Pauline, Let me first say that I don't think the differences you find are of any practical consequences, so probably not an "error". But I like that you are so careful.
First I must ask where you found that qpack2 should mimic arts_y exactly? This is basically, true but there some subtle differences around HSE (and that qpack uses automatically the ATMDATA fields). > - T field identical to the first dimension of Q.T.ATMDATA.DATA Is Q.T.ATMDATA.DATA then just a vector? Otherwise this is not a sufficient criterion. If you want to check, this is what qpack does to set Q.T_FIELD: Q.T_FIELD = qarts_atm_field( Q, 't', mjd, ho ); where mjd and ho are set based on data information in Y. > - VMR field identical to the ABS_SPECIES.ATMDATA.DATA : ok Same comment here. > - Y.HSE_P equals to Q.HSE_P This part is more tricky. First of all, if you have HSE.ON=true, Y.HSE_P and Y.HSE_Z will result in an altitude profile, that overwries anything you have in Q.Z_FIELD and Q.Z.ATMDATA. I will make this clear in qpack2.pdf (for v2.3). With HSE.ON = true we have in fact a difference between running qpack and arts_y. To mimic exactly what qpack is doing you need to do Q.Z_FIELD = qarts_hse( Q, Y.HSE_P, Y.HSE_Z ); As you noticed, there is no Q.HSE.Z. When running outside qpack2, "HSE_Z" is taken from Z_FIELD by interpolation to HSE_P. And you have likely a small difference between Q.Z_FIELD and the Z_FIELD produced by qarts_hse. If you set Q.Z_FIELD and set Q.HSE.ON=false (and don't set Z.ATMDATA), you should use identical altitudes both when running qpack2 and arts_y. I hope this clarified things around HSE!? > - Y.ZA is equal to Q.SENSOR_LOS (for the zenith angle) > - Q.SENSOR_POS equals Y.Z_PLATFORM OK Bye, Patrick _______________________________________________ qpack mailing list [email protected] https://www.sat.ltu.se/mailman/listinfo/qpack
