June 25: One week on board

With one week down in the cruise and one to go we have some questions answered and many more generated. So far we have taken 32 CTD and  230 VMP casts and have covered 173.37 km with Polaris and   178.29 km with our two REMUS vehicles.  These measurements have helped to map two different salinity intrusions in our study region.

A map of the study site showing the location of all data collected so far (Updated June 25th).

Below you can see a plot of the  temperature versus salinity measurements from all 32 of our CTD casts until now. Temperature-Salinity scatter plots help oceanographers identify the different water masses present in our profiles. Intrusion water looks very different than the surrounding shelf waters.  The intrusions are warm and salty, i.e., they appear in the upper right corner of the plot, whereas the shelf waters are cool and fresh and appear in the bottom left of the plot. The Z shaped profile is particularly unique to intrusion profiles. The relatively fresh but warm surface waters are in the upper limb of the ‘Z’, while the colder and saltier bottom waters follow along the lower limb of the ‘Z’.

TS plot showing the distinctly different water masses present in intrusion profiles. Red dots shows points from profiles with intrusions.


In the Week to Come . . .  

  • Front tracking with AUVs. This morning Polaris was launched once again after a short recovery to recharge and is now off on a new mission – this time using its front tracking algorithm. This will hopefully outline the intrusion and give us an idea of its extent.
  • More CTDs and VMPs! The intrusion have been much patchier than expected and as much data as possible will be needed in order to get a complete 3D picture. The VMP’s turbulence measurements will also help us understand how long these features will last.
  • Squid squid squid! Though our first attempts of squid jigging were unsuccessful,  we know they are out there and we will try again.

Leave a Reply

Your email address will not be published. Required fields are marked *