Handles the retrieval specifics for the aerosol species including configuration of retrieval method, measurement vector and jacobian calculations and updating of atmoshperic state with new aerosol profile.
The aerosol measurement vector is a long wavelength radiance normalized by high altitude, a second wavelength, and a modelled measurement vector assuming zero aerosol loading.
The high altitude normalization helps to remove dependence on characterization of upwelling radiation and absolute calibration
The wavelength calibration decreases sensitivity to the background atmosphere and particle size. However it may decrease senstivity to aerosols as well depending on scattering geometries.
The normalization by a ‘clean atmosphere’ measurement vector is not neccessary for Jacobian based methods, but helps to determine the best reference height for normalization.
Holds the atmospheric state, including climatologie, optical properties and species identifiers (GUIDs)
configure_instrument_and_method(ret_inst, meas_inst, method)¶
Configures the retrieval method and retrieval instrument with appropriate values. Uses information from the measurement instrument to do this, such as the measured wavelengths.
The instrument used to generate simulated level one data for the retrieval
The instrument used to generate the ‘real’ measurements. Used to generate the measurement vectors, y
least squares minimization technique. Must support weighting matrix.
wavelength (1d array):
array of wavelengths suggested by the retrieval
Generates the measurement vector
Instrument that provides level 1 used to generate the measurement vector.
do_error : (optional)
Whether or not to compute the error on the measurement vector. If false, the error is returned as zeros.
y : 1d array
The measurement vectors stacked into a one dimensional array.
Computes the measurement vector jacobian using either analytic or numerical perturbation methods.
J : 2d array
The Jacobian of the measurement vector. Elemenent J[i,j] give the sensitivity of the measurement vector y[i], to the perturbations of the atmospheric state x[j], or dy[j]/dx[i].
Computes the unnormalized measurement vector jacobian using simple numerical forward difference method.
Computes the measurement vector jacobian using analytical methods from the HR sasktran model.
Generates the measurment vector unnormalized by high altitude and rayleigh
y : 2d array
An array of height x num meas vectors
dy : 2d array
An array the same size as y, containing the measurement vector error
Returns: the profile in units of extinction per km
Update the aerosol profile in the atmosphere at based on the recommendations given by delta.
delta : 1d array
The suggested numerical change of the profile. Must be the same length as the tangent altitudes.