# ARTS built-in documentation server

## Workspace Method iySurfaceRtpropCalc

### Description

Applies surface_los, surface_rmatrix and surface_emission. This method is designed to be part of iy_surface_agenda and should be mandatory when using methods describing the surface radiative transfer properties by surface_los, surface_rmatrix and surface_emission. The task of this method is to apply these three WSVs to obtain the upwelling radiation from the surface. This upwelling radiation is the sum of surface emission and reflected downwelling radiation. The later part is calculated by calling iy_main_agenda. See further AUG.

**Authors: **Patrick Eriksson

### Synopsis

iySurfaceRtpropCalc( | iy, diy_dx, surface_los, surface_rmatrix, surface_emission, dsurface_names, dsurface_rmatrix_dx, dsurface_emission_dx, iy_transmittance, iy_id, jacobian_do, suns_do, jacobian_quantities, atmosphere_dim, nlte_field, cloudbox_on, stokes_dim, f_grid, rtp_pos, rtp_los, rte_pos2, iy_unit, iy_main_agenda ) |

### Variables

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

OUT+IN | diy_dx | (ArrayOfTensor3) | Derivative of iy with respect to retrieval quantities. |

IN | surface_los | (Matrix) | Downwelling radiation directions to consider in surface reflection. |

IN | surface_rmatrix | (Tensor4) | The reflection coefficients for the directions given by surface_los to the direction of interest. |

IN | surface_emission | (Matrix) | The emission from the surface. |

IN | dsurface_names | (ArrayOfString) | Name of surface retrieval quantities. |

IN | dsurface_rmatrix_dx | (ArrayOfTensor4) | The derivative of surface_rmatrix with respect to quantities listed in dsurface_names. |

IN | dsurface_emission_dx | (ArrayOfMatrix) | The derivative of surface_emission with respect to quantities listed in dsurface_names. |

IN | iy_transmittance | (Tensor3) | Transmittance to be included in iy. |

IN | iy_id | (Index) | Identification number of iy. |

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

IN | suns_do | (Index) | Flag to activate the sun(s). |

IN | jacobian_quantities | (ArrayOfRetrievalQuantity) | The retrieval quantities in the Jacobian matrix. |

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

IN | nlte_field | (EnergyLevelMap) | The field of NLTE temperatures and/or ratios. |

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

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

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

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

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

IN | rte_pos2 | (Vector) | A second geographical position to define the geometry for radiative transfer calculations. |

IN | iy_unit | (String) | Selection of output unit for radiative transfer methods. |

IN | iy_main_agenda | (Agenda) | Agenda calculating the single monochromatic pencil beam spectrum. |