Influence of local and remote climate processes on driving the salinification followed by freshening phases in the eastern Arabian Sea

Interannual Variability of Surface Salinity of the Northwestern Shelf of the Black Sea Based on Satellite Information and Reanalysis Data

Consistency and uncertainty in marine heatwave monitoring using multi-source satellite sst products: insights from marginal seas and open oceans

Warming in the Arabian Gulf: insights from satellite data and climate models

This study evaluates Sea Surface Temperature (SST) variability over a 30-year period (1994–2023) and future projections in the Arabian Gulf, with a focus on the coastal waters of Qatar. Analysis of satellite observations at the select stations reveals warming trends of the order of 0.022–0.034 °C/y. The station-based analysis suggests a potential latitudinal gradient, with SST trends showing higher values at the northern stations, including those along the Qatar coast. For the first time, SST from CMIP6 climate models was compared against observations in this region. The multi-model mean demonstrates reasonable agreement at the studied locations. Climate projections indicate that SST may increase by 1.95–2.19 °C and 4.53–5.04 °C by 2100 under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. Multiple-linear regression using air temperature and wind speed as predictors shows a strong positive association between SST and air temperature, while wind speed shows a weaker negative association. The findings of this study show an accelerated increase in the SST, suggesting an elevated risk of thermal stress on the regional marine ecosystem in the Gulf.

Assessing Mediterranean Sea temperature and salinity trends using Argo float data and reanalysis products between 2012 and 2025

This study compares temperature and salinity changes in the Mediterranean Sea over the period 2012–2025, using Argo float profiles and operational reanalysis products in three open-sea regions: the Western Mediterranean, Ionian, and Levantine basins. The temporal evolution of conservative temperature and absolute salinity is examined using Hovmöller diagrams (time–depth), and linear regression is applied to quantify long-term trends. The results reveal consistent and significant warming in the Western Mediterranean and Ionian Sea, with trends reaching 0.8-0.9 °C per decade near the surface. In contrast, a negative salinity trend (up to -0.2 g kg - ¹ per decade) in the upper 100 m is observed, likely linked to the freshening of the North Atlantic. The intermediate layers associated with Levantine Intermediate Water exhibit a clear increase in salinity, up to 0.1 g kg - ¹ per decade, indicating ongoing modification of this key Mediterranean water mass. While significant discrepancies arise in the upper water column of the Ionian and Levantine seas due to sparser and intermittent Argo coverage and higher variability, both datasets consistently indicate warming and salinification below 800 m. Near the surface, reanalysis temperature trends significantly exceed those found with Argo data in both the Ionian and Levantine seas. In contrast, Argo salinity trends are larger compared to reanalysis in the upper Levantine Sea, but they are comparable in the surface Ionian. Overall, these findings confirm that the Mediterranean Sea continues to experience significant warming and subsurface salinification, and that these trends can be effectively monitored by Argo floats, provided sufficient spatial coverage across all subbasins. The persistence of these trends through 2025 highlights the continuing impact of global climate change on the Mediterranean thermohaline structure.

Intercomparison of Four Level-4 Satellite Sea Surface Temperature Products in the Complex Coastal Seas of the Shandong Peninsula

Sea surface temperature (SST) is a key variable regulating ocean–atmosphere interactions, yet the performance of global Level-4 (L4) SST products in complex coastal environments remains insufficiently evaluated. This study assesses four global L4 SST products (C3SSST, OSTIA, MGDSST, and OISST) in the coastal waters surrounding the Shandong Peninsula using both the iQuam dataset and regional moored buoy (MB) observations. Statistical metrics (COR, RMSE, MAE, BIAS) were employed to quantify accuracy. All four SST products show strong agreement with in situ observations, with correlation coefficients exceeding 0.97. Validation against iQuam showed that OISST achieved the lowest RMSE (~1.008 °C), while coastal buoy observations showed that C3SSST achieved the lowest RMSE at Zhifudao (RMSE ≈ 0.833 °C). Pronounced warm biases at Shidao station during summer suggest that L4 SST products may underestimate coastal upwelling along the Shandong Peninsula. The leave-one-out (LOO) ensemble analysis further revealed consistent differences among the four L4 SST products, with C3SSST and OSTIA showing relatively higher consistency, while OISST exhibited larger deviations from the other products. These results indicate that L4 SST performance depends on both product characteristics, including observational data sources, and local environmental conditions. These findings provide useful guidance for SST dataset selection in the Shandong Peninsula.

Atmospheric and Oceanic Parameter Responses to the Super Typhoon Lekima over the Zhejiang Coast

This study investigates the atmospheric and upper-ocean responses associated with Super Typhoon (TY) Lekima (2019) during 4–12 August, including its landfall over Zhejiang Province, China. Variations in sea surface temperature (SST), latent heat flux (LHF), water vapor flux (WVF), total column water vapor (TCWV), vertical integral moisture divergence (VIMD), mean sea level pressure (MSLP), wind circulation, precipitation, subsurface temperature and salinity, and Ekman pumping velocity (WE) were analyzed throughout the typhoon life cycle. Before intensification, SSTs of 29.5–31.0 °C indicated favorable ocean-surface conditions. During and after the storm passage, SST decreased to approximately 26.0–27.5 °C along portions of the track and below 25.0 °C near the Zhejiang coast, with stronger cooling on the right-hand side of the track. Surface salinity decreased by approximately 0.3–0.8 PSU during 8–10 August, with freshening extending through the upper 30–40 m. The Ekman pumping field identified regions where wind-stress curl favored upwelling and downwelling, with stronger positive signals occurring on the right side of the track. During the active maritime stage, LHF values of approximately −300 to −200 W m−2 indicated enhanced upward latent heat transfer. WVF reached 1800–2200 kg m−1 s−1, TCWV exceeded 70 kg m−2, and VIMD decreased below approximately −100 × 10−5 kg m−2 s−1, indicating enhanced moisture transport and convergence. These conditions coincided with daily precipitation exceeding 120 mm and locally reaching approximately 160 mm over northern and northwestern coastal Zhejiang. The minimum daily mean MSLP decreased from 1000 to 972–976 hPa during peak intensity and subsequently increased as Lekima approached landfall and weakened inland. While these responses are qualitatively consistent with previous TY case studies, our study provides new quantitative benchmarks and process attribution through heat budget analysis. This integrated, stage-based analysis provides a comprehensive quantitative reference for model validation and future comparative studies of landfalling typhoons in the western North Pacific.