Re: questions about cz2ccm

Yi-Hui,

I've attached cz2ccm_dp.f to this message.

Note that you can get access to any processing routine in NCL by
downloading the source code and looking in the directory
$NCARG/ni/src/lib/nfpfort (a few others are in $NCARG/ni/src/ncl or
$NCARG/ni/src/lib/hlu).

--Mary

On Mon, 8 Sep 2008 yihuiw_at_uci.edu wrote:

> Hi,
> Thank you for your help. I use the function cz2ccm to calculate
> geopotential height successfully.
> Can I have the original codes of function cz2ccm? I wrote a script to
> calculate geopotential height by myself. The pattern of geopotential
> height is almost the same while its value is 5% larger than the result by
> using cz2ccm. So I'd like to know how does cz2ccm calculate geopotential
> height. Thank you again.
> All the best,
> Yi-Hui
>
>
>> Hello,
>>
>> [1] It is likely a memory issue. You script ran just fine on our systems.
>> Try the attached script. If it fails you may have to run on a few
>> months, create a netCDF file [time =>unlimites); then use
>> ncrcat to concatenate the files.
>>
>> [2] You could improve your memory management by
>>
>> reusing variable space.
>>
>> [3] FYI: you do not need to read netCDF, you can read the grib
>>
>> directly.
>>
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>
>> begin
>>
>> f = addfile("U78614.grb","r")
>>
>> qf = addfile("U78615.grb","r")
>>
>> P0 = 100000.
>>
>> Rd = 287.
>>
>> Rv = 461.
>>
>> T = f->T_GDS4_HYBL_123
>>
>> Q = qf->Q_GDS4_HYBL_123
>>
>> T = T*(1+(Rv/Rd-1)*Q) ; compute virtual temperature
>>
>> T_at_long_name = "Temperature (virtual)"
>>
>> delete(Q) ; delete to save memory
>>
>> Zs = f->Z_GDS4_HYBL_123
>>
>> ps = f->LNSP_GDS4_HYBL_123
>>
>> ps = exp(ps) ; replace
>>
>> hyai = f->lv_HYBL_i4_a ;interface hybrid coefficient A
>>
>> hybi = f->lv_HYBL_i4_b ;interface hybrid coefficient B
>>
>> hyam = f->lv_HYBL3_a ;mid-layer hybrid coefficient A
>>
>> hybm = f->lv_HYBL3_b ;mid-layer hybrid coefficient B
>>
>> z2 = cz2ccm(ps,Zs,T,P0,hyam(::-1),hybm(::-1),hyai(::-1),hybi(::-1))
>>
>> copy_VarCoords(T,z2)
>>
>> z2_at_long_name = "geopotential height"
>>
>> z2_at_units = "gpm"
>>
>> ;---- Create 'nominal' pressure level coordinate and
>>
>> ; replace the integer hybrid level coordinates.
>>
>> ; This is what the CAM model does.
>>
>> delete(z2&lv_HYBL3) ; delete the integer values
>>
>> lev = (hyam+hybm)*P0*0.01 ; calculate nominal pressure levels
>>
>> lev!0= "lev"
>>
>> lev_at_units = "hPa"
>>
>> z2!1 = "lev" ; assign new name and p values
>>
>> z2&lev = lev
>>
>> printVarSummary( z2 )
>>
>> ; print one vertical profile over the
>> ocean
>>
>> ; Use nominal pressure levels for p
>>
>> print (z2&lev+" "+z2(0,:,{45},{180}))
>>
>> end
>
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