Saturday, June 27, 2009

Asperatus (?)

There's been a lot of fuss over the last three weeks or so about a new class of cloud form, the so-called "asperatus" (which is supposed to be pronounced, I understand, to rhyme with "asperagus"). I say "so-called" for several reasons. First, I don't think anyone (who knows what they're talking about) is claiming that this is a truly "new" class of clouds; rather it may be a class that has existed since before the dawn of humanity, but has never been given a formal name and recognition. This is not unique, or even unusual, in any branch of science- pushing science forward often involves recognizing as distinct things that have been right in front of our collective faces for as long as we've had faces. Second, there has been a rush to name all sorts of cloud structures and textures as "asperatus," as if it's a done deal- as if the meteorological community has already accepted and condoned this name. It hasn't. Third, since it hasn't been accepted as a formal term, the criteria for determining that a particular cloud, or sky full of clouds, should be described as asperatus, do not exist. As a result, all of us cloud watchers have different ideas of what that term does or should mean.

In my mind, this rush to put up (albeit beautiful) pictures labeled"asperatus" is more likely to lead to confusion rather than forward motion and resolution. On the other hand, having a wide variety of examples available for examination and study can only be useful. My compromise is shown in the title: unless and until this name is formally adopted, the term should be written as asperatus(?).

While these have been described as "rare," my perception is that, here in western Oregon, we get these types of clouds several times a year, most often in late spring and fall, and most often in association with (what seems to us) a fairly unusual combination of high humidity and temperatures. The dewpoint according to accuweather just after taking these photos was 64 (typical summer dewpoints around here are about 45 to 55), and the temp was about 80. These are from Wednesday June 3, and were taken between 7:00 and 7:10 PM (actually, I need to check my camera's clock to be certain of the time), near the corner of 16th and Monroe in Corvallis, Oregon (Outside The Interzone). I think I've accidentally overwritten one of the original photos with a processed version, but otherwise, I still have the originals. All of the below are heavily processed to bring out the contrast, but are a more accurate repsentation of what I remember than the sort of gray, washed-out photos as they came out. Click to enlarge. Beautiful!
Looking ~SSW over the OSU campus
From the parking lot off 16th, looking ~SE.
Same as the previous location, looking ~ESE, a few minutes earlier.
Looking east along Monroe Ave.
Same as above.

Several sources have put out articles on this proposed classification over the last few weeks, including The Daily Mail, The BBC, and National Geographic. Many more stunning photos can be found at The Asperatus Gallery at Cloud Appreciation Society. (I subscribe to all four of those in RSS, but if you like a steady dose of pretty cloud pictures, about 5 a day, the latter is a treat. Front page here; incidentally, these are the same folks who are pushing for the new designation.)

Finally, I asked a blogging meterologist what he felt about this (as I described it) "media blitz" over "asperatus." I was pleased to see his reaction was pretty much the same as mine. Take it away, Weather Moose...

1 comment:

pygalgia said...

Very interesting. We sometimes get similar cloud formations here in Flagstaff, and they usually portend serious wind and rain. I'll try to pay more attention to them in the future.
Ya' got a real interesting blog here, and I'll be adding you to my b'roll soon.