Scotscar Log - July 12, 2001

Thursday, July 12, 2001

From Oscar

After a slowdown due to a temperamental instrument, the Walford ran the first optical transect line of this summer season. The Walford occupied 10 stations along the A-line. Sampling along the A-line was guided by morning AVHRR SST and FY1-C ocean color data. The flow-through spectrometer system, set up by Mote Marine Lab, was a smashing success. A second set of stations was collected across a front seen in the hourly updated CODAR data. Other big news was John Kerfoot's birthday was celebrated upon his return to shore.

From Scott

Clear skies overnight gave us a good IR image of the upwelling. The cold surface water generally follows the 10 m isobath, with the front very near shore on the N lines, and about 1/3 of the way out on the S lines.

Caleta left the dock this morning at 6:06. Not bad for the first day. Plan is to run 2 northern lines (N3 and N1) and 2 southern lines (S1 and S3). Get the experience with the minibat in the deep water to the north first. Surveying the southern lines is much more challenging with the shallower topography and multiple ridges. The bottom will just come up on you and slam, you're digging clams.

15 hours later ….

Caleta worked hard today. 4 lines. Bob Chant is excited about the near shore mixing. Very tight thermocline offshore. Intermediate temperature nearshore mixed through nearly the entire water column. Big fluorometer signal over the full water column nearshore, same magnitude fluorometer signal at the thermocline. So the question is, what happens to the intermediate density water nearshore after it is mixed. Does it head offshore in the thermocline? Or is the peak in the offshore thermocline simply vertical processes, mixing nutrients up from the bottom and light through the top layer. We asked ourselves the same question about 2 weeks ago in the halls up at IMCS. We'd like to get the models to help us here, but it seems to be a particularly tough problem. Once the nearshore water mixes in the model, it flows straight along the coast, just like shallow water Ekman says. In the offshore stratified water, you get something that looks more like deepwater Ekman layers. The model tends to build a wall at the transition zone between the two regions, and there doesn't appear to be much cross-shelf exchange through this zone. Maybe we need to tag this water in the model and see where it goes.

Chip is running the LISST in the nearshore and offshore water to check on particle sizes. Bob had one wing-bending crash of the minibat today. Pretty good. The Minibat ran on autopilot most of the day, in very shallow and bumpy water, and we have 30 spare wing rods, enough for exactly one wing-bending crash per day. So we are on track. If we don't break it once per day, we're just not pushing hard enough..

Josh and I decided we'd set up the 4th long range CODAR today at the station instead of letting it sit in a box. Best part was blasting the radio outside in the swamps of Jersey. Liz does have every tool necessary, and Kristie made a grand tour of Jersey to collect the missing parts. We're hoping we can get through the channel and maybe over the barrier islands with the lower frequencies. If it works, we may be able to get cross-shelf radials near shore and fill in the gap between the standard CODAR vector fields and the coast. Almost like the offshore bistatic test we did last spring. We'll know more on Saturday.

Walford went out, way out, past the old A6 station. Chased after a peak in the FY1-C chlorophyll. Another conference call on the satellite imagery today. Guess I'll find out tonight what went on. Looks like REMUS is coming after all.