Determination of ice water content (IWC) in tropical convective clouds from X-band dual-polarization airborne radar

Nguyen, Cuong M.; Wolde, Mengistu; Korolev, Alexei

doi:https://doi.org/10.5194/amt-12-5897-2019

Articles | Volume 12, issue 11

https://doi.org/10.5194/amt-12-5897-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-12-5897-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 11

Research article

|

08 Nov 2019

Research article |

| 08 Nov 2019

Determination of ice water content (IWC) in tropical convective clouds from X-band dual-polarization airborne radar

Cuong M. Nguyen, Mengistu Wolde, and Alexei Korolev

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Final revised paper (published on 08 Nov 2019)
Preprint (discussion started on 18 Mar 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Comment', Alexander Ryzhkov, 14 Apr 2019
- AC1: 'Response to Referee 1', Cuong Nguyen, 11 Jul 2019
RC2: 'comments', Anonymous Referee #2, 02 May 2019
- AC2: 'Response to Referee 2', Cuong Nguyen, 11 Jul 2019
RC3: 'First comments', Anonymous Referee #3, 08 May 2019
- AC3: 'Response to Referee 3', Cuong Nguyen, 11 Jul 2019

Peer-review completion

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

AR by Cuong Nguyen on behalf of the Authors (01 Aug 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (07 Aug 2019) by Brian Kahn

RR by Anonymous Referee #2 (18 Aug 2019)

RR by Anonymous Referee #3 (19 Aug 2019)

Suggestions for revision or reasons for rejection

The authors well revised the manuscript taking into account all review’s comments. I have minor comments below.

1. Please provide brief case descriptions for: 1) the two cases in section 5.1 and section 5.2 and 2) each case in Table 2. The case description would be important to understand which types of clouds the technique can be applied to and which types of clouds are suitable for the technique. For example, what MCS type did each case represent; continental convective system or oceanic convective system? Are they multi cell convective system, leading stratiform type, or parallel stratiform type? What was the stage of these systems (e.g., developing/mature/dissipating)? Some readers may want to use the coefficients estimated in this study, because there are many cases that only radar data are available. For many observations, it is very difficult to obtain in-situ IWC and particle image data from aircraft rather than radar data. In that case, case descriptions are very useful to know which types of clouds are suitable for the technique and which coefficient values can be used.

2. Were there differences in estimated coefficients or error values between convective regions and stratiform regions?

3. I am not sure why the flow chart of Kdp estimation is more important than a flow chart of the IWC retrieval presented in this study (to me, a flow chart of the IWC retrieval is more useful). Can the Kdp estimation settings impact the IWC retrieval or error values? Can the Kdp estimation be a source of uncertainty in the coefficient estimates and IWC retrieval? When using different filtering size, can these values change?

4. Figures 6 and 12: Please add bias and RMS values for the Z-only estimate (green dashed line) for reference.

5. P. 21, line 21: I think that “narrower” is not a good word for Fig. 14. Because the y axis is not the same scale in the two plots, it is very difficult to compare the variability. Can you use a different word or a different parameter comparing the two plots (e.g. normalized value); for example, standard deviation divided by maximum value (or divided by range of IWC ((1-Zdr^-1)*IWC))?

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ED: Publish subject to minor revisions (review by editor) (20 Aug 2019) by Brian Kahn

AR by Cuong Nguyen on behalf of the Authors (18 Sep 2019) Author's response Manuscript

ED: Publish as is (23 Sep 2019) by Brian Kahn

AR by Cuong Nguyen on behalf of the Authors (02 Oct 2019)

Short summary

This paper presents a methodology for high ice water content (HIWC) (up to 3.5 g m⁻³) retrieval from a dual-polarization side-looking X-band airborne radar. Z_dr and K_dp are used to mitigate the effects of ice crystal shape and orientation on the variation in IWC – specific differential phase (K_dp) joint distribution. Empirical analysis shows that the proposed method improves the estimation bias by 35 % and increases the correlation by 4 % on average, compared to the method using K_dp alone.