Category: silbo (Page 19 of 22)

The mystery eddy… Solved ????

August 8, 2011 / admin

Hey guys

just complementing the post sent by Nislen, the current pattern follows flowing to the NW all the weekend (Figure 1).

Figure 1.- SIlbo surfacings on weekend 5-7 august 2011.

This has confused to the Silbo team this weekend, since we expected SW current associated to the central cold sun of the solar system that we actually cross. The solution to the mistery may come moving a step back and look the problem with some perspective. When we did it, solution appeared nitid and clear. It came observing the altimetric landscape given by the update of the SSHa today. Data say that there are 2 guilties to this NW strong and regular current flow.

1.- If we observe the SSHa, there are a strong anticlockwise pattern that seems to be the responsible of such a NW flow. The central cold eddy (the sun of the solar system that we cross) targeted by a negative SSHa (green color), has been opened in his SE side and has been converted in an “altimetric channel”. This channel seems to be built by a strong current flowing to NW (to silbo) like a river (Figure 2).

Figure 2a.- SSHa 8 august 2011.

This channel/river continues sorrounding the warm eddy South Silbo. It is a mesoscale pattern of 500 km of longitude (24-29 W), and 200 km of latitude (54.5-52.5 N) aproximately (Figure 2b).

Figure 2b.- SSHa 8th august 2011.

This mesoscale anticlockwise pattern would explain the NW flow. But whats its origin ? Who is the builder/guilty ?

2.- The thermohaline general pattern is the main characteristic of this particular N Atlantic ocean domain. Thus, the global pattern of the salinity is a good indicator of the global circulation. The N arm of the gulf stream is flowing to NW (Southwestern Iceland) and NE (Eastern Iceland). Silbo is crossing the SW limit (strong salinity front) of this global salted river flowing north (Figure 3).

Figure 3.- Salinity field and thermohaline flow. 8th august 2011.

It could explain such a mesoescale anticlockwise flow associated to the thermohaline NW strong flow (Figure 4).

Figure 4.- Mesoscale anticlockwise pattern showed in the SSHa and Salinity fields (8h august 11).

As Nilsen proposes, we would have to move the WP to get the strong warm eddy located SE to silbo (we would have to be at 25 W, 53 N to find good and constant South oriented currents). Apparently, the NW river would flow for a while. So the course of silbo would be S-SW with the actual WP. We would have to fly to silbo to SE (100 km in longitude E, 200 km in latitude to S).

For that it would be neccessary to move the WP to the North and to the East to head it course to the SE, to 25 W, 53 N.

greetings all

Antonio Ramos

RCO Division, ULPGC.

Mystery Eddy

August 7, 2011 / admin

Good Afternoon everybody,

Well, it looks like Challenger has succumbed to a mysterious eddy that we did not think would have as much of an effect on us as it has.

As of yesterday, the general path of the currents seen in both the hycom model and the model provided to us by our good friends at ULPGC both showed currents flowing in a south-easterly direction, while Challenger has been reporting the currents moving in a 180° difference to the North West. Today, the ULPGC model continues to show the same flow, while now the hycom is agreeing more closely with the currents that Challenger is reporting.

Fig. 1: SSHa with Current Vectors from ULPGC

In Figure 1, there shows that there is a difference in sea level to the south west of Challenger, but the currents show that there is a strong south east movement in our vicinity.

Fig. 2: Location of a cold core eddy to the South West

Fig. 3: HYCOM model of currents and Sea Surface Height

Figures 2 & 3 show today’s imagery from ULPGC and HYCOM respectfully. Although the eddy in question is not very clear in the SSH model, the currents do show a slight circular movement to show where the eddy lies, while the ULPGC model shows currents moving in a clear south east direction. This discrepancy may be due to only receiving daily updates from both models, and with the most recent storm that has going through, I am sure the seas are all jumbled up.

Fig. 4: The 18 (?) storm Challenger has flown through

Oceanweather’s wave forecast also gives us some insight on how the storms are effecting the area:

Fig. 5: Oceanweather's wave forcast for today

For now, we will wait to see where we surface to see how the current conditions are effecting our flight. When we surface, if it looks like we are being dragged too far to the west, we may change the way point to try and follow a path along these lines:

Fig. 6: Possible path for Challenger 1 to follow. Depicted in both the ULPGC and HYCOM model respectively

Stay tuned for tomorrows update!

Nilsen

PLOCAN::MaReS Summer School

August 5, 2011 / admin

The Oceanic Platform of the Canary Islands (PLOCAN) is a general marine science and technology mobilisation initiative that seeks to obtain the international socioeconomic business competitiveness derived from access to the oceanic space. PLOCAN is working in different fields as renewable energies, focused in ocean’s energy resources, oceanographic buoys and underwater vehicles.

As one of its most important areas, PLOCAN Training Program has been working in the last year with underdegree students and graduates, mainly with Spanish students.

But this summer we are carried out the MaReS Summer School, an international initiative with the collaboration of Rutgers University, University of Madeira (Madeira Tecnopolo), and with the University of Azores, with an international student exchange program.

Two of our MaReS Summer School students are now in RU-COOL helping with SILBO glider mission between Reykjavik to Las Palmas.

MaReS Summer School

Welcome to the VIG Club

August 5, 2011 / admin

“..You have grown up, Median….” Saruman in “the lord of the rings”

Hey guys,

Nilsen and Antonio speaking.. Definitely, Silbo has grown up. He flew 1048 km in 42 days (25 km/day) at 1,05 km/h (0.29 m/s). Now it is official: Challenger has joined the VIG (Very Important Gliders) Club !

A feet (> 1000 km run) that has only been accomplished by a handful of gliders before now, including Rutgers Electric Gliders RU 15 (first long distance, international flight from NJ to Halifax, Nova Scotia) RU 17 (first attempt at crossing the Atlantic), RU 26 (1000m+ runs off of St Thomas and in the Ross Sea in Antarctica), RU 27 (The first Atlantic Crossing) and Thermal Gliders Cook & Drake (attempts at crossing the Atlantic at the 26.5° latitude).

Fig 1. Very Importan Glider (>1000 km) club.

But now lets zoom back in to the Northern Atlantic where Challenger 1 is continuing to make his way south. We have suffered 15 storms since the beginning. One each 3 days. However, today it looks sunny in the North Atlantic.

Fig 2. Weather conditions 5 aug 11.

Definitely we are leaving the convection belt area of the North Atlantic determined by a high salinity and W NW flow of the currents over the silbo geographic domain.

Fig 3.- Thermohaline belt in the NE Atlantic.

Fig 4.- Salinity field the NE Atlantic (5 aug 2011).

Current path becomes clearer now and submesoscale dynamic seems to determine the day by day of silbo. Thus, over the past couple of days, we have been discussing a possible change of way point as we have come across another solar system of warm and cold eddies.

Fig 5.- Solar system: A anticlockwise sun (cold eddy) and

clockwise planets (warm eddies)

One possible path to take would be to weave our way south by catching the west side of the cold core eddy to our south (which rotates in a counter clock wise manner) which hopefully will drag us south and to the east where we will then catch the strong southerly currents of the large warm core eddy further to our south. The warm core eddy, which rotates clock wise, will hopefully then pull us further to the south and beyond.

Fig 6.- Path planning to cross this marine solar system.

Finally we would like to congrat to all of you (RUcool, TDW, ULPGC, PLOCAN), great team, for your great job and for this new great success.

Today we wish you all

force, wind, sea and honor

Nislen STRANDSKOV and Antonio RAMOS

Some Luck at Last

August 3, 2011 / admin

Morning everyone,

The above picture is Challenger 1’s position Monday, with a sea surface temperature overlay where the wind has advantageously blown us slightly to the East.

This picture is of the Chlorophyll A concentration provided by Antonio.

Here is Challenger 1’s location yesterday with a sea surface temperature overlay.

Moving ever so closer to our waypoint! Over the past few days we’ve harnessed the currents of the eddys so that their natural flow will help push us South / Southeast. Here’s to hoping that the next few days and currents will push us a bit faster than usual as we glide through the solar system of eddys.

Also, RU22 was deployed yesterday off of Barnegat Bay.

Oliver & Nilsen

Today

Right handed and left handed marine solar systems.

July 29, 2011 / admin

Hey ¡ Buenos días a todos ¡

Obviously, it looks that challenger 1 mission, a huge international oceanographic mission becomes by moments the MCXXIII chapter of STARTREK and our brave Silbo, more than a glider, becomes the mythic Enterprise …

As Nilsen posted, he has generated an intense traffic of emails and procedures this week. Homework has been focused on battery power consumption forecasts, converting to kmz the data sets available to be included in the website of the mission in real time, Barnacles and finally, object of this post, liquid solar systems. Not so bad: “barnacles and liquid solar systems”.

Some weeks ago, on 24 june, we reported the presence of a liquid meccano of alternatives eddiies belt of different sign at different meso and submesoescales space time. When we made a zoom we observed that this marine eddy galaxy (!??) was engaged forming by different solar systems that seemed to follow the same premise. A belt of eddies was sorrounding another of contrary sign. Thus on 8th july, Silbo was flying the first of this gears. We had a number of cold core eddies surrounding a warm core eddy that were in our path (figure 1).

FIGURE 1. SSHa 8 jul 11. Left handed solar system formed by a warm eddy (sun) in the centre and cold eddies (planets) gyring and translating anticlockwise around.

Two weeks later, Silbo (“enterprise”) follows finding and sailing/flying some liquid solar systems organized in a very espectacular, effcient and simple way. Look that he is heading a new one. However there are some differences with the previous one. This new target is right handed marine solar system (cold sun and warm planets). We would also expect translation movement (to the right) around the cold eddy of the centre that we expect that will not move (figure 2).

Figure 2. SSHa 27th jul 11. A right handed marine solar system.

When we compared both solar system the simetry and size appear evidents. Both translate around a static sun located in the middle at (to check it) apparently the same speed of 8-12 km/day (figure 3 a,b).

Figure 3a and 3b. SSHa field on 8th and 27th jul 11. Left handed and right handed marine solar systems.

We thought the best course of action is to follow these eddies around and try and shoot ourselves as far south as we can by using the alternating currents caused by the cold and warm eddies (cold eddies spin counter clockwise while warm spin clockwise). And we did it. Now, we are applying the symetric protocol to cross this new but right handed liquid system. To cross the initial planetary belt of warm eddies by its right side and, (W path) cross the sun (55 N) by the western side and then the eastern side of the warm eddy located at south (54 N). However there is another solution. To move the Waypoint to the E and attack the warm eddies located SE silbo until arriving to 22 E. Then turn again to SW to leave the solar system and heading the warmer South (figure 4)…

Figure 4. SSHa 8th and 27th jul 11. Path plannings to cross both marine solar systems.

Incredible…Isnt it ? Force, wind, sea and honor to all

Antonio G Ramos

RCO Division (Robotic and Computational Oceanography, ULPGC)

Changing currents from one hour to the next

July 28, 2011 / admin

Hey All!

Well Challenger has been continuing on it way south while combating the draw of a number of eddies.

The above picture is where Challenger 1 surfaced Monday, with a sea surface height overlay. After a few days of strenuous battle, Challenger 1 was almost completely clear of the Eastern eddy field’s influence (next picture is of yesterday’s update with a sea surface temperature overlay).

We have sailed along the Western edge of the eddy for roughly 112km (70miles) and are slowly inching our way out of its pull. And what’s to our South? Southernly heading currents for the time being! The HYCOM does not reveal it but it seems as if there is another eddy Southeast of our position. If the past repeats itself, there will be more storms ahead for Challenger 1 and hopefully bring us fast flowing currents past any hurdles.

Currents and everything that affects them are a curious thing. Just as I update Google Earth, a hour after my previous statement yesterday, the currents end up looking like this. They are all facing completely north and there does not seem to be any relief to our West or East, be we shall keep pressing on!

Today, July 27th, the currents aren’t looking much better, still all completely North and no relief is in immediate sight.

And just like that, the currents have changed a little since the last hour. Now we have a little room for maneuvering, even though these currents do seem a little powerful.

The image above was provided by Antonio and shows sea surface height of our journey ahead. We have a solar system of eddies ahead of us, but we have a number of defeated eddies under our belt already, so they should be no sweat. We will just need to keep an eye on our surfacings to make sure we don’t get dragged full circle around one of the stronger ones.

To try and make more accurate predictions about what the currents will be doing, I overlayed the currents provided to us by ULPGC on top of the geostrophic currents from HYCOM. In the figure below, we can see how there are some similarities and differences between what each of the models are showing.

U. Las Palmas Gran Canaria Currents overlayed with HYCOM geostrophic currents and sea surface height model relative to Challenger's latest position

Looking at the weather conditions, we see what may be causing the discrepancies between the models. It looks like there is a strong wind system blowing directly north courtesy of the jet stream. There also seems to be another storm headed our way which will undoubtedly add more mixing to the direction of the currents between the movements of the eddies.

It looks like there is a long road ahead of us but I have no doubt Challenger will fight valiantly.

Oliver & Nilsen

Estimated end date

July 26, 2011 / admin

Hi all!

I have rewritten the script for the Estimated_End_Date and the up-to-date results are in

http://marine.rutgers.edu/~marrero/figures/Silbo_Estimated_End_Date.png

Click on the image to get the up-to-date image

The blue curve is a linear fit for all the m_coulomb_amphr_total data, that actually predict the end on 31-Jan using 718Ah.

The green one is another approximation that calculates an average with different weights for the last 5 days ah/day in order to be able to follow the last changes in the way we use the energy. On this method the prediction actually is 7-Feb.

Let’s see how it changes!

Alberto & Rubén

Flying downhill ….

July 21, 2011 / admin

Buen día a todos …

“Ents love to go South, my dear hobbits … It is like walking downhill”…

Treebeard in “the Lord of the rings” ..

Definitely, Silbo agrees with this deep, magic and wisdom thought… In two days, after our 7th and 8th storms (figure 1) current field finally changed and turn to SW.

Figure 1a and 1b.- Inertial oscillation generated by the 7th storm on 17 and 18 july.

To express it simply, “we were hanged to 11,s km”, Oscar dixit. Our brave Silbo flew 39 km in 24 hours… He had 2 stints flying at 0.46 m/s and 0.46 m/s (!), the second record (0.47 m/s) of the hole mission (figure 2).

Figure 2.- Last surfacings. Inertial oscillation generated by the 9th storm today ??

If we observe the SSHa anomaly and the chl a field, our primary target is crossing the eastern side of a warm eddy (W Silbo) and then, the western side of a cold eddy (S SIlbo) (figure 3 and figure 4).

Figure 3.- SSHa field on 20th july 2011.

Figure 4.- Chl a field on 20th july 2011.

Our focal point is located at 57 N 26.5 W. Here we have a toll in the highway with three good options/roads. Eastern, Central or Western road. All of them out of the < 1000 m depth. (figure 5).

Figure 5.- The next…SSHa field on 20th july 2011.

Finally the 9th storm arrived today. It perturbated the current field (as expected) and the last surfacing shows that current turned from SW to W (figure 2). However, one important remark: it keeps the speed up to 0.35 m/s, we would expect a new change again to SW at good speeds like yesterday.

That would means that Silbo would follow “flying downhill without brakes” for a while .… (fasten your seatbelts again).

However “the man proposes, and the sea decides”.

Thanks again to mi great team and have a nice day dear friends and colleagues.

Antonio G. Ramos (RCO Division, ULPGC).

“Fasten Your Seatbelts!” -Antonio

July 20, 2011 / admin

Hey All!

So after being bombarded with a number of storms and unfavorable currents, Challenger 1 has finally caught a break.

Yesterday afternoon, Antonio (ULPGC) and Ben (TWR) proposed options for a new way point if we felt changing would be advantageous. I looked into what the two proposed options were and we had the choice of moving our way point to the east and try and catch an eddy in that direction, or to continue along our path.

Antonio's SSH and Currents figure for 7/18 with the two arrows showing our options

The team at Rutgers then decided that we wanted to keep the most recent way point and ride the eddy south instead of making strictly easterly movement by moving the way point. We proposed our thoughts to Antonio and Ben who agreed with us and we continued with the current way point. By making this decision, Challenger 1 continued on its path and was rocketed south, hitting 1.25 km/hr and covering over 33km in just under 1 day.

This is excellent news, as we have been reminded of how close we will be cutting it battery wise as we move our way to the Canaries. After nearly a month at sea, Challenger 1 has covered 15% of the distance needed to reach the Canaries (~4000km), however we need to begin saving more battery power to guarantee we have enough juice to reach our destination. As we continue on our general south-west direction it seems like keeping the Azores as an option for a pit stop may be a good idea as a possible place to rebattery and brush off the biological growth that will undoubtedly slow us down.

But as for now, we continue on our path to the south, but as we continue jumping eddy to eddy, we will discuss where we want to fly and if we will swing west to the Azores.

On another note, we are just being relieved of the influence of the 7th storm since deployment. This one had much less of an effect on the currents than we have seen in the past and so did not disrupt our flying too much compared to the gyring force of the eddies.

Nilsen & Oliver