Archive for November 4th, 2009

Scarlet’s 7,000th Kilometer.

Wednesday, November 4th, 2009

Three glider experiments looking through three breaks in the clouds.


Oscar is posting updates on the NSF experiment on the Middle Atlantic Bight Blog.

Here we'll focus on the two Trans-Atlantic gliders.  Teledyne Webb's deep thermal glider Drake is approaching its first test along the 26.5 N line.  There is a clockwise rotating eddy centered on the line at 51 W.  How Drake crosses right through the middle of this feature will be interesting to watch in the current vectors, how its track is deflected, and in the resulting temperature structure and heat flux.  Once past this eddy, Drake looks to have a tail current along 26.5 N all the way to the edge of this plot at 45 W.


Scarlet crossed the 7000 km mark today, with it's current path length reading at 7022 km.


The approaches to Spain and Portugal are shown here. The red circle is the area of uncertainty discovered this past weekend - the area we are working to avoid. The green circle is our target region for the end of November. The eastern side of the circle is 120 nautical miles from Vigo (orange line), and the western side is at the edge of the Spanish Exclusive Economic Zone, 200 nautical miles offshore.  Inshore of the vertical yellow line, a strong current heads south along much of the peninsula towards Lisbon.  This alongshore current is likely to be faster than Scarlet can fly.  We'll try to stay just offshore of these as we wait for pickup in early December.



Zooming into Scarlet's local area, she is now just less than 200 km from Spanish waters.  We hope to follow the looping white line into the green circle, then spin around the eddy towards its shoreward side.  Once in this region, there are several options depending on timing.  We can either continue to spin in the eddy or head into the strong alongshore current to move along the coast.  Whichever is preferred for pickup.


Thought from JPL after today’s excellent telecon!

Wednesday, November 4th, 2009

Thoughts from Yi:

As we discussed at the telecon, there is a really interesting outflow feature from the NY harbor,  see attached SST images for yesterday from GOES (11+12 at 6-km), TMI+AMSRE (25-km),  and MODIS (1-km).  All these data are blended using 2DVAR into a 1-km image, also attached.

We just post the SST comparisons with the four models on the CI portal, see attached difference maps (model-observation) for HOPS, NYHOPS, COAWST, and Rutgers ROMS.  As you can see, all four models are warmer in that outflow region, suggesting a weak or no outflow from the NY harbor.  Presumably  there will be a big difference for the salinity signature, that we don't have any observations now.
It would be great if we can send one glider to this area to first map this feature, and second assimilate it into the models to improve their forecasts.








Operation Ice Bridge

Wednesday, November 4th, 2009

nasa-dc-81This is just a little bit of fun science for everyone... NASA currently has a satellite called ICESat up in space that is about to reach its operational life expectancy. ICESat stands for Ice, Cloud and Land Elevation Satellite and it is critical because it monitors the massive ice sheets that cover the polar regions. The replacement satellite, ICESat-II, won't launch until 2014 at the earliest. This leaves researchers with a 6 year gap but NASA has a plan, Operation Ice Bridge. NASA is launching the largest airborne survey of Earth's polar ice ever flown. They have outfitted a DC-8 jetliner with various sensors including ones that were not on the original ICESsat. The jet flies out of Punta Arenas Chile and will crisscross ice shelves, sea ice, glaciers and the massive western ice sheet collecting critical data for researchers. Here is a link to the article.

What was really cool for us here at Palmer is that on Saturday Oct. 31st the DC-8 radioed into our station letting us know they were going to be flying over head. So we laid out our bright orange float coats to spell out "HI" and gathered on the pier to watch them fly overhead. They later sent the overhead picture to us.

JPL Executive summary for 11/4/2009

Wednesday, November 4th, 2009

JPL Executive Summary of 11/04/2009

Winds have switched to Northwesterly. NAM forecasts indicate weak winds Thursday in from the southeast direction. Northwesterly winds will resume Friday but increasing amplitude (up to 30 knots by the end of Friday). We continue to receive four ocean model forecasts daily. These model forecasts are compared with the daily mean observed surface current. It should be pointed out that the server that has HF Radar failed overnight. At least the Rutgers’ group is rerunning their model that will be available later today. We continue to generate the multi-model ensemble forecast based on the equal weighting method. There is a good agreement on the current flowing in the southwest direction, although the ensemble model forecasted current is significantly weaker than observed. There are discrepancies for the in/out flow at those major fresh-water input locations. All three gliders are moving along the predicted path, but at a much slower speed

Avijit’s late night thoughts

Wednesday, November 4th, 2009

Late night thoughts from Avijit Gangopadhyay:

Hi Oscar:

I was reading through your blog of this evening and was intrigued by the Glider current map...

Then I was looking at the model out at our site
and was trying to see what the model is showing at that location for today and next couple of days. You can go frame by frame or run
a quick animation...

What struck me is that the model is showing a variable pattern of shelf eddies interacting with each other making the currents go in different directions depending on which side of an eddy (of which kind) and the front you are on... It is quite variable near the Glider location around
73.5W, 39.2W. To begin with there were two shelf eddies opposing each other to the east of the Glider location, and then new eddy-like
formations are happening..

I have not checked the other models yet (its late now), maybe they show similar things even better resolved. Ours is pretty coarse resolution.

I am copying Wendell who can also take a look and let me know what you think... Its interesting nonetheless...

You can go to our site and then choose Mid-Atlantic shelf zoom and browse through the recent forecast...

Good night!