The end is nigh

Harken, brethren and sisters, it is soon that VERDI hath passed its last of days! Behold this heavenly sign, unmistakably foreboding the final hour! The Sun itself, our celestial guide, hath covered its radiance with a selenic veil.

The safe way to observe this partial solar
eclipse: project the solar disk through
a detached photo camera lens.

Without exposing the eye, a camera
can take a decent photo with the
shortest exposure, the smallest
aperture, and sunglasses.

Today's solar eclipse was annular (ringförmig) in the central Pacific Ocean and the western USA. In Inuvik, it was still a partial eclipse (50%).

We prepare to leave

On Friday all of the equipment that goes to Muskoka with the Polar 5 was packed into the aircraft. Saturday morning the aircraft left for Muskoka (with an overnight stop planned for Winnipeg). Sunday most of the science team left as well, partly for Muskoka, partly home to Germany. Only Eike and myself stay until Monday, then we leave as well for Muskoka.

Calibrating: Drive in circles

This rather cryptic message from our rental car left us somewhat confused!

Last Science Flight!

A hyperspectral image of Inuvik Airport,
converted to true colours.

On 17 May 2012, we performed the last VERDI research flight. We probed the same cloud area as on the previous days. Again, there were some ice crystals in the cloud although the temperature was pretty warm, between -4°C and +4°C throughout the cloud. We followed a pair of parallel tracks above and through the cloud layer, and in the end we flew two butterfly patterns for the geometrical calibration of the hyperspectral camera, Eagle. For that we need to look at a distinct surface pattern at different angles.

With this flight, we have used up all our flight hours. Thanks to Alfred Wegener Institute for providing the aircraft and the generous flight hours, and to Aurora Research Institute for the excellent support in Inuvik!

Flight May 16

Inuvik from above

Another flight into the same area. Having snow showers (flurrys as the showers with low intensity are called here) at the airport we were sure that these clouds have to contain ice. In the target area this time we continued heading west expecting a change in the cloud properties indicated by a second cloud field in the satellite images and almost reached US airspace. The cloud field in the west we just missed. But indeed the clouds did change. Cloud top decreased and thickness as well. On the way back we first did not found many ice particles. Later further east the number of ice crystals increased more and more. On our way back to Inuvik we stayed below cloud bottom and collected some more precipitating ice crystals and images of Inuvik and the Mackenzie Delta,

It's winter again

Surprisingly it did start snowing again during this night. Remember the T-shirt weather two days ago!!! Similar to yesterday northerly winds blow cold air into the Mackenzie delta and generate clouds and even precipitation. We expect to have another flight into the same area sampled yesterday. Hopefully it will also snow there.

(Some) ice is back: Flight on 15 May

Turning back to go through this nice
Cumulus cloud once more.

Today we flew into the same area as yesterday. The cloud was still there, and it was in fact a little different than the first time. We even saw ice crystals in the cloud! We probed it on a east-western and a north-southern leg, and found differences between all the waypoints. The "icing on the cake" of this flight was a cumulus cloud on the way home. There were no convective clouds in this area before yesterday, so this something new for VERDI, and of course we did a few turns inside it. The cumulus contained aggregate ice particles, and finally the flights became a little bumpy.

The Niagara Falls of Inuvik

The high temperatures of the last days lead to heavy melting and a lot of runlets bringing water from all over the town to the Mackenzie.

Today a strong and cold wind from the north produced fog in our area with temperatures again below zero.This delays the flight planned for today. Hopefully we get into the air around noon heading for the same area and clouds as sampled yesterday.

Flight into clouds, 14 May

Canada Is the country of lakes. There is no
official estimate of the total number of
lakes in Canada; three millions is a first
inofficial guess. Start counting here: The
Mackenzie delta is nothing but river arms and
lakes between small dry stretches with trees.
The contrast between dark trees and white
ice makes the counting easier in winter!

Finally, after a couple of days of sunshine and leisure, the clouds came back. Inuvik itself is still sunny, but a low cloud deck has formed over the southern Beaufort Sea. And it seems it's there to stay, so probably today's flight is the first of a series. We targeted two cloud areas. The first ended earlier than expected, and the second had a double cloud layer. We probed the cloud at several altitudes in both layers, and inbetween. Alas, it is too warm to find ice particles in the cloud! Nevertheless, clouds over the sea ice are always of interest. And these ones were different from the ones on all the previous flights, so we are quite happy.

Current weather forcast

Although everybody of the locals might be happy with such a forecast for our reasearch flights this picture is a bit frustrating. Fortunately the ECMWF forcast differs and predicts clouds above the Beaufort sea for late Monday and Tuesday.

Wildlife

On  a day without flying, we have time to explore the surroundings of Inuvik. Even up here, there is considerable wildlife. There are also moose, but all we saw of that was brought to us in a pot, hot and very tasty, by local hunter and guide Donald.

The local variety of the arctic hare

Female grouse/ptarmigan, in transition to summer plumage

Bald Eagle

Road Closed

Today we made a day off (with very nice weather) and six of us took the Dempster-Highway southbound. About 110 km south of Inuvik the "Highway" crosses the frozen river.

But the ice river crossing was already closed because of the warm temperatures. And for good reaosn, as I found out when I sank through the snow and found out that there is indeed liquid (but ice cold) water underneath. My tennis shoes and socks were soaked!

Inuvik vs. Leipzig

After flight on May 10th the big melting started

Thursday was temporalily the last flight for the next days. Since yesterday spring has started in Inuvik. Everything melts, ponds an small lakes are filling up, cars and other things appear again below the melting snow. Unfortunately the temperatures are above zero as well in the altitude levels of potential clouds. This means, there is defenitely no ice in this clouds. That's why we decided to have a break and wait for colder temperatures before having further flights. From Monday conditions are predicted to improve. Until then we hope to reassamble all instruments on board of Polar 5. The repaired 115V-inverters will be installed again and hopefully the CAS-DPOL will arrive everyday that we can start the last week of measurements with full strength.   

A short recapture of Thursdays flight. Again we probed low level clouds above the beaufort sea. Close to the coast we also observed a second higher cloud layer which we intended to probe on our way back. Unfortunately these clouds almost have cleared away when we arrived. Only a small fraction could be probed. The low level showed up to be thicker than the days before. The icing was heavier forcing us to leave cloud top before the probing was complete. After letting the ice melt in the sun the last remaining probing level could be repeated. 

Home cooking

In preparation for the incredibly expensive food (e.g., 1l milk=3 $), one box of basic food supply was send to Inuvik. Most of us are cooking now in the kitchens of our row houses. Only pasta seems not to be welcome anymore. Or someone just miscalculated the demand on noodles. These are 2kg packs!

With everyone being filled up the next flight is planned for tomorrow before the temperatures increase above freezing point. Unfortunately this is unfavorable for the ice crystals we are looking for.

Flight on May 8

This was my first research flight on the Polar 5. We thought we had the ALABAMA mass spectrometer repaired, but in flight some new problems came up, so I had a lot do to with the instrument. In the end I did not record more then 3 (!) mass spectra, which is close to nothing. However, we think that we fixed some problems after the flight and on the next day, so there is still hope. As far as I heard, all the other instruments worked well.

De-icing required

The snowfall during the night and temperatures around zero show up to be a bigger problem for todays flight than expected. Polar 5 was covered with a thin ice film which made a de-icing of the entire wings neccessary. This delayed the planed take off about 1 1/2 hours. Fortunately the cloud situation did not change dramatically during this time, as seen from the ground. Now we have to wait what the crew will report after coming back from the flight.

No flight today, but lots of snow

The cloud situation was not very promising today. So we decided to spend another day to work on some instrument issues and wait for long-awaited spare parts. The local weather was not good either. Snow during the whole day. Everybody was reminded of christmas time. Even the Dempster highway was covered by snow again. In the forest close to the Dempster we could find a lot of large Bigfoot traces. Maybe worth to be published in Nature or Science.  

Row Houses

This is where most of us are staying: Friendly small row houses, each with three bedrooms, a living room and a kitchen. Eating out is quite expensive here, so the opportunity to cook for ourselves is highly appreciated.

Ice Road

Although today we had maximum temperatures of about -10°C, the ice road season has been officially closed now. Obviously for the good reasons as some local did learn today. However, on foot it is still traversable. At some places you can see how thick the ice is. Looks like more than one meter.

Flight on 3rd of May

Thin clouds that are barely visible
on the satellite image (NASA
MODIS-Terra, 3 May 2012)

On the third day of May, our flight brought us to a very low and shallow cloud deck over the sea ice of the Beaufort Sea. We had taken the coordinates for our flight destination from cloud forecasts and satellite images, but by the time we arrived at the location where the cloud should have been, all we saw was the sea ice and a blue sky. So we kept going north (whither the cloud was withdrawing), and soon we could see first patches of clouds. We cannot go into a cloud when it is very low, because the aircraft needs a safe distance from the ground. But with AMALi, our lidar instrument, we knew that the cloud was in fact just high enough to go in. So we scanned the cloud from above for a while, and then went down and flew through the cloud on the same way back.

Our team

Photo by Ralf Weigel

We are having a little break due to an unattractive cloud situation. We use the time to look at the data collected so far, to give the aircraft due maintenance, and to take this picture of our team in front of the Polar 5 at Inuvik Airport. Greetings to the folks at home who enjoy 20°C — look at the snow in the background and our hats. Temperatures here will stay below freezing for the next days.

Ice clouds and snow

A 22° halo brightened by a lower
tangent arc indicates columnar
ice crystals

On 30 April, we flew through a more complex cloud pattern, with a patchy layer of an ice cloud at around 3 km altitude, and a low mixed-phase cloud near the surface. A snowing cloud was probed at various levels, and should provide a good challenge to test precipitation models.

The perfect low cloud

The ideal model cloud

On the flight on 29 April, we found the ideal textbook cloud: an extensive low-level mixed-phase cloud with clear sky above it. This is what one-dimensional radiative transfer models have been written for! In this cloud, we found liquid droplets that were 20 micrometers large on the top and 10 micrometers at the bottom. Toward the bottom, ice crystals were also found in this cloud.