Subject: Offshore vs nearshore sonde composite
Date: Sat, 03 Aug 2002 17:58:37 -0400
From: "James Franklin" <James.Franklin@noaa.gov>
Organization: NOAA/Tropical Prediction Center
To: Colin J Mcadie <Colin.J.Mcadie@noaa.gov>,
     Edward N Rappaport <Edward.N.Rappaport@noaa.gov>,
     Richard J Pasch <Richard.J.Pasch@noaa.gov>,
     John L Beven <John.L.Beven@noaa.gov>,
     James M Gross <James.M.Gross@noaa.gov>,
     Brian R Jarvinen <Brian.R.Jarvinen@noaa.gov>,
     Mark Powell <Mark.Powell@noaa.gov>,
     Peter Black <Peter.Black@noaa.gov>,
     Max Mayfield <Max.Mayfield@noaa.gov>,
     Christopher Landsea <Chris.Landsea@noaa.gov>

After scouring the sonde database for nearshore and comparable offshore
sondes, I was only able to come up with a sample of 10 nearshore sondes
and 9 "comparable" offshore sondes, the 6 each that I identified
previously for Georges, and a few more for Bonnie.  All 19 sondes were
dropped on the right hand side of their respective storms' eyewall over
a relatively short period of time.

I normalized the wind speed in each profile by what I call the boundary
layer top wind speed, which I define simply as the average wind speed in
the 300-700 m layer.  I then composited the normalized profiles for each
sample, and the resulting composite profiles are given in the
attachment.  The profiles only go down to 30 m, because too many sondes
start dropping out of the sample below that point.  For whatever it's
worth, the nearshore sondes wind is about 92% of the offshore sondes
wind speed, at 30 m.

This is about all I can think of to do by way of additional research,
given the existing data, unless someone has a specific request or idea.

James
--
James L. Franklin

Hurricane Specialist, National Hurricane Center


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