Modifying minimum values REFL_10CM

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Posts: 5
Joined: Mon Oct 22, 2018 8:10 am

Modifying minimum values REFL_10CM

Post by DCC364 » Sat Oct 26, 2019 5:18 am

Dear all,

I am running WRFV3.9.1 and I am trying to assimilate reflectivity observations using the EnKF. The main problem I have, is that in areas where it is not observed reflectivity values (clear air), the model produce a default value of -35 dBZ. This produces a problem when I try to assimilate obs, because the data assimilation algorithm try to correct this -35 dBz to 0 dBz, generating in this way values close to 0 dBz (but not exactly 0 dBz), so generating reflectivity values in regions where we should have 0 dBz. In other words, if the minimum default value of the model was 0 dBz, then during the assimilation, the model would remain the same and no spurious reflectivity would be generated.

On the figure attached you could observed what happen when I try to assimilate 0 dBz values using the WRF3.9.1 version. In older versions, I did not experience this behavious because the model gave 0 dBz values.
Screen Shot 2019-10-26 at 3.44.05 pm.png
Any suggestion on how I can solve this problem (e.g., modifying the default minimum value for the reflectivity)?

Best regards,

Posts: 2347
Joined: Wed Feb 14, 2018 9:21 pm

Re: Modifying minimum values REFL_10CM

Post by kwerner » Tue Nov 12, 2019 6:50 pm

I have moved this topic to the Radar DA section for WRFDA Support. Someone from that group will hopefully respond to your inquiry soon. Thank you for your patience.

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