Re: how to determine whether a gridpoint is in Europe base on lat & lon information?

True, there is no function the will explicitly return a yes/no if you
are over Europe.
What about a country like Turkey ... part Europe/part Asia?

The question is not clear:
    Do you mean the entire area [land+ocean+Mediterranean] that
encompasses Europe?
    Do you mean the just land? Iceland/Svalbard/Novaya Zemlya [ISNZ]
are officially part
                                                 of Europe. Should these
be included?

Let's say that a *crude* regional approximation that excludes ISNZ but
includes
water area is sufficient. Your data array is x(time,lat,lon).

The region could be ....
latS = 36
latN = 70
lonW = -10
lonE = 60

Set up a 'Europe' mask

    work = x(0,:,:)
    LAT = conform( work, work&lat, 0)
    LON = conform( work, work&lon, 1)
    eMask = new ( (/nlat,mlon/), "logical", "No_FillValue")
    eMask = where(LAT.ge.latS .and. LAT.le.latN .and. \
                              LON.ge.lonE .and. LON.le.lonW, True,
False)
    copy_VarCoords(work, eMask)
    delete(work)
    delete(LAT)
    delete(LON)

========
If you want to exclude water [ocean/Sea] areas ... Do you have a
land/sea mask?
If so, this would have to be included in the above 'where' atatement.

If you do not have a land/sea mask, you could use NCL's
http://www.ncl.ucar.edu/Document/Functions/Shea_util/landsea_mask.shtml

See, Example 5 at
http://www.ncl.ucar.edu/Applications/mask.shtml
==========

Wei Huang wrote:
> Kai,
>
> Unfortunately, there is no such function available yet.
>
> Wei Huang
> huangwei_at_ucar.edu
> VETS/CISL
> National Center for Atmospheric Research
> P.O. Box 3000 (1850 Table Mesa Dr.)
> Boulder, CO 80307-3000 USA
> (303) 497-8924
>
>
>
>
>
> On Sep 16, 2009, at 6:29 AM, Kai Zhang wrote:
>
>
>> Dear all,
>>
>> I want to calculate the total amount of emission over Europe based on
>> gridded data. Is there a way to determine whether a grid point is in
>> Europe base on lat & lon information?
>>
>> Thanks and best regards,
>>
>> Kai
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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 |
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