the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Delayed-mode reprocessing of in situ sea level data for the Copernicus Marine Service
Jue Lin-Ye
Begoña Pérez Gómez
Alejandro Gallardo
Fernando Manzano
Marta de Alfonso
Elizabeth Bradshaw
Angela Hibbert
Abstract. The number of tide gauges providing coastal sea level data has significantly increased in recent decades. They help in the issue of coastal hazard warnings, the forecasting of storm surges and tsunamis, and in operational oceanography applications. This data is often automatically quality controlled in near-real-time, as is the case in the Copernicus Marine Service. However, machine and visually inspected validation of historical sea level time series from these platforms is required. It has long been requested by the oceanographic community at large. As a result, a new initiative seeks to provide such validated data for the Copernicus Marine Service, by developing a new delayed-mode reprocessed in-situ sea level product. The existing software for the near-real-time product has been adapted to this end. After being visually controlled by a team with expertise in sea level reprocessing, the new product was launched in November of 2022. The entire reprocessing is discussed, in detail. An example of the information that can be extracted from the delayed-mode product is also given.
Jue Lin-Ye et al.
Status: final response (author comments only)
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RC1: 'Comment on egusphere-2023-733', Anonymous Referee #1, 01 May 2023
Summary
This manuscript presents a new re-processing product for tide gauge data.
Major comments
To be honest, I found this a quite difficult paper to review. To me, it reads more like a deliverable from a project then as a scientific publication: there are references to contracts, manuals and deliverables, while the explanation of what is actually done, what are the scientific advances, and how does this new method improve previous products is relatively limited. For starters, the manuscript doesn’t explain what delayed-mode reprocessing is – quite crucial to get all readers along. It also doesn’t mention other tide gauge databases/products and how this new dataset relate to other existing ones such as PSMSL, GESLA and GLOSS. One thing that might help also is to improve the figures and the discussion thereof, most labels are really small and the figure captions are very short, and I think these should be expanded to aid the reader and explain what is actually shown in the figures. When a figure goes into more scientific analyses (figs 7/8), the data shown and reasoning why this particular example is chosen, is not very clear. Something I’d for instance be interested to see is how does near-realtime compare to delayed-mode: are there large differences, what is the added value?
Minor comments
P1
- The abstract lacks clarity, for instance
- L15-16 - why is this required?
- L 16 – ‘from these platforms’; not clear which platforms are referred to here?
- L18 – can you explain what ‘delayed-mode reprocessed’ means?
- L19 – ‘visually controlled’ – what does this mean?
P2
- L10-11 - ‘tide gauges are emerging’ sounds a bit odd. ‘are being installed/set up’ or ‘new tide gauge data is retrieved/available’?
Figures general: In addition to the captions (see above) the figures are not very colour-blind friendly and tend to have small text labels.
- Fig 1; ‘global’ dots are difficult to see, can the symbols be larger?
- Fig 5: red and pink are difficult to distinguish; axis labels are very small. Perhaps mention which stations these are?
- Fig 6; figure text is very small. Which station is this?
- Fig 7/8; increase symbol sizes? Could the authors please explain what is shown as it is very puzzling how the ‘relative maximum/minimum’ is non-dimensional? Also from reading the main text (p4) it doesn’t become very clear what the meaning is of these ‘relative maxima/minima’ – how to interpret them, why is this shown in this way? On p4, l30-36 talk about ‘absolute’ water levels, why are these not shown?
Grammatical; please check uses of ‘it’ and if possible replace them - it is not always clear to what ‘it’ refers to exactly (for instance p1- L 16, L30, L32; fig2 caption)
Citation: https://doi.org/10.5194/egusphere-2023-733-RC1 -
RC2: 'Comment on egusphere-2023-733', Laurent Testut, 26 May 2023
General comments
The main objective of this article is to present the reprocessing strategy used by the Copernicus Marine Service to compute a new delayed-mode sea level product based on the reanalysis of many tide gauges timeseries. This objective is of major interest for the scientific community and more broadly for many coastal engineers using intensively tide gauges data to design coastal defences for example. The number of stations included in the new produt is very important (#639) and I guess the effort made to achieve this reprocessing is huge. However, the presentation of the work certainly detracts from the quality of the underlying work. Many sentences are approximatives, the quality of the Figure is often poor and the abstract/introduction and conclusion quite below what one would expect from a scientific publication. I really recommend the authors to concentrate on the core of the paper by (i) presenting a detailed version of the process and (ii) demonstrated the added-value of such a product (which I guess should be quite easy). If this article focuses on the data quality control and its contribution, especially in comparison with real-time, then this work would certainly make a good publication.Specific comments
The Abstract/Introduction is full of approximate statements that should be cleared off the text (see some examples in the next section "Technical corrections"). I encourage the co-authors of this preprint to help in the rewriting of a more concise et precise Abstract/Introduction/Conclusion.
The presentation of the Copernicus Marine Service from P2, L1 to P2, L13 (and P2, L21 to L26) is very interesting. It can be extracted from the introduction, extended a bit and put into a dedicated section that briefly present CMEMS, the In situ TAC and the main data product on which is applied the QC.
The actual section 2 and 3 on the presentation of the real-time and delayed-mode are the core of the paper. They are easy to follow, but the section on the delayed-mode could be extended to show the real added value of the delayed-mode QC. More examples of the capability of the processing to flag wrong data could be interesting to see. Comparison between the delayed-mode and real-time is also important to discuss, to cearly see in which case the delayed-mode is able to correct what real-time have missed. What is the % (or number) of values that is flagged by the real-time and by the delayed-mode (in the worst and best case, or the mean stats).
The last section on the possible application, does not in my opinion add any value to the paper. I'm sure it is necessary at all to have this section on "possible application". A sentence or two in the conclusion should be enough to convince the reader of the interest of this new product. The author should concentrate on the quality of the strategy they use to reprocess the data and on the added value of this new product.
Technical corrections
P1, L13-14 : TG can helps in triggering the warning system but not really sure that it helps in forecasting the tsunamis.
P1, L15 : When you speak about the "historical sea level timeseries" of the Copernicus system, I guess you are talking the "archived sea level timeseries". In the sea level community "historical sea level" can be confused with very long sea level records, which is not you are talking about I guess.
P1, L32-33 : (i) I'm not sure it is convenient to define ocean variable by their price (ii) I pretty sure that many other ocean variable are more easy and cheap to measure than sea level (ie temperature) (iii) atmospheric parameters were systematically recorded way before sea level. This sentence is a typical example of an "approximate" statement that is present a lot in the introduction.
P2, L14-20 : This section on the physical processes affecting the sea level is particularly weird in between the presentation of the CMEMS system. I suggest to remove this section.
P2, L44-45: remove "control of the total sea level time series" in the sentence
P3, L5 : How do you deal with the maximum surge event ? Is the maximum total sea level can be wrongly flag in case of extreme surge ?
P3, L18 : I don't understand the meaning of the last sentence, please develop.
P3, L41 : Give more explanation about the new module dealing with the attenuation of the data.
P4, L10 : from ". Produc enhancement ..." this should be moved to the conclusion part of the paper.
Figure 1 : I'm not sure this global is really necessary
Figure 2 : The image resolution is not good on the pdf.
Figure 3 : Not easy to see the useful information on this global map. An histograms of the timeseries length could be more informative than a map.
Figure 4 : ok
Figure 5 : There is a problem in the x-axis of sum of the subplots that are not corresponding. The most obvious case is the two right bottom subplots.
Figure 6 and > : Not needed in my opinion.Laurent Testut
Citation: https://doi.org/10.5194/egusphere-2023-733-RC2
Jue Lin-Ye et al.
Jue Lin-Ye et al.
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