def is_circumpolar(self, var):
        """
        Test if a variable is on a circumpolar grid

        Parameters
        ----------
        %(CFDecoder.is_triangular.parameters)s

        Returns
        -------
        %(CFDecoder.is_triangular.returns)s"""
        xcoord = self.get_x(var)
        return xcoord is not None and xcoord.ndim == 2
Test if a variable is on a circumpolar grid

        Parameters
        ----------
        %(CFDecoder.is_triangular.parameters)s

        Returns
        -------
        %(CFDecoder.is_triangular.returns)s