air_potential_temperature / (K)     (time: 6; model_level_number: 70; grid_latitude: 100; grid_longitude: 100)
     Dimension coordinates:
          time                           x                      -                  -                    -
          model_level_number             -                      x                  -                    -
          grid_latitude                  -                      -                  x                    -
          grid_longitude                 -                      -                  -                    x
     Auxiliary coordinates:
          level_height                   -                      x                  -                    -
          sigma                          -                      x                  -                    -
     Derived coordinates:
          altitude                       -                      x                  -                    -
     Scalar coordinates:
          forecast_period: 0.0 hours
     Attributes:
          source: Iris test case