Buoys
Posted by Chris in Tampa on 9/19/2020, 5:38 pm
https://twitter.com/GBlack22wx/status/1307363158282194944


https://twitter.com/GBlack22wx/status/1307364663810719749


https://twitter.com/GBlack22wx/status/1307365549572325387


https://twitter.com/bsbarret/status/1307402116919701504




Data:
http://argo.whoi.edu/alamo/



Screenshot from the file here you load into Google Earth:
http://argo.whoi.edu/kml/master-auto-update.kmz

Lots of floats around the world!

Saved image:



From: http://argo.whoi.edu/



I was thinking these were short duration floats. The AXBTs I had seen previously were something that dropped a sensor down deep and measured the temperature of the water. That temperature profile was then reported back somehow. I think then it was just the one time they worked, not sure. Maybe then the data was sent to the plane, not sure. But now it is sent to the Iridium satellite constellation I guess. These, as the tweet says, are ALAMO buoys (Air-Launched Autonomous Micro-Observer) so they are different.

These are long duration. I don't know if they drop a probe or if they actually submerge. Captain Sanabia was the person I was working with to try to get the AXBT data at the time on my site. But this kind of thing is different now since they keep reporting data. Previously the AXBTs I tried getting data for had one depth profile and it was in a text format I could process.

Here is 9265 in that image above, a saved image of temperature profiles:



When the storm passed over, the water got cooler. Neat to see that.

Lots of various information for each one, more from that one in particular:
http://argo.whoi.edu/alamo/9265/index.html

https://twitter.com/musicscott/status/1307380266260787207


It seems that decibars is a close approximation to meters.

"A unit of pressure used principally in oceanography.

One decibar (105 dynes cm-2) equals 0.1 bar. In the oceans, hydrostatic pressure in decibars very nearly equals the corresponding depth in meters."

From: http://glossary.ametsoc.org/wiki/Decibar

From something here:
https://www.unidata.ucar.edu/mailing_lists/archives/idvusers/2008/msg00066.html

And a PDF file here:
https://www2.whoi.edu/site/miso/wp-content/uploads/sites/52/2019/08/NTU-TowCam-Manual-Appendix_B5_14969.pdf
Which is from the Woods Hole Oceanographic Institution where all this data is stored.

That says:

"RELATIONSHIP BETWEEN PRESSURE AND DEPTH
Despite the common nomenclature (CTD = Conductivity - Temperature - Depth), all CTDs measure pressure, which is not quite the same thing as depth. The relationship between pressure and depth is a complex one involving water density and compressibility as well as the strength of the local gravity field, but it is convenient to think of a decibar as essentially equivalent to a meter, an approximation which is correct within 3% for almost all combinations of salinity, temperature, depth, and gravitational constant."




I suppose these are pictures of these newer type of AXBTs here:

https://twitter.com/FlynonymousWX/status/1306969823994417158


Compared to the smaller dropsonde, also pictured, that measures wind, temperature and dewpoint on the way down from the aircraft. AXBTs don't start their work until they are in the water, dropsondes are done when they hit the surface.
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10am CDT Friday on T.D. Twenty-Two: Slow-moving depression close to tropical storm strength - Chris in Tampa, 9/18/2020, 1:31 pm
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