The authors investigate surface ocean dynamics in Ligurian Sea. The authors are all experts in such observations and analysis and very familiar with this interesting region. Their contribution is valuable and of interest to other researchers in the Med Sea region as well as elsewhere. Latest observing systems and analysis methods are used; the paper is concise and well written. I have no significent feedback to criticise or improve the manuscript. Thus I recommend publication as is.

Review Ms Egusphere-2023-688 ‘’ Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea’’ by Poulain et al.

The Ms present a 3-day  experiment aimed to characterize the sub mesoscale circulation in the Ligurian Sea using a large set of lagrangian drifters plus a profiling float.  Drifter velocities were used to derive dispersion as well as different kinematic properties with the aim of explaining the dynamics in the area. 

Although being a research area that is receiving increasing attention, the present manuscript has two major drawbacks ;

• First, the scientific problem is never stated. Although using several eulerian diagnostics (and one lagrangian), the scientific question is not clear. Besides providing a review of different metrics, largely used in the last two decades,  the Ms as it is now, looks like a review of these techniques (technical report) used to describe the short term dynamics in a coastal area.  For the reader it is not clear if the objective is to show how drifters arrange towards an eddy (a mesoscale structure), or towards the filaments shown in Figure 3 (scales between meso and submesoscale). 
• Errors in the different metrics are not provided. For example, the slopes in the FSLE spectrum are not conclusive since the standard deviation for each initial separation distance is not given. Why not fit the FSLE spectrum data and compute the value of the slopes at the different spatial scales ranges?
• What is the error in the computation of the kinematic quantities due to the error in the drifter positions and to the least square approach?

Specific comments: 

• The description and expression of Eq 2 can be improved. I would add, at least, a reference to the theoretical paper “Nonasymptotic properties of transport and mixing”,Boffetta et al., 2000, Chaos 10, 50-60. Appendix A describes the correct operational definition of FSLE.
• I suggest the Authors discuss in some more detail the outcome of their FSLE computation. Did they consider the fastest growth time (as arbitrarily assumed by some authors) or the average growth time (as prescribed by the correct FSLE definition) ? 
• Eq’s 3 and 4 correspond to the linear terms of the correction to the first order velocity of the taylor expansion (u_0 is missing)
• Figure 4. It will be helpful to superimpose currents from the CMEMS model together with the paths. Also the FSLE/FTLE maps would provide a good overview on the dynamics in the area. 
• Figure 6. Plot each curve with a different color. Also discuss the implications of each relative dispersion on the dynamics of the area. 
• Figure 7. Include errors. 
• Figure 8. Can you explain in terms of the specific dynamical conditions the peaks on the speed?. A quick look at Figure 2 shows that this is nothing related to wind and waves. 
• Figures 9-12. I suggest changing in a band near zero the green color to white (this will provide better insight on the different metrics presented in this small area. Besides, what is the difference between the DIV/f in figure 9 and Figure 10 a?.  Show position of the eddy discussed in the text in Figure 9. 
•   Figures 10-13. Why using Eulerian metrics instead of Lagrangian ones?.  In particular, the use of the Lagrangian Divergence could give an indication of the upwelling/downwelling in the drifters path and confirm what is speculated in the document about the vertical velocities. 
• Ln 226-227. There are in the literature examples of such a comparison. 
• Ln 262 -> why?
• Ln 294 -> This is something that an statistical analysis will ensure (only 8 pairs of drifters fall within this distance). 
• Lns 320-322. I agree totally on this.  
• The references are largely biased towards the author's work and several relevant papers on the topic are missed.