Imaging the Cryosphere

Well, they are long workdays, but we’re actually getting closer and closer to August 7, the summer’s first sunset at Summit. It’s amazing how much less light is in the Big House late at night, compared to earlier in the summer. We’re actually turning lights on, in order to keep working after midnight. That doesn’t mean the tents are any darker, but on clear days you can see the sun thinking about putting on some color as it dips towards the horizon near midnight, before changing its mind and climbing again. He’s gettin tired, that sun.

Today John and I worked hard at putting up another powerful supporting instrument – thegoniometer, which John mentioned in his last entry.  The dangerous looking box with flashing red and green lights (see below) is actually the brain center of the instrument, controlling a suite of spectrometers mounted on a robot arm.  The goniometer measures the directional reflectance of light from 145 points in a hemisphere around a single point on the snow surface. Snow is an anisotropic surface, which means the brightness of the surface depends on both the angle of the incoming light as well as the angle of observation – when you are facing the sun, the brightest snow you can see will be between you and the sun. The goniometer is designed to measure the magnitude of anisotropy, which is an important piece of knowledge because remote sensing platforms such as satellites and our UAV observe the surface with a fixed viewing angle, so translating the energy coming off the surface at that specific angle to a full albedo measurement requires a knowledge of the anisotropy.

Our biggest challenges remaining with the instrument will be taming the mess of control cables, data cables, power cables, and fiber optics flying everywhere, as well as administering an accurate and precise calibration to sensors which are awfully sensitive to changes in temperature.

In other news, congratulations are in order once again to the flight crew! Cryowing has been haunted throughout the campaign by communication issues, dropped connections through the Iridium satellite modem, and sensors on the fritz at exactly the wrong times. It seems as though Rune and Kjell-Sture managed to overcome many of these hurdles today, with an excellent flight that lasted well over an hour thanks to stable communication with the plane. The plane made several passes of reflectance measurements over our ground station, then flew three times through a grid pattern covering several square kilometers west of the skiway. Great flight, and we hope to see great data out of it!

As with every flight of the Cryowing, John and I were kept busy late into the evening characterizing the snow surface observed by both the plane and our ground station.

We inherited some instrumentation (beautifully engineered by the Swiss)… but of course, I wanted to make some changes. Nothing much, just adding some triggering options for our spectrometers. The prior instruments used with the goniometer were triggered manually or through a serial interface. Our setup requires a simple 5V trigger from the data logger.

It wasn’t too much of a hassle, but in order to see what was happening with the datalogger since it wasn’t connected to the goniometer (it’s too big for our lab — stayed tuned, we’ll have photos of that once it is up and running) I connected some LEDs to a breadboard.

Well, after a few hours of tinkering, we’re under way! Tomorrow we’ll hope for some good weather to get the instruments up and running on the goniometer.

And in other news… I arrived back up here at Summit last Friday. It’s amazing how quickly the days go by. It’s already nearly 5 days I’ve been on station. We’ve had quite a large crew up here. Of particular interest has been the IGERT group. It’s a crew from Dartmouth of interdisciplinary graduate students. As the culmination of several graduate courses, they come here to Greenland to share with one another their research and also to share the research with the Greenlandic community. It’s a truly inspiring program. Watching the students work together, interact together, and learn about the research we’re doing here is really tremendous somehow. It’s hard to find words, but I can see from my experience teaching Outward Bound that the bonds being developed and the lessons learned will be more than ‘classroom’ or ‘text book’ experiences.

They have a great blog too! (http://dartmouthigert.wordpress.com/ )

A lot of science… a lot of logistics. Thought this painted a pretty good picture of the flight period operations here in Greenland. It’s a poster on the CH2 Polar Services field operations office here at the Kangerlussuaq International Science Support center.

Today I left Oslo at 05:00 bound for Greenland. Well, sort of. I’m heading back this time via Italy!

Ill be stopping through Bologna first to pick up NOAA’s sun photometer. We’ll be setting it up at Summit for some side by side comparisons with the instrument that is there already and also to provide some valuable input to our albedo experiments as well.

On my way through CPH this morning I saw Air Greenland’s unmistakable Red Bird … their A-330 coming in to the terminal. Ill guess I’ll be catching up with it in a few days.

Marco Tedesco’s group from JCET The City College of New York is up at the Summit station to study microwave techniques as tool to detect snow melt. Part of their work is to study the snow properties down to 4 metres depth in a trench dag about 1 km west from the Station. Our VAUUAV-group is lucky to get to use the trench for our contact spectrometer measurements and near infrared photographing.
PhD student Nick Steiner in Tedesco group works also with infrared photographing of snow and comparing our measurements and methods to his will be really valuable!

All the meals at Summit Camp have been delicious, but Friday dinner was something special. We were served Alaskan king crab, a very entertaining dinner. Stian and science technician Lana were the ones to thank; both were celebrating their birthday that day. Rosemary, our chef, made two delicious birthday cakes. Stian’s one was a Norwegian recipe, a cream cake with cherries.

The last week at Summit did not permit us to do much snow science or flights. The winds were strong, up to 36 knots. When the weather is at its best, you can’t see the other buildings of the station from all the blowing snow. Waiting for the weather is a big part of our job up here.

The International Polar Year has officially ended and was closed at the Polar Science Conference in Oslo, Norway last week (June 6-12, 2010).

Polar Science Conference

We presented an overview of our project and some of the early results from 2010. The data presented in the attached file is entirely preliminary, but it shows the progress we’re making and the state of some of our analysis. You can grab a copy of the file here.

How is life on an ice cap? The view is flat. During good weather  days we see the plane horizon. On bad weather days, everything is just white. The sky is most of the time covered with rapidly changing clouds. At night time the station is often in an icy fog.

The nightly fogs bring about frost, large flowerlike features building up on the snow surfaces, tents, buildings, us, and
everywhere.

The less you see, the more you experience. Life on an ice cap makes you appreciate the details you would not notice elsewhere.

Although it feels like we have only been able enjoy Summit Station for a short while, Sanja and I have already finished our first week of digging in the snow and enjoying the peaceful yet stimulating atmosphere up here on the ice sheet. So far in that week we have seen two very successful UAV flights, and we are hopefully adding a third today. We have also made several snow pits to gather data on the characteristics of the snow we are studying. Furthermore, along with the infrared camera to study grain size, we have begun using a field spectrometer to do the same. In order to maximize the quality of our data, we have constructed a pit cover from pieces of black tarp and black trash bags duct taped to a blue tarp. The instrument works best when ambient light is limited.

Yesterday the weather was not so cooperative. The wind was strong and from the North, and the visibility was also low.  While waiting for better weather, a few of us went out to the ski way to fly a kite. It was pulling us so much that I decided to get on cross-country skis and let it pull me.  A little bit more wind would have made the ride even better.

Perfect flying conditions, temps were moderate and winds less than 12 knots SW. Stian and Andreas had the plane prepared and we were set for a day of flying. The plane took off ~11:30. It was flying very well with Stian, easy handling and climbed quickly. COMS were stable. We turned it over to autopilot and it took off for the SW way point. After it turned the corner N from the SW waypoint, the engine cut. It was too far (~2km) to see clearly, but eventually I could see it spiraling downward… a classic stall spin some said.

We went to recover the plane and found it in remarkably solid condition, but still a total loss. The strobe was flashing, the camera was taking pictures… but when Andreas connected is ethernet cable to log in, when asked for ‘password’, he was only told ‘ass’. Well, I guess planes have feelings too! But we don’t really know what it was that drove the crash. The most frustrating part for Andreas and Stian was that there were no logs to be recovered from the autopilot. Generally, after every flight the first thing to check are the flight logs. These have various bits of information recorded from the autopilot, essentially, the black box. For some reason, the logs were not recoverable, so there was very little information available to diagnose what caused the fault.

A priority for me was of course the instruments. What was the status of our spectrometers. We conducted some quick tests, and it seems they have survived overall, but we have yet to complete a detailed calibration using our Spectralon (C) panels.

By afternoon, word had spread through the station. It’s a tough thing to accept that you lost a piece of equipment. We were certainly discouraged.