I.14 ->SPAV - Spatial averaging
Four different kinds of spatial averaging may be requested:
1) an arbitrary band of longitudes may be averaged along all
latitude lines (*ZONA);
2) an arbitrary band of latitudes may be averaged along all
meridians (*MERA);
3) an arbitrary subset of contiguous vertical levels may be
averaged over the full horizontal domain (*VERA);
4) all points above a specified surface type or types (land,
ocean, sea ice) may be horizontally averaged, level by
level, within an arbitrary latitude-longitude rectangle
(*HORA).
All spatial averaging options are Case independent, i.e., they apply to all
Cases being processed.
There are, in general, two possible ways to proceed after computing spatial
averages. After plotting, the averages may be discarded, and processing can
continue using the full, three-dimensional fields. Alternately, the full,
three-dimensional fields can be discarded, and processing can continue using
the spatial averages as the starting point for subsequent operations. For
zonal, meridional, and vertical averaging, which of these approaches is taken
is determined by a secondary option specified independently for each type of
average. The options available for subsequent processing of spatial averages
are somewhat limited (e.g., spectral processing is not allowed, and horizontal
projection plots cannot be drawn for zonal averages), but all averages can be
the basis for user-defined derived fields (*UDFL), and the averages can be
written to most types of Save Tapes (*SAVT). A particular type of spatial
average cannot be computed more than once on the same data; if zonal or
meridional averages are written to a Save Tape, vertical cross-section plots
may be requested in subsequent runs with the ICPs and ,
respectively.
Each type of spatial average is discussed individually in the next four
topics.