tcorr()

tcorr (expr1, expr2, tdim1, tdim2)

This function produces a spatial map of temporal correlation coefficients.

expr1   - a valid GrADS expression that varies in time
expr2   - a valid GrADS expression that varies in time and may also vary in X and Y
tdim1   - starting time dimension expression
tdim2   - ending time dimension expression

The expr1 time series is correlated to the time series at each grid point in expr2. The result is a grid of correlation coefficients that matches the X and Y dimensions of expr2.

Usage Notes

1. If both expr1 and expr2 vary only in time, the output is a single value.

2. Use the scorr function to do correlation over the spatial domain.

Example

1. This example calculates the temporal correlation between sea level pressure and the defined variable elnino, an areal average of surface temperature in the equatorial Pacific.

   set x 1
   set y 1 
   set z 1 
   set t 1 100
   define elnino = aave(ts,lon=-160,lon=-80,lat=-10,lat=10)
   set lon -180 180
   set lat -90 90
   set z 1
   set t 1
   d tcorr(elnino, slp, t=1, t=100)