From model to radar variables: a new forward polarimetric radar operator for COSMO

Wolfensberger, Daniel; Berne, Alexis

doi:https://doi.org/10.5194/amt-11-3883-2018

Articles | Volume 11, issue 7

https://doi.org/10.5194/amt-11-3883-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-11-3883-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 11, issue 7

Research article

|

04 Jul 2018

Research article |

| 04 Jul 2018

From model to radar variables: a new forward polarimetric radar operator for COSMO

Daniel Wolfensberger and Alexis Berne

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Final revised paper (published on 04 Jul 2018)
Preprint (discussion started on 21 Dec 2017)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Review on "From model to radar variables: a new forward polarimetric radar operator for COSMO'"', Anonymous Referee #1, 18 Jan 2018
- AC1: 'Answers to Anonymous reviewer #1', Daniel Wolfensberger, 29 Mar 2018
RC2: 'Review of 'From model to radar variables: a new forward polarimetric radar operator for COSMO' by Wolfensberger and Berne', Anonymous Referee #2, 26 Jan 2018
- AC2: 'Answers to Anonymous reviewer #2', Daniel Wolfensberger, 29 Mar 2018

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Daniel Wolfensberger on behalf of the Authors (29 Mar 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (06 Apr 2018) by Marcos Portabella

RR by Anonymous Referee #1 (26 Apr 2018)

RR by Anonymous Referee #2 (02 May 2018)

Suggestions for revision or reasons for rejection

Review of 'From model to radar variables: a new forward polarimetric radar operator for COSMO' by Wolfensberger and Berne

General comments
I think that most comments have been taken into account and the quality of the manuscript has improved. However, I think that the following comments should be addressed before the manuscript is published.

Specific comments
• p4l16-19. 'In terms of terminal velocities, in the version of COSMO that is being used (5.04), neither ice crystals nor cloud droplets are sedimentating.' is repeated twice.
• p10l34-p11l5. Please either remove these explanations or merge them with the newly introduced ones (in blue p10l25-32).
• p11l6. 'Trilinear downscaling' should be mentioned before. Otherwise, the previous explanations are wrong in the general case: for example, nearest-neighbour interpolation preserves the mathematical relations between radar observables. By the way, the term 'interpolation' seems more appropriate to me than 'downscaling' in this context.
• p13eq8. The 3-dB beamwidth should be squared.
• p13eq9. In my first review, I mentioned an inconsistency in this equation. I admit it may not have been very explicit. Actually, I was referring to the fact that $z_k'$ is added either to $\theta_0$ or $\phi_0$. Shouldn't $z_j'$ and $z_k'$ be swapped in the arguments of $y$? Moreover, I find the notations confusing because if $J\neq K$ and $j=1$ and $k=1$, then $w_j'\neq w_k'$ and $z_j'\neq z_k'$. I would make it explicit that weights and abscissae depend on either $J$ or $K$. Please also adjust the following text lines (p13l11-p14l2) accordingly.
• p24eqs28&29. I thought that the fraction in eq 28 could be simplified by dropping $Q^s$ in the numerator and denominator, and that the fraction in eq 29 could be simplified by dropping $Q^g$ in the numerator and denominator. After doing so, isn't it obvious that $f_{wet}^{ms}=f_{wet}^{mg}$?
• p45eqC2. The upper limits of the integrals are misplaced.
• p46-52. Please check the references carefully. There are still typos here and there, such as 'reectivity' and missing conference name in Furukawa et al. (2016).
• p58fig20. I am not sure I understand the y axes. Which density is meant here? What is the reference? In panel c, density does not seem to be normalized (ie, the area under the curve is not equal to 1) since the density of GPM observations can exceed 1. I am actually wondering whether the densities of observations and COSMO in panel c are comparable. GPM can certainly not detect low values such as 1E-3 mm/h (by the way 'hour' should be abbreviated with 'h' in the international systme of units). In panels a and b, the x axis starts at 14 dBZ, which corresponds to the sensitivity of GPM observations (by the way, in panel c, the x-axis legend is wrong). In contrast, in panel c, the sensitivity of GPM observations does not seem to be taken into account.
The same remarks about the meaning of 'density' apply to p56fig17 and p59fig21.

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ED: Publish subject to minor revisions (review by editor) (02 May 2018) by Marcos Portabella

AR by Daniel Wolfensberger on behalf of the Authors (12 May 2018) Author's response Manuscript

ED: Publish as is (07 Jun 2018) by Marcos Portabella

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Short summary

This work presents a polarimetric forward operator for the COSMO weather prediction model. This tool is able to simulate radar observables from the state of the atmosphere simulated by the model, taking into account most physical aspects of radar beam propagation and backscattering. This operator was validated with a large dataset of radar observations from several instruments and it was shown that is able to simulate a realistic radar signature in liquid precipitation.