Thanks again Dennis, you've been a great help.
I've tired running the scrip but I keep getting the error message:
"Fatal: Number of dimensions in parameter (0) of (local_min) is (3), (2)
dimensions were expected"
The scrip I have so for is:
a = addfile("$NCARG_ROOT/netcdf/hgt.2002.nc","r")
x=a->hgt(:,5,{60:},:)
t = x&time
ntim = dimsizes(t)
delta = 0. ; 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)
end
The problem has to do with the time component of the field "hgt". Local_min
doesn't seem to work when all time steps are extracted.
Do you know how can I solve this issue?
Alex
-----Original Message-----
From: Dennis Shea [mailto:shea_at_cgd.ucar.edu]
Sent: Tuesday, May 02, 2006 2:46 PM
To: ncl-talk_at_ucar.edu; alexg_at_ualberta.ca
Subject: RE: [ncl-talk] High Pressure Ridge Identification Algorithm?
>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 [mailto:shea_at_cgd.ucar.edu]
>Sent: Monday, May 01, 2006 3:35 PM
>To: ncl-talk_at_ucar.edu; alexg_at_ualberta.ca
>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
>
>
>http://www.ncl.ucar.edu/Document/Functions/Built-in/local_max.shtml
>
>An example is at:
>http://www.ncl.ucar.edu/Applications/minmax.shtml
>
>good luck
>
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Received on Wed May 03 2006 - 11:36:19 MDT
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