Dec 14 - Stanley and South
Stanley and South
And so after encountering two of her sister ships the James Clark Ross arrived back at FIPASS for the second time this season. After anchoring out in Port William Sound the night before, we arrived into berth in the early hours of the 2nd December. As described at the end of last weeks entry a lot was planned in this call into Stanley, and all in just a few days. It was friday, and was to be a long weekend for all members of the crew. For the deck crew there was a large amount of cargo to get shifted prior to departing, and for the cooks and stewards there was a formal occasion, with the ship as hostess to many dignitaries from the local community, aswell as the arrival of 38 new members of BAS staff on their way down to Rothera.
Both these tasks started almost straight away. Soon after berthing, the deck crew were straight into transferring cargo and every berth on the ship needed to be ready to accomodate at least one new occupant. The change-over was to happen at 3pm, with a bus bringing the three dozen or so 'FIDS', as they are called by the crew, and leaving with the dozen who were now due to fly back home after their month or more working down around the sub-antarctic islands. Flight delays, as it was, left these last individuals waiting around in Stanley until after the ship had actually sailed. Those joining the JCR had been in a similar position due to our own delays. They had arrived into Stanley a week prior to The JCR, so were all itching to get on board, either to start their oceanographic work, or get to where they were due spend the coming months/years as soon as feasibly possible.
The morning of the 3rd December was a chance for some of the children of the Stanley Infant/Junior School to have a school visit to the ship. It was an opportunity for some year 6 children to find out exactly what it is that the James Clark Ross does when it is coming in and out of Stanley for two thirds of the year. Science, engineering and ships logistics, all washed down with a glass of orange squash!
The next day was a formal function, for a variety of dignitaries from the local community. A huge amount of preperation was put in by the catering staff for the event, with the whole bridge being converted into a function room with a view. When the Governor of the Falklands arrived, the flag was raised by Simon, the deck cadet on board at present, and the evening could then be started. Approximately 100 individuals from all fields of the local community were entertained, acknowledging the necessary role they all play in enabling BAS to undertake the scientific research it does, almost all out of the Falklands.
Throughout all of this the deck crew continued with the movement of cargo back and forth. With the coming plans for work at Rothera Base, our next major port of call, the quantity of stuff to be moved was significant. Everything was eventually on board by the evening of 5th December. The ship set sail at around 8pm and, prior to leaving Port William Sound, everything was fully lashed down, ready for a mildly rocky first few days for the many individuals new to the ship.
On ship, the first few days of the cruise were particularly quiet. Given the number of people on board, there was initially an eery silence. The scientific staff were quickly into working on a 12-hour shift system once they had started a long CTD transect, whilst, at the same time, getting used to the effects of a moving vessel on the bodies various physiological processes. Those simply on passage and not of a seafaring persuasion just had the seasickness to contend with. This though was not to last, with the seastate settling out to no more than an easy swell. The skies cleared and during the week the ship experienced some of the most pleasant weather that Drake Passage is ever likely to throw at a ship, perfect for bobbing up and down on the open ocean doing science.
The main question though for next week is 'Will the James Clark Ross get to Rothera?' Last year the ship was unable to make it in due to the state of the ice around the peninsular. There has been much examining of the satellite images to predict how things will be. We will just have to wait and see what the next week brings.
Science Across Drake Passage
with Kate Stansfield
Drake Passage repeat hydrography section. (JR139)
WOCE Southern Repeat Section 1b – Burdwood Bank to Elephant Island. Dec 5th to Dec 12th.
Scientists: Kate Stansfield (NOC), Mike Meredith (BAS), Mags Wallace (BAS), Nuno Nunes (UEA), Oliver Browne (U. Reading), Jo Hopkins (NOC), Martin Miller (AFI), Helen Rossetti (BAS)
The Southern Ocean is unique in that it connects all the other major oceans and influences the properties (temperature and salinity) of deep ocean water over a large proportion of the world. By largely setting the properties of deep ocean water the Southern Ocean plays a key role in driving the global ocean circulation, which in turn regulates the global climate.
The Antarctic Circumpolar Current (ACC), the major Southern Ocean current, transports approximately 136 million tonnes of water a second from the west to east around the continent of Antarctica. Between the southern tip of South America and the northern tip of the Antarctic peninsula, the ACC is squeezed through the gap known as Drake passage, this makes Drake passage an ideal location to make measurements across the ACC as the northern and southern extent of the ACC are constrained by the land masses. Here then the properties of the ACC can be measured efficiently using a relatively small number of stations (we occupy 30 stations across the 753 km section– see map below).
JR 139 is the eleventh occupation of the Drake Passage hydrography section in a time-series that extends back to 1993. At each station a package of instruments (CTD – see photo below) is lowered from the ship to near the seabed, measuring pressure, temperature, salinity and water velocities. In addition, at ten to twelve depths, water samples are captured in bottles ( See photo below). These samples are analysed onboard ship to make a very precise determination of the sample's salinity - variations in salt of the order 1 part per million can be measured. Underway measurements including navigation, vessel-mounted ADCP (current velocity), sea surface temperature and salinity, water depth and meteorological parameters are also logged as proceed across the transect.
By repeating the section on an annual basis we can begin to answer questions regarding the natural variability of the different water masses in the Southern Ocean. The hope is that with a long enough time series it may be possible to relate the observed variability to changes in atmospheric forcing - climate change.
This year’s Drake Passage section got off to a slow start with the ship being delayed by about 5 days in Port Stanley, Falkland Islands. The ship is carrying 36 passengers, in addition to the normal crew members, and several hundred tonnes of cargo (including several JCBs) destined for the Antarctic bases at Port Lockroy and Rothera. On departure from the Falkland Islands we headed out into some moderately rough seas which was a shock for many of the first time sailors and had the effect of making the ship a very quiet place for about 36 hours. Although the poor weather caused an additional delay to the section (the ship cannot travel at full speed in rough seas) in fact this gave the scientists a chance to get the equipment ready and working for the first station; for some reason this proved to be especially challenging this year with just about every sensor having to be replaced before the system was ready.
Our run of luck then changed for the better and with especially kind weather conditions after the first day, we managed to complete the entire section in record time as well as recovering and re-deploying several bottom mounted pressure landers for the Proudman Oceanography Laboratory along the way. It was a relief to complete the final station late on December 12th against the misty, rocky, and rather spooky backdrop of Elephant Island.