Dear Patrick, Thank you so much for the reply and I am sorry for not be clear. I set Qpack to retrieve only ozone. Other gases and T (H2O, O2 and T) I set as Q.ABS_SPECIES.RETRIEVE=false, because I am not interesting in water vapor, oxygen, and T, but I include NCEP profiles of these gases and temperature in Q.DEFINITIONS.m for ARTS calculation and to model the spectrum. O2 is included because the frequency range of measurement is 110.83GHz and this gas also absorb the signal. These profiles have some uncertainties and I want to introduce these uncertainties in the covariance matrix for the cost calculation and so on. What I need is to include these uncertainties in the covariance matrix.
I think that I can include it in the covariance matrix doing: S^(-1)=Se^(-1) + Kb^T*Sb^(-1)*Kb where Kb is the jacobian of non-retrieval parameters (in my case H2O, T, and O2), Sb is the covariance matrix related with the non-retrieval parameters and Se is the covariance matrix related with noise. S is the covariance matrix used to calculate the cost as following. cost=[y-F(x,b)]^T * *S*^(-1) * [y-F(x,b)] + [x-xa]^T * Sx^(-1) * [x-xa] At this time, I introduce the covariance matrix only related with noise (S=Se) and I not include the uncertainties for water vapor, T and O2 profiles. I think that the Jacobians of non-retrieval parameters are similar for different measurements. So, my idea is to calculate these jacobians one time and use it then for the calculation of different measurements. It will avoid the calculation of these jacobians in each measurement. My problem is that I do not know how to include the uncertainties for non-retrieval parameters profiles in the covariance matrix S. Thanks in advance Best regards 2015-10-27 16:55 GMT-03:00 Patrick Eriksson <[email protected]>: > Dear Facundo, > > As I understand your question, the answer is no. Or at least, this can not > be done automatically. > > However, if you think that H2O and temperature can give substantial errors > (I can not see how O2 should give rise to an error), you should retrieve > H2O and T in parallel to O3. That will decrease the impact of H2O and T. In > short, OEM will then adjust as far as possible to H2O and T uncertainties. > The impact of H2O and T will then be included in the standard error > estimate. > > You have seen that Qpack can give you the error covariance matrix? > > If you retrieve H2O and T, what you call df/dH2O and df/dT are part of the > (total) Jacobian matrix, that you can trigger Qpack to output, i.e. L2.J. > The fields L2.jq and L2.ji give you information about what part of J that > belong to H2O and T etc. That should give you a way to calculate separate > errors. > > Bye, > > Patrick > > > > > On 10/27/15 20:15, Facundo Orte wrote: > >> Dear all, >> I am very new using Qpack. I am setting Qpack to retrieve ozone profiles >> using ARTS. At this moment, I am able to retrieve coherent ozone >> profiles, but to calculate covariance matrix I am trying to get the >> jacobian for water vapor (df/dH2O), oxygen(df/dO2) and temperature >> (df/dT) (to include the uncertainties of these gases and temperature), >> due to these gases absorb radiation in the frequency range of >> measurement. Is it possible to get these jacobians at the same time as >> the retrieval species (O3)? >> Thanks in advance >> >> Regards >> Facundo >> >> >> _______________________________________________ >> qpack mailing list >> [email protected] >> https://www.sat.ltu.se/mailman/listinfo/qpack >> >>
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