Hi,
Very hard to answer without more specific information what you want to do.
If you want to do OEM-type inversion involving scattering, then iyHybrid
is the only option inside ARTS. It is reasonable fast, if used with e.g.
DISORT.
DISORT is the fastest scattering solver inside ARTS, but has several
limitations.
iyMC is the slowest, but still the one to use for 3D calculations.
To retrieve atmospheric temperature or humidity with scattering present
is a very hard problem.
Bye,
Patruick
On 2023-11-02 13:44, suifengbenpao2023 wrote:
Hi Patrick,
Thanks again for your help! Is the iymc method generally slower than the iydoit
method? If the radiative transfer rate calculated by the scattering method is
very slow, does it mean that it is difficult to invert the atmospheric
temperature and humidity profile from the scattering scene? Is there a quick
way to calculate scattering?
Looking forward to your reply again, thanks!
Sincerely，
Jiaan He.
At 2023-11-02 16:15:43, "Patrick Eriksson" <patrick.eriks...@chalmers.se> wrote:
Hi,
In general, it works perfectly fine to use PlanckBT from start. But
could depend on the calibration of the instrument you simulate.
There is one exception, and that's iyMC. It does not accept PlanckBT,
just RJBT.
Bye,
Patrick
On 2023-11-02 08:42, suifengbenpao2023 wrote:
Hi Patrick,
Thank you for your help! Based on your suggestion, I will no longer use
iyfos and instead use iyMC to handle scattering situations. But I have
another question that confuses me. I often see routines that use
StringSet (iy_unit, "1") for unit conversion before calculating
scattering, and then ultimately convert to StringSet (iy_unit,
"PlanckBT"). Why do we do this? Can't we just switch to Planck
brightness temperature?
Looking forward to your reply again, thanks!
Sincerely，
Jiaan He.
At 2023-11-02 14:17:07, "Patrick Eriksson" <patrick.eriks...@chalmers.se> wrote:
Hi,
FOS is "dead" and no plans to get it back to live.
A main reason for starting FOS was to have scattering calculations,
providing the Jacobian. This was newer completed. Instead, also iyHybrid
was started and that method provides a Jacobian (not the totally full
one, but seems to be good enough).
Bye,
Patrick
On 2023-11-02 01:20, suifengbenpao2023 wrote:
Dear ARTS community,
I am dealing with scattering situations and have used the iyFOS method
in Arts-2.2 version, but there is no FOS method in Arts-2.4. May I ask
if the method name has changed? I know and have consulted relevant
literature on MC and DOIT methods, but is there any reference to FOS
methods?
Looking forward to your reply！Thank you!
Best wishes,
Jiaan He
