Every great scientific campaign has to come to an end. The POLSTRACC/GW-LCYCLE/GWEX/SALSA campaign as well. Today HALO took off for the last time in Kiruna and is on its way home to Oberpfaffenhofen. And of course HALO also has to say goodbye to Kangerlussuaq, where it refueled so many times during this campaign phase. So right now they are approaching Greenland again for a last stop over. As always you can follow HALO on Gloria Watch.
Don’t be sad now, it is not the very last flight of this campaign. There will be one or two more flights heading from Oberpfaffenhofen to the South (or at least towards subtropic air masses – let’s see where that will be), before the campaign finally finishes next Sunday.
After yesterdays 11 hours flight with refuelling stop in Kangerlussuaq in Greenland, today we are already preparing for take-off again. And we are going to – try a guess – Greenland. There are already jokes going on, that we should have taken the base in Iceland, as many flights brought us to the Canadian coast and over Greenland. Luckily HALO has such a long range – it could fly till San Francisco without refuelling.
Combining different scientific goals into one flight is a very complex process. The flight planning for the 15th scientific flight of the POLSTRACC/GW-LCycle Campaign started three days in advance. Different Teams presented their ideas about where to fly. Fast (that means after just 3 hours of discussion) a conclusion was made that a complex tropopause structure approaching over the Atlantic was a very interesting scientific goal and that could be combined with sampling a gravity wave structure over Northern Scandinavia. Two days before the flight, the plans got more detailed and everyone concluded on probeing the structure the moment it hits the Norwegian coast. A preliminary flight plan was made and handed over to the airtraffic control of the different countries. One day in advance another flightplanning meeting was set at 10:30am to finalise the flightpath according to the latest meteorological forecasts. Just when everything was finalised the info arrived that there will be a big military excersise in Norway exactly when and where we wanted to fly and the airspace will be closed. The planned flight was not possible anymore.
Today I will mainly show you the advantages of being close to the Artic Circle. Every few days you can see an Aurora. For those of you who have never seen one my colleagues made an awesome video, which you can see below. There you can see how they move across the sky. Another advantage of the location of Kiruna in the far North are the low temperatures throughout the whole winter season. That makes the Icehotel possible, which is built every winter since 1989.
Today a flight with both planes HALO and Falcon to southern Scandinavia was planned. On that flight we want to measure gravity waves. Gravity waves are periodic movements of the air, which lead to temperature and wind fluctuations. Gravity waves are excited in the troposphere for example through wind blowing over a mountain ridge. They transport energy from the troposphere into the higher stratosphere. The breaking waves deposit energy and drive global atmospheric circulations. Over southern Scandinava the polar jet is today blowing over the Norwegian Alps, where then mountain waves (one kind of gravity waves) are excited. The wave fronts are oriented parallel to the mountains and therefore in North-South direction. The flight pattern crosses the wave fronts on different altitudes several times to get a full picture of the wave.
Yesterday there was a HALO flight towards the North Pole to measure polar stratospheric clouds. On that flight HALO followed the CALIPSO satellite track to compare the measurements. During this flight the ground crew had some hours off during the afternoon. This opportunity we took to visit the nearby village of Jukkasjärvi. The village is next to a big frozen lake. So we walked over the lake where we met some dog sledges and jetskis. Afterwards we could warm up with tea and coffee in a Sami tipi at an open fire place.
Today I will show you a bit around and tell you what we do besides preparing scientific flights. This post will be mainly a collection of pictures. At the end today’s HALO flight will be presented shortly.
Today we want to do a long flight with HALO towards Greenland. How is this decision made? Why today? And why to Greenland? In my blog post today I will give a short overview about how the planning process looks like.