Hi
Wendy,
Yes, in general give Ferret a variable on a latitude, longitude grid.
If the
units of the Y axis is latitude, the cosine latitude correction is
applied.
The result is in units of square meters. Here's a bit from the
documemtation
about the definite integral transformation.
Ch3
Sec2.4.4. @DIN—definite integral
The
transformation @DIN computes the definite integral—a single value that
is the integral between two points along an axis (compare with @IIN).
It is
obtained as the sum of the grid_box*variable product at each grid
point.
Grid points at the ends of the indicated range are weighted by the
fraction
of the grid box that falls within the integration interval.
If @DIN is specified simultaneously on multiple axes the calculation
will
be performed as a multiple integration rather than as sequential
single
integrations. The output will document this fact by indicating a
transformation
of "@IN4" or "XY integ." See General Information (p 92) for important
details about this transformation.
Example:
yes? CONTOUR/X=160E:160W/Y=5S:5N u[Z=0:50@DIN]
In a latitude/longitude coordinate system X=@DIN is sensitive
to the COS(latitude) correction.
...
Wendy Wang wrote:
Hi
Ferret_users,
Can Ferret calculate a surface area given Lat. and Lon.?
Will the land area be taken into account?
Any help will be appreciated.
Wendy Wang