Category Archives: IOP2

A tale of two drifters

We have recovered all of our (SIO, Feddersen) instruments, and the fun of sorting out and QCing the data has begun, however, I thought I’d share a sweet tale of loss and love. We were fortunate to only leave 2 instruments at Pt Sal, drifter 23 and 24, although I do believe their fate may have always been intertwined. Their tale begins during experiment preparation during final drifter assembly, when drifters were being labeled with a sharpie: 1… 27 – then 23 and 24 were shipped to Pt Sal, right next to each other in a large box. During IOP-1, both 23 and 24 rose to the occasion and provided excellent data from which internal waves, fronts, and surface waves were observed. However, on the final day of IOP-1, Sept. 17, drifter 23 (red in the figure) decided he/she wasn’t long for this world and sacrificed itself (for science, I presume) on the rocks, either that or that the point (0,0) in Pt Sal (x,y) is some sort of worm hole? (actually, we checked some mooring lines, which were kelp free! delaying recovery of 23). Regardless, we had finally lost a drifter, much to everyones dismay (delight?).

Now drifter 24 was sad, however, he/she performed admirably throughout IOP-2 collecting much data. On the final day of IOP-2 (Oct. 14), about 1 month after losing drifter 23, 24 decided enough was enough and attempted to reunite with 23. Upon release at 8:05, 24 went directly shoreward (green in figure), hitting the surfzone at 12:39. Realizing that 23 was 1 km to the south, 24 stumbled down the beach for 4 hours, getting about 200 m from 23’s final resting place. At this point, after stumbling down the beach for 4 hours (a difficult task for an old drifter from the 80s), 24 needed a rest. After a long 24 hour nap, drifter 24 made tje final push south toward 23, coming to rest about 100 m from his partner in science. Although we mourn the loss of these two drifters, we are happy they are once again together enjoying their retirement on a beautiful coastline. (in the figure, contours are at 2.5 m intervals, and the 20 m contour is thick)

 

IOP2 fun around Pt Sal

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.

The Kalipi kicks off another week on the water

The Kalipi is back in action starting today. The OSU group recovered the 10-meter temperature string mooring and the ADCP lander this morning. The seas were glassy calm and the instruments were all returned ondeck safely. The recovery could not have gone better. As Jim Lerzcak said when we brought the lander onboard: “There’s nothing like the warm fuzzy feeling when an ADCP comes back pinging.”

The five of us will be running CTD and ADCP surveys for the rest of the week from the Kalipi. Look for us out there, Oceanus, Sounder, and Sally Ann!

— Jenessa Duncombe and the Kalipi team

Jim Lerczak showing excellent

cotter-pin-removal form

Hoisting a lander onboard:

85% winch and 15% muscle

All smiles after a successful recovery

(from left to right: Jack McSweeney,

Dean Henze, Taylor Eaton,

Jim Lerczak)

The R/V Oceanus sets sail once again

The crew on the R/V Oceanus left port today from San Francisco under a fortuitous blue sky. We are headed south to Point Sal and expect to arrive in the morning on Thursday. We plan to recover and re-deploy up to 8 moorings and 9 landers over the next five days, as well as continue surveys with the towed Mini-bat/Acrobat (fingers crossed that the kelp forests stay out of our way this time). We have a new instrument as well— a bow chain equipped with thermistors and two GusT’s (pressure readers for depth and turbulence).

Our departure marks the beginning of turnarounds for the long-term moorings and we are excited to get our hands on the data. We do not know what we will find when we make it to the first station tomorrow. Has our mooring “walked” away from its original location? Has any fishing activity inadvertently interacted with our surface buoy? Or is our mooring and its all parts bobbing where we left it last, instruments dutifully recording data?

We hope the last option, but we are prepared for whatever we find. We have fresh batteries and all hands on deck for the recoveries.

Speaking of the team, we have some new faces aboard. The group hails from Oregon State University, Scripps Institution of Oceanography, and the University of Miami. We have five research scientists, two graduate students, two technicians, one postdoc, one engineer, and lastly, one volunteer scientist/journalist (that’s me!). We also feel grateful for our MarTech and Oceanus crew.

Here are a few photos of our time on land, as well of us exiting the bay under the illustrious Golden Gate bridge.

Stay tuned to hear about mooring and landing recoveries.

— Jenessa Duncombe and the R/V Oceanus team

R/V Oceanus at sunrise with the San Francisco skyline in background

Engineer Sara Goheen readies the bowchain

Engineer Pavan Vutukur and Technician Marnie Jo Zirbel service the mini-bat instrument

The science team

scripps oceanography uc san diego