density of pressure lows

From: Alexander Semenov <asemenov_at_nyahnyahspammersnyahnyah>
Date: Thu Sep 26 2013 - 11:37:01 MDT

Hi ncl-talk,

I am trying to calculate the number of cyclones for each grid cell in
the Arctic Ocean domain based on the data from the ascii file
(all_sum_ens1.asc). A while ago, Adam Phillips suggested the approach
to calculate the number of storms and although the code compiled, I
believe that the pattern of cyclone density was wrong, particularly
over the Central Arctic. In the attached plot, you can see that the
cyclone density over the Central Arctic is close to 0 which is too
low. I was hoping for the purposes of verification, maybe you could
suggest another approach to calculate the number of storms (density)
passing each grid cell?

Adam Phillips suggested to calculate density by setting "arr" array:

 arr = new((/100,110/),integer,-999)
  arr!0 = "lat"
  arr&lat = fspan(53.82,90,100)
  arr&lat@units = "degrees_north"
  arr!1 = "lon"
  arr&lon = fspan(0,358.9,110)
  arr&lon@units = "degrees_east"


  arr = 0 ; set array to all 0's
  do gg = 0,dimsizes(slp)-1
     if (.not.ismissing(lat(gg)).and..not.ismissing(lon(gg))) then ;
check to make sure lat/lons are present
        arr({lat(gg)},{lon(gg)}) = (/ arr({lat(gg)},{lon(gg)})+1 /)
     end if

Attached you will find the code and plot.

The data file (ascii) is on your ftp server under name all_sum_ens3.asc

I appreciate your help with this,

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Received on Thu Sep 26 11:37:19 2013

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