RE: [ncl-talk] High Pressure Ridge Identification Algorithm?

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Tue, 2 May 2006 14:45:49 -0600 (MDT)

>Thank you very much for the help Dennis,
>The min and max functions will do what I want. What I eventually want to do
>is output the min value, lat and long for each month of a 2 year monthly
>mean netCDF file for the region North of 60 deg North. Ideally I would like
>to run a script that could output a single txt file with the year, month,
>value, lat, and long for each month of the 24 months the netCDF. Does anyone
>have a script where they have used the locmin or locmax functions with a
>netcdf file and output the results as a txt file?
>Any help would be greatly appreciated.

quick/dirty/ and untested

   f = addfile (... , "r")
                                      ; read data nort of 60
   x = f->X(:,{60:},:) ; x(time,lat,lon) => (24,:,:)
   t = x&time
   ntim = dimsizes(t)
   delta = ... ; user specified
   nmin = local_min(x, True, delta)
                       ; ????
   ncol = 4
   data = new ( (/ntim,ncol/) , typeof(x) )
   data(:,0) = t
   data(:,1) = nmin_at_minval
   data(:,2) = nmin_at_xi
   data(:,3) = nmin_at_yi
   opt = True
   opt_at_fout = "alexg.txt"
   write_matrix( data, "f10.1,3f10.2", opt)
>-----Original Message-----
>From: Dennis Shea []
>Sent: Monday, May 01, 2006 3:35 PM
>Subject: Re: High Pressure Ridge Identification Algorithm?
>>I know it's a long shot, but does anyone know if there is an atmospheric
>>ridge detection (from netCDF files) function that has been developed for
>>NCL? I'm looking to develop statistics on ridging event over a particular
>>region and was hoping that maybe someone has done similar work.
>I know of no ready made software.
>Having said that ...
>What do you mean by "atmospheric ridge detection"?
>Are you talking about atmospheric "blocks" ?
>ie: blocking highs , blocking patterns
>There are functions that can automate detection
>of local min and max of 2D fileds
>An example is at:
>good luck

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Received on Tue May 02 2006 - 14:45:49 MDT

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