Re: [arts-users] Problem about caculating the impact of winds
Dear Wang, note that using the lookup table may not be your best option for wind retrieval. The reason is that it can only interpolate between the precalculated values. If you calculate the absorption on the fly, the line will be Doppler-shifted, which is exact. You can achieve this by setting up propmat_clearsky_agenda accordingly. Depending on the details of your calculation, this could be a bit slower, but it could also even be faster (in case your line list is not very long). Best wishes, Stefan On 21 Apr 2021, at 7:59, Wenyu Wang wrote: Hi Everyone, I had a question about caculating the impact of winds by using lookup table in ARTS. I use the larger frequency grid when generate the table, such as 3 GHz band, 0.5 MHz setp. However, when I caculate the y using the frequency grid with 1 GHz band and 1 MHz step, error messages occur as follow (But it is OK when I set the frequency step to 2 MHz): Runtime-error in source calculation at index 0: Run-time error in agenda: propmat_clearsky_agenda Run-time error in method: propmat_clearskyAddFromLookup Problem with gas absorption lookup table. At least one frequency is outside the range covered by the lookup table. The version of ARTS is 2.4.0. Regards, Wang___ arts_users.mi mailing list arts_users.mi@lists.uni-hamburg.de https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi ___ arts_users.mi mailing list arts_users.mi@lists.uni-hamburg.de https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi
Re: [arts-users] Problem about caculating the impact of winds
Hi Wang, How do you setup the f_grid for the y calculation? Depending on how you generate the f_grid for y, it might end up with a value that lies just a bit outside the boundary of the f_grid used for the lookup table due to slight numerical inaccuracies. These inaccuracies can be depending on your chosen step size. That could explain why it works for 2 MHz, but not for 1 MHz. You can try to extend your lookup table grid a little bit to ensure that your new f_grid lies inside of it. Cheers, Oliver > On 21 Apr 2021, at 07:59, Wenyu Wang wrote: > > Hi Everyone, > > I had a question about caculating the impact of winds by using lookup table > in ARTS. > > > > I use the larger frequency grid when generate the table, such as 3 GHz band, > 0.5 MHz setp. However, when I caculate the y using the frequency grid with 1 > GHz band and 1 MHz step, error messages occur as follow (But it is OK when I > set the frequency step to 2 MHz): > > > > Runtime-error in source calculation at index 0: > Run-time error in agenda: propmat_clearsky_agenda > Run-time error in method: propmat_clearskyAddFromLookup > Problem with gas absorption lookup table. > At least one frequency is outside the range covered by the lookup table. > > > > The version of ARTS is 2.4.0. > > > > Regards, > > Wang > > ___ > arts_users.mi mailing list > arts_users.mi@lists.uni-hamburg.de > https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi ___ arts_users.mi mailing list arts_users.mi@lists.uni-hamburg.de https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi
