Don's Log

   12 August - 18 August: A westward excursion

Friday 12 August
Aboard Healy Northbound in the Chukchi Sea
77 13.71 N, 155 58.7 W
We expected to hit station 3 at about 0600. But when I woke up at 0630 we were still moving. The small boat briefing has been postponed from 0730 to 0800. Great news at the briefing; once we get on station we will get a Zodiac ride to the ice.

I picked out a nice looking multiyear floe off the starboard side and at 0910 we climbed into the Zodiac and were lowered over the side. The weather was the usual fog, but occasionally the sun would be barely visible. A quick boat ride and we were at the floe. We found a nice harbor, without any underway ice shelves, and we disembarked. As always, it’s great to be on the ice. The weather was the usual fog, but occasionally the sun would be barely visible. Bruce and I immediately started an ice thickness survey. We use an instrument called an EM-31. It is an electromagnetic induction sensor that measures the distance to the ocean, which gives us the ice thickness. The instrument weighs about 25 pounds and has an antenna that is about 10 feet long. It’s not too hard to carry around. Measuring ice thickness with the EM-31 is much faster and easier than drilling holes. Bruce and I were able to cover a circuitous, 1-km-long path around the floe. There were many places we couldn’t go because of melt ponds that had completely melted through the ice. The other melt ponds were about 35 to 40 cm deep. Just about the level of the top of my boots.

While Bruce and I were surveying, Tom and Jeremy were photographing the ice crystals in the surface scattering layer. This layer is critical in keeping the albedo of the bare ice large. These crystals look like coarse grained wet snow, but they are really rotting ice. We had to cut our ice station a bit short when the ice began to close. We were only on the ice for an hour and a half, but we got quite a bit accomplished.

After a delicious pasta lunch we went to the helo deck for the usual fog report. Fog is the standard condition this time of year in the Arctic. There is just a lot of moisture in the atmosphere from the melting ice and the open water and because of the ice the temperature is always around freezing. Maybe tomorrow the fog will lift.

Figure 1. Our transportation to the ice - a Zodiac.

Figure 2. Don and the EM-31 making measurements of ice thickness.

Saturday 13 August
Aboard Healy Northbound in the Arctic Ocean
78 0.00 N, 151 07.753 W          
Waking up the porthole looked very bright getting my hopes up for good weather. Unfortunately it was just the diffuse radiation inside the cloud of fog that we have been in for several days. It does not look promising for flight operations. Indeed they are cancelled before lunch. Having spent a fair amount of time in the Arctic during summer, I expected fog. Maybe not quite as pervasive as this, but fog is to be expected. We are currently enroute to Site 4, with an expected arrival time of Monday.

Even though we can’t get on the ice there is still plenty to do. First of all Saturday is inspection day. There is a bunch of trash to be burned in the incinerator and even better some power vacuuming to do. My theory of vacuuming is that the faster you go the better.

After the cleaning was completed, Bruce and I spent the morning unpacking the ice coring gear. We are going to try to take some cores at our next site. In the afternoon it is time for reflectance measurements from the rail. Normally we would be on the ice walking along making measurements of albedo. Today we let the ship do the “walking.” We set our gear up on the maindeck, starboard bow and waited for interesting pieces of ice to go by. Albedo measurements can’t be made because the ship obstructs part of the view. However, it is possible to make reflectance measurements. Albedo is a measure of the light reflected at all angles, while reflectance is at a particular angle. We picked angles around 45 degrees and used a very narrow 1 degree field of view lens. It has a laser spotting scope to help aim the lens. Under the cloudy foggy conditions of today, the reflectance can be related to the albedo. We measured 25 different cases including leads, bare ice, and a wide variety of melt ponds. A photograph is taken at each site to help interpret the observations. That’s one nice thing about working with solar radiation; at visible wavelengths what you see is what you get.

After a quick battery recharge we do a different experiment. The narrow field of view lens is removed giving an 18 degree field of view and the location is shifted from the maindeck to up high on the flying bridge (outdoor deck above the bridge). We aimed the instrument at the surface at a 45 degree angle and took a measurement every minute. These measurements provide information on the area average of reflected light and can also be used in the interpretation of satellite observations.After 18 minutes the experiment was called on account of rain, as the fog transitioned from mist to drizzle.

The Saturday night morale activity is the movie Sahara playing on the big screen in the helo hangar. I just saw it a couple of months ago, so its data reduction and Ipod tunes instead. We just crossed 78 North.

Figure 1. Optical measurements from the rail. Note the big lens with the telescoping site.

Figure 2. Melt pond with a commonly complex bottom.

Sunday 14 August
Aboard Healy Westbound in the Arctic Ocean
78 0.04.979 N, 155 08.976 W
There are days when I have a great job and today was one of them. The morning started uneventfully, breakfast and the usual fog. Bruce and I worked in the hold to set up one of our ice mass balance buoys. We found all the pieces and hooked everything together. By then it was lunch time. Walking outside to the mess hall I saw an unexpected site – the sky. The fog had lifted showing clouds at 3000 feet and great visibility.

Right after lunch (cheeseburgers and fries) Bruce and I were called to the helo hangar to install our camera and get our helo briefing. We lifted off at 1345 and it was beautiful. Great visibility and a fascinating ice cover to look at. As always the ice looks like a giant jigsaw puzzle. This puzzle had lots of melt ponds as well as ice floes. We flew a modified box pattern at an altitude of 2000 feet and a speed of 90 knots. The legs were 10 nautical miles east, 10 north, 20 west, 20 south, 10 east, and 10 north closing the box. The camera mounted in the pod worked great and I also took over 200 photos out the window of the helicopter. Digital cameras are great, you can just snap away to your hearts content.

After the flight there was time for the daily incident measurement. I took several incident scans every 5 minutes from 1535 to 1405 under cloudy skies with no fog and the sun peaking through. All in all, a very productive day.

Figure 1. Helicopter lifting off from the Healy.

Figure 2. View of the ice cover from 2000 feet looking down.

Monday 15 August
Aboard Healy Westbound in the Arctic Ocean
78 18.948 N, 161 26.934 W
During the night Healy has been moving west and slightly to the north. We are on our way to coring site 4. Our expected arrival time is midnight. Sky conditions are still totally overcast, but the fog is gone. The character of ice has definitely changed. There is more open water and thinner ice than yesterday. There is a considerable amount of first year ice that is only about 0.5 m thick and is heavily ponded. I spent an hour on the bridge and the bow watching and photographing the ice as it went by. The ponds were well developed with intricate shapes. Often there are small “shelves” on the perimeter of the floes. There are extensive “shelves” at the edge of floes, with lengths of several meters. While still intact, the edge shelves are honeycombed with holes and seriously rotted.

After lunch (excellent Mexican food) the weather looked promising for a helo photography flight. The ceiling was lower than yesterday, so we prepared for a flight at 1000 m, with the same 80 nautical mile flight path. Only one passenger today and it is Jeremy’s turn. He is psyched and ready for his first Arctic helo flight. Unfortunately, it was a rather short 10 minute flight instead of the 1 hour scheduled. Shortly after takeoff the weather rapidly deteriorated with some light snow.

Bruce and I did some afternoon optics from the flying bridge. First we did the daily incident spectral irradiance. We then switched from the optics on the spectroradiometer from the “cosine” collector to a bare fiber optics probe. The cosine collector sees an entire hemisphere, while the bare fiber has a 18 degree field of view. We made a series of reflectance measurements by aiming the bare fiber at the surface at an angle of 45 degrees. Each minute, for 35 minutes, we made a pair of measurements; reflectance from the surface and reflectance from a white reference standard. During that time we covered around 1.8 nm. Basically we are getting an average over area of the albedo and are also simulating what a satellite would see.

I just learned that we are scheduled for a 2 AM ice station. Time to take a nap.

Figures 1 and 2. The many faces and shapes of melt ponds.

Tuesday 16 August
Aboard Healy Westbound in the Arctic Ocean
78 16.5811 N, 166 58.1403 W
Time for some midnight madness. We arrived at coring station 4 at 1 AM.There is a nice, though thin and melt pond ridden, floe just off of starboard, within easy boating distance. The floe is documented in a panorama series of photographs from the bridge. The position is 78 26.555N, 162 41.405 W. There is a boat briefing at 2 AM, and we are in the water at 0215. Seven of us are in the boat; four from the ice team and three from the crew. The Zodiacs are really slick – fast, maneuverable, and easy on/off to the ice.

We brought the same gear as last time, EM-31, thickness auger, thickness tape, graduated ski pole, salinometer, camera, and stage. Plus, since everything went so well at the first site, we added a new activity, ice coring. In ice coring you don’t just drill a hole through the ice, but you use a special barrel that removes a cylinder of ice about 4 inches in diameter and as long as the ice is thick. This entailed adding some gear; a core barrel, a black mat for core photographs, and four tubes for transporting and storing the cores. The cores will be analyzed to determine the structure of the ice, the salinity of the ice, and the amount of air and brine in the ice. Also isotopes of oxygen and other elements can provide information on the origin and evolution of the ice. There is quite a bit of information in a few kilograms of ice.

We hit the ice like a well-oiled team, particularly considering it was the middle of the night. Luckily I had a couple packs of cookies for fuel. I took off on an EM-31 thickness survey. It was a meandering collection of straight line segments going from point to point and avoiding the bottomless melt ponds. I was careful not to repeat any sections or even to cross the survey line. The survey was done only on bare ice. Bruce and Jeremy drilled a couple of holes for comparison with the EM-31 observations and then characterized the melt ponds measuring pond depth, the ice thickness below the water, and the pond salinity and temperature. Tom characterized the surface scattering layer by measuring its depth and photographing grain size. He also took samples to measure soot. This floe was different than our last stop. The ice was thinner with less topography. It was also a little cooler, though this may have been due to the early hour. Some of the smaller ponds had a small skim of ice and the white ice surface was hard and crunchy, rather than soft and mushy like the last floe. Finally before leaving we took 4 ice cores: two of the white ice and two from the melt pond bottoms.

We were back on board at 0340 and I was dozing by 0430. Got up around 8AM and spent the morning moving the web cams around so that they get a better view of the sky and processing data from yesterday. After lunch it was the 1300 helicopter briefing. It was actually very nice, but as the briefing progressed the fog rolled in. After an hours’ wait for improvement the flight was cancelled. Bruce and I measured incident solar irradiance and surface reflectance from the flying bridge. For the reflectance we were once again in survey mode where we measure surface reflectance every minute and take a photo for documentation.

We are headed towards Site 5 making excellent progress through heavily ponded 1.1 m thick ice, with a concentration of 70 to 80 %. Estimated time of arrival will be mid-day Thursday.

Figure 1. Working at Ice Site 2 under the midnight sun.

Figure 2. An ice core removed from the bottom of a melt pond. The pond had 30 cm of water with 64 cm of ice below. The unponded ice was 1.2-m-thick on average.

Wednesday 17 August
Aboard Healy Westbound in the Arctic Ocean
78 17.63637 N, 174 7.14178 W
Bright light filled the cabin this morning, but unfortunately it was not the bright light of a sunny blue sky, only the diffuse white glow of the low thick fog we are in. There was a flight brief right after breakfast, so that we could maximize our chances for a flight. We are good to go for a photo flight, if the weather breaks. Until then we work at combining patience and preparedness.

With the fog and the transit to Site 5 we will not be getting out on the ice today. This gives us a chance to get ready for the days to come. First on the list is preparation of the ice mass balance buoys. We advertise these as “a field experiment in a box.” It’s a way to autonomously measure the mass balance of the ice. So what is the ice mass balance? It’s simply the temperature of the ice, how much ice grows and melts on the bottom, how much melts on the top, and how snow accumulates and melts on the surface. There will be more about the buoys when we actually install one. For now we spent the morning finishing the testing of buoy number 1 (A-OK) and begin testing buoy number 2.

From 11 to 12 there is a “webinar” from the ship with educators in Alaska, Texas, and other places. We communicate on a conference phone over the Iridium satellite system. There are even questions and answers. It’s pretty amazing. There are many excellent questions regarding life on the ship, icebreaking, seismic studies, sediment coring, sea ice, and wildlife. One interesting fun fact is that the Healy left Dutch Harbor with 1.2 million gallons of fuel for the cruise.

By early afternoon it’s clear that flight operations will not happen today, so its time for afternoon optics on the flying bridge. Today Tom, Bruce, and I made a detailed map of objects on the flying bridge that may obstruct the radiometers. With this information we can calculate a correction factor to adjust the incident radiation. After that it’s the usual optics measurement sequence: a) incident solar irradiance and b) spatial survey of reflectance. We measure along the rail for 45 minutes, sampling a track length of almost 3 nautical miles.

There is a hint of autumn in the air, with temperatures just below freezing. A change of a couple of degrees might not seem like much, but when it’s from 33 to 31 Fahrenheit, it’s the difference between water and ice. As we travel through the fog we pick up quite a bit of moisture. Yesterday there were wet decks and rails on the ship. Today we have icy decks and rails; so much that the decks are salted for safety.

Dennis Darby was today’s science seminar speaker. He gave a fascinating talk explaining how information from the sediment cores can provide insight on past climates and climate change. Here is a totally non-scientific tidbit. Both Dennis and I grew up in Pittsburgh. And more importantly between us we’ve seen two of Pittsburgh’s greatest sports moments. Dennis was in the left field bleachers in October 1960 when Bill Mazeroski hit the walk-off home run to win the World Series over the Yankees. I was in the upper deck of Three Rivers Stadium on Christmas Eve 1972 when Franco Harris made the Immaculate Reception to beat the Raiders in the AFC playoffs. We also met a member of the Healy crew from Pittsburgh. We talked about the Steelers, the Pirates, and Kennywood Park. We may be in the Arctic, but it is still a small world.

Finally, best birthday wishes to a member of the Hotrax 05 Ice Team –Happy Birthday Tom!

1. Rime ice buildup on an antenna strut. Accumulation was about 2 cm in 12 hours.

2. Measuring reflectance from the rail. The white square is the reference standard.

3. Spectral reflectance averaged over a 3 nm mile track.

Thursday 18 August
Aboard Healy Westbound in the Arctic Ocean
78 18.3305 N, 177 2.3732 W
Last night’s sunshine is gone. There is a low stratus cloud deck, but the fog is pretty thin. There may be a possibility of a flight. The weather continues to improve during the 0830 flight brief and the decision is made to fly a photo survey flight. There is room for one member of the science party, so Bruce flies. They are able to do most of the flight pattern at an altitude of 1000 feet, with only a couple of detours to avoid fog banks. Over 500 photographs were taken during the flight. It’s always a relief to download the camera and see that the photographs are really there and look pretty good.

During most of the day the Healy cruises in the vicinity of Coring Station 5, mapping the bottom and sediment layers. This mapping will help determine the location of the coring station. The estimated time of arrival on station is between 8 PM and midnight. Whatever the time, we’ll be ready to go. We’re hoping to get another ice site.

After another delicious pasta bar lunch (I stopped at 2 serving, call me Mr. Willpower), we backed up the aerial photos, our personal photos, and all of our data for a grand total of 9 gigabytes of information. It’s great to have all of the data digitally, but it’s a little scary. What happens if the hard drive crashes, or if the files get erased by mistake, or if no one remembers to save the file? This may sound a little paranoid, but when it comes to data, “every point is precious.” So we have a backup plan. Everything is recorded to Tom’s 240 GB external drive, and to Bruce’s 80 GB external drive, and to my 80 GB external, and burned onto DVD-ROM. We’re doing our part to help the storage industry.

Our estimated time of arrival at coring station 5 is 10 PM. It could be another late night. Stay tuned tomorrow for details.

1. The Healy in the ice.

2. The many shapes and colors of melt ponds as seen from 1000 feet.

3. Extensive ponding, with many ponds melting through to the ocean. Some ponds have grayish looking ice in them. This is the remnants of the bottom of the pond. The ice at the pond bottom can become so thin that it no longer has the strength to resist the force of buoyancy. It breaks off and floats to the surface.

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