Assimilating All-Sky Infrared Radiance Observations to Improve Ensemble Analyses and Short-Term Predictions of Thunderstorms

Round 1

Reviewer 1 Report

Review of Manuscript ID: remotesensing-2399031:

Assimilating All-Sky infrared Radiance Observations to Improve Ensemble Analyses and Short-Term Predictions of Thunderstorms

by

Huanhuan Zhang, Qin Xu, Thomas A. Jones and Lingkun Ran

GENERAL COMMENTS: The paper analyses the impact of rapid-cycling ensemble Kalman filter (EnKF) assimilation, by using the convection-allowing ensemble-based Warn-on-Forecast System (WoFS) on the study of the severe storm event occurred in Oklahoma on 2 May 2018. The experiments have been performed assimilating the sky infrared brightness temperature (BT) observations from GOES-16, radar wind and reflectivity observations, in addition to conventional observations. Furthermore, the methods for adaptive observation error inflation and background error inflation and the method of time-expanded sampling are also implemented to test their effectiveness.

The article is well structured, clear, and very interesting. In my opinion it can be published after a minor revision.

SPECIFIC COMMENTS:

1.     P2, L84: “2 May 2 2018” eliminate one of the two 2.

2.     P3, L122: WRF-ARW is arrived at the 4.5 version (April 2023), instead the 3.8.1 one is implemented in your study, do you think this issue can affect the performances of the analysis?

3.     P6, L225: The fourth experiment has not added to the Table 2.

4.     P8, L279: “Figure 3b” instead of “Figure 4b”.

5.     P11, L375-384: The values of the ETS are not correct. For example 3.3 is 0.33, 2.2 is 0.22, 0.8 is 0.08, 0.6 is 0.06 and so on. Let’s correct them.

6.     P12, L389-390-136: Equal to the comment above (0.57 instead od 0.075, 0.5 instead of 0.05, etc.).

7.     P12, L402: “Figure 4” instead of “Figure 6”.

Author Response

See the uploaded "Response-1.pdf".

Author Response File: Author Response.pdf

Reviewer 2 Report

Reviewer comments to the authors.

The manuscript titled “Assimilating All-Sky infrared Radiance Observations to Improve Ensemble Analyses and Short-Term Predictions of Thunderstorms” presents results from the assimilation of all-sky infrared radiances from the GOES-16 of different wavelengths and its impact in a Warn-on-Forecast System based in an EnKF system. The manuscript also present the results of improvements in the computational cost of the system through the application of the Time-Expanded Sampling technique, which helps to speed up the ensemble assimilation. The subject of the paper is relevant since it discusses the application and improvement of a system to predict extreme weather events. The challenges concerning its matter and the proposed improvements by assimilating all-sky radiances are important to aid the community in the use of such data and also present methods and techniques that are important to the use of ensemble in the convective scale.

I recommend that the presented paper be published after considering all the suggestions and corrections pointed out in the following sections.

General comments:

The paper is well written, and there are just a few typos that can be easily addressed. The number of references is adequate and well distributed throughout the text. The abstract summarizes the results in a different manner. In general, the abstract should be concise and short and must sum up the key findings, letting the discussion be appropriated in the relevant sections of the text. I suggest the authors review the abstract to make the findings part shorter, so it takes less space in the abstract. Although it is clear what is being said, the authors must consider merging the three paragraphs into one to make it shorter. There are a number of acronyms that are given in the style “time-expanded sampling (TES)”, while it should be “Time-Expanded Sampling (ETS)”. All of these are pointed out in the next section. Figure 2 has a poor image quality and should be improved. I guess whether it was an author’s production or not. If it is possible, please, improve it. Equations are typed in the inline style while it is not necessary. Since they are all typed in between paragraphs, they should be clear to the reader. Please, see the next section for an example how it should look. Speaking of which, I wonder why the authors frequently used the equivalence sign (see Equations 1, 2 and, 4)? The use of equal sign would be perfectly fine; otherwise it gives the impression to the reader that what was calculated it not necessarily what it being shown in the equations. The experiment names are sometimes confusing. In Table 2, there are the experiments E-AOEI and E-AOBEI. In the text, however, there are references to experiments called ABEI (see lines 278, 314, 321, 324, 382 and, 558) and AOBI (see lines 342, 406 and, 518). It is confusing and the authors should consider taking shorter names to avoid it.

Specific comments:

Line 12, Abstract: Please, change “ensemble Kalman filter (EnKF)” to “Ensemble Kalman Filter (EnKF)”.

Line 13, Abstract: Please, change “NSSL” to “National Severe Storm Laboratory (NSSL)”.

Line 25, Abstract: Please, change the “(or heavy)” and “(or 4)” to “(heavy)” and “(4)”, respectively. To the reader, it may seem ambiguous. It  happen frequently in text and suggest the authors to carefully revise the whole text in order to fix it accordingly.

Lines 25-34, Abstract: As commented in the previous section, I suggest the authors to write the items (i), (ii) and (iii) in one paragraph. Like “The primary findings from the two groups of experiments are summarized: (i) assimilating radar…; (ii) assimilating all-sky…; (iii) time-expanded sampling…”.

Line 63, Introduction: Please, change “brightness temperature (BT)” to “Brightness Temperature (BT)”.

Line 65, Introduction: Please, change “cloud water path (CWP)” to “Cloud Water Path (CWP)”.

Line 77, Introduction: I suggest to change from “These authors showed…” to “These studies showed…” since there is no explicitly reference to the author’s names.

Line 78, Introduction: Please, change “convective initiation (CI)” to “Convective Initiation (CI)”.

Line 84, Introduction: Please, fix the date “2 May 2 2018” to “2 May 2018”.

Line 88, Introduction: Please, change “time-expanded sampling (TES)” to “Time-Expanded Sampling (TES)”.

Line 98, Introduction: Please, remove the extra space before “By sampling…”.

Line 102, Introduction: Please, change “valid-time-shifting method (VTS)” to “Valid-Time-Shifting (VTS) method”.

Line 119, WoFS and rapid-cycling EnKF: Please, change “ensemble Kalman filter (EnKF)” to “Ensemble Kalman Filter (EnKF)”.

Line 122, WoFS and rapid-cycling EnKF: Please, change “Community” to “community”.

Line 123, WoFS and rapid-cycling EnKF: Which version of the GSI was used? Please, include this information in the text.

Line 138, WoFS and rapid-cycling EnKF: Please, change “HRRR ensemble (HRRRE [24])” to “High-Resolution Rapid Refresh Ensemble (HRRRE) [24]”.

Line 151, WoFS and rapid-cycling EnKF: Please, change “WSR-88D” to “Weather Surveillance Doppler Radar 88D (WSR-88D)”.

Lines 167-168, WoFS and rapid-cycling EnKF: Please, include informations about the described method in [6].

Line 171, Table 1: Please, remove the degrees mark next to the Kelvin unit (there is not degrees Kelvin). It happen at lines 1, 2, 8 and 9 in Table 1.

Line 174, Figure 2: This figures needs quality improvements. Also, the caption is too big.  Please, consider to sum up it or to include part of the information in the body text. Please, remove the phrase “The color scale for the composite…” from the paragraph.

Line 175, Figure 2: Please, change “(a)” to “(b)”.

Line 198, Event overviews: Please, “time-expanded sampling” with “TES”.

Line 202, Event overviews: Please, change “Figs.” to “Figures”.

Line 206, Event overviews: Please, change “Hen Egg” with “hen egg”.

Line 227, Experiment design: Please, change “relaxing posterior spread to prior spread (RTPS) to “Relaxing Posterior Spread to Prior Spread (RTPS)”.

Line 228, Experiment design: Please, remove the extra space after the “E-“ in “E-RADAR”.

Line 253, Verification methods: Please, change “root mean square errors (RMSEs)” to “Root Mean Square Errors (RMSEs)”.

Line 255, Verification methods: Please, change “equitable threat scores (ETS; [30])” to “Equitable Threat Score (ETS) [30]”.

Equations 1, 2, 3 and, 4: Please, rewrite these equations like (in the same style) – please, see the attached document if the equation does not appear here.

I wonder if this is correct because it is hard to understand in the way it was written in the text. Please, improve all the equation typing and correct the formulas if needed. Please, consider the correct usage of the equal sign as commented in the previous section.

Line 278, Assimilation statistics for the first group of experiments: Please, change “Figure 4b” to “Figure 3b”.

Line 300, Assimilation statistics for the first group of experiments: Please, change “Here, (3)…” to “Here, Equation 3…”.

Lines 302-303, Assimilation statistics for the first group of experiments: Please, change “consistency ratio (CR)” to “Consistency Ratio (CR)”.

Figure 3: In this zig-zap figure, please, make it clear to the reader which points are regarded to the priors and posteriors.

Figure 4: The phrase “The color scale is shown on the right-hand side of the figure.” can be remove from the figure caption.

Figure 5: In the figure caption, please change “(b) As in (a)” to “(c) As in (a)”.

Line 431, Forecast performances for the first group of experiments: Please, change “Figs 6 and 7” to “Figures 6 and 7”.

Lines 442 and 443, Forecast performances for the first group of experiments: Please, include an extra space after the tau letter.

Figure 8: Please, put the “CR” label further away from the y-axis in Figure 8c.

Line 478, Forecast performances for the second group of experiments: Please, change “Figs. 10b and 10c” to “Figures 10b and 10c”.

Line 496, Conclusions: Please, change “brightness temperature (BT)” to “BT”.

Line 525, Conclusions: Please, change “Figs. 6 and 7” to “Figures 6 and 7”.

Line 551, Conclusions: Please, clarify if it is correct that “…the computational cost for data assimilation cycles in the TES experiment is 4/3 of the cost in E-BT73”.

Comments for author File: Comments.pdf

Author Response

See uploaded "Response-2.pdf".

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments for author File: Comments.pdf

Author Response

See uploaded "Response-3.pdf".

Author Response File: Author Response.pdf