Re: [arts-users] O3 Jacobians
Hi, On Thu, Apr 4, 2019 at 12:35 PM Richard Larsson wrote: > [...] > In your jacobianAddAbsSpecies, you set the unit of x to be logrel. So, the > unit in your case of J will be [iy_unit / logrel(O3)]. > our main issue here is to understand what unit logrel(O3) implies. following Patrick's advice from the previous (wind) thread, I checked the AUG (and the correct one for that matter - cause we're still using arts2.2; 'logrel' retrieval unit seems to be gone in arts2.3) - et voila! (it's sec. 16.4 for all others interested in the matter) so, according to my understanding of Sec16.4, 'logrel' is (at least regarding the Jacobian output) identical to 'rel', which in turn for the (semi-)analytical jacobians corresponds (or, is scaled) to a 100% change in the abs species (here, O3) with respect to the species' VMRs (as given by the vmr_field interpolated to the species' Jacobian p_grid). Is that understanding correct? and how is that for 'vmr' then? would the jacobians correspond to a '1' (or 10^6 ppm) change in the species? or a 1ppm change? (i'm unsure what VMR's SI unit is...). best wishes, Jana -- = Jana Mendrok, Ph.D. (Geoscience) Email: jana.mend...@gmail.com Phone : +46 (0)708 860 729 = ___ 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] Wind calculations (resent)
Hi, On Wed, Apr 3, 2019 at 4:30 PM Richard Larsson wrote: > [...] > Indeed, the description seems coherent but difficult to follow. Can you > point out where in the docs you found this? It should be updated to > clearly read that a positive wind_v in 1D equates to a positive v in the > standard (1 - v/c) Doppler shift expression. > I took my info from the built-in doc for wind_v_fields and sensor_los. I did now update the wind field section in the AUG with an explicit statement that positive/negative v-winds in 1D correspond to tail/head winds, respectively (incl a reference to the AUG section Patrick pointed out). On Wed, Apr 3, 2019 at 6:40 PM Patrick Eriksson < patrick.eriks...@chalmers.se> wrote: > The definition of the winds do not change between 1D, 2D and 3D. That > would at least lead to messy code. > I'm aware of this. And no critisism of that at all. > > This is in fact a question of the azimuth angle of the sensor. There is > also a north direction in 1D and the sensor is assumed to be looking > exactly North for 1D. This is explained in Sec 3.2 of AUG: > > 1D ... The sensor is assumed to by directed towards the North pole, > corresponding to an azimuth angle of 0 ◦. > > Maybe few are looking in AUG so I just also added this information to > the built-in doc of sensor_los. > I had indeed not checked the AUG, but used the built-in doc instead. Thanks for adding the clarification there, Patrick! However, the tricky part here (and on other occassions), particularly for people not that familiar with ARTS, is to know what to look for and where look for it specifically: for the 1D wind case, even with Patrick's clarification, the crucial point is/was join the information available in the wind_v_fields and the sensor_los/atm_dim documentation. I am not sure, if I had taken a look into the AUG regarding that matter that this would have included the atm dim (3.2) section. But, that's why the mailinglist is so great! there are people out there with better overview and better detail knowledge, who can answer questions or at least point one in a (better) direction where to look for. :) So thanks, Patrick & Richard (and everyone else contributing on other occassions) for your valuable feedback! Best wishes, Jana -- = Jana Mendrok, Ph.D. (Geoscience) Email: jana.mend...@gmail.com Phone : +46 (0)708 860 729 = ___ 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] O3 Jacobians
Hi again Rita, The ARTS approach to all this comes from the idealistic view of a computer model as a simple linear algebra system, J · x = y, where J is 'the model', or the Jacobian matrix, x is the model input, i.e., O3, and y is the model output, i.e., the simulated radiation. From this, the units in J must, when multiplied by x, give the unit of y. You have iy_unit in ARTS to set the radiation unit of J and y. You can read about iy_unit only in the individual *Standard iy-functions, like iyEmissionStandard. In your jacobianAddAbsSpecies, you set the unit of x to be logrel. So, the unit in your case of J will be [iy_unit / logrel(O3)]. Note that if you add more components to the Jacobian, such as wind or temperature or whatnot, then these additions will have different units in their respective positions of J and x. With hope, //Richard Den tors 4 apr. 2019 kl 12:46 skrev Rita Kajtar : > Hello! > > > Since it is hard to trust that the e-mails sent from my LTU account are > reaching everybody in the ARTS users list, I will, from now on, use my > Gmail account. > > Thank you to those who helped out with my first problem. > > Below is another short question I addressed to the community yesterday, > but I am not sure who received it or if anyone received it at all. If > someone did, my apologies for spamming again. > > This time my question is related to the calculation of Jacobians for O3. > > I am considering a no winds, no specific atmospheric background case and > the jacobianAddAbsSpecies in my control file is set as it follows: > > > > > > > > > > > *jacobianAddAbsSpecies( g1=p_grid, g2=gas1_jac_lat_grid, > g3=gas1_jac_lon_grid, species="O3", method="analytical", unit="logrel", > )* > > When looking at the change in Bt in my plots, in what units the change of > O3 is being represented? > > > Best regards, > > Rita Kajtar > ___ > 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
[arts-users] O3 Jacobians
Hello! Since it is hard to trust that the e-mails sent from my LTU account are reaching everybody in the ARTS users list, I will, from now on, use my Gmail account. Thank you to those who helped out with my first problem. Below is another short question I addressed to the community yesterday, but I am not sure who received it or if anyone received it at all. If someone did, my apologies for spamming again. This time my question is related to the calculation of Jacobians for O3. I am considering a no winds, no specific atmospheric background case and the jacobianAddAbsSpecies in my control file is set as it follows: *jacobianAddAbsSpecies( g1=p_grid, g2=gas1_jac_lat_grid, g3=gas1_jac_lon_grid, species="O3", method="analytical", unit="logrel", )* When looking at the change in Bt in my plots, in what units the change of O3 is being represented? Best regards, Rita Kajtar ___ arts_users.mi mailing list arts_users.mi@lists.uni-hamburg.de https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi
