SIO-Whaler Sally Ann on her offshore (west) survey leg passing to the south of Ghost Reef on 10 October. Photo was take by Falk Feddersen from the RV Sounder
IOP2 has been a great deal of fun all around sampling both Pt Sal and Oceano with the Sounder, Kalipi and Oceanus. Speaking of Oceanus, On 14 Oct, Mike Kovatch took some cool photos on of her from east of Pt Sal looking between Lion Rock on the left and Pt Sal on the right as the Oceanus was doing her onshore leg and making the turn.
We had three great days at Pt Sal and below are some plot of both the first day (9 Oct) and the last day (14 Oct). On 9 October, Sally Ann and Sounder repeated the survey lines they did for the first IOP. Survey lines and CTD data is shown beow. Lots of repeatable frontal structure.
What might that frontal structure look like from the surface? Well it looks like foam scum lines that are filled with algae. The two photos below are from 9 October which had Hs>2 m. The first photo is looking north at Pt Sal and Lion Rock. Note the big foam/algae streak (scum line) heading from Pt Sal to the right of Lion Rock. The scum line can be very dense – even a few inches thick of foam!
Algae scum line coming off of Pt Sal and heading SE indicating the presence of a front where downwelling is occuring.
Close up of massive algae scum line coming off of Pt Sal on 9 October.
On IOP2 Day 6, 14 October, we again had 4 vessels doing joint surveys with the APL plane flying IR & visible and helping guide us. The Sally Ann did a survey box much tighter near the strong bathymetric variations around Pt Sal. The survey box below started east just offshore and south of Ghost Reef, passed Seal Rock and then Lion Rock, before turning north for a short leg and then offshore again between Pt Sal and Lion/Seal Rocks.
Here are some photos of those features.
A wave breaking at Ghost Reef up close on 15 Oct. The depth goes from 15 m to <4 m very rapidly (Mike Kovatch).
The NPS boat “SandCrab” racing to the south past Ghost reef to recover instruments. They did not stop for tea and biscuits (Mike Kovatch)
Waves breaking on Seal Rock just south of Pt Sal. Drifters recirculated behind this feature (F Feddersen)
All boats passed through many strong frontal features that had more wake, eddy, and recirculation properties than of NLIW. Notice the repeatable front properties as the Sally Ann drove the box 4 times.