The Smiles Cruise– JR311
When & where?
During SMILES we are investigating the dynamics of submesoscales from two perspectives; one is the numerical modelling lead by Cambridge University and described in the Modelling section. However, the model needs to be developed for realistic conditions, so we need to know what is actually happening in the ocean in the first place. Of course, the point of the model is to provide much more information over space and time than we can ever hope to gather from a single ship but the measurements that we can gather beforehand are crucial to making sure that the model at least starts with the right conditions. Similarly, after developing models, we need to test them to make sure that the predictions they make are consistent with what is actually happening in the real ocean.
To gather these measurements, we spent 35 days at sea during a research cruise aboard the RRS James Clark Ross. The cruise was designated JR311 and departed Stanley in the Falkland Islands on April 19th, 2015, arriving back into Stanley on May 22nd. Everyone on the project team participated in the cruise and a few other people, not directly involved in SMILES, came along to help us out and get some experience of working at sea.
The study site has been chosen due to the strong likelihood of favourable conditions for submesoscale generation being found and their importance to subantarctic Mode Water transformation in this particular location. However, this is a big ocean, so how do we decide exactly where to go during the cruise? The precise region within which JR311 will conduct operations is to be defined at the time of departure from Stanley based on operational forecast output and remote sensing data. Our intention is to survey a portion of the SAF that is unstable and has developed into a large-scale meander (or closed core eddy) that you can see in the animations of surface velocities (link to animations to come). We expect these parts of the subantarctic front to be most susceptible to the generation of submesoscales so being able to know where the meanders are before we set sail is critical.
Fortunately, our colleagues at Plymouth Marine Laboratory and the Met Office will be sending us daily satellite images and ocean forecasts of the area so that we can anticipate where to plan our measurement campaign after leaving Stanley.