>
>Are there ncl commands or functions to compute averages of quantities
>over continents and/or oceans?
>
>Continents: Africa, Asia, Australia, N.America, S.America
>Oceans: N.Pacific, S.Pacific, N.Atlantic, S.Atlantic, N.Indian, S.Indian
The short answere is "no".
However,
assume you have some array ("flags") that indicates if a grid point
is Africa (=1), Asia(=2), ...,etc. Let flags(nlat,mlon) and that
variable "x" has rightmost dimensions of nlat,mlon.
Africa = mask (x, flags, 1)
aveAfrica = wgt_areaave(Africa, ...)
or
aveAfrica = wgt_areaave( mask(x, flags, 1), ...)
aveAsia = wgt_areaave( mask(x, flags, 2), ... )
if x(nlat,mlon) then the result is a scalar.
if x(time, nlat,mlon) then the result (time) ... one area ave for each time
if x(time, lev, nlat,mlon) then the result (time,lev)
etc
Let's say you have an array (loiFlag) that contains
flags for ocean, land, ice: ; ocean=0,land=1,sea_ice=2
land_only = mask(x,loiFlag,1)
ocean_only = mask(x,loiFlag,0)
for examples of the latter, see:
http://www.cgd.ucar.edu/csm/support/CSM_Graphics/mask.shtml
The weighted area average is at:
http://ngwww.ucar.edu/ngdoc/ng/ref/ncl/functions/wareaave.html
Reghards,
Dennis Shea
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