Re: how to do definite integration over given levels

Use dpres_plevel to get the layer thicknesses.
http://www.ncl.ucar.edu/Document/Functions/Contributed/dpres_plevel_Wrap.shtml
See Examples

Generically,

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

   diri = "./"
   fx = addfile(diri+"x.mon.mean.nc", "r")
   fp = addfile(diri+"pres.mon.mean.nc", "r")

  ;x = fx->X
   x = short2flt( fx->X ) ; if X is type short
   lev = fx->level

   ps = fp->pres

   ptop = 300
   dp = dpres_plevel(lev, ps, ptop, 0)
   printVarSummary(dp)

   xdp = x*dp
   copy_VarCoords(x, xdp)

   xInt = dim_sum_n_Wrap(xdp, 1)
   xInt@long_name = "vertical integral [weighted sum]"
   printVarSummary(xInt)
   printMinMax(xInt, True)

   xAvg = xInt/dim_sum_n(dp, 1)
   xAvg@long_name = "vertical weighted average"
   copy_VarCoords(xInt, xAvg)
   printVarSummary(xAvg)
   printMinMax(xAvg, True)

Good luck

> On Mar 5, 2010, at 11:11 AM, samir pokhrel wrote:
>
>>
>> Hello NCL users,
>>
>> I want to integrate humidity fields (NCEP reanalysis), from
>> surface to 300mb. Is there any simple definite integral
>> function is available in NCL or just summation is a solution. I hope
>> summation might not be that accurate as integration.
>>
>> Thanks in advance
>>
>> Regards
>> --
>> Samir Pokhrel
>> Climate and Global Modelling Division
>> Indian Institute of Tropical Meteorology
>> NCL Post, Pashan
>> Pune-411008
>> INDIA
>>
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>
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Received on Fri Mar 12 13:48:44 2010