future of the MRF PBL scheme

Topics related to current and future physics in the WRF as well as any problems you may have.

future of the MRF PBL scheme

Postby ivan » Sat Dec 20, 2008 7:13 am

Is it definite plan to exclude MRF scheme from future releases?
We had tested WRF against the recent extreme flood event in Carpathian mountains (Ukraine), and obtained very good results with the MRF scheme against the scheme of Ysu. 48 h accumulated precipitation averaged over about 10 stations in a region was predicted with 10% error (relative to total measured precipitation) with MRF scheme and with 30% error with Ysu scheme. All other parameters were the same. The best was Mellor Yamada , but it was rather slow for real-time applications.
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Re: future of the MRF PBL scheme

Postby wrfhelp » Tue Dec 23, 2008 8:35 pm

We will be keeping MRF for foreseeable future. But one case isn't enough to
show it is a good scheme or not - it could be just luck. If you can test it with
more cases, it might be more convincing.

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Re: future of the MRF PBL scheme

Postby ivan » Wed Dec 24, 2008 12:53 pm

Thank you for answer.
I agree, that more cases is required to say something definite about particular parameterization.
However, I would like to note 3 things.
1. The event (23-25 July 2008) was very rare. About 3 mean monthly precipitation norms fall down in 24 hours. As a results it was one of the greatest flood events in the last 50 years in that region.
2. From my past experience with MM5 I rarely observed such a significant sensitivity of the results with respect to PBL parameterizations.
3. Calculations of WRF and MM5 with 'almost' the same parameterizations resulted in rather close results. Here 'almost' means that if we not able to find exact correspondence between parameterizations (e.g. in microphysics) we tried to find the closest.
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