FROM THE FIELD
Ocean of Extremes
WOW-ing and RAW-ing in the South Pacific
The Southern Ocean is not only far-off, but also unambiguously the stormiest region of the planet. Of the sectors of the Southern Ocean, the South Pacific is the most remote — there aren’t even islands. It is just this vast stretch of ocean, about 10,000 kilometers between Chile and Australia. Both of these features — its remoteness and its notorious weather — explain, in no small part, why the region is understudied. Scientists do not have sufficient information about the modern state of the Southern Ocean and there are virtually no available sediment cores to reconstruct past ocean and climate variability.
Nevertheless, because the region is so important for our global climate system, we set out with Expedition 383 to fill at least part of this gaping hole in South Pacific records. We did so in spite of unavoidable weather-related challenges, as Expedition 383 targets areas of the South Pacific Ocean that experience the fastest wind speeds of the Southern Westerly Winds. In planning this expedition, we requested for it to be scheduled in the middle of the Southern hemisphere (austral) winter. Although winter may not seem like the most pleasant time for a research expedition, winters in the Southern Hemisphere are climatologically less stormy than other times of the year, i.e. mean winter wind speeds are substantially slower relative to spring, summer and fall. This may seem counter-intuitive for many of us in the Northern Hemisphere, but is well known to anybody living in Punta Arenas. Even though May/June/July is the least stormy time to be in the South Pacific Ocean, a good fraction of my work as co-chief scientist on this expedition was spent looking at weather and wave forecasts, communicating with Captain Jake and the navigation officers on the bridge, and trying to come up jointly with the best way of dancing around the unavoidable storm systems we were facing.
After a fairly calm transit to our first study region, smack in the middle of the South Pacific, we started drilling and recovering beautiful sedimentary sequences. A couple of days into drilling the first site, the winds and seas started to pick up. As a consequence, the heave (the up-and-down motion) of the ship increased. Drilling operations on board of the JOIDES Resolution entail a drill pipe that connects the ship to the seafloor; at that first site this “drill string” was about 12,000 feet long. The ship has a heave compensation mechanism that keeps the pipe as stable as possible, but beyond a certain threshold — about 12 feet of heave — drilling becomes impossible and we had to stop coring operations. The official term for this situation is WOW, Waiting on Weather. It essentially means that we stayed on site, with the ship in position, and waited until the seas calmed sufficiently for us to continue drilling. We WOW-ed many times during our expedition — sometimes for just a few hours, sometimes a couple of days. The “waiting” part in WOW requires a lot of patience from all, and it’s a loss of operational time, but no risk to the safety of the ship.
The situation changed about halfway into our two-month expedition, when a huge storm system, the size of the continent of Australia, came rolling across the South Pacific. We were drilling at our westernmost site and could see a storm system develop on our weather forecast maps. With each forecast update, the wave height projections became larger and larger, significantly higher than we had ever observed before (50 feet and more!). This monster storm forced us to leave our site in the middle of our operations. Captain Jake came to our chief scientist office and said in no uncertain terms that we needed to leave. When? Now. And this is what we did. We pulled up the pipe and transited at maximum speed to the northeast on a bad weather avoidance course across the South Pacific, in the exact opposite direction from our next planned drill site. The official term for this is RAWing (Running Away from Weather).
We spent about two weeks RAW-ing and hiding from this scary storm. The image above illustrates our RAW-ing track: at the time of the decision to RAW, we were at the south western (lower left) corner of the triangle. We then steamed on a northeast course to almost 40° south (the top of the triangle). We “parked” the JOIDES Resolution at that spot and, when the 50ft+ monster storm had rolled through, we continued on a southeastern course, towards our second major study region at the Chilean Margin. There was no drilling in these long two weeks, but our nannofossil team took surface water samples every six hours along this RAW-ing triangle, to investigate assemblages of various nannofossil species in the South Pacific. So at least we got some interesting surface ocean science done while RAW-ing. After the RAW-ing period, the weather calmed down (relatively), and we were able to work for the remaining time of the expedition without too much interruption.
Despite encountering weather-related challenges, we were still able to complete much of our scientific drilling program and successfully recover many exciting new sedimentary climate records. To me, the most amazing aspect of all the WOW-ing and RAW-ing is that the spirit and enthusiasm for the expedition’s objectives remained high and allowed us to get through all these challenges, thanks to great cooperation across the science team and crew of the ship.