Archive for October 19th, 2007

Buzzing at PA

Friday, October 19, 2007


The storm had settled, but there was still no sign of the whales, so we decided to sail over to Port Angeles.  After scrambled eggs for breakfast and offloading our recycling, garbage and compost, we untied the Gato Verde from the dock at Friday Harbor Labs.  Progress was slow through Cattle Pass, but we passed the time debating ethics of intelligent mammals in captivity.  There were a number of Steller sea lions feeding on salmon at the surface as we reached the mouth of Cattle Pass.  We hoisted the main and unfurled the screecher to take advantage of the 15-20 knot winds.  Liz and Elise prepared egg salad for lunch and reached Port Angeles around 4 pm.  Shannon, Elise, Liz, Kenna, and Heather headed into Itsy Bitsy Buzz café for internet and caffeine fixes.  After Buzz, we enjoyed the evening stroll back to the docks.  Kenna and Shannon prepared veggie stir-fry for dinner and we settled in for the evening—drinking tea, reading manuscripts, and writing this blog.

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It's almost crunch time

I think the first time I ever heard the phrase “crunch time” was when I was working in a microbiology lab in high school for the Intel Science Talent Search contest. It was probably about a month before my final paper was due. This was also around the time that my mentor actually got serious about REALLY working with me. Anyway, different setting, different story, another lifetime.

I’ve been calculating and analyzing, and then recalculating and analyzing over and over, the data that I’ve gathered on vessel noise, both individual and cumulative, and the VaTorecordings of orca calls. I managed to localize 81 calls so those are what I’m using to calculate source levels, and I have 19 individual noise files, 11 cumulative vessel noise files. I’m hoping that these are acceptable sample sizes. Already I’ve gotten calculated numbers, some of which seem so implausible that I almost fell out of my chair when I saw what Excel was showing me, but having gone over my equations several times, it looks like they do in fact reflect the findings of my raw data. Whether or not everything is RIGHT is a whole other story. It’s funny, I used to think that the natural sciences were the only place where “right” and “truth” actually meant something, (because it’s all relative everywhere else), but I’m finding more and more that even in physics you’re not safe (of course I would never be safe in physics). For sound propagation to determine my SLs, I’m using the spreading experiment we did out on the boat a few weeks ago, which gave me what appeared to be a questionable number, but I’m no scientist, who am I to say what makes sense and what doesn’t here? Literally every paper I’ve read involving sound propagation uses a different model, whether theoretical, empirically derived, or computer-generated. So taking that into account, I suppose my method is as good as any other, especially over small distances (or so Val has reassured me).

So now another crazy thing came up today that seemed to throw everything out of wack for a little while, but now I’ve got everything under control. I think. It had to do with some long and rather complicated discussions I had with both Jason and Val regarding the frequency range I’d be looking at for my analysis. Back when I was doing sound spectra, I thought I’d limit myself to the call range of 1-10 kHZ, but now I’m not doing spectra anymore, and it would involve a lot of extra math if I were to zero in on that range for every one of the files I’m including in my data analysis. And also…I don’t like math very much. The most straightforward option that Val suggested was just using the numbers I’ve already calculated anyway, i.e. considering the entire broadband range from 0-25 kHz. So…how do I justify THAT? Read enough papers, as I well know, and you’re bound to find what you’re looking for. While calls are mostly in the 1-10 kHz range, the audiogram extends well beyond that, and the frequency at which hearing is most sensitive is actually 20 kHz (thanks Szymanski). And vessel noise, the really crucial variable in my project, that definitely goes way over 10 kHz, and even over the upper broadband range limit of 25 kHz. So I’ve decided that it makes perfect sense to work with the numbers I’ve already spent hours figuring out…and that is what I am going to do.

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