Calculates and removes the median of the (rightmost) dimension at all other dimensions.
function dim_rmvmed ( x : numeric ) return_val [dimsizes(x)] : float or double
A variable of numeric type and any dimensionality.
The output is of type double if the input is double, and float otherwise.
The dimensionality is the same as the input dimensionality.
The dim_rmvmed function calculates and removes the median from all elements of the n-1th (rightmost) dimension for each index of the dimensions 0...n-2. Missing values are ignored.
Use dim_rmvmed_n if you want to specify which dimension(s) to remove the median from.
Use dim_rmvmed_Wrap if retention of metadata is desired.
Let x be a 1-dimensional array: (a) Create a new variable, xNew, that contains just the deviations from the median; (b) replace the variable x with the deviations.
xNew = dim_rmvmed(x) ; new variable x = dim_rmvmed(x) ; overwrite with deviationsExample 2:
Let x be a 3-dimensional array with dimension sizes (ntim, nlat, nlon). To remove the medians of the "nlon" dimension:
xRmvLon = dim_rmvmed (x) ; new variable containing deviations (no metadata) xRmvLon = dim_rmvmed_Wrap (x) ; with metadata x = dim_rmvmed (x) ; overwrite with deviations from medianExample 3:
Let x be a 3-dimensional array with named dimensions (time, lat, lon) and dimension sizes (ntim, nlat, nlon). To remove the median of the time dimension from all lat/lon indices, use NCL's Named Subscripting to reorder the input array such that "time" is the rightmost dimension.
Note: in V5.1.1, you will be able to use dim_rmvmed_n to avoid having to reorder your data.
xRmvTime = dim_rmvmed(x(lat|:, lon|:, time|:)) xRmvTime = dim_rmvmed_n(x,0) ; no reordering neededExample 4: Let x be as in Example 3 and let x contain monthly medians for (say) 10 years of data (ntim=120). Monthly anomalies for each month could be calculated using array subscripting and Named Subscripting to reorder the input array such that "time" is the rightmost dimension.
xRmvJan = dim_rmvmed(x(lat|:, lon|:, time|0:ntim-1:12)) xRmvJuly = dim_rmvmed(x(lat|:, lon|:, time|6:ntim-1:12)) xRmvJan = dim_rmvmed_n(x(0:ntim-1:12,:,:),0) ; no reordering needed xRmvJuly = dim_rmvmed_n(x(6:ntim-1:12,:,:),0)