Well the Nor’Easter has passed.  Lots of storm erosion at the shore and the people are picking up the mess.  Meanwhile the gliders still fly.  We had many interesting conversations on Friday through the weekend.  On Friday, the RU and UDel gliders teams tried to figure out the best strategy to keep us from the beach given the worst case forecasts.  This discussion was had with the 2 gliders being smack dab in the middle of the shipping lane.  In an ideal world, we would have the 2 Southern gliders linger between the shipping lanes until pickup on either Tuesday or Wednesday.  The currents at the time made this look optimistic if not dream land.  But to our relief currents lessened and the gliders regained control and seem to be making a good go of moving where we want.  This bodes well for a Delaware Bay pick-up. The Northern gliders were directed to fly towards Tuckerton for a pick-up  One glider has already arrived and will linger.  The other glider which was advected well to the South is making good progress and should be there in a day or two.  One of the gliders will be cleaned and shipped to California for the US-Norwegian NORUS program next week.

While this was going the team was taking a deep breath with RU27 officially reaching European waters in Saturday.  Pick-up is scheduled for the first week of December.  Drake continues its path across the Atlantic, and the deep water Antarctic glider was launched last week and has surveyed the penguin feeding colony before heading out to sea to survey the shelf. It is never boring but always great to be at sea!

As highlighted by David, the Mid-Atlantic got hammered today.  This was an epic event and caps off the 2 weeks of great efforts.  We had one week of calm conditions that allowed us to test several behaviors for the glider fleet, yesterday a very diverse group we coordinated a mission (based on community, not science), monday-tuesday model differences coordinated the fleet and tonight we face the strong fury of the nature awakened!  The general mission uploaded to the fleet today was to simple, try to hold position.  The currents have been building, and coastal innudation has been knocking out the CODAR sites, but as an ocean going person, all I can do is appreciate the awesome power of an angry sea and hope all people are safe.  The building CODAR currents are shown below, the sites being knocked out by the storm are denoted by the red dots in the last picture.

The weather and ocean models all showed the big storm. The weather model showed the big southwest winds.  Weather forecasts for tonight is starting to show the reversal of wind, and down south the eye is visible.

The ocean models all show the storm.  There are differences between the models but the strong southward flow is present in  all the models.  Yi and his group this week added an objectively weighted model ensemble.  The lowest two figures show the difference between the mean and objectively weighted ensemble model.  The mean ensemble definetely showed weaker southern flowing currents. There is alot interesting science to explore lining up the observations, weather model, and ocean forecasts.  The differences in  the picture to speak opportunity, and despite the variances, the fact I use observations, multiple models and see a “relatively” similar ocean is awesome.  What a great time to be an oceanographer and environmental scientist!

So these features are dramatic, let us check on our intrepid sea going gliders tonight.Not surprisingly, the gliders lose!  Most are being advected south, the northern glider is not impacted suggesting the southward wind driven currents is variable over the shelf.  Models support this. The depth variability in salinity  in the cross shelf have not changed dramatically.  What little temperature structure we saw in the water column has been erased.  This is coincident with a decline in chlorophyll.  Not surprisingly however, as the winds and waves pick, particle loads increase as seen in the optical backscatter.  The SEDIMENT & SAND returns for a late night Nor’Easter party.  As my Spanish colleagues often say “Force wind and honour all”.

Storm David & all,

I was just informed of the impending weather for our gliders:

This is nearshore, it could be worse where some of the vehicles are:
http://forecast.weather.gov/MapClick.php?site=phi&FcstType=text&zmx=1&zmy=1&site=PHI&map.x=259&map.y=168

Right now we are blowing 20-30 knots from the NE, smack into the gliders:
http://www.ndbc.noaa.gov/station_page.php?station=44025

This is going to last into Sunday, its going to be very interesting.

I am not sure what the plans are for the gliders but each one is going to likely fall at least 20 miles to the SW.  Gliders can swim perpendicular to currents and get places but not into them.  I think that is what is happening for ru21.  The predominant current in that area is to the SSW:
http://marine.rutgers.edu/cool/codar/real-time/archiveviewer_mab.php

I am sending these links because there is a Nor’easter coming and were not going to be able to go anywhere.  These are the links we usually use so that all can track.

No gliders are in danger.

ud_134 is going to be blown quite south.  This might seal the deal on a Delaware recovery I was throwing around.  We will see come Sunday and how we approach this storm and where we end up + remaining battery life.

ru05 will get blown too and hopefully have enough battery to make it back.  We will look at battery levels come end of the week to see if we need to turn off upcast sampling to buy us some time.

What we need to decide is what we want to do for the next 3 days or so for science. Were forcasted 30 knots through Friday.  Do we want to station keep (we will lose but will fall away the least amount) as best we can?  Waypoints to the NE at a decent distance will do this and leave current correction on.  If we want the gliders to get somewhere its going to take some fancy flying and should be discussed on case by case basis and no NE waypoint is likely going to be obtained.  We will start to see the blow soon, ru21 is seeing because of the direction it is heading.

I will continue to monitor the gliders and send out another email if need be.

Thanks for reading.
David Aragon

Today at the community workshop at the end of lunch, we asked the room to decide on a group mission.  The room has spoken, and the answer is muddeled!!!!!  I gave the room around 100 people 2 choices.  The first choice was to fan out, the second choice was to come together.  In grand fashion it was a 50/50 split, so as a compromise we will bring two gliders together.  And we will fan two gliders out.  So here is the plan

Lets move RU21 and the Blue Hen to meet each other.  The rendevous site is 39 degrees and 26 minutes.

For the other gliders to split them out, RU05 and RU23 lets move them apart.  I don’t have any strong opinions so leave that to the roup, I just want to avoid shipping lanes.

I am unlikely going to be able to make the phone call, can the group using the planning tools to drive home the potential to room tomorrow morning.  Make us look smart!!

From Lisa to the group:

Attached are the most recent tracks,  11/11/09
Includes tomorrows EO-1 target.
Too cloudy to update SST.
FYI, target alert has been posted this AM for EO-1 tasking. (the red thumb tack)

Quick update as I sit in the back of the room at the OOI community workshop.  We will be re-tasking the gliders based on input from the community here at the workshop.  So a quick check on the progress from last night.  The gliders have made good progress overnight and I believe we will be able to reach the way-points defined by the reachability envelop.  Of course there is variability in the envelops depending on the ocean forecast used and we should get valuable glider  information on which model envelop provided the best representation of the ocean experienced by the gliders.  Yesterday, the ensemble was spot on to the glider location.

Today I am going to be a biologist, once again showing my obsession with the Mid-Atlantic Bight winter bloom.  The bloom appears to be growing in intensity, and there appears to be increasing water column structure.  The phytoplankton appear to inceasingly found in the upper water column, earlier in the deployment the phytoplankton were distributed throughout the water column.  The intensity of the blooms appears to have increased as blooms have segregated int the surface waters.  One of the paradigms is that winter blooms are driven by light regulation.  Historical analysis suggests that the phytoplankton bloom in the winter when winds are low and the water column is somewhat stable allowing the cells to maintained in the upper water column where there is sufficient light to grow.  Looking at the temperature records from the gliders it appears that the water column shows some increased stability as indicated by the evolution of some moderate thermal structure.  The blooms appear to be associated with the changes thermal structure.  The salinity has not changed over the deployment period, with a nearshore slug of low salinity water.

We had a great telecon yesterday.  I look forward to another great call today! The decision was to conduct two experiments.  The first experiment which was championed by Pierre was to send one glider North to survey the Hudson Canyon which shows some interesting features. Pierre’s plan and reasoning was laid out in some figures which I have posted below.

The second experiment was assess how different models impact the glider path planner.  Using the JPL tools we checked with each glider the projected paths over the course of day.  The potential envelops of the glider being able to reach a specific location varied with model, not surprising as all the models show some differences.  This reflects differences in the models, the assimilation schemes, the assimilation data used, etc.  We for each glider chose a track where the “reachability” envelops between the different models showed the greatest differences.  For the three gliders, this lead us to send two gliders to the south and send the third north to complement the glider surveying the Hudson canyon.  we have another satellite pass on the 12th, so today’s discussion will need include some of that location choices.  Unfortunately today is very cloudy,,,, it better clear out before the Hyperion system arrives.

Executive Summary of 11/10/2009

Southerly winds are observed Tuesday with relatively weak amplitude (less than 10 knots). NAM forecast indicates a transition to the Northerly and Northeasterly winds in the next two days with increasing amplitude reaching 20 knots by Thursday. Excellent SST images are obtained on Sunday. No microwave data (TMI+AMSRE) were available Sunday, confirming the important role of the geostationary satellite data in the blending process. SST comparisons consistently suggest a band of warm model bias at the shelf break, probably due to the mislocation of the SST front simulated by these relatively coarse resolution (~4-km) models. The HF radar data on Sunday show a northward flow on the southern shelf, and an offshore flow north of the NY harbor. While the northward flow on the shelf is reproduced by most models, the four models show major differences in simulating the offshore flow on the northern shelf. We have added the UDel glider (ud134) to the glider data vs model comparison. It is interesting to note that the COAWST model has the near perfect agreement with glider temperature on the shelf, but the largest discrepancy in temperature off-shore (~3 deg) and in glider salinity on the shelf (~1 psu).

Executive Summary of 11/09/2009

Very weak wind conditions are observed today. Near perfect NAM forecasts are seen when compared with buoy measurements. NAM indicates a continuous 2-day cycle in wind amplitude showing weak to moderate amplitude. Excellent SST images are obtained Saturday and Sunday. We are getting the new glider data from UDel, and the data should be online in the coming hours. We are developing a new weighting method to produce the multi-model ensemble, which should be available tomorrow Tuesday.

Hi all,

We kick-off the second week of OSSE activities with lots of great accomplishments in the first week, but now look to a final push for the next 7 days. In order to structure the efforts in the coming days, here is an outline of the “events” for the week and the planning of what we want to accomplish with the mobile assets.

We have flown the gliders together to demonstrate the ability to pull assets together. This behavior test complements the tests from the week before where we had 1) gliders fan out away from each other to cover the shelf, 2) gliders fly parallel to each other in cross shore mode, 3) coordinate spatial locations to provide potential cal/val for the Hyperion overflight on Saturday, and 4) demonstrate the ability to swarm by having assets come together. These gliders were complemented nicely with a multiple vehicle deployment last week having several AUVs fly a high resolved box in the nearshore environment. Here not only swarming but vehicle/vehicle communications was tested.

Science efforts have focused on the formation of the winter bloom and initial examination of the unique hydrographic signatures north near the Hudson canyon. There have been nearshore discussions about coastal jets, radiant heating and tides. What has been particularly gratifying is we have been conducting nice behavior test, several very use science data sets have been collected. The question is what is the best use of the assets in the coming week. I toss out candidates that I mined from last weeks dicussions. This first test will be conducted Monday through Wednesday, Wednesday we will have the community choose waypoint missions.

Technology tests:

1) Having the gliders together, choose a mission but have each glider directed by a different model. We have 4 gliders and 5 models + the ensemble. I am still uncertain about how much control we have on the blue hen. Eli can help?

2) Use the variance plots of the ensemble to redirect gliders to areas of maximum uncertainity. Latest plots suggest this offshore, more out in fishing areas, but there are regions on the shelf.

3) There still interesting features on Northern shelf associated with Hudson canyon. Do we fly one or several systems up there? This will be a little challenging given the shipping lanes, but I am open.

Given OOI is supposed to serve the wide range of oceanographers in a distributed manner. I picture the next few days being a test of how a marine IO (me this week) coordinates the activities of science users. You, the modelers are the users. So for today, let’s you guys drive, I will just make sure we fly in safe areas. So think of yourself as the teenager with the keys to the car. I will send our glider status in a few.

osc