Sorry for this completely off topic post, but I have found the erudition on the forum pretty good at satisfying some of my random befudling thoughts:
How do they measure sustained winds and wind gusts in a hurricane? If it is the hard way, I would hate to be the poor sucker in the row boat with a windsock in one hand and a Bible in the other.
Gabe
Gabe,
That wouldn’t be a windsock in his hand, it would be an anemometer. The windsock would be of absolutely no use to him.
We could get Dr. Dave Vollmer (Maj, USAF) from the model forums in here…he just got his doctorate in meteorology. However, and this is just a guess, I would guess that Doppler Radar would also do a fairly good job for the average speeds. As Ted says, right under/in it, the anemometer would do the trick. It would be highly useful in getting the gusts speeds right.
-Crandell
There are sondes getting dropped out of airplanes all over the place. Differential doppler radar is hard at it too.
In my mind the only thing that would be of any use is a life jacket.
Naturally, I realize doppler radar could be of use. But, doesn’t that only work in areas where there are rain drops for the doppler radar to pick up? In otherwords, doppler radar doesn’t pick up wind does it?
Moreover, they have been measuring wind speeds of hurricanes for a lot longer than they have had doppler radar and I suspect most hurricanes spend the vast majority of their life outside of the range of doppler radar (which I imagine is land based, and can’t have infinite range).
Thus, it leaves me wondering, how they know how fast hurricans really are blowing.
Gabe
What is a sonde? I trided to google it, but I really didn’t see anything that would tell me how they are used to measure windspeed and wind gusts.
Gabe
Go to this website… http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqHED.html … and scroll down to Section H, which is titled Tropical Cyclone Observation. The first three or four links explain what you’re looking for.
I would also recommend exploring these two websites:
http://www.aoc.noaa.gov/index.html
http://www.hurricanehunters.com/
This 4th link is rather technical, but it could also be of some help:
http://www.nhc.noaa.gov/aboutwindprofile.shtml
And yes, when the tropical cyclone is close enough to land, Doppler radar velocities can also be used to measure intensity. The Airforce Hurricane Hunter aircraft also have onboard radar which allows them to use radar estimates even when the hurricane is not close to any land-based radars.
It’s actually “dropsonde” rather than “sonde” which explains why you couldn’t find it.
http://en.wikipedia.org/wiki/Dropsonde
I know it’s Wikipedia, but Wikipedia isn’t all bad.
OFF TOPIC, PERHAPS
BUT VERY INTERESTING
PL
We look out the window…
If the pine trees are bend sideways, its a hurricane…if they are just bent a little, its a tropical storm…if they are just swaying a little, its a thunderstorm…[:D]
I learned a good one in Kansas when I was in the Army out there.
You hang a rope off the porch. If it’s dry, the weather is nice. If it’s wet we have rain. And if it’s standing straight out, we head for the cyclone cellar.
To get back to topic, we also looked down toward the motor pool to see if the switch engine was still there.
I used to get a kick out of the table of record wind speeds in The World Almanac. Can’t recall the details of the highest speed in that table (over 200 mph, IIRC), but the entry had an asterisk by it. The speed, it seems, was recorded just before the anemometer blew away.
Probably Mount Washington.
Dropsondes and radiosondes both have a place in determining windspeed. Ships at sea (even though most try to avoid that kind of weather) generally have the ability to do at least basic surface weather observations and report them.
Methinks part of it is also extrapolation. If you see enough of a certain condition, you can start to make assumptions about what is involved.
An example of extrapolation is in this National Hurricane Center discussion on Hurricane Wilma from 2005:
http://www.nhc.noaa.gov/archive/2005/dis/al242005.discus.016.shtml
Correct. 231mph before the anamometer went byebye. Detailed story follows:
There is a weight to wind speed ratio: if you go out in it and you get blown away, it is a hurricane. weigh yourself, then try it.
Another way of phrasing the question is “Do they measure wind speeds ACCURATELY?”. I assume that as methods evolved the measurement has gotten better, for example assuming doppler radar is one method, before it was invented the measurement was not as good as after it was invented.
That’s one of the excuses for crime statistics, it’s not that crime’s getting worse (or better) it’s that the methods of measuring are evolving.
Continuing this theme, one could say “Katrina was a category xx hurricane, the levees used to be able to withstand category xxx hurricanes so the broken levees are because the Louisiana coast has lost protective wetlands due to Army Corp of Engineers dredging that prevented replenishing silt from maintaining the wetlands” and one could counter that measurement techniques in the past were not as good as now, so what we thought were category xxx storms were actually only category x and Katrina is the first storm that really was as strong as category xx.
Related to that: “All the old levees, buildings, railroad bridges, embankments, etc… survived the storm, earthquake, alien from outer space invasion, etc… But the new construction collapsed, so we must no longer be able to build things as well as we could 100 years ago. Or hurricanes are getting worse because of global warming.” A rebuttal could be that one way you get to be an old structure is by not getting knocked down in the prior disaster, the fact that your old structure survived or new structure failed may have had just as much to do with luck as it did to good design.
A friend of mine tied a pebble to the end of a string, so I guess it was a small scale prototype of a weather rock, an improved version of the weather rope. This gave him the added ability to measure temperature and type of precipitation. He mounted this on a pedestal which displayed the operating instructions:
a) if rock is dry and warm, it’s sunny.
b) if wet, it’s raining
c) if cold and wet, it’s snowing.
a) 10 degree angle, slightly windy
b) 20 degree angle, very windy
c) 45 degree angle, run like hell, it’s a hurricane!
Based on information printed on a tag on the pedestal it seems he contracted with a firm in China to manufacture the prototype, and it appears they charged him $1.99. If anyone is interested in a prototype, they look useful as portables, or even the full scale model, please let me know and I’ll see how much they would cost delivered. I’m sure we could negotiate volume discounts.