Re: How to calculate the area integrated evaporation in Atlantic

Dennis,

Being familiar w/ POP output, that looks correct.

In CCSM output, the Atlantic region is defined to be REGION_MASK==6.

But you probably want to examine what it looks like to verify that it
matches the region that you are truly interested in. Do not assume that
the model's region definition matches your application.

Keith

On Thu, 14 Jan 2010, Dennis Shea wrote:

> I am not particularly knowledgeable about POP files.
> It is probably best that you ask an expert. However,
> the variable
>
>         double TAREA(nlat, nlon) ;
>                 TAREA:long_name = "area of T cells" ;
>                 TAREA:units = "centimeter^2" ;
>                 TAREA:coordinates = "TLONG TLAT" ;
>                 TAREA:missing_value = 9.96921e+36f ;
>
> could be used.
>
>     do nt=0,ntim-1
>        evap_area(nt) = sum( where(rmask.eq.?? , tarea*evap(nt,:,:), 0.) )
>     end do
>
> weighted average
>
>     swgt = sum( where(rmask.eq.?? , tarea, 0.) )
>     do nt=0,ntim-1
>        evap_area(nt) = sum( where(rmask.eq.?? , tarea*evap(nt,:,:), 0.) )
>     end do
>     evap_area = evap_area/swgt
>
>
> On 01/14/2010 03:02 PM, Wei Liu wrote:
> Hi, Dennis
>    Thanks, Dennis. rmask can be found from "REGION_MASK",
> but how can I get the global weight: wgt[] from the POP output?
>
>
> W
>
>
> On Thu, Jan 14, 2010 at 3:40 PM, Dennis Shea <shea@ucar.edu> wrote:
> Well assuming there is a regional maskfor the region of interest
>
> rmask[*][*]     ; global mask that contains flags
>                ; to indicate different regions
> wgt[*][*]       ; global weights
>
> evap(time,lats,lons)
>
>     evap_area = new ( ntim, typeof(evap), getFillValue(evap) )
>     do nt=0,ntim-1
>        evap_area(nt) = sum( where(rmask.eq.?? , wgt*evap(nt,:,:), 0.) )
>     end do
>
>
> Wei Liu wrote:
> Hi, there
>
>    I want to calculate the area integrated evaporation in Atlantic.
> The data EVAP_F is on POP grid which is not regular.
> So how to calculate the area sum of EVAP using two-dimensional weights?
> Thanks.
>
>
> V
>
>
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> --
> ======================================================
> Dennis J. Shea tel: 303-497-1361 |
> P.O. Box 3000 fax: 303-497-1333 |
> Climate Analysis Section |
> Climate & Global Dynamics Div. |
> National Center for Atmospheric Research |
> Boulder, CO 80307 |
> USA email: shea 'at' ucar.edu |
> ======================================================
>
>

******************************************************************
Keith Lindsay http://www.cgd.ucar.edu/oce/klindsay/
email: klindsay@ucar.edu phone: 303-497-1722 fax: 303-497-1700

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Received on Thu Jan 14 16:01:53 2010