ARTS built-in documentation server

Workspace Method iyClearsky

Description

Standard method for radiative transfer calculations with emission
and a direct (solar) source
.
Designed to be part of iy_main_agenda. That is, only valid
outside the cloudbox (no scattering). For details se the user guide.

The possible choices for iy_unit are
 "1"             : No conversion, i.e. [W/(m^2 Hz sr)] (radiance per
                     frequency unit).
 "RJBT"          : Conversion to Rayleigh-Jean brightness
                     temperature.
 "PlanckBT"      : Conversion to Planck brightness temperature.
 "W/(m^2 m sr)"  : Conversion to [W/(m^2 m sr)] (radiance per
                     wavelength unit).
 "W/(m^2 m-1 sr)": Conversion to [W/(m^2 m-1 sr)] (radiance per
                     wavenumber unit).
Expressions applied and considerations for the unit conversion of
radiances are discussed in Sec. 5.7 of the ARTS-2.0 article.

iy_unit is only applied if iy_agenda_call1 is 1. This means that
no unit ocnversion is applied for internal iterative calls.

Recognised choices for rt_integration_option are:
   "first order": A first order integration is applied.
   "second order": A second order integration is applied.
   "default": Another way to select the first order option.

Some auxiliary radiative transfer quantities can be obtained. Auxiliary
quantities are selected by iy_aux_vars and returned by iy_aux.
Valid choices for auxiliary data are:
 "Radiative background": Index value flagging the radiative
    background. The following coding is used: 0=space, 1=surface
    and 2=cloudbox.
 "Optical depth": Scalar optical depth between the observation point
    and the end of the present propagation path. Calculated based on
    the (1,1)-element of the transmittance matrix (1-based indexing),
    i.e. only fully valid for scalar RT.
 "Direct radiation": Stokes vector of direct radiation. It dimensions
   are number of frequencies and stokes_dim. If no sun is present 
   in the line of sight, it is zero.
 "Radiation Background": Stokes vector of the radiation at start of
   the propagation path. It dimensions are number of frequencies and
   stokes_dim.
If nothing else is stated, only the first column of iy_aux is filled,
i.e. the column matching Stokes element I, while remaing columns are
are filled with zeros.

IMPORTANT: No jacobian calculation is supported when suns or gas scattering is included! This will be implemented in a future version.

Authors: Patrick Eriksson, Richard Larsson, Oliver Lemke, Manfred Brath

Synopsis

iyClearsky(

iy, iy_aux, diy_dx, ppvar_p, ppvar_t, ppvar_nlte, ppvar_vmr, ppvar_wind, ppvar_mag, ppvar_f, ppvar_iy, ppvar_trans_cumulat, ppvar_trans_partial, iy_id, stokes_dim, f_grid, atmosphere_dim, p_grid, lat_grid, lon_grid, z_field, t_field, nlte_field, vmr_field, abs_species, wind_u_field, wind_v_field, wind_w_field, mag_u_field, mag_v_field, mag_w_field, z_surface, refellipsoid, ppath_lmax, ppath_lraytrace, cloudbox_on, gas_scattering_do, suns_do, iy_unit, iy_aux_vars, jacobian_do, jacobian_quantities, ppath, rte_pos2, suns, propmat_clearsky_agenda, water_p_eq_agenda, rt_integration_option, iy_main_agenda, iy_space_agenda, iy_surface_agenda, iy_cloudbox_agenda, gas_scattering_agenda, ppath_step_agenda, iy_agenda_call1, iy_transmittance, rte_alonglos_v, surface_props_data )

Variables

OUT	iy	(Matrix)	Monochromatic pencil beam radiance spectrum.
OUT	iy_aux	(ArrayOfMatrix)	Data auxiliary to iy.
OUT+IN	diy_dx	(ArrayOfTensor3)	Derivative of iy with respect to retrieval quantities.
OUT	ppvar_p	(Vector)	Pressure along the propagation path.
OUT	ppvar_t	(Vector)	Temperature along the propagation path.
OUT	ppvar_nlte	(EnergyLevelMap)	Non-LTE temperatures/ratios along the propagation path.
OUT	ppvar_vmr	(Matrix)	VMR values along the propagation path.
OUT	ppvar_wind	(Matrix)	Winds along the propagation path.
OUT	ppvar_mag	(Matrix)	Magnetic field along the propagation path.
OUT	ppvar_f	(Matrix)	Doppler adjusted frequencies along the propagation path.
OUT	ppvar_iy	(Tensor3)	iy-values along the propagation path.
OUT	ppvar_trans_cumulat	(Tensor4)	The transmittance between the sensor and each point of the propagation path.
OUT	ppvar_trans_partial	(Tensor4)	The transmittance between the points along the propagation path.
IN	iy_id	(Index)	Identification number of iy.
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	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	t_field	(Tensor3)	The field of atmospheric temperatures.
IN	nlte_field	(EnergyLevelMap)	The field of NLTE temperatures and/or ratios.
IN	vmr_field	(Tensor4)	VMR field.
IN	abs_species	(ArrayOfArrayOfSpeciesTag)	Tag groups for gas absorption.
IN	wind_u_field	(Tensor3)	Zonal component of the wind field.
IN	wind_v_field	(Tensor3)	Meridional component of the magnetic field.
IN	wind_w_field	(Tensor3)	Vertical wind component field.
IN	mag_u_field	(Tensor3)	Zonal component of the magnetic field.
IN	mag_v_field	(Tensor3)	Meridional component of the magnetic field.
IN	mag_w_field	(Tensor3)	Vertical component of the magnetic field.
IN	z_surface	(Matrix)	The surface altitude.
IN	refellipsoid	(Vector)	Reference ellipsoid.
IN	ppath_lmax	(Numeric)	Maximum length between points describing propagation paths.
IN	ppath_lraytrace	(Numeric)	Maximum length of ray tracing steps when determining propagation paths.
IN	cloudbox_on	(Index)	Flag to activate the cloud box.
IN	gas_scattering_do	(Index)	Flag to activate gas scattering.
IN	suns_do	(Index)	Flag to activate the sun(s).
IN	iy_unit	(String)	Selection of output unit for radiative transfer methods.
IN	iy_aux_vars	(ArrayOfString)	Selection of quantities for iy_aux and when applicable also y_aux.
IN	jacobian_do	(Index)	Flag to activate (clear-sky) Jacobian calculations.
IN	jacobian_quantities	(ArrayOfRetrievalQuantity)	The retrieval quantities in the Jacobian matrix.
IN	ppath	(Ppath)	The propagation path for one line-of-sight.
IN	rte_pos2	(Vector)	A second geographical position to define the geometry for radiative transfer calculations.
IN	suns	(ArrayOfSun)	Array of Sun.
IN	propmat_clearsky_agenda	(Agenda)	Agenda calculating the absorption coefficient matrices.
IN	water_p_eq_agenda	(Agenda)	Agenda to calculate the saturation pressure of water.
IN	rt_integration_option	(String)	Switch between integration approaches for radiative transfer steps.
IN	iy_main_agenda	(Agenda)	Agenda calculating the single monochromatic pencil beam spectrum.
IN	iy_space_agenda	(Agenda)	Agenda providing the downwelling radiation at the top of the atmosphere.
IN	iy_surface_agenda	(Agenda)	Agenda providing the upwelling radiation from the surface.
IN	iy_cloudbox_agenda	(Agenda)	Agenda deriving the intensity at boundary or interior of the cloudbox.
IN	gas_scattering_agenda	(Agenda)	Agenda calculating gas scattering extinction and phase matrix.
IN	ppath_step_agenda	(Agenda)	Agenda calculating a propagation path step.
IN	iy_agenda_call1	(Index)	Flag to handle recursive calls of iy_main_agenda The agenda iy_main_agenda can be used recursively and this flag is used to tell the methods inside the agenda which is the primary call.
IN	iy_transmittance	(Tensor3)	Transmittance to be included in iy.
IN	rte_alonglos_v	(Numeric)	Velocity along the line-of-sight to consider for a RT calculation.
IN	surface_props_data	(Tensor3)	Various surface properties.