# ARTS built-in documentation server

## Workspace Method iyInterpCloudboxField

### Description

Interpolates the intensity field of the cloud box. Determines the intensity field at the position and direction specified by rte_pos and rte_los. The position can be both inside the cloud box or at its edge. The interpolation in the spatial dimensions is linear. For the zenith angle dimensions several options for controlling the interpolation are at hand. Default is linear interpolation. Higher order polynomial interpolation is activated by setting *za_interp_order* to a value > 1. Default is to perform the interpolation separately for [0,90[ and ]90,180]. To handle 90 degree or use the full range ([0,180]) as basis for the interpolation, set *za_restrict* to 0. You can select to use cos(za) as the independent variable (instead of za) by setting *cos_za_interp* to 1. For the azimuth dimension the interpolation order can be selected, in the same manner as for zenith.

**Authors: **Claudia Emde, Patrick Eriksson, Jana Mendrok

### Synopsis

iyInterpCloudboxField( | iy, cloudbox_field, rtp_pos, rtp_los, jacobian_do, cloudbox_on, cloudbox_limits, atmosphere_dim, p_grid, lat_grid, lon_grid, z_field, z_surface, stokes_dim, za_grid, aa_grid, f_grid, za_interp_order, za_restrict, cos_za_interp, za_extpolfac, aa_interp_order ) |

### Variables

OUT | iy | (Matrix) | Monochromatic pencil beam radiance spectrum. |

IN | cloudbox_field | (Tensor7) | The spectral radiance field inside the cloudbx. |

IN | rtp_pos | (Vector) | Position of a radiative transfer point. |

IN | rtp_los | (Vector) | Line-of-sight at a radiative transfer point. |

IN | jacobian_do | (Index) | Flag to activate (clear-sky) Jacobian calculations. |

IN | cloudbox_on | (Index) | Flag to activate the cloud box. |

IN | cloudbox_limits | (ArrayOfIndex) | The limits of the cloud box. |

IN | atmosphere_dim | (Index) | The atmospheric dimensionality (1-3). |

IN | p_grid | (Vector) | The pressure grid. |

IN | lat_grid | (Vector) | The latitude grid. |

IN | lon_grid | (Vector) | The longitude grid. |

IN | z_field | (Tensor3) | The field of geometrical altitudes. |

IN | z_surface | (Matrix) | The surface altitude. |

IN | stokes_dim | (Index) | The dimensionality of the Stokes vector (1-4). |

IN | za_grid | (Vector) | Zenith angle grid. |

IN | aa_grid | (Vector) | Azimuthal angle grid. |

IN | f_grid | (Vector) | The frequency grid for monochromatic pencil beam calculations. |

GIN | za_interp_order | (Index, Default: 1) | Zenith angle interpolation order. |

GIN | za_restrict | (Index, Default: 1) | Flag whether to restric zenith angle interpolation to one hemisphere. |

GIN | cos_za_interp | (Index, Default: 0) | Flag whether to do zenith angle interpolation in cosine space. |

GIN | za_extpolfac | (Numeric, Default: 0.5) | Maximum allowed extrapolation range in zenith angle. |

GIN | aa_interp_order | (Index, Default: 1) | Azimuth angle interpolation order. |