sum

The sum filter computes the sum over multiple variables. This can be useful for computing total precipitation from its components (snow, rain) or summing the components of total column integrated water. This filter needs to follow a source that provides the list of variables to be summed up. These variables are removed by the filter and replaced by a single summed variable.

input:
  pipe:
    - source: # mars, grib, netcdf, etc.
      # source attributes here
      # ...
      # Must load the variables to be summed

    - sum:
        params:  # List of input variables
          variable1
          variable2
          variable3
        output: variable_total    # Name of output variable