Properties of Cirrus Cloud Observed over Koror, Palau (7.3°N, 134.5°E), in Tropical Western Pacific Region

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Authors presented manuscript containing the results of studies of the geometric and optical properties of cirrus clouds in the Tropical Western Pacific region. The topic is of interest to the community, and the manuscript is well structure. However, I found some major issues need to be addressed before it can be considered for publication.

Specific comments:

a)        As can be seen from section 2.21 and Figure 12, there is no data for June; Data from July and August alone cannot be used for the entire summer.

b)        Does cirrus monthly percentage occurrence in Figure 6 refer to all data for the same month in the period 2018-2022? For example, does the May data refer to all the data from August 2018 to May 2022? If so, then the January data is only for January 2019, while the May data refers to all the May data for 2018, 2019, and 2022, which leads to the absence of data, which is very unfavorable to the analysis of the research results.

Other minor errors:

1.        Line 51: higher->greater

2.        Line 52-54: “Apart from the three typical types of cirrus as defined by Sassen and Cho [24], we use a subdivision definition of the cirrus cloud of COD less than 0.005, which is an Extremely Thin Tropical Cirrus (ETTCi), adapted from Immler et al. [9].” Change this sentence to the end of the paragraph.

3.        Line 85: “With this, we fill the observational gap in this region and can improve the understanding of the formation mechanisms of cirrus clouds in different seasons and meteorological conditions over the TWP region.” This sentence is changed to “This fills the observational gap in this region and improves our understanding of the generation mechanisms of cirrus clouds in different seasons and meteorological situations across the TWP.”

4.        Line 144: What does ECC stand for?

5.        Line 305: On a yearly average->On a monthly basis

6.        Figure 7: August->Summer

Note: There are other similar errors, please find yourself to change, and use recent references.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This article presents a climatological study of cirrus clouds in the tropical western Pacific region (Palau Atmospheric Observatory). The authors use data produced by a 3-wavelength lidar with polarization. The authors also use ozone and meteorological radiosondes. The study is based on data obtained during two periods, first between April 2018 and May 2019, and then between March and December 2022. The study presents statistics of the height of cirrus clouds, their optical and geometric thickness, the mean depolarization ratio and discusses the link between cirrus clouds and different atmospheric processes (convection, monsoon, stratosphere-troposphere exchanges and UTLS dynamics, cold point tropopause, Kelvin waves …etc).

The article is overall well written, the figures are clear, the methodology is well explained with many equations and the results seems reasonably supported by the data. I am therefore in favor of the publication of this article, with however some comments and requests which must be integrated in a revised version.

1) Line 1 Abstract. The first sentence of the abstract seems inappropriate to me. The article does not present a lidar system, it presents an analysis of the properties of cirrus clouds with data produced by a lidar system.

2) Line 2 Abstract. It is incorrect to write that the study covers the period 2018-2022 when the lidar system was shut down for technical issues between May 2019 and March 2022. I suggest indicating the periods corresponding to operation of the lidar.

3) Figure 2 is difficult to read in black and white, and contain very few information. It has to be completed, as example with colors and arrows to differentiate the different parts (laser, telescopes, etc.). A scale to give an idea of the size of the system would also be interesting for some readers.

4) Line 134. I didn't really understand how the polarization channels work. Are there additional photodetectors? On the 3 wavelengths (355/532/1064nm) ? Is there a permutation between the parallel and perpendicular modes and the measurements are made alternately in one polarization mode then in the other? This should be better clarified in the text.

5) Figure 6 If I understood correctly, Figure 6 brings together the two measurement periods of 1 year (2018-2019 and 2022) separated by the shutdown period of 3 years. Are the results from each of the two measurement periods consistent, or do they present significant differences? This could be highlighted before mixing the two data sets.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Authors presented manuscript containing the results of studies of the geometric and optical properties of cirrus clouds in the Tropical Western Pacific region. The topic is of interest to the community, and the manuscript is well structure. It can be considered for publication.

Author Response

The authors thank you for your comments.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have taken my comments into account and I am in favor of agreeing to publish this article.

Author Response

The authors thank you for your comments.