air_potential_temperature / (K)     (grid_latitude: 100; grid_longitude: 100)
     Dimension coordinates:
          grid_latitude                           x                    -
          grid_longitude                          -                    x
     Auxiliary coordinates:
          surface_altitude                        x                    x
     Derived coordinates:
          altitude                                x                    x
     Scalar coordinates:
          forecast_period: 0.0 hours
          level_height: 5.0 m, bound=(0.0, 13.333332) m
          model_level_number: 1
          sigma: 0.9994238, bound=(1.0, 0.99846387)
          time: 2009-09-09 17:10:00
     Attributes:
          source: Iris test case