, a glacier very near Longyearbyen, for a full day of practice. Fortunately, it was not windy on the glacier, which helped withstanding the cold and setting up the camps. After rotating over five rescuing and survival tasks, all the students were invited to observe a demonstration of a rescue operation by a Super Puma helicopter. Pictures of that day were taken by Stefan Claes, who was one of the instructors during the week; see here.

After this very busy and intense week, the regular courses can now start. And I guess for all the students this safety course was an amazing experience and a fantastic training for both their field work expeditions and their private excursions.