Archive for June, 2012
As of the last surfacing, Ru 29 is mere hours from crossing the shelf into the depths. We were cautious over the past day as we were trying to time our crossing of the shelf as perfect as possible. Now that summer has started, fishing levels shipping traffic have spiked as people enjoy the warm weather. Knowing that if we continued straight towards the shelf, we would arrive mid afternoon when the traffic would be at its highest. So we decided to enter station keep mode to bide our time for a few hours so we could put off making the crossing until late at night.
After 4 surfacings of following the station keep protocol, we moved the way point back out to the east as 29 now is making her way towards the shelf.
Looking at the bathymetry, it is really incredible. By the last surfacing, we were flying in 150m of water, yet 5 km east, the ocean floor drops to 500m, in 10 km it is 1250m and the further we go the deeper it gets.
One observation we did make today was that there seems to be a bit of a lag on the inflection at depth.
Chip however shed light on this issue by bringing up the fact that 29 is a deep glider and the oil pump takes longer. The problem may also adjust itself as we make our way into deep water which the glider is made to fly in. Aside from that, She has been flying pretty well and has even minimized the time spent at the surface to between 7-9 minutes.
For the future planning, we made a list of points to take into account. First off, in order to avoid ship traffic, we are doing our best to avoid fishing zones which also include keeping an eye on the Sea Surface Temperature as a front of 2 degrees could attract large amounts of fish and thus fisherman. We have also increased the time between surfacings, and instead of making our top inflections close to the surface, we are making them at 20m. We also have proposed to adjust the use of the altimeter to turn on at a deeper depth in order to conserve battery power.
Finally, the Gulf Stream is not less than 90 km from 29. If we want to see this glider again, we must do everything we can to stay away from this massive current. This year, the Gulf Stream has come up very close to the coast of NJ, and if we were to accidentally enter it, 29 would be in incredible danger. With the battery packs on board, 29 only has roughly 20 days at sea giving us enough time to run two weeks to testing and get back close enough for recovery. However if we get caught in the current, we will surely get launched out to sea. Knowing this, we are doing our best to keep an eye on the currents to make sure we do not get anywhere close to the dangerous area. To do so, we are using the RTOFS Ocean Basin Forecast, real time satellite imagery, CODAR, and myocean from Antonio. But as for now, we have two way points waiting for 29 so she is set through the weekend
So a little while back, I had mentioned that Rutgers had received the first of what will be the fleet of 16 gliders meant for the Challenger Mission: Ru 29, Challenger 01. This summer, while we were finishing up Silbo's mission, a team consisting of Rutgers and U.S. Naval Academy students began preparing Ru 29 for its test mission. Then, early yesterday morning, we departed from Rutgers and drove down to Atlantic City where we boarded the Sea Tow boat Cape Hatteras.
Once secured, we set off on a 50 mile, 2.5 hr trip to get out into deep enough water for Challenger to fly.
Once we were out far enough, the three students from USNA cast the Sea Bird ctd and ran the final checks in preparation for launch.
Then 29 was wheeled to the edge and it's maiden voyage was under way!
Once in the water, the team moved into the cabin, where they ran a few tests to confirm everything was working correctly, before we sent 29 on its way.
Now, it is time to shift gears and focus on piloting. We have a few things to consider over the next couple of weeks as we conduct 29's test flight. As of right now, we are flying in pretty shallow water (61 m). Challenger, however is a stretch deep glider and so we need to get to waters over 1000m to run tests. So we head to the shelf where the bathymetry drops from 150m to 2100m over 21 km. However, between 29 and our our goal, there are quite a few obstacles: shipping lanes that can strike and sink us in the blink of an eye, fishing boats armed with nets that can capture us damaging the wings tail and ctd, and strong currents that can push us back towards shore.
To protect us from the shipping lanes and fishing traffic, we have a number of ais and shipping over lays for google earth that will steer us clear of the ships. We also have a protocol which calls for making our inflections sub surface and making more yo's between calling in to minimize time spent near the surface to keep away from the hulls of the ships. One the weekends, the fishing traffic on the shelf tends to pick up, and as today is the first day of summer, we can expect the area to be quite busy this weekend. Judging by the currents, it looks like we will be roughly 4 days until we reach the shelf so we are discussing the possibility of waiting to cross until Monday, loosing us a few days of valuable testing, or risking the shipping and making a break for the shelf through the danger.
The other hazard at hand is the currents. Looking at the previous 24 hrs compared to the most recent surfacing, it looks like we are seeing an inertial oscillation in which the direction of the currents do a complete 360˚ giving us a variation of stints of good and bad distance covered. As we close in on the shelf, we need to keep an eye on the position of the canyons. There, we see strong jets of water that could also slow us down, or potentially push us back towards shore.
Finally looking into the future, we need to understand what is happening in the deep water. Once we get out, we only have a couple of weeks to run our tests. We need to see how the currents are moving, that way we don't get caught and pulled out too far away from shore. This could potentially cut down the already limited time we have to run the tests we need. It will be crucial to keep an eye on all of these factors as we continue this test flight through the weekend.
Here is a link to the Ru Cool Flickr page for a complete set of the pictures I took along with a video of the deployment: http://www.flickr.com/photos/rutgers_cool/sets/72157630207739484/