Sea-surface temperature variability and climate drivers in Cuba's Jardines de la Reina National Park (2003&ndash;2022)

Castillo-Alvarez, Maibelin; Pizarro, Oscar; Muñoz-Caravaca, Alain; Pérez-Santos, Iván; Carrasco, David; Bustos-Usta, David F.; Castellanos-Torres, Laura

doi:10.5194/egusphere-2025-4807

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https://doi.org/10.5194/egusphere-2025-4807

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07 Oct 2025

| 07 Oct 2025

Sea-surface temperature variability and climate drivers in Cuba's Jardines de la Reina National Park (2003–2022)

Maibelin Castillo-Alvarez, Oscar Pizarro, Alain Muñoz-Caravaca, Iván Pérez-Santos, David Carrasco, David F. Bustos-Usta, and Laura Castellanos-Torres

Abstract. Coral reef systems on the southeastern Cuban shelf are exposed to rapid warming and increasingly frequent marine heatwaves (MHWs). However, the physical drivers of local sea-surface temperature (SST) variability remain poorly quantified. The present study examines seasonal-to-decadal SST variability in and around the Jardines de la Reina National Park (JRNP) and investigates the extent to which atmospheric–ocean processes and large-scale climate modes influence that variability. The study analyses daily 1-km Multi-Scale Ultra High Resolution (MUR) SST from 2003–2022, in conjunction with ERA5 surface heat fluxes and GLORYS12 mixed-layer fields. A mixed-layer heat budget, compiled from daily values and averaged to monthly values, is used to attribute the seasonal cycle; long-term trends, MHWs and modes of variability (Orthogonal Functions) can be used to explain interannual to decadal changes and their links to El Niño Southern Oscillation (ENSO), the Western Hemisphere Warm Pool (WHWP), the Tropical North Atlantic (TNA) and the North Atlantic Oscillation (NAO).

Net air–sea heat exchange sets the seasonal evolution of SST, whereby horizontal advection provides a smaller modulation near the shelf break; a characteristic ~2-month lead of heat flux over temperature is consistent with mixed-layer heat storage. This thermodynamic control explains a marked autumn–winter shelf–offshore contrast between the shallow gulfs (Gulfs of Ana María and Guacanayabo) and the adjacent Caribbean Sea. Superimposed over this area is a warming trend of ~0.28°C decade⁻¹ (strongest in winter/transition months, peaking around April at ~0.48°C and November at ~0.35°C decade⁻¹) and a step-like shift in 2011–2013 towards a persistently warmer state. MHWs intensified during the second decade; the mean event-wise maximum intensity was higher inside GAM, while upper categories occurred more frequently offshore. EOF1 (87.5 %) is a basin-wide mode linked on an interannual basis to ENSO/WHWP and latent-heat flux and at low frequency to the NAO, while EOF2 (6.2 %) captures a shelf–offshore dipole related to TNA.

The aforementioned results provide a physical basis for which to issue early warnings from forecasts of net heat flux and mixed-layer depth, thus encouraging the use of regional high-resolution modeling and targeted observations. Key limitations to the present study include a 20-year MHW baseline and an under-resolution of currents in highly shallow and complex bathymetry.

Received: 29 Sep 2025 – Discussion started: 07 Oct 2025

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Maibelin Castillo-Alvarez, Oscar Pizarro, Alain Muñoz-Caravaca, Iván Pérez-Santos, David Carrasco, David F. Bustos-Usta, and Laura Castellanos-Torres

Status: final response (author comments only)

RC1:
'Comment on egusphere-2025-4807', Anonymous Referee #1, 07 Dec 2025
Review comments on “Sea-surface temperature variability and climate drivers in Cuba’s Jardines de la Reina National Park (2003–2022)” by Castillo-Alvarez et al.
The manuscript analyzes the seasonal-to-decadal sea-surface temperature (SST) variability and its climate drivers within Cuba's Jardines de la Reina National Park (JRNP) from 2003 to 2022, a region facing increased marine heatwaves (MHWs) and rapid warming. The seasonal cycle is primarily governed by net air-sea heat exchange. Superimposed on this is a warming trend, strongest in winter and transition months, alongside a notable step-like shift towards a persistently warmer state between 2011 and 2013. MHWs intensified during the second decade, with the mean maximum intensity being higher inside the gulfs, while upper categories occurred more frequently offshore. Empirical Orthogonal Function analysis reveals that the dominant, basin-wide warming mode (EOF1) is linked to interannual variability of ENSO/WHWP and latent-heat flux, and to low-frequency variations of the NAO; a secondary shelf-offshore dipole mode (EOF2) is tied to the Tropical North Atlantic (TNA) index. The findings suggest that monitoring net heat flux, mixed-layer depth, and large-scale indices like ENSO/WHWP and NAO can aid in providing early warnings for MHW risk and guiding conservation efforts in the JRNP. This is a well-written manuscript with well-prepared graphs to support the research.
Below are my major and minor comments
Major comments
Data Uncertainty and Consistency: The analysis relies on data from diverse sources (remote sensing, reanalysis datasets), which are known to have significant uncertainties/errors, particularly in coastal regions. Crucially, the lack of in situ measurements for validation makes an uncertainties analysis vital. A more detailed comparison of data consistency is necessary. For example, while a correlation between remote sensing Sea Surface Temperature (SST) and reanalysis SST (ERA5, GLORYS12) is mentioned, more in-depth quantitative details of this comparison are required to address the lack of in situ validation.

Sensitivity of Box Selection: The selection of the two analysis boxes in the GAM and CS appears arbitrary. A sensitivity analysis should be performed to evaluate how the results change based on the location and size selection of these analysis boxes.

Repetitiveness and Discussion Depth: Sections 4.1 and 4.2 largely reiterate information already presented in Section 3. These sections should either be combined, or the discussion should be substantially deepened. For instance, the discussion could benefit from comparing the findings to previous studies or similar studies conducted in other regions.

Mechanism for Regime Shift: The observed regime shift between 2011 and 2013 is a significant and interesting finding. However, the current paper does not present a mechanism to explain this shift. A more in-depth discussion is needed to explore the potential causes and implications of this regime shift, which would substantially enhance the paper's contribution.

Climatology section for MHW: The climatology used for Sea Surface Temperature (SST) analysis, which spans approximately 20 years, deviates from the standard practice of using a 30-year climate normal in Marine Heat Wave (MHW) studies. This choice of a shorter baseline may hinder the comparability of the results with other studies that adhere to the climate normal. It is suggested that the authors either adopt a 30-year climate normal from alternative datasets or, at minimum, quantify the influence of the chosen baseline period on the determination of MHWs.

Minor Comments
Line 46: A period is required after the word "progresses."

Lines 164-165: The Access statement should be moved to the Acknowledgement section.

Lines 172-173: This information is redundant as it has already been presented in Section 2.2.

Line 179: More detail is needed regarding the determination of the effective sampling size and effective degree of freedom.

Lines 197-199: In the equation, the terms Delta_h, u_{-h}, and w_{-h} must be defined.

Figure 10c: The line is labeled as PC-1, but the legend incorrectly mentions PC-2. PC-2 appears to be an error.
Citation: https://doi.org/10.5194/egusphere-2025-4807-RC1
- AC1: 'Reply on RC1', Maibelin Castillo Alvarez, 17 Feb 2026
  
  We sincerely thank the reviewer for the valuable comments and suggestions. All issues raised have been carefully considered and addressed in the revised manuscript. Detailed responses to each comment are provided in the supplement document.
  
  Citation: https://doi.org/10.5194/egusphere-2025-4807-AC1
RC2:
'Comment on egusphere-2025-4807', Anonymous Referee #2, 07 Jan 2026

This work examines the physical drivers of sea surface temperature (SST) trends and variability in an area encompassing the Gulf of Ana Maria, the Jardines de la Reina National Park, and the Caribbean Sea off the southern coast of Cuba. The authors find differences between the shallow gulf waters and the much deeper Caribbean Sea, which appears to be primarily a result of the mixed layer depth. They correlate modes of local SST variability with large-scale climate modes, finding (potentially) significant correlations with the North Atlantic Oscillation and the El Niño-Southern Oscillation. The authors note that understanding the mechanisms that cause SST trends and anomalies (and hence marine heatwaves) can be used to better predict the occurrence of marine heatwaves for coral ecosystems in this region.
The paper is well written and the analysis is presented in a thorough manner such that the authors’ conclusions are supported by the data (with a few relatively minor exceptions; see below). The analysis is well done, although perhaps not particularly novel and the conclusions reached may not be broadly applicable outside of the study region. Still, I would recommend the paper for publication if the comments below can be addressed in a satisfactory manner.
Line 246-247: The results of this sensitivity test should be shown in supplementary material.
Lines 270-271: It would be nice to see a supplementary figure with the cross-correlation vs. lag to support this sentence.
Lines 298-299 and Fig. 6: In the text the significance test is written as a p-value (“p<0.05”) and in the figure it is as the equivalent percentage level (“95% level”). I recommend using the percentage level for both as it seems to be more common in our field.
Lines 308-313 and Fig. 7: Has the determination of the transition points of the piecewise/step fits been done empirically? If so, by what method? See Reeves, et al. (2007). A Review and Comparison of Changepoint Detection Techniques for Climate Data. Journal of Applied Meteorology and Climatology, 46(6), 900–915. https://doi.org/10.1175/JAM2493.1
Lines 353-366 and Fig. 10: The results of the significance testing of the correlation coefficients appear to be missing despite the mention of the method of significance testing. Additionally, are the effective degrees of freedom calculated before or after low-pass filtering. adjusted for the low-pass filtering? This is especially important for the PC1-NAO correlation because after low-pass filtering both time series have very few degrees of freedom left (perhaps around N=5 judging by the number of peaks and valleys).
Fig. 10c: The text in the correlation box should be “PC1-NAO,” not “PC2-NAO.”
General comment: It is a matter of personal taste, but I think that a more standard first-person voice (e.g., “We diagnosed…”) may improve readability compared with third-person voice (e.g., “The authors diagnosed…”).

Citation: https://doi.org/10.5194/egusphere-2025-4807-RC2
- AC2: 'Reply on RC2', Maibelin Castillo Alvarez, 17 Feb 2026
  
  We thank Reviewer #2 for the careful evaluation of our manuscript and for the constructive comments and suggestions. All points raised have been carefully addressed and the corresponding revisions have been incorporated into the revised manuscript. Detailed responses to each comment are provided in the supplement document.
  
  Citation: https://doi.org/10.5194/egusphere-2025-4807-AC2

Maibelin Castillo-Alvarez, Oscar Pizarro, Alain Muñoz-Caravaca, Iván Pérez-Santos, David Carrasco, David F. Bustos-Usta, and Laura Castellanos-Torres

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Short summary

We examine 2003–2022 sea-surface temperature (SST) in Cuba’s Jardines de la Reina National Park. Using standard marine heatwave metrics and climate-mode indices, we show how large-scale patterns drive SST changes at different scales and in marine heatwave frequency, duration, and intensity. Findings help explain recent extremes and support reef conservation and early-warning efforts in the Caribbean.


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