Sunday, March 14, 2010

Sunday 14 March, Day 59

Today was the last day of the cruise! We arrived near Montevideo yesterday afternoon, but couldn't get a place along a dock until this morning, so the ship anchored outside of the harbour for the night. Today, after lunch on the ship, John and I walked through the streets of Montevideo and along a seashore walk. It was sunny and 22 degrees, it felt great. But we walked for 4 hours, and at the end our legs and hips felt sour, we were not used to walk such distance any more...
Tomorrow we catch the plane back to the UK. I can't wait to see Marion, Margot and Anael! Last night I dreamt I was coming back home, and could not believe how Anael had changed while I was away! I guess in two days it will be like in my dream...

Back to the cruise narrative catch-up. After recovering the moorings, we headed to Creek 3 where we had to supply some equipment for the Halley base and take the Halley VI (the next version of the base) builders onboard.
When we arrived, the Shackleton was already there:

It was good to see it again, and I wanted to go onboard to say hello to the captain and crew. There were also 2 shuttles being arranged to visit Halley. Since I had already been there last year, I let people that had never gone there catch the first shuttle. While we were waiting for them to come back, I kept working, thinking I would have ample time to walk on the ice shelf and visit the Shackleton later. But in the meantime the wind picked up, and since the area was clear of sea ice for miles, waves built up and it was becoming dangerous to stay near the ice ledge. So, as soon as the people that went to visit Halley had come back, the ship left the ice shelf and we waited some distance offshore for the wind to drop... We waited for two days. Finally, the weather improved:

and by the end of March 1st, the wind had dropped suffciently to allow us to quickly come along the ice egde again to take the Halley builders onboard. To make operations wafer, the Shackleton was pushing the ice to prevent an eventual break-up of the ice ledge:

while we were taking people onboard:

and offloading equipment...

for Halley:

The next day, it was our turn to push the ice...

for the Shackleton to offload its cargo for Halley:

Then both ships said goobye to the winterers:

While we were still sheltered from swell by sea ice, Dr. John and I analysed salinity from the water samples with a salinometer:

On the way back North, we met penguins dancing on the ice:

and seals laughing at us:

Finnaly, the last iceberg before leaving sea ice behind:

When we came out of the sea ice area, I felt a bit nostalgic. Was I seeing Antarctica for the last time? I have some ideas of research projects to carry on in Antarctica, but will I ever get the opportunity to write and submit them to funding agencies, and the chance to get one funded?...

We finally arrived in Montevideo, and Julian, Alex, Matt, Pete and I celebrated the end of the cruise with a gin Tonic:

To finish, I'll share my first experience of the green flash, which I had come to believe was a myth!...

The end!

Friday, March 12, 2010

Friday 12 March, Day 57

After having recovered the deepest mooring, we turned back to go and retrieve the shallowest mooring that we had redeployed for a short 24-hour time-series. The idea was to check whether tides or higher frequency signals had a significant impact on the water sample properties, since the latter were only taken weekly during the whole year, and any strong signal at frequencies higher than weekly, such as tides, would get aliased in the weekly measurements.
But half-way on the way back, we stumbled upon a huge iceberg, which had drifted over half of the mooring area while we were recovering the deeper moorings!

The ship's radar indicated that the iceberg was terminating no too far to the west, but it could not see the end of it to the east, so the captain decided to go around the iceberg to its west. We then arrived in the zone between the iceberg and the ice shelf, and were soon prevented from going further by very compact sea ice which was being squeezed between the iceberg and the ice shelf, the contours of which are visible on the radar screen below, with the cloudy white area indicating the sea ice around the ship:

It looked as a death trap, so the captain decided to back away and go around the iceberg on the other side, to the east. It took a few hours to complete the loop around the 18-mile long and 5-mile wide iceberg! It was so big it looked like an ice shelf:

I did not know penguins knew how to build pyramids!

Finally, we managed to reach the shallow mooring, which was lying just between the iceberg and the ice shelf. I was relieved to see the water sampler come back on deck, for the samples it contained, and because it costs £40,000!

During this last mooring recovery, we had two spectators watching us:

Do you remember the iceberg in front of the ice shelf in the background? There is a similar one next to it, and I called them the "gates to Antarctica" last year. I was surprised to see them again! They must be grounded for having not drifted with the coastal current.

Thursday, March 11, 2010

Thursday 11 March, Day 56

Back to the mooring recovery.
At and between each mooring, we lowered some instruments attached on a metallic frame with 24 Niskin bottles (to take in situ water samples) to the bottom of the ocean. The instruments measure the conductivity, pressure and depth (CTD) of the water (salinity can be inferred from these), and the currents (using lowered Acoustic Doppler Current Profilers, or LADCPs). Here is the instrument package coming back to the surface:

and hauled onboard:

When we arrive on a mooring position, we lower an acoustic device in the water to "talk" to a device at the bottom of the mooring, called an acoustic release. This is one of the most important piece of equipment of a mooring, since if it does not open, we cannot retrieve the mooring! Last year we had some instances when we couldn't "talk" to the acoustic releases, or would send the release signal but nothing would happen, and we were not able to retrieve some moorings of other projects. Thankfully, all the releases worked perfectly for the SASSI moorings, and we were able to recover all of them!
Below is the top buoy of the deepest mooring after having reached the surface (the game is to be the first to spot it out after the release command has been sent to the acoustic release!):

The next game is to catch the retrieve line with a grapple:

But the line seemed to be stuck, so everybody gave a hand to pull it out:

They did not manage to pull the line in, but they managed to break the grapple! So Dave, the bosun, had to climb a ladder down to the water level to attach a shackle with another line on the buoy (falling in the water would not be a pleasant experience...):

Finally the mooring could be hauled onboard:

And we discovered why the retrieve line was stuck: it was completely tangled around the main mooring line! Everything on this mooring turned out to be tangled. Perhaps it is due to the length of the mooring (2000 m), or to the way it was deployed, "anchor-last", which means everything was floating in the water before the bottom weight (called the anchor) was dropped into the ocean, and since we could not move much because of the sea ice around the ship, the line was probably loose and making turns on itself...

(to be continued...)

Tuesday, March 9, 2010

Tuesday 9 March, Day 54

To change a bit from landscape and instrument pictures, let's show a glimpse of what life is sometimes onboard! Last Saturday night, Alex organized another quiz night, with lots of difficult questions to answer, and a funny physical challenge in between two question sessions. The goal was to form teams of 2 people, and while keeping our feet behind a line on the ground, try to put a napkin ring on the ground as far away from the line as possible, without any part of our body ever touching the ground past the line! John and I decided to have a go. While some other teams were already trying some moves, we trained and came up with the following move, which put us momentarily in first position:

But soon we were overthrown:

Then another team pushed the limits even further:

And finally a team seemed to be unbeatable, thanks to a perfect combination of a tall and heavy guy with a small and light girl:

But John and I decided to take the challenge and beat them, which we did!

Another team tried to reproduce this winning move, but they couldn't get back behind the line, so we won!

Pictures courtesy of Pete.

Sunday, March 7, 2010

Sunday 7 March, Day 52

As promised, let's get back in time to show some pictures.

As we headed south after the geological survey of the South Sandwich Islands was completed, we finally reached the ice covered parts of the Weddell Sea, and I could enjoy again the beauty of this landscape and the stillness of the sea surface undisturbed by waves:

I could also enjoy again the presence of my favorite animal in his natural environment:

Then our work began: the recovery of the moorings we had deployed last year.
We started with the shallowest mooring, where an automated water sampler had been deployed. Once the instrument was on deck, I could read John's mind: "Are you gonna come and help me drag this thing inside the lab, or are you gonna keep taking your bloody pictures?"

Once in the lab, I inspected the instrument, which looked in good shape after having spent a whole year in freezing cold waters where huge icebergs ocasionnally drift by and could have smashed it into pieces...

I immediately started to retrieve the water sample bags from the plastic bottles, and put new bags in place for a short 24-hour redeployment, in order to have an idea of the high-frequency variability which could have aliased our weekly sampling measurements. I owe a big thank to Simmon Day, one of the geologists, who patiently helped me through the whole day, and without whom I would not have been ready for the redeployment by the end of the working day!

In the meantime, John was bringing in the lab other instruments from the moorings, such as this Acoustic Doppler Current Profiler:

(to be continued...)

Saturday, March 6, 2010

Friday 5 March, Day 50

Even longer silence, but not due to a lack of events to report, this time. We have indeed successfully recovered all our instruments, including a short redeployment of one of them. I have been too busy with the subsequent water samples analysis to update this blog. Then, 25 people from the Halley research base on the Brunt Ice Shelf came onboard, and the only two computers with an internet connection available for us on the JCR have been occupied most of the time since then, with sometimes even a queue to have access to them. Not ideal to keep up with this blog. I miss the internet connection in my cabin I had last year on the Shackleton!

We are now on our way back north, our destination being Montevideo. We should arrive there on the 13th or 14th, and fly back to the UK on the 15th, arriving at Heathrow on the 16th. I am counting the days before I can take Margot and Anael in my arms and kiss Marion!

I have loads of new pictures, but no time to upload them, sorry... I'll see if I can upload some from time to time before the end of the cruise.

Friday, February 19, 2010

Friday 19 February, Day 36

Long silence: not much to report as the geological survey of the South Sandwich Islands was progressing, and I was working hard on another paper! Nothing like being isolated at sea from everyday life tribulations, with meals prepared for you, to write those papers I have kept in the back of my head but never found the time to write yet. This one is about a new derivation of the Coriolis force (the force that makes all things moving on a rotating body drift sideways, and playing a central role in the atmospheric and oceanic movements), which sheds light on the fact that there are two slightly different contributions to it, and helps explain some counter-intuitive results in the dynamics of inertial waves (wind-generated currents that turn in circles because of the rotation of the Earth).

But I still found time to take some pictures.
Let's start with the volcano theme:

Saunders Island in the sunset, with steam rising from Mount Michael.

Montagu Island, with steam rising from Mount Belinda (hugging the crest, but hard to distinguish from clouds).

Steam rising from Bellingshausen Island caldera, the smallest of the three islands composing the Southern Thule island group. The largest of this group is Cook Island:

Now, a bit of history (source: Wikipedia):
From 1976 to 1982, Argentina maintained a naval base named Corbeta Uruguay, in the lee (southern east coast) of Thule Island (the third of the Southern Thule group). Although the British discovered the presence of the Argentine base in 1978, protested and tried to resolve the issue by diplomatic means, no effort was made to remove them by force until after the Falklands War. The base was eventually removed on June 20, 1982. Here are some remains:

And to finish, another round of iceberg shots (I can't get bored of them, they come in so many different shapes and colors!):

At last, the geological survey of the South Sandwich Islands has come to an end, and we are heading South again! In three days, we should arrive at the SASSI mooring sites, for a frantic 48 hours or so of uninterrupted work! I hope we will be able to recover all moorings... I forgot to mention that John (last year's McGuiver who made a cable from scratch to connect to an instrument) has developed in the past few days a horrible toothache, and is not in very good shape. I hope he is going to get better, otherwise the mooring recovery is going to be like hell for him!