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Has it been three weeks or a lifetime? Today was the first day that I think collectively the ship showed some signs of fatigue. We're all a little disheveled and relying on caffeine more by the day. But today also marked the beginning of our transit home. Newport Rhode Island here we come!

cleaning data :)

I love that I have a super wide audience for this newsletter. It brings me much joy knowing that people from all backgrounds are interested in ocean exploration, life at sea, the wonders of the big blue.

Since everyone is invited to the science party that is this newsletter, I want to make sure everyone feels included when I use more scientific terms. I acknowledge that not all of my readers have experience working with “data”, and therefore might not understand what I’m saying when I’m “cleaning data”. So, although this may sound VERY boring, I’m going to take a second to talk about cleaning data!!

Our job on the ship is to clean the sonar data. This involves finding bad sonar readings and removing them from the dataset that we then send to shore.

How can sonar pings be messed up?

1.    Heavy seas. As the ship rocks and rolls the timing of the sonar is less uniform than what it would be if the seas were flat. The choppier the seas the more irradic points you are likely to acquire. In addition to the actual rocking messing up the timing of the sonar pings, heavy seas cause white caps to form and more bubbles within the surface waters. The air in the bubbles manipulate the speed of the sound wave, causing an inaccurate reading.
2.    Disturbance around the sonars. One of our engineers started doing maintenance very close to the sonar systems a couple of days ago. As the data started coming in we knew something was wrong, but didn’t realize it was due to a jackhammer causing vibrations mere feet away from the sonars for about an hour. Although a good amount of the data was messed up there was still enough to salvage a good product and we all had a good laugh about it.
3.    Marine life. Whales and fishies have gas in their bladders, which will enevitably change the speed of sound going through them.

What does this look like?

Here are some images of raw sonar pings once they are imported into the software cleaning interface (Quimera) I apologize in advance for the terrible quality images...

Uncleaned

Heres the surface we start with. Each color is a different set of files and each point is an individual record. The orange file was recorded while the ship was turning, and during a turn the excess roll heave and pitch of the ship can cause interference. We exaggerate the surface vertically to check for bad points.

This is the same file exaggerated! See all those orange points above and below the surface that just dont look right?  Those are from a specific file in which there was a lot of interference. We remove those bad boys.


Cleaning the bad data is more of an art than a science. Some mapping leads prefer to remove less than others, but all the data is later QC’ed multiple times to ensure we removed the appropriate amount of noisy data.

Eventually we end up with a pretty pretty seafloor product. If you want to see our preliminary work, this map usually updates our daily products but I've heard its down for server maintenance this week :(. You can not download the data as it still needs a couple more quality checks to make it an official NOAA mapping product. Still, kinda cool to think I'm helping a tiny bit in the massive undertaking of mapping our global ocean!
 

explorers log

4-20-22
And just like that were done with all of our science objectives! Today we begin our transit to the ships home port of Newport Rhode Island.

The last week or so has been run and rather uneventful. I’m savoring all the silly little morale events we’ve had in the evenings after dinner. Friday was “Spa night” with facemasks, electric candles, and Legally Blonde. Saturday I did a "dry tri" in which I raced a triathalon against myself and replaced swimming with rowing. Sunday began the duck hunt, where every day 30 rubber ducks are hidden around the ship- the ducks can be redeemed for prizes at the end of the week. Last night we played a role playing game called werewolf, and pretty much every night we watch the sunset together. Tonight we begin a Lord of the Rings nightly marathon. It’s the little things!

Last night we finally saw bioluminescence :). The moon was covered by clouds and it was dark enough to see the sparkling phytoplankton churning in the stern. I stood there in my PJ’s just leaning over the side staring at all the tiny little explosions of sparkle. Theres no way to capture it with any of the camera equipment I have so you’ll just have to use my silly little explanations to imagine it. 

Now say a prayer for us as we start into the Bermuda triangle…

XOXO Paige
 
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