Tag: Nilsen Strandskov (Page 9 of 11)

Hey All!

Well Challenger continues to plunge its way through the intersection of currents that lie in our area due to the overwhelming amount of eddies.  Last night we changed the way point further south as to prevent us from being pulled too far east by the warm core eddy next to us.  The changed way point successfully steered us out of its pull to the north, but for the time being we are sailing in a bit of a head current until we can break free from its control.

Even though we have lost some speed, we are predicting that we may break even our most recent high speed record of 0.57 m/s over the next couple days as the strongest southerly current we have seen to date lies only a short distance to our south.  This will launch us at high speeds southward along the eastern side of three warm core eddies before we may change direction and try and aim for the western side of a cold eddy to weave ourselves back around.  But that decision will be made for certain in the future.

Aside from our success with last nights change of way point, we have some really beautiful imagery from both our HYCOM and ULPGC models that all seem to match up fairly well (not always the case but really leaves us with a good feeling about what our plan is for the time being).

Sea Surface Height with Currents from the HYCOM model

Sea Surface Height with Currents from ULPGC model

Although the scales are different for the color on the two sea surface height images above, the correlation of the currents are the same showing the strong southerly flow.

Sea Surface Temperature with Currents from HYCOM model

Satellite Sea Surface Temperature with Current model from ULPGC

Unfortunately due to cloud cover courtesy of the storm number 20, there isn’t any temperature data for the imagery, same with chlorophyll a below.

Satellite Imagery of Chl a with Current model from ULPGC

Sea Surface Salinity with Currents from HYCOM model

As described in our post from a few days ago, when on the east side of a warm eddy, salinity, temperature and currents all tend to match up.

Sea Surface Density and Currents from HYCOM model

We will keep everyone updated over the next couple of days.  Have a great weekend everyone!

Nilsen & Oliver

Hey All,

Well Challenger is now being pummeled with his 20th storm in the 49 days since being deployed way back on June 23.

As you can see from the figure above, the presence of a strong system in the jet stream coincides with some wave activity reaching 8 ft swells, and a cloud system all in the vicinity of Challenger 1.

This storm however has not been able to slow us down as we have now had 7 consecutive segments all above 0.52 m/s!

Although it also seems that the currents are changing as we continue on our way to the south east so these speeds may not be around much longer.  As it says in the figure below, we are beginning to feel the effects of the currents moving to the north from the west side of the warm eddy to our east.  Depicted by the three lines, we can see that we have been leveling off and turning to the east because of this influence.

So we proposed a new way point of 49N 23 W to try and steer ourselves away from the eddy to our east’s influence and to try and continue to surf the eddy to our south.

If we continue on our current path, we will be dragged into this North East flow

Zooming out, we can see the next two solar systems that we will be navigating over the next two weeks.

Hopefully moving the way point to our south will be enough to put us on the right path to follow the yellow arrows down the stream of warm planets to the next system.  The new way point will be set at the next surfacing in a couple of hours, so hopefully it won’t be too late to try and change our course to catch the more southerly currents.  Tomorrow we will make sure to give everyone an update on how Challenger flying.

Nilsen, Antonio, and Oliver

‘Afternoon everyone,

Yesterday was a big day for us here at IMCS, we were honored with a visit from the Assistant Secretary of Commerce for Environmental Observation and Prediction, Dr. Kathy Sullivan and Director of the Integrated Oceans Observing System (IOOS) Dr. Zdenka Willis, along with a number of other high ranking government officials.  After a tour and discussion of the glider lab, COOL room, and the Challenger Mission (which consisted of a skype call with our partners at PLOCAN), everyone proceeded to the Alampi Room.  There, various awards were given out for Rutgers appreciation and collaboration and Dr. Sullivan even presented us with an award for the success of the Atlantic Crossing and luck on the completion of the Challenger Mission.

Scott Glenn, Zdenka Willis and Kathryn Sullivan touring the COOL room

Our friends at PLOCAN (including past students of the COOL room, Dara, Adri and Alvaro)during a skype session while our visitors were here.

But back to Challenger 1.  There has been a lot that has happened piloting wise over the past two weeks so first we would just like to do a quick re-cap.

Jumping back a bit, we were entering a new solar system, which we carved a path straight through the middle where we snaked back and forth jumping from one eddy to the next.

Moving on from there, we found a strong warm core eddy, the “warm planet” that really slowed our progress as we were dragged nearly directly to the west as we were pulled into it’s strong clockwise gyre.

This was then followed by our encounter with a “Mystery Eddy” on Sunday that again caught us off guard with its strength, reminding us that the ocean is a formidable foe that is still widely unknown and which should not be underestimated.

These were all very good learning experiences that will aid us on the remaining 75% of our journey.  Antonio pointed out after we were liberated from the allure of the mystery eddy, that when we cross the west side of a cold eddy (general counter clockwise), it seems that the currents we observed (as we crossed the past two solar systems) is going to the North- North/West direction, flowing in the same direction as the thermohaline pattern, but do not completely follow what the models say the currents should be.  However, when we fly on the eastern side of a warm eddy,  the currents agree with what the models predict, going East-South/East (clockwise motion) and thus opposite of the North-North/West thermohaline flow we see in this region.  The result of both of the counter currents we see is to the south, which are the currents we must ride until we find more favorable currents. This explains the trouble we were having when it came to flying to the west side of a cold eddy and our experience with the mystery eddy.

The North Atlantic Thermohaline Circulation showing the N-NW flow in our area that we have dealt with recently

So what we have to look for now, is to aim for the eastern side of the warm eddies, where we have found much better luck propulsion wise versus catching the western side of a cold eddy.  This however we think will change when we reach the Canary current, where we should find better luck on the western edge of a cold eddy.

After this break through, Monday we saw some strong currents to our south east that we thought may be ideal so we began looking into the changing of the way point for Challenger 1.

Our two options for waypoints. Yellow would be the range we followed keeping the waypoint, Green if we changed it

After much discussion, Antonio and I decided we should move our way point further east and aim for the stronger currents we saw to the south east of our position.  Below we can see the strong currents turning from east to south/east as it curves around the large red-yellow swirl to our south.

With this way point move, Challenger went from being a glider to a rocket ship as we broke our previous speed record not once, or twice, but on our past 4 segments!

The first two segments that broke our speed record

Previously, we were holding a record of 0.47 m/s, but on our past 4 surfacings, we blasted that away going 0.52m/s on the first two segments and the most recent two at 0.53 m/s!

Now we look to the near future to see when the next plan of action shall take place.  As the conditions are now, when Challenger gets to the vicinity of the circle drawn on the map above, we will move the way point back to the south to  try and take the most advantage of favorable currents.

As always, force, wind, sea and honor

Nilsen Strandskov, Antonio Ramos, and Oliver Ho

Good morning all!

Just a quick update on the Challenger mission

So last night after Antonio and I conversed and changed the way point, Challenger came close to breaking its speed record for the mission by hitting 1.52 km/hr (0.42m/s)!  What contributed to this speed, was we moved the way point further east, allowing us to catch the outer edge of the east side of the warm eddy to our south.  This launched us on a south east trajectory following these new currents shown below.

That’s all for now, we will have another post later today

Nilsen

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

“..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

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

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

Hi all!

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