Measuring Salinity and Density of Seawater Samples with Different Salt Compositions and Suspended Materials
Round 1
Reviewer 1 Report
The paper is devoted for density and salinity of seawater investigations by electrical and ultrasonic measurements. The topic is generally interesting, however the paper contains a lot of unexplained places (below) and need major revisions.
Page 5, line 140, "and it can be equal to zero in some cases" please specify in which cases?
Page 5, lines 145-146, "when considering impedance, it is wort noticing that the parasitic impedance is especially evident at higher frequencies" why? the impedance of capacitor is smaller at higher frequencies. Cpar is not indicated in Fig. 2.
line 148, Cpar=0, it denote that the dielectric constant of water is zero?
page 6, line 164, "becomes insignificant at frequencies above 1 kHz", the value of constant η is not clear, so that the conclusion is not evident.
Figs. 3 and 4, measurements units for depth z should be indicated.
More details about measurements conditions should be added in the paper text. For example, maybe your measurements results can be different in different years seasons?
English need minor revisions.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This is a solid paper but needs some re-work.
The format does not follow the recommended template for MDPI Metrology. i.e.
Abstract:
- Introduction
- Materials and Methods
- Results
- Discussion
- Conclusions
- Patents
The paper reads well but it is difficult to find information as the introduction also contains elements of the materials and methods and results and discussion.
Consider re-formatting this into clear sections. If it is acceptable to the editor as it is, then it is fine.
Line 43: ΔTA and ΔDICare mentioned but are defined later, on Line 46. Please define these on first usage.
Figure 1
On the image indicate what is the SBE911 and what is the ISZ-1. Also indicate the roseett of sampling bottles.
Table 1
1375 ÷ 1900 the division sign is inappropriate here.
Line 111: The meaning of this sentence is unclear. “Since the used cells have almost zero external field impacts, the sensor has good metrological parameters.”
Figure 2
Where does this diagram come from? Is it drawn by the author?
The equivalent circuit diagram is unclear and does not contribute to the understanding of the concept.
Numerous terns in the diagram are not defined in the text, e.g. A1, if, Rm, Cii, U(f)
After the opamp A1 there is a summing block connected to a hysterysis block. The function of this is unclear.
Please redraw using a visual representation of the 4 electrodes to aid understanding.
The equivalent circuit of the current carrying electrodes consist of 2 capacitive paths. i.e. CD in parallel with CW (+ series resistors). Why is this so? I would expect to also see a parallel resistance (charge transfer). Would a standard randles cell including Warburg impedance be appropriate?
Line 161: Rs is undefined.
Line 166: Cs is undefined.
Line 167: addiction = addition?
Line 173: What is “one faraday of electricity”
Line 196: Please detail the functioning/setup of the “impedance measurement module” in sufficient detail for the work to be replicated.
Line 211: Please include details of the excitation voltage used: amplitude, waveform etc
Line 238: Please detail all the terms in the equation.
Line 288: please clarify the term “impedance amplitude”.
Figure 3
Depth axis has no label.
Figure 6
What are the units on the Y axis (uB)?
Figure 7
Place a reference point (latitude and longitude) on the map or a zoomed out section of the map in the image to allow the reader to understand the location.
Figure 8
The numbers beside the colour codes are in small font so are barely legible. Please enlarge.
The X and Y axes of the graphs have numbers (I assume these to be coordinates) please label the axes for clarity.
Line 326: “gulf of Feodosia near the cape Chauda.” Please Mark these locations on the map.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors discussed the measurment of the solute mass amount in seawater using the CTD and SVP devices. Based on the results of joint measurements, the authors present tests of water samples of various salt composition for the presence of solid suspensions. This is an interesting study. However, the manuscript needs to be revised. The specific comments are as follows:
(1) The structures of CTD and SVP devices are not clearly explained and the working principle of CTD and SVP devices need to be added. The experimental relationships between the CTD and SVP output responses and the solute mass amount in seawater are also not explained.
(2) The authors were asked to provide a detailed description of the use of CTD and SVP devices to jointly decouple the solute mass amount in seawater.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors make proper corrections according to referee remarks and I suggest to
publish the paper as it is.
Author Response
Dear reviewer!
Thank you for your follow-up review.
