KenMankoff

Ice Tethered Profiler

Yesterday was different. We parked the boat in some fast ice (ice locked to land) and had an ice party. We put out the gangplank and were allowed off the boat. Penguins came over to inspect us.
 
The reason for this was we needed 12 hours to deploy an Ice Tethered Profiler (ITP), and Ice Mass Balance (IMB) system, and take an ice core. The ITP sits on multi-year ice that will hopefully last another year or two in the current location. Hanging off the ice/buoy is a 750 m tether and a small robot that once a day climbs up and down the tether collecting oceanographic data. Each day it communicates via an inductive modem to the surface base which sends it home via Iridium modem. You should be able to see the buoy we deployed here: http://www.whoi.edu/itp
 
The ship crane lowered several hundred pounds of equipment onto the ice including a snowmobile. A route was scouted almost three miles away from the boat, and we towed all the gear out there. The ITP deployment design allows two people with just a wrench and a screwdriver to deploy a ~ 400 pound anchor and ~750 m cable (also weighing hundreds of pounds). Photos will come later.
 
While we set up the ITP another team installed an Ice Mass Balance system. The IMB is a sensor suite that measures approximately the top meter of water, the ice and snow from water to air, and then the top meter of air. It gives a complete picture of the ice-ocean-atmosphere interface. Couple that with the ~800m data from the ITP and it is quite an impressive data set.
 
It was nice to get off the boat for 10 hours and to do some hard physical labor. And while we worked we watched the nose and gigantic soft black eyes of a seal that used our ice holes as a breathing hole.

PIG Micro

Image is approximately 5 mm across. See recent post “PIG Macro” to compare and contrast scales.

Another Iceberg

Under the Ice

Most of last week was spent sitting around Pine Island Bay doing CTDs while the AutoSub (a small autonomous yellow submarine) was exploring under the ice. It is seven meters long, powered by 5000 D cell batteries (manually inserted).
 
I haven’t mentioned AutoSub much because we were waiting to see how the project went. It has done very well, including surviving an underwater bump with some ice that left a dent on its nose and still making it home. It has done multiple missions under the ice, some of them almost 30 hours in length and up to 150km total distance. It maps the ocean floor and the bottom of the ice shelf, in addition to sampling water properties.
 
Tonight while it is getting repaired we’ve had the opportunity scout the ice conditions to the west, where we will head next once AutoSub operations are complete. We sailed for 50 nautical miles near the Thwaites Glacier Tongue at location (lat:-74.3766 lon:-105.4643). For the past two hours we have been sailing along the edge of a massive piece of Pine Island Glacier that broke off in 2007, drifted here, and has been stuck on a high bottom feature for the past few months. This iceberg is 10s of miles long and covered a large chunk of the horizon while we were still quite far away from it. Now, right next to it, it towers over us and fills our view on one side.
 
On the other side is open ocean with bits of ice containing dozens of penguins (mostly Adelie), and the occasional seal. Throughout the night we’ve sailed past hundreds of penguins.
 
The sun is getting lower each day as the earth rapidly tilts from solstice toward equinox, which means the colors are getting better. The solar minimum is still about 30 degrees above the horizon, and occurs around 4AM ship time, right in the middle of my shift.
 
 
location: lat:-74.3766, lon:-105.4643

Flipped Bergs

We’re still in Pine Island Bay collecting data. The bathymetry map has been filled in so we know what the bottom looks like, and from all our sailing we have most of the surface sampled at one point in time or another. We’re slowly filling in the space between the surface and the bottom with CTD samples at regularly gridded locations. This will give us a 3D view of the bay.
 
You’ve seen the photo I posted earlier of the Minke whale. Yesterday morning there was a pod of 20 or so of them that spent a few hours within view of the ship. Not close enough for any good photos, but with a pair of binoculars you could see dozens of fins at a time and blowspouts all over the place.
 
Later in the day we sailed by a massive iceberg that had rolled over. If the image is attached to this post hopefully you can see it. We aren’t sure of the scale but we estimate the ridges at about 25 feet. That puts the berg at around 600 feet long or so. These things move slowly and often in circles and it might remain here for weeks if not months and years. If we sail by it again we can get our distance with the radar, and then use a sextant or shadows or even just a ruler and parallax to get accurate measurements. Or maybe a penguin will be sitting on it for scale. Then one could start to ask and answer all sorts of interesting questions about the bottom morphology, how bergs get stuck and eventually released, how they get scraped apart from below and how they in turn change the ground beneath them…

Pine Island Glacier and Minke Whale

PIG

I woke up this morning in Pine Island Glacier. We are surrounded on three sides by the towering cliffs of the floating tongue of the glacier. They rise 50 or 60 m above the water and therefore 500 or 600 m below. I’ve never seen the white cliffs of dover but I imagine they would look small and yellow compared to these. (Maybe H will take me there someday).
 
A CTD cast was coming up at the beginning of my shift. I spent the first hour doing samples, and the rest of the night should be easy. We’ll be doing bathymetry mapping swaths and no sampling, so my job will be to enjoy the view.
 
Weather: -2.5 (Air) -0.5 (Water)
Location: lat:-74.9601, lon:-101.6803
 
Bright sun, blue sky, blue water, white cliffs, some ‘berg bits and a few gigantic tabular icebergs floating in the bay.
 
In other news, someone commented on my blog! (Thanks Mom). No, the sun moving West to East is not a typo. Normally the sun moves east to west, but at night it needs to ‘reset’ to the east, so relative to you, it moves west to east around the back side of the planet. Since I’m close enough to the pole to see over it (so to speak) I get to watch the sun move in a circle 24 hours a day. After it moves east to west during my ‘day’ while I am sleeping, I watch it move west to east on the other side of the earth during our ‘night’.

Icebergs and Whales

(Out of Order Repost)
 
The iceberg I saw a few hours ago was a sign of things to come. We are now surrounded by a dozen or so of them. Big and small, nearby and drifting over the horizon. These are just big ice cubes, nothing huge and tabular yet, and no sea ice yet.
 
And playing near the ship are a pod of Minke whales.
 
Not a bad day at the office…

Breaking Ice Trails

A Perfect Day

Today was a good day. We’ve had a few frustrating days where nothing seemed to go right, but overall the cruise has been nice, even if the instruments are confusing, the seas were rough and the weather gray. But days like today are the reason we are all here.
 
It was our first sunny day (sunny night too). There was not a cloud in the sky and the bright sun drifted lazily, West to East, over the pole all night long while I worked. The sky was bright blue, with some shades of pink around 4AM ship time (solar midnight). The snow and ice bergs were bright white. The water was a clear dark blue. The moon, almost full, hung in the sky opposite the sun, drifting East to West.
 
I woke around 9PM, ate at the midnight meal, and started work shortly after midnight, lowering a CTD and rosette sampling system 750m down, waiting for it to come back up, and then collecting samples of cold deep Antarctic water. Cold to touch, but at around 2C significantly warmer than the surface waters of -1.7C.
 
After the CTD came the best part: I got to leave the ship. We spent about two hours finding a nice stable ice floe. The crane picked us and our gear up, reached over the side, and lowered us. We were dressed for safety with hard hats and floater jackets and harnessed into the basket. We reached over the side, probing the snowpack for stable ice below. After finding it we unclipped and stepped off.
 
We spent the next hour or two digging away the snow cover, drilling holes through the ice, and taking measurements of temperature, salinity, and ice structure. We then packed up samples to take back to the ship, freeze, and analyze at a later date.
 
All the while, in the distance, some Emperor penguins paid us no attention.
 
Location: lat:-71.729, lon:-103.033