Review of the article titled “Effects of longwave radiative cooling on advection fog over the Northwest Pacific Ocean: Observations and large eddy simulations” by Yang et al. for publication in atmospheric chemistry and physics.

The authors have analyzed a fog event in the Northwest Pacific region using observations and LES model. The focus is on advection fog that crosses the SST front thereby advecting over a scenario with the sea surface heating the fog layer as opposed to cooling it. The article is overall well-written, easy to follow, and the analysis support the conclusions. I recommend minor revisions before the article is published and hence mention few things below that can further improve the manuscript.

Title: Solar radiation is included in all of the analysis, so not sure why the authors have “longwave” in the title?

Figure 6c suggests that there is a lot of cloud water in the fog. Especially towards the end the cloud water content is constant at ~1 g/kg throughout the layer. I assume that at this high value, there is got to be some cloud water to rainwater conversion. Now if the rain is leaving the fog and falling into the sea surface, it will thin the fog layer and also affect the budget terms. Normally the surface rain flux is a heating and drying term in boundary layer budgets, see Caldwell and Bretherton (2005 JAS). Can you please expand on this a bit more? The cloud droplet number concentration is set constant in the simulations, but there is no mention of rain, so it is hard to tell what might cause this. Lack of rain might be the reason that the fog is persisting over a long time. I assume there are no aerosols in the model.

Section 2.2: please mention the vertical and horizontal resolution of the LES model.

Line 151-152: you mean “respectively”?

Line 169-170: How were the fog events tracked, was there a trajectory model used for this analysis?

Figure 1: Please show the scale of the wind barb and mention the contour levels. I understand that you have mentioned two SST contours in the legend shown in thick lines, but it will be good to show them in the figure.

Figure 4: A lot of work has gone into this figure. I think snapshots of visible satellite imagery will be hugely beneficial to the readers.

Section 4.2 heading: “Heat and Moisture Budgets”

Figure 10b and Figure 12 are fascinating. Compared to those in the constant solar radiation simulations, the fog layer bottom and top undulate a lot during the diurnal cycle simulations. Can you please elaborate causes of this? Thank you.

Please see the attached file. Best,