|Review of Upwelling characteristics in the Gulf of Finland (Baltic Sea) as revealed by Ferrybox measurements in 2007-2013|
The paper is almost there. The authors did there best in making it more of a discussion with more physics. All the ingredients are there. However, their logic is sometimes hard to follow. The physics are still not well explained, although the authors now refer to the papers that discuss these upwelling mechanisms. The authors should better guide the reader and explicitly explain the physics, instead of leaving it to the reader to read these cited papers to complete the story. That leaves a somewhat unsatisfying feeling. The connection between the paragraphs is not always clear. Many of my suggestions relate to wording and clarity. The paper is also quite long. I made some suggestions here and there to shorten the text.
L64-l73. Since the paper is quite long, is this discussion on biochemical interaction relevant to this paper? I suggest to take it out.
L110. 'two coastal areas' Sometimes it is better to be specific (as elsewhere in the paper). You mean the north and south coasts?
L124. Instead of “is in use” use “has been in use”
L245-248. I am not sure if I understand this discussion on the accuracy. Also I am not sure if the calculation of the maximum uncertainty of 1.6 (40x0.04) is correct. Why not omit this?
L259. You mean there is a 20 degree bias that needs to be corrected for?
L334. “it was suggested”. Who suggested this? Incorrect English language usage.
L347. Incorrect English language usage: “so distinct than in”. You mean “distinct as the variability”?
L349. Use “at a distance of”
L376-377. “Thus...C” Incorrect English language usage.
L379-429. This section has a lot of boring statistics (boring to the average reader). Can these be transferred to a table and then only discuss the ones most relevant to the main story?
L471. Here you say that the mean for 2007, 2009 and 2012 is 0.029 N/m2. Is that correct?
L478-480. “It can be … region” I do not understand this sentence. What are the differences? What is the mean value. Where are they discussed in the text?
Figure 7. The lines are too thin and the colors are to similar. You can also use dashed lines.
L519. Why the use of “obviously”?
L576-L577. “analysis of wind data”. Be more precise here and better guide the reader. You mean that up-estuary wind stresses are larger than down-estuary stresses (as found in this study and elsewhere) and that this should result in stronger upwelling along the northern coast?
L584-L590. These arguments are not clear to me. How does Laanemets arguments explain the difference in north-south upwelling? How does “the steeper slope and greater” make “the upwelling outcome [...] more intense in the southern Gulf”? Please explain in terms of physics.
L585. Please be precise and explain in phyiscal terms how the slope can affects upwelling. Is this through bottom drag?
L586. Is this the along-channel or cross-channel return flow?
L592. An “alternative” to what? You mean the “the higher position of the thermocline, steeper bottom slope and greater depths in the southern part”? It is not yet clear. Can this also be an “additional” explanation?
L595. Please explain how the southwesterly wind forcing and rotation cause the horizontal cyclonal circulation?
L596-L598. “Such circulation … of the gulf” To me if there is cyclonal circulation in a geostrophic balance both (out) sides should have a higher water levels and deepere thermoclines (and the center SSH depression and a shallow thermocline). But this is not the case.
What is the role of estuarine circulation in this? Geostrophy pushes the outflowing freshwater against the northern coast, deepening the thermocline there. Are you trying to say this? I do not understand your explanation of cyclonal circulation due to wind.
See also this paper and references therein:
Thomson, R. E., S. F. Mihaly, and E. A. Kulikov (2007), Estuarine versus transient flow regimes in Juan de Fuca Strait, J. Geophys. Res., 112, C09022, doi:10.1029/2006JC003925
The deeper thermocline then requires a stronger SW wind impulse to cause upwelling along the north shore.
L609. “If the strong southwesterly winds prevail, a downward movement of the thermocline in the gulf as a whole occurs”. You mean that there is a “bunching” of water in the upper layer as the estuarine outflow (part of the “estuarine circulation”) is countered by the wind driven circulation?
L611. “In contrary, the down-estuary winds cause a general upward movement of the thermocline in the gulf.” Because now all the water in the surface layer is pushed out due to the wind and estuarine circulation acting in concert?
These in phase and out of phase forcings enhance southern and counter northern upwelling, correct? Then explicitly say so.
L625. What is the “general circulation scheme”. The estuarine circulation modified by rotation? Did you discuss this earlier?
L642. To what does the “latter” refer? 'Gradual fronts'. Pleas say so. What are upwelling filaments? Do they only occur with gradual fronts and not sharp ones? Can you indicate the filaments in Figure 7?
L651. You do not have a lot of data points that confirm the relation between sharp/gradual fronts and wind strength. Maybe shorten this discussion and omit Figure 8?
L656-L679. What is the purpose of these two sections? Do you want to explain why two easterly wind events corresponded to two southern gradual fronts? That is not very clear now.
L658. Please explain to the reader what “squirts” are.
L665. Where and what is the upwelling jet? You implicitly suggest it has been discussed earlier?
L670. What do you mean with “when the thermocline had a deeper position that might enhance the influence of the bottom irregularities to the upwelling dynamics.” ?
L673 'deepening' this is related to the 'bunching' (L607-619)?
L697. Maybe say (just be clearer and more precise): “a stronger southwesterly wind impulse to cause upwelling along the northern coast as compared to a weaker northeasterly impulse to cause upwelling along the southern coast”
L704. What is the “latter”?