The drifters are adrift here in Monterey Bay

Well, the drifters are adrift here in Monterey Bay. They were deployed mid day today, local time by a team from the Monterey Bay Aquarium Research Institute (MBARI) and three Oceanography students from Monterey Peninsula College. The study is part of an intensive effort to look at the physical oceanography associated with harmful algal blooms (HABs) After four messages to the satellite (configured at 48/day), the image looks like this:

 You can see two drifters are out there; the single position is from when the ship was on the way to deployment. Both of the drifters are drifting south or southeast. This is somewhat unexpected as we thought the circulation in Monterey Bay was counterclockwise as I explained in my previous blog.

Wonder why the drifters are drifting southsouthwest? They are moving directly towards the Salinas Valley, probably as a result of seabreezes that pick up every afternoon here. At least that’s my current (ha ha) hypothesis. The winds today are shown on the image above, blowing straight towards the Salinas Valley, which is between Moss Landing and Del Monte Beach on the image above. The drifters were deployed northeast of Moss Landing, somewhat north of the MO buoy as shown on the image above.

 Follow along at the usual spots. I’ll share the response of the students in a later installment.

 Over and out for now,

 -Fred

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Getting Started at Monterey Peninsula College

Greetings from the Central Coast of California. This is my first attempt at blogging, so I hope I do it right. From what I’ve read on other blogs, I think I’m supposed to record my stream of consciousness and try to stay somewhat on topic. We’ll see how that goes.

In an effort to kick-start our drifter program out here on the shores of Monterey Bay, I went and visited Jeff Paduan at the Naval Postgraduate School. Jeff had to put me on a special list just to allow me to walk onto the grounds of NPS. Jeff is the local HF radar guru and has written papers on the circulation of Monterey Bay. Jeff is PI for the Central California component of the Coastal Ocean Currents Monitoring Program, perhaps better known as COCMP. The COCMP website has a nice pdf brochure imaginatively entitled the COCMP Reference Guide (How Ocean Current Mapping Works and How it is Useful) (image at right). It has some nice information that would be useful for teaching students how the HF radar works as well as beautiful color photographs of HF radar antennas in some of the most stunningly picturesque locations in the world. Strangely enough, the best images of Jeff’s HF radar ocean current data are at his Central California Currents page. Here’s what the currents look like for today in our area:

Those circular patterns you see in Monterey Bay on the image on the right are not tidal. They have a 24 hour periodicity and form in response to offshore and onshore breezes that cycle back and forth throughout the day.

Jeff and I talked quite a while about HF radar and I learned quite a bit. I still can’t explain all the intricacies of which frequencies they use to get the best Doppler Effect and why, but at least my eyes won’t roll too far back in my head next time we go through it.

We also talked about “typical” ocean circulation patterns in Monterey Bay. The image below is from one day back in 1994—exaclty 15 years ago from our drifters workshop.

The image shows ocean currents layered over sea surface temperatures. It shows the typical counterclockwise circulation in the bay and the clockwise eddy just outside the bay. As was true on this day in 1994, the northeast portion of the bay is the warmest, and this water is pulled out into deeper water by the currents.

I looked at some of the drifters that Jeff uses in his research. They’re commercially made by Pacific Gyre. They have a floating sphere that contains the transmitter and then a sail system that opens up like an umbrella.

The next stop in my tour of ocean current researchers was the world famous MBARI, the Monterey Bay Aquarium Research Institute, to visit Erich Rienecker and John Ryan. Erich is one of the marine technicians and John is a researcher specializing in phytoplankton blooms. Here’s John and I looking at some eye-popping data on John’s computer. I was just blinking, I swear.

Here’s that eye-popping data John and I were looking at:

The left image shows satellite-generated data for chlorophyll in the water, whereas the right image shows sea surface temperatures. Clearly there are other factors besides just temperatures driving the magnitude of plankton concentrations.

The last week in September and the first week in October, John and Erich will be involved with an intensive data gathering effort in this area involving satellites, AUVs, moorings, and………..drum roll please……… OUR DRIFTERS!

On Monday September 28 and Monday October 2 we’ll send students out on their cruises to deploy our drifters and launch their AUVs among other tasks for this study. Later in the week, we’ll send students out with them to try and retrieve the drifters. Should be fun, and a great experience for the students.

Back in the classroom, we’ll be following the progress of the drifters on the computers. Hopefully this will set the stage for increased interest in learning about atmospheric circulation and ocean currents. Then, in early November, we’ll take the whole class out on a cruise and release one of the drifters once again (assuming all goes well with the MBARI guys).

Over and out,

-Fred

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Drifter Newsletter #1

Sept 2009

Newsletter plan
This is the first of what I imagine to be a nearmonthly “newsletter” on drifter issues. Now that there are a few dozen labs using the SMCC/eMOLT drifters, we should probably try to compile our notes. If you have anything you would like to share with others (photos, funny stories, bad experiences, etc), please send it along to james.manning@noaa.gov. Keep in mind that most of the information regarding the drifters is now linked from the realtime website http://www.nefsc.noaa.gov/drifter but these periodic newsletters will provide your information on “what’s new”. If you want to be removed from the mailing list or you want some of your colleagues to be added, let me know.  This first issue is going out to all users that have deployed, or plan to deploy, this fall.

Check transmissions for a day or two before deployment
Given that the transmitter technology is constantly evolving and not all of these units work flawlessly, it is a good idea to set your transmitter outside the day before you deploy it under a clear sky view to make sure you are getting good fixes.

Set transmitters outdoors after shutting them off to verify they are indeed off.
Those of you who were at the workshop in August should put your transmitters outdoors to make sure they were properly turned off. There was at least one case where the transmitter was left on which probably resulted in a 2030% battery loss. A transmitter makes 3 attempts to get a fix with each sampling period so, if it is hidden from the satellite, the battery will run down 3times faster.

Watch for fiberglass rods wearing due to buoy stick chaffing
We recovered several fiberglass rods this summer which, after having been at sea for a multiple weeks, were worn down at the point of contact with the plastic buoy stick. This might have been due to the holes in the buoy sticks being two small so that they didn’t swing easily with wave movement.

Refrain from enabling the “advanced configuration” motion sensor
After experimenting with the this function on a couple units attached to my bicycle, I found that it didn’t work as it was suppose to. So, we may need to wait for another generation of transmitters before implementing this setting. We have however made use of the advanced configuration in order to get
“48 samples per day”.

Hoseclamps vs cable tie transmitter mounts
In our quest to minimize the cost of drifters, we recently started using heavy cable ties to secure the transmitters (where we used stainless hose clamps in the past). Last month, there was at least one documented case of the cable tie breaking. While this may have been due to the unit crashing on the rocks, it is worth noting nevertheless. If you experience any faults like this, PLEASE let us know.

Marine Advanced Technology Education (MATE) deployments
We are very excited to have expanded the use of these drifters around the country thanks to a NSF funded workshop in August where nine schools each went home with two drifters. As noted on the realtime site, UMaine Machias and Cape Fear CC, for example, have already made deployments.

Documenting your deployments
One of the links under the realtime website allows you to document your deployment. Based on the information you enter it is suppose to give you the “deployment ID”. If you want to know this deployment ID BEFORE you deploy, see the “deployment ID convention” link that is under the “construction and technology” notes. Please keep in mind that these websites are constantly under development in our attempts to automate things as much as possible.

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