| Unregistered User |
| (Unregistered) |
| Tue Aug 16 2005 12:38 AM |
how do they determine hurricanes?
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How do they determine how strong a hurricane is from say 1890 or 1930's. I know they didn't have all the great technology that they have now? Can anyone give a good link or quick primer on this subject/ Thanks
| CoalCracker |
| (Weather Hobbyist) |
| Tue Aug 16 2005 01:16 AM |
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Re: how do they determine hurricanes?
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fatmike (hope you don't mind me calling you that),
I'm no met but will try to give you an educated guess. Although the meteorologists in the past did not have the sophisticated tools available today, they, and mariners as well, were able to record barometric pressure readings, and I believe that the barometric pressure readings are what determines tropcial depressions, storms and hurricanes as well as their strength. Thus, if accurate barometric readings are available for past hurricanes, mets could calculate their relative strength.
Perhaps someone with more knowledge than I can chime in here.
| Clark |
| (Meteorologist) |
| Tue Aug 16 2005 01:57 AM |
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Re: how do they determine hurricanes?
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Most information on storms that long ago comes from times when they passed over some landmass or in the vicinity of a ship at sea. You'll notice that there are very few storms way out at sea in the historical database of storms in those times (good example -- 1933, with 21 named storms in total -- http://weather.unisys.com/hurricane/atlantic/1933/index.html), while there are also quite a few storms with only a couple of points near land -- as no one knew that a storm was even out there at the time. Thus, the majority of observations potentially underestimate a storm's true peak intensity, and it is likely that there were more storms out there that were never tracked in the past.
The intensity of these storms generally is determined from recorded historical accounts, land- or sea-based measurement systems (wind speeds in general, occasionally barometric pressure), and pictoral recordings of damage for those storms that made landfall. Some years in the historical database are more complete than others, with efforts underway (and complete for some time periods) to update and revise the historical database -- see the Hurricane Reanalysis Project for one such example. I think they are into the early 1900s now, as evidenced by a decent number of Cape Verde storms in the historical record for the late 1800s/early 1900s.
| Unregistered User |
| (Unregistered) |
| Tue Aug 16 2005 02:52 AM |
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Re: how do they determine hurricanes?
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Thank you cracker and clark. Do you have a link to the hurricane analysis project that was mentioned?
| CoalCracker |
| (Weather Hobbyist) |
| Tue Aug 16 2005 03:04 AM |
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Re: how do they determine hurricanes?
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fatmike,
Think this is what Clark was referring to
http://www.aoml.noaa.gov/hrd/project2003/hurdat.html
| Clark |
| (Meteorologist) |
| Tue Aug 16 2005 04:17 AM |
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Re: how do they determine hurricanes?
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Thanks for posting that, CoalCracker -- I didn't have a link off-hand to the project website. I've been anxiously awaiting our (FSU) contribution to the project, as that may involve some work for me as well, but I think we don't really come in until the 1930s or so, given that our primary involvement is upon cyclone structure, detection, and phase change using model analyses, which only become decent about that time.
Nevertheless, it is a very interesting project that has produced some good work already -- see the Hurricane Andrew upgrade for the most memorable example, with the San Diego hurricane of 1858 (http://flhurricane.com/cyclone/showflat.php?Cat=0&Number=34947&an=0&page=0#34947) being another -- with the more recent parts of the database still to come.