Using transport pathway, time scale and the concentration as indicators, this study examined the influence of tides on the river water behaviours over the shelf of the marginal sea. The results are important to understand and improve the climate model in the global water and biogeochemical cycles. The methods are solid, and the results are reasonable. Several points can be further clarified at this stage.

1. Several indicators including the pathway, time scales, tracer concentrations were used in this study. The links and discrepancies among those indicators can be further explained, thus give better illustration on the influence of tide. Such as there is high water age in the region of YSCWM, which trapped the river waters, while the emergence possibility there is relatively low.
2. The transit time shows high STD, which is comparable to the mean values. There is also remarkable seasonal variability. While those variabilities were not well discussed or explained.
3. How the emergence possibility represents the “pathway” of the river water? The emergence possibility is discontinuous spatially, should give a better explanation
4. Why the tidal effect induced more dispersed transport for the Yellow and Yalujiang Rivers’ waters but more concentrated transport for the Changjiang River water? 
5. The tide has different effect on the river behaviour in Bohai& Yellow Seas and the East China Sea, due to the semi-enclosed geometry or the water depth?

Some minor comments:

1. What’s the frequency of the hydrodynamic model data used to drive the particle tracking and passive tracer model.
2. For the transit time and water age, did authors consider the re-entry processes?
3. The changes of mixing intensity can be shown
4. Line 165: “The Yalujiang River water passes mainly through the western Yellow Sea”, western or eastern?
5. Figure 10 should be improved to make the arrows more clear
6. In some figures, the STD is too larger. Refine the figure to make it clear

In this paper the authors investigated the tidal effects on freshwater transport in shelf seas of China with a numerical model. The results indicated that tide slows down the shelf currents and increases the time scale of freshwater retained in the shelf seas. Then the authors argued that only parameterizing the tidal mixing in model cannot faithfully reflect the actual tidal effects, thus they suggest the climate models should include the tidal forcing in an explicit way. Over all the scientific point of this paper is very clear and the conclusion is well supported by the model results. I enjoyed in reading this paper and recommend to accept it after some revisions.

       1) My major concern is on the dynamics. The authors attribute the slowdown of shelf current under tidal effects to the enhanced bottom stress. This mechanism was discussed too in their earlier paper (Lin et al., 2020, JGR) by citing the results of previous papers. I should say that this mechanism applies more or less to barotropic region only. In stratified region, tidal can also adjust the baroclinic structure thus affect the currents in other ways. It is a complicated process and the authors cannot simply attribute it to the enhanced effective friction. More discussions are necessary besides the sensitivity experiments, and also the authors should cite the seminal paper instead of just Lin et al. (2020).

       2) Between Line 285-290 the authors stated that “the decrease in coastal currents results in a smaller gradient of sea surface height across the continental shelf, thus weakening Yellow Sea Warm Current in the control run compared to the no-tide run”. This mechanism needs justification because 1) under the tidal effects the currents is no longer geostrophic 2) it is unclear why the decreased SSH gradient would weaken the YSWC, mechanism and citations are needed. I understand such a mechanism could be discussed in previous results, but here you might give a clear explanation.

       3) Line 190 “suggesting the YSCWM region could trap river water for several years”. YSCWM is in the bottom, how could it trap the surface river water? Mechanism should be given.

       4) Can you provide a more in-depth explanation as to why tides induced more dispersed transport pathways for the Yellow and Yalujiang Rivers, but more concentrated transport pathways for the Changjiang River? It is very interesting to know the underlying mechanism.

In this paper, the authors use POM with an offline particle-tracking model to reveal the behaviors of the fluvial fresh water discharged from three major rivers in the eastern shelf seas of China. This is an important study that may serve to better understand influences of tides on transit time, water ages, and pathways of the fluvial fresh water on the shelf seas, and could further help in calibration/validation of the tidal parameterizations for the Earth system models. The results of the particle-tracking model clearly demonstrate that the tides change the behaviors of river water. But I struggled to interpret some of these behaviors shown with different types of tracers. With additional clarifications in the hydrodynamic processes on which the spatial distributions of tracers rely, and more details in model setups and methodology, the readability of this paper could be largely improved. For this reason, I would recommend returning this manuscript to the authors for revision.

The following are detailed comments:

Line 77: “… from the perspectives of transport pathways, transport timescales, and water concentration distribution”. This is a general comment about these river water behaviors. The authors represent details in each behavior with tracer results, but do not explain well what oceanographic processes or properties they are presented. For example, as RC1 commented, why the water ages are high in the Yellow Sea, but the emerging probabilities are low? It may help to have an extra paragraph to explain oceanographic processes or properties that different types of tracer represent, such as the water age reflects the residence time, emerging probability depends probably on both buoyancy and atmospheric forcings, and the tracer concentrations could show the effects in salinity field, etc. Then the effects of tides can be rooted through differences in tracer fields for physical reasons.

Line 91: In general, it would improve the readability with some level of detail in model setups. The authors provide a list of references containing very detailed information about the model they used, but I must stop reading and search for them.

Line 94: What are these tidal constituents?

Line 95: How many vertical layers does POM have?

Line 96: What forcings are used in the POM; are wind, radiation, and evaporation considered?

Line 125-126: “… by dividing the number of particles emerging in the grid cell by the total number of particles released.” Is the denominator the total tracer released per day, or for the entire simulation of 30 years?

Line 148: Does reenter account on the shelf boundary, or is t1 accounted for the first leave?

Line 152-153: This should be mentioned earlier in 2.1, and emphasize the tracer model is decoupled from the hydrodynamic model, as I thought the tracer module was running with POM. Are three years long enough for POM to get equilibrium of the water exchanges along the shelf boundary? If the hydrodynamic fields are not in a steady state, would it affect the results of particle-tracking model? Which outputs of POM are used to force the particle-tracking model? Does POM consider evaporation? Does tracer-tracking model consider surface sink?

Line 170: “Figure 2 …” Is the emerging probability calculated only for surface layer, or integrated vertically? Why is the spatial pattern of emerging probability discontinued at Yellow Sea trough for Changjiang River? 

Line 199: “Figure 3 …” It would be helpful to show the annual mean vertically averaged velocities, and to explain why the water ages are high in Yellow Sea, but the emerging probability is low.

Line 213: Consider replacing Figure 4 with Figure 9, as both contain the transit time for “control” and “no-tide” cases.

Line 225: “Figure 5 …” Why the tracer concentrations are low in Cheju Strait for all rivers, but their emerging probabilities are high?

Line 297: “Figure 10 …” Please consider changing the color scheme to increase readability. As all tracer fields are shown in annual mean, what are the net effects of these seasonal differences in shelf currents? Generally, a set of annual mean vertically integrated plots of velocities and/or tidal current ellipses would greatly help better understand the tracer patterns.

Line 309-310: The seasonal velocities (Figure 10) also show differences in mesoscale eddies. Would they affect the river water behaviors?