So, I have been kept quite busy the past week. My FOO (Field Operations Officer) was kind enough to ask our sister ship (the Fairweather) if I could be of any assistance in the field. They agreed to let me tag along on a couple of projects.
On Tuesday (5/22/2012), we drove to a remote location where the Fairweather crew has a tide gauge set up, in order to to do some measurements. While we were out there, one of the NOAA Coprs officers walked me through the entire process of the tide gauge and why we need to take measurements. We also walked around the property and looked at all five of the Geodedic Survey Benchmarks installed.
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| Chart of Port Ludlow - Tide gauge and survey location |
The process of tide gauge surveying is simple; watch the tides, record the high and low tides every six minutes for three hours. We then use our collected data to compare it to the tide gauge sensor data. This will show any discrepencies and really just verifies that the tide gauge itself is functiong properly. After observiwng the tides, we downloaded the most recent numbers from the tide gauge sensor to bring back to the ship and compare.
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Observing the tides every 6 minutes for 3 hours.
High and low tides were recorded and averaged.
This infomation was then compared to the data the tide gauge sensor collected...
essentially to verify that the sensors are working properly. |
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| Tripod with optical level viewing the tide gauge |
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| View through the optical level to the tide gauge |
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| Downloading data from the tide gauge sensor |
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| Benchmark |
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| Private dock where the tide gauge sensors are kept |
On Wednesday (5/23/2012) We went out on the launch to do some surveying with our multibeams. This was a two-hour voyage just north of Seattle back to Port Ludlow. We ended up having some problems with the CTD (a device used to measure conductivity, temperature and depth in order to calculate the sound velocity in the area of surveying). The sound velocity changes from place to place due to salinity levels, temperatures, etc. Because the CTD wasn't working properly, we had to go back to the ship and try again the following day. It is amazing how many different components are involved in obtaining data. If any one of those components is not working, it can be a great challenge in collecting accurate and valid data.
So, on Thursday (5/24/2012) we went back out on the launch to the same location (with a new CTD) to complete our surveying.
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| Our course from the ship at the Federal Center South to Port Ludlow where we surveyed |
Once we arrived on location (which was about 2 hours from the ship) we cast the CTD. The process for this is fairly simple. You turn on the device, cast it into the water and let it sit for 2 minutes. After 2 minutes you let it drop to the bottom and reel it back up. We then hooked the CTD up to our computers in the launch to download the measurements.
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| Deploying the launch from the ship |
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| Our computers in the launch |
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| Setting up your systems before during departure to be ready to survey |
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| CTD (Conductivity, Temperature, Depth) |
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| Casting the CTD |
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| CTD in the water |
After the cast was complete, we spent the afternoon driving slowly over all the areas in need of surveying, all the while using the multibeams. The multibeam data we collected is stored on an external hard drive that we then plug into the computers on the ship to process the data.
Our Coxswain was nice enough to even let me drive the launch, while collecting data. Here are a few more pictures of the trip to Port Ludlow. It was a bit rainy in the morning but ended up being a beautiful day.
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| View of Seattle from inside the launch on our way to Port Ludlow |
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| Rainy Seattle morning |
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| Our Coxswain Chris |
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| Sunny afternoon in Port Ludlow |
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| Yea...they let me drive |
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| Back to the ship |
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