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11/27/00 COAST meeting summary

Summary of 27 November 2000 COAST Mooring (and Aircraft) Discussion
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(reported by J Barth, 1 Dec 2000)

We started the mtg by reviewing the schedule for mooring deployment/recovery
and ship surveys during 2001.  Given the 15 May mooring deployment and
the 14 May start of the Thompson profiling work, the concensus was that
it would be highly advantageous to have the aircraft operation start at that
time also.  It was recognized that having a recent survey (SST, sea-surface 
color, subsurface info) of the region would be useful for the scientists
aboard Thompson.  Although satellite imagery may be useful, it might not
be available in the previous week or so due to cloud cover.
One scenario might be that a SeaSoar survey could be done
on Wecoma starting on 15 May if the mooring and SeaSoar operations can be
comingled.  If that cannot happen, and chances are that the logistics will
be difficult, it would be very useful to have an airplane surface survey and
AXBT subsurface information.  It was unknown how long John Bane could maintain
his operation in Corvallis, but we hoped that with starting in mid May that
he could still make measurements throughout the August survey cruises.
As during the July mtg, the group liked the idea of airplane surface and
subsurface data inbetween the survey cruises (mid-June to end of July), but
again we were unsure of John Bane's resources to pull this off.

Murray Levine reported that he will talk with Jim Moum to perhaps move
the mooring recovery from 1-6 Oct to the last few days of August or early
Sep.  The argument was to get the data back as soon as possible after the
survey cruises end to insure safe return of the mooring data.  That would still
give a 100+ day data record.

We discussed fouling of the moored bio-optical sensors (spectroradiometers,
fluorescence).  The fluorescence sensors have a windshield wiper mechanism, but
the efficacy of this is still unknown.  Ricardo reported that the radiometers
usually foul in 2 months or so based on drifting radiometer experience.
In the absence of occasional cleaning of the shallow instruments by divers, it
was suggested that dedicated profiling near the moorings during the survey 
cruises might be sufficient to detrend the data.  The bio-optical guys will
pursue this.

The fl+light-scattering+battery+logger will be at about 25m on each mooring.
So the additional light-scattering sensors contributed by van Geen and Chase
need to have loggers and battery packs as well.

Murray discussed the "survivability" of the moorings given the fishing
activity.  Mike Kosro reported that it was possible that bottom trawling would 
be banned offshore of the 50 fm line sometime in the near future.  Trawling
pressure may then shift to 50fm and inshore.  The moorings guys are looking
into the use of additional inexpensive guard buoys.

We spent a good deal of time talking about the ideal locations for the
moorings.  In the north, it was suggested that the line be right off the
northern radar site at Roads End, just south of Cascade Head, rather than
just north of Cascade Head as in our draft experimental plan.  This would
place the northern moorings under the radar region.  Moorings would be at
50m, 80m and the shelfbreak.  The shelfbreak mooring could be in 200m of
water or so.  It will have an upward looking ADCP at 125m.  There was some
discussion about whether a lower-frequency ADCP could be obtained to increase
range and look upward from deeper in the water column.

The southern line is more complicated, but we all agreed that the inner
shelf mooring should be on the same isobath as the northern inner shelf
mooring (50m).  The shelfbreak mooring should be offshore of Heceta Bank
to see the influence of the coastal jet as it passes around the Bank.  Murray
was concerned about fishing pressure at the shelfbreak offshore of the Bank.
He asked if placing the mooring several km offshore, say at the 1000m isobath
where trawling might be less, would still accomplish the science goals.
Historical data suggest that this location might be okay to capture the jet, 
but it was also recognized that it would be advantageous to having it on the 
same isobath as the northern shelfbreak mooring.  It was suggested that the 
midshelf mooring should be on the inshore side of the Bank to capture the 
northward return flow known to occur in that region.  That is, on the ~100m 
isobath of the Bank, not on the ~100m isobath of the shelf.  In our draft map,
that would be near 124.7W rather than 124.35W.  Jack Barth suggested that 
since 44.0N was a regularly occupied hydrographic line by GLOBEC, that perhaps 
the moorings ought to be moved south to 44.0N.  Another suggestion is to place 
them directly offshore of the PISCO site (15m mooring) which is at 44.1N.

Roger was asked about the location of the met buoy presently set for the
midshelf northern site.  He thought that that was fine, but wanted to make
sure that the air temperature sensor saw cold air during upwelling at that
location.  Historical SST data suggests that this will be true.  Roger
also indicated that air temperature on some of the other moorings might
be useful.

It was suggested and agreed that having a point velocity measurement as close
to the bottom on the midshelf and inner shelf moorings would be useful for
discerning flow in the BBL.  This would probably be most useful for the
northern mooring line.  The mooring group will investigate the cost of
this.

The mooring group agreed to work on a couple of possible scenarios with
existing and planned equipment purchases, then to report back to the group.
There are many possible trade-offs that can be made when considering the  
purchasing of the new instrumentation, such as, should we buy single point 
current meters rather than more T/C recorders.

The meeting concluded with a few words about aircraft sampling lines, but
there was not sufficient time to do that justice.  Roger and Jack are
interested in this and will follow-up with John Bank.  Jack reported that
there are now a fair number of regularly occupied hydro lines in the region
which would be used to choose aircraft sampling lines.  He can supply the
latitudes of these lines to Bane.

Postscript (1 Dec 00)
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On 30 Nov, representatives from W S Ocean visited OSU to present their
in situ automated nutrient analyser.  This is the same unit being used
by Terry Whitledge at UAF and by Largier et al in the CoOP WEST project.
At the 2000 EPOC mtg,  John Largier presented results from their pilot 
experiment during 2000 off Pt Reyes and the results looked quite promising.  
The W S Ocean unit seems to work
and many COAST investigators think it would be worth using on the 2001
moorings.  The cost per unit is 20K +- a few K.  The WEST experience is
that they had some failures among the four they tested off the Scripps pier.
They elected to deploy only one (maybe two?) during their pilot experiment.
The mooring group is willing to work with others to deploy the nutrient
sensors, but does not have the time or interest to be responsible for
preparing, testing, etc.  Murray suggests a good safe place to
deploy a nutrient sensor might be at the surface just below the met buoy
presently planned for deployment on the 80m isobath off Cascade Head.
The question arises as to whether we're interested in more than one nutrient
measurement given our north-south comparison, and further the known vertical
structure in the water column.  Regarding $$, I am hesitant to go to Larry
Clark with a request for 20K which is only 1% of the Yr2 COAST budget.  Larry's
position is that he has given us generous funding and expects us to take
responsibility for budgeting to get the science done that we want done.
So, I would like to hear back from those of you interested in taking
the lead on a possible moored nutrient sensor(s).  I'm also interested in
suggestions for how to pay for acquiring the sensors.  If we do this, it
needs to be ASAP so that we can get an order in to W S Ocean.