Review of “Examining cloud vertical structure and radiative effects from satellite retrievals and evaluation of CMIP6 scenarios” by Luo et al.

This study investigates the global scale spatial pattern and vertical extent of cloud vertical structure using the new CCCM dataset. The cloud radiative effect for each classified cloud vertical structure type is quantified. In addition, long-term changes in cloud vertical structure are explored in the context of climate change using CMIP6 models. Valuable conclusions have been achieved, which can improve our understanding of cloud vertical structure, its long-term trends, and radiative effects from the perspective of satellite observations and climate models. Overall, this work addresses relevant scientific questions within the scope of ACP and presents interesting ideas using the new data and solid methods. Also, the paper is well written and the figures are displayed in a good manner. For these reasons, I would recommend its acceptance for publication in ACP after minor revisions.

Detail comments:

Line 13, the full name should be stated on the first occurrence in the Abstract. It seems that CVS stands for cloud vertical structure after reading the entire text.

Line 58, “…from ground-based remote sensors and from radiosonde measurements”, please strike out the second “from” in this sentence.

Line 89-90, in the introduction, the authors state that “Due to the interference with solar and terrestrial radiation, changes in CVS can strongly affect the Earth’s energy budget, even when the total cloud fraction remains constant”. How to understand “strongly”? since the authors did not make an explanation or cite any references. I would recommend omitting this word unless a reasonable explanation is provided by referring to relevant literature.

Line 90-91, “Satellite observations are insufficient for examining long-term trends in CVS, not only because of the limited time records…”. In my opinion, satellites have decades of records so far, and satellite-based long-term trend analyses have been conducted in previous literature. The authors could say, compared to ground-based observations and models, the satellite time records are limited. So, the expression here is not accurate, and should be rephrased.

Line 148, one concern here is that the authors did not claim the cloud pressure boundary of the layered clouds in the CMIP6 models.

Line 276, “the SW CREs further increases as the…”, change “increases” to “increase”.

Line 327-330, this sentence depicts two figures including Figs. S3 and S4, to avoid misunderstanding, should be split into two sentences.

Line 420, why do the authors think the trends in Fig. 9 is “nonlinear”? I personally cannot see a noticeable non-linearity, and suggest removing this word and only saying “noticeable”.

Review of "Examining cloud vertical structure and radiative effects from satellite retrievals and evaluation of CMIP6 scenarios" by Luo et al.

This study aims to investigate cloud morphologies and their radiative effect on the global scale. The authors use and present the new product CCCM RelD1 and compare it with 2B-GEOPROF-LIDAR, proving the reliability of the new dataset. The CCCM dataset is used to classify the clouds into 12 classes as a function of their vertical structure. The spatial distribution and the radiative effect of each class are studied in detail and presented in a clear and complete manner.

In the second part of the paper, the authors use CMIP6 models to investigate cloud amount trends during both the historical period and future projections. A comparison between models and observation is given in order to evaluate the reliability of the time series obtained from the models.

This work addresses relevant scientific questions within the scope of ACP using clear and valid methods. Moreover, the paper is well written, it is easy to follow and the figures are very clear. Overall, I find this work to be very valuable and interesting, and I recommend its acceptance for publication in ACP after minor revisions.

Specific comments:

Line 20: The word "variance" is generally used to indicate the square of the standard deviation. I suggest replacing it.

Section 2.1: The authors mentioned the horizontal resolution of all the relevant instruments. However, I would recommend mentioning also the horizontal resolutions of the two final products 2B GEOPROF-LIDAR and CCCM.

Lines 131, 147, 196: Could the authors clarify the meaning of the word "interpolation"? Does it mean "average in the 2x2 gridbox"? If so, I would suggest to substitute it with the word "average", if not, I would suggest explaining the meaning.

Lines 245-247: The negative correlation between the low cloud tops and the distance between low and upper clouds looks like an artifact coming from the definitions (e.g. given X,Y uncorrelated, then R(X,Y-X) is negative). I suggest removing these lines.

If instead, this is not the case, and if the negative correlation is significant, I suggest explaining better why.

Line 312: it is not clear if "high-, middle- and low-level" are identified from cloud top of the highest cloud or not. For example, are clouds of HMxL labeled high-level? Or they are included also in middle- and low-level classes?

Lines 325-330: Figures S3 and S4 are shown to compare the MME mean and the two models available for the future period. I suggest adding in the supplement material a figure similar to Figure 8, but using only GFDL-CM4 and IPSL-CM6A-LR, in order to compare them with the data in the period 2007-2010.

Line 380: The "CSV" identifies just low-, middle-, and high-cloud in this line, while it identifies the 12 classes of vertical structure in the rest of the paper. Could the authors substitute "CSV" with "low-, middle-, and high-level cloud amounts"?

Figures 5 & 6: Figure 6 shows that all the CSV classes have a net cooling effect on the surface, while Figure 5 shows that there are some regions where the net CRE on the surface is positive. Could the author comment on this?

Technical corrections:

Line 13: Please write CVS as full name before using the acronym in the abstract.

Line 154: SSP245 and SSP585 are capitalized in this line, while they are lower letters in the rest of the paper.

Lines 178, 185, 191: equation numbers are not correctly written.