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August 22 - AutoSub

Update (22th August 2004)

Noon Position : lat 79° 30.3' N, long 014° 12.8' W
Air temperature @ noon today : 0.2°C
Sea temperature @ noon today : -0.1°C


Ice: An Under & Over Story

You find us this weekend off the North-Eastern coast of Greenland, just over six hundred miles south of the North Pole. The map below should help to you to see exactly where we are; the North Pole is top centre, click to enlarge.

To See where we are today click to enlarge

We have come this far north to allow the science party to study the sea ice in and around the Fram Strait. This is a stretch of water on the edge of the Arctic Ocean between Greenland and Svalbard (sometimes also referred to as Spitzbergen). It is important to understand and study the ice in this region as it is the path by which water and ice leaves the Arctic Ocean. The party are using mainly two methods of investigation; an unmanned underwater vehicle called AutoSub and the more traditional approach of stepping onto the ice to measure its thickness manually. Both methods are shown below with a little more detail.

The sad news to date is the lack of polar bear sightings i.e. none, but we have a week left up here so we remain hopeful. Next Sunday will see us on our way back to northern Iceland to exchange some of the science parties before moving our area of operations to the ice shelves of southern Greenland. In the mean time we will continue the sampling here and hope to do a combined experiment with the German research vessel Polarstern, before heading southwards.


AutoSub Goes Exploring

Over the next four weeks our main tool for studying the ice around Greenland is the autonomous underwater vehicle called AutoSub. It was developed by engineers based at the Southampton Oceanography Centre and funded by the Natural Environment Research Council. The vehicle has been designed to provide an underway platform with a ‘cargo space' easily adaptable to take a wide variety of scientific instruments. This is the sub's third visit to the JCR; having previously looked at krill under the ice in the Weddell Sea (January 2001) and conducted a sea ice survey similar to our present work, but that was in the Amundsen Sea to the west of the Antarctic Peninsula in February 2003. Click on the links to look at those experiments and the associated weeks, and on the picture below to sea the sub about to launch. The earlier part of the week was spent completing a few final tests on the sub before starting its under ice missions. These began with relatively short voyages which have then been lengthened in the following days.

AutoSub ready for launch! Click to enlarge
AutoSub ready to launch from its gantry on the stern of JCR. Click to enlarge.


Whilst compiling this week's page, AutoSub has just returned from its longest under ice mission to date which lasted over twenty-four hours, during which time it has been surveying the underside of the ice to ascertain its thickness over a distance of about seventy-two miles. Though as usual things became a little more interesting as the weather has changed in the last day and what was open water yesterday this evening is a jigsaw puzzle of ice flows. Despite this, the sub obeyed its homing beacon when called and is now safely back in its garage.

Andy Webb guiding the Sub out of its garage. Click to enlarge The Sub diving to start its latest mission. Click to enlarge. Collecting the recovery line. Click to enlarge.

Andy Webb guiding the Sub out of its garage. Click to enlarge

The Sub diving to start its latest mission. Click to enlarge.

Collecting the recovery line. Click to enlarge.


The pictures above show briefly the operational process. The left hand picture shows the sub emerging from its warm workshop garage to be positioned on its gantry (very top picture) from here the sub is lowered into the water and released. The centre picture shows its propeller turning as it picks up speed in order to dive. The final picture shows it back alongside where its ropes are pulled up to the ship's side to allow it to be lifted back onboard. I'm sure you'll see many more pictures over the coming weeks so this is just a brief introduction.


Walking On Water

Once the sub is away on its missions it's time for the ship to steam into the fast ice herself, though bash through it rather than gliding under it like the AutoSub.

The ice turning over as we power through it. Click to enlarge.
Bashing into the fast ice. Click to enlarge.


We push into the ice until the area around the bows is deemed suitable and safe for sampling. Then the transfer basket and the forward crane (below left) are used to lift the scientists and their equipment onto the ice. You might think it would be just a matter of climbing over the side and descending onto the ice. However, we use the crane and basket to lift people away from the ships side as this ice has been disturbed by the ship herself and might have hidden holes for people to fall down. Then it's to work drilling holes to allow the thickness of the ice to be measured. This is what we can see Duncan Mercer doing in the picture below centre, but the ice is just part of the story as the snow itself is of interest and areas are marked off for closer study. To measure the thickness thin holes are drilled right through the floes. but sections of the ice floes are being removed as well in the form of ice cores. To take these a hollow drill bit is used, which as it enters the ice collects a continuous sample in the shape of a rod within the drill bit's centre which is about 100 mm in diameter. The core is then brought onboard and stored in the freezer for analysing later, apparently the salinity content of the ice and snow indicates the age of the ice and the conditions under which it formed. There has even been talk about drilling for "dirty" ice which apparently contains algae trapped within it and possibly traces of sediment material from the areas where it formed.

Ariel transportation. Click to enlarge. Duncan Mercer drilling the flows to find their actual thickness. Click to enlarge Working on the ice. Click to enlarge

Aerial transportation.
Click to enlarge.

Duncan Mercer drilling the ice flows to find their actual thickness and take samples.
Click to enlarge

Working on the ice.
Click to enlarge



Wildlife Corner

We had hoped to see a polar bear, but to date all we have seen have been some tracks on nearby ice floes. Hopefully you can make them out once you've enlarged the picture below and maybe we'll have the real thing next week!

 

Can you see the bear tracks? Click to enlarge.


And Finally

Despite the grey cold conditions we are seeing this evening the past week has offered us some amazing views from the sun shining off the mountains of Greenland some forty miles distant to the seascapes below. Click to enlarge. It's hard to imagine we're actually at sea many miles from the nearest coast.

Fog on ice. Click to enlarge. Mirrorscape. Click to enlarge

Fog has been a recurring theme this week as the sun tries to break through.
Click to enlarge

Mirror calm seas by day and by night (well what passes for up here as the sun never sets).
Click to enlarge.



Many thanks to Guy Williams, Nick Hughes and Ruth Mugford for their photographs.