SEARCH controls the search radius in an objective analysis program.
The radius is the maximum distance that a station may be from a grid
point to be used in the analysis for that point. The search radius
is set so that stations whose weighting factor is less than
EXP (-SEARCH) are not used. SEARCH must have a value in the range
1 - 50. If the value is outside this range, a default value of 20
is used. If SEARCH is given a very small value, many grid points
will not have three stations within the search area, and consequently
will be set to the missing data value.
SEARCH may also be used to set a flag to allow extrapolation of data
values to grid points on the periphery of the data area. To do this,
follow the value of SEARCH with /EX; for example, SEARCH = 20/EX will
result in data extrapolation.