MSEAS Daily Prediction Summaries and Lagrangian Analyses

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Wednesday, August 15

Here are our predictions for tomorrow's planned release at 6-7am. They have been on the web and sent to Berkeley this morning.

We forecast that there has been some upwelling due to the winds to the east/northeast (with some daily variations). This brings some of the subsurface fresher waters along MV's coast up, and pushes the light (warmer/fresher) near coastal surface waters offshore. Interestingly, we thus forecast that:

For tomorrow morning, here is our forecast for the MVCO section around 8am:

You can see the forecast changes here: http://mseas.mit.edu/Sea_exercises/NSF_ALPHA/2018/Sections/Maps/Aug15_Hz600m050_8am/sec1Z/index.html.

Around 8am tomorrow morning, our forecast for south of MV is:

Of course, this pattern will change rapidely with the tides. For the more detailed flows, see our webpage.

Drifter trajectories, 3D FTLEs, and flowmaps forecasts are also available on our site.

For the dye release, if I understood well where you released Wed morning, I think you can release at a similar location this Thursday. It depends if you want to target the 15m/lower salinities or the surface flow more. The former may mean just a bit more to the west/northwest, while the later a bit more to the east/southeast (so you have longer trajectories). With the upwelling, things may be interesting. Too bad we could not release drifters this afternoon and overnight, but it should still be interesting tomorrow.

Monday, August 13

We emailed with Tom and Irina several times today and posted one of our new forecasts for tomorrow on mseas. We have six forecasts uploaded on Berkeley.

For the possible tracking of the die for 6hr tomorrow, here are some 3D flow map restricted to my understanding of the possible region of interest. The release is at 15m and forecasts are given every hour: of course, the actual pathways will also depend on the die density. The fields are computed/prepared by Chinmay, Arkopal and Deepak, using PE forecasts from Pat/Pierre/Chris/Jade/Wael:

Also useful:

Here is another suggestion a bit more offshore and downstream. This location is still in the near-coast front, but a bit more within the core of it and not so close to the lower salinity edge (closer to the coast):

See also this cross-section, the proposed location/15m-depth/8am-time should be within the lower salinity pocket: http://mseas.mit.edu/Sea_exercises/NSF_ALPHA/2018/Sections/Maps/Aug13_Hz600m041_5pm/sec1Z/csec_Ssec1Zoom_Hz600m041_001.gif

Of course, there are a lot of uncertainties. We have not had any deep in situ data in the region for 13 days.

Thursday, August 9

For the main experiment, we need to cover a larger area so as to really sample the basin of attraction of the LCS within the Muskeget channel and also on the other side of the LCS (south of the FTLE and OECS features). This was in Margaux's drawing - she emailed us - and in our selected regions (see above). In summary, to be closer to what I understood from our meeting, I recommend:

I don't think the integrated plan above has been done before.

What we learned from the mutual information fields is that trajectories that cover the upstream and downstream of the features tend to be most informative about the FTLE field itself.

MSEAS Muskeget Channel Release recommendations (pdf)

Wednesday, August 8

We posted 9 different forecasts on Berkeley's website at 8:30am. They cover this period 12Z Aug 07 - 12Z Aug 10 and have varying wind mixing, "tidal" mixing and bottom stress. This is not an ensemble forecast proper, more some tests on model parameters.

We noticed that yesterday's weather forecast may have had the medium warm winds from the south (1.5 dyne/cm2 or 0.15 N/m2 wind stress) coming in a few hours late compared to their analyses today (updated wind estimates by NAM based on weather data). By Ekman transport, such southward winds lead to slow a mean surface transport towards the east-northeast for the drifters. Wind-driven ocean responses right along the coast due to the slightly higher water levels there are also a factor in increasing near coast currents and thus the drifter motions just along the coast (advected eastward).

Tuesday, August 7

Monday, August 6

Sunday, July 29 and Monday July 30