Levante and Poniente are regional winds that appear in the Strait of Gibraltar with great intensity and frequency. However, they have not been the focus of many modelling studies so far. For this reason, the present work has two aims. First, to evaluate the capability to describe both winds using the largest available set of outputs from regional climate models and different wind data frequencies, spatial resolutions and atmosphere-ocean coupling characteristics. Second, to study wind changes between present (1950-2005) and future climate conditions (RCP8.5, 2006-2099). Results indicate that available spatial resolution is essential for a proper wind description. Internal physics are also a source of variation. Coupling effect does not lead to important changes on any of the studied regional winds. Levante occurs in the historical period between 110-130 days per year, covering 42%-44% of the Strait, with future increase of 10-20 annual events, depending on the model. Levante spatial extension varies with mixed trend signs. Poniente is detected between 135-155 days per year over 45%-50% of the Strait for the historical period and shows future debilitation in its magnitude with around 5-20 less days. This pioneering work manifests the capability of regional climate models to quantify Levante and Poniente events. Future climate change projections should be further studied to obtain as much regional climate model outputs as possible and to increase the robustness of such projections. Besides, a deeper analysis of weather variability patterns related to these wind conditions would strongly increase our understanding of the atmospheric mechanisms behind such important regional winds.

Tidal dynamics play an important role in Kara Sea circulation, influencing currents, sea ice formation, and biogeochemical processes. However, accurate numerical simulation of these processes in regional models depends on the choice of tidal forcing at open lateral boundaries. This study evaluates the performance of three tidal models – TPXO9, FES2014, and Arc2kmTM as sources of boundary forcing for a high-resolution regional Kara Sea model based on MITgcm numerical kernel. The goal is to identify the optimal tidal forcing that best aligns with observations from coastal stations. Numerical experiments have revealed significant discrepancies in tidal energy estimates among the models. The FES2014 model has shown the closest agreement to observations, while Arc2kmTM exhibits the largest errors. However, when used as boundary forcing in the regional Kara Sea model, Arc2kmTM yields the smallest errors in simulated tidal amplitude and phase. Overall, the regional model reproduces M2 tidal amplitudes well but introduces slight phase shifts in the southwestern part of the Kara Sea. Our findings emphasize that no single tidal model can be considered universally optimal. The choice depends on regional conditions and modeling objectives. For our regional model, Arc2kmTM is recommended as a source of tidal forcing at the open boundaries of the regional model, though global models like FES2014 remain viable alternatives. This work emphasizes the need for improved validation methods and highlights the challenges posed by limited observational data in the Arctic region.

Rapid Arctic sea-ice retreat is exposing the upper ocean to intensified mesoscale variability, yet whether the mechanism by which eddies deliver heat to the ice base evolves with this retreat remains unclear. Here we use an eddy-resolving coupled model to examine how basal heat-transfer mechanisms evolve over a century-long simulation of sea-ice retreat. As the marginal ice zone expands, eddy-driven ocean-to-ice heat flux intensifies and contributes an increasing share of the sea-ice heat budget. A decomposition of this eddy-driven flux into thermal, mechanical, and covariance components shows that the thermal and mechanical terms remain substantial across contrasting ice states, but neither exhibits a systematic increase across marginal ice regimes during sea-ice retreat. The overall strengthening is instead driven by the growth of the covariance term. As sea ice thins and retreats, intensified friction-velocity fluctuations become more tightly coupled to upper-ocean temperature anomalies, allowing mesoscale variability to transfer heat more efficiently to the ice base. These results reveal a state-dependent mesoscale pathway for Arctic sea-ice loss that is not captured by mean-gradient-based parameterizations in current climate models.

The Beaufort Gyre (BG) is a key freshwater reservoir in the Arctic Ocean, and its variability could have vast impacts on global climate. Current-generation climate models (e.g., CMIP6) typically operate at coarse resolutions (~20 km) that cannot resolve boundary currents transporting Atlantic Water (AW) in the Arctic Ocean. This leads to large uncertainties in the pathways of AW and its impact on BG dynamics. Here, using an ultra-high-resolution (2 km in the Arctic Ocean) simulation of the AWI-CM3 model with substantial improvements in simulating AW inflow and boundary current structure, we demonstrate a fundamentally different BG response under warming. After excluding the influence of surface processes, we found that the resolved, intensified AW boundary currents transport more AW into the Amerasian Basin, which results in a contraction and strengthening of the BG. Our results highlight that inadequate representation of boundary currents in coarse resolution models may lead to a systematic underestimation of future BG strengthening and its climatic implications.

Earth's climate response to increasing greenhouse gas emissions occurs on a variety of spatial scales. To assess climate risks on regional scales and implement adaptation measures, policymakers and stakeholders often require climate change information on scales that are considerably smaller than the typical resolution of global climate models (O(100 km)). To close this important knowledge gap and consider the impact of small-scale processes on the global scale, we adopted a novel iterative global earth system modeling protocol. This protocol provides key information on earth's future climate and its variability on storm-resolving scales (less than 10 km). To this end we used the coupled earth system model OpenIFS–FESOM2 (AWI-CM3; Open Integrated Forecasting System – Finite volumE Sea ice–Ocean Model) with a 9 km atmospheric resolution (TCo1279) and a 4–25 km ocean resolution. We conducted a 20-year 1950 control simulation and four 10-year-long coupled transient simulations for the 2000s, 2030s, 2060s, and 2090s. These simulations were initialized from the trajectory of a coarser 31 km (TCo319) SSP5-8.5 transient greenhouse warming simulation of the coupled model with the same high-resolution ocean. Similar to the coarser-resolution TCo319 transient simulation, the high-resolution TCo1279 simulation with the SSP5-8.5 scenario exhibits a strong warming response relative to present-day conditions, reaching up to 6.5 °C by the end of the century at CO2 levels of about 1100 ppm. The TCo1279 high-resolution simulations show a substantial increase in regional information and climate change granularity relative to the TCo319 experiment (or any other lower-resolution model), especially over topographically complex terrain. Examples of enhanced regional information include projected changes in temperature, rainfall, winds, extreme events, tropical cyclones, and the hydroclimate teleconnection patterns of the El Niño–Southern Oscillation and the North Atlantic Oscillation on scales of less than 1000 km. The novel iterative modeling protocol that facilitates coupled storm-resolving global climate simulations for future climate time slices offers major benefits over regional climate models. However, it also has some drawbacks, such as initialization shocks and resolution-dependent biases and climate sensitivities, which are further discussed.

The development of offshore renewable energies has accelerated to replace non-renewable sources and meet current energy demand. Hybrid platforms could enhance energy generation and reduce resource variability, though uncertainties remain about the impact of climate change on these resources. This study assesses wind, solar, and wave energy potential in Spanish offshore locations by the late 21st century using a high-resolution regionally coupled ocean-atmosphere model (5 km resolution). Under the RCP8.5 scenario, wind resources show increased seasonal and spatial variability, with gains in northern Spain during winter and summer, and nearly year-round in the Canary Islands. In contrast, wave energy is projected to decrease uniformly, particularly in Atlantic regions, with less impact in the Mediterranean. Solar resources remain nearly unchanged, though variability is expected to decrease. The study emphasizes that while resource levels shift, optimizing hybrid platforms requires addressing variability. Results indicate that in northern Spain, variability is minimized by increasing the share of solar and wave energy, reducing wind dependence. In the Alboran Sea, Canary Islands, and Balearic Islands, wave energy is crucial for reducing variability, as wind and solar resources alone could increase it. Adjusting the proportional use of each energy source is thus essential to optimize offshore energy platforms under future climate scenarios.

We present the first digital twin framework that operationalizes the production of multi-decadal, global climate projections at kilometre-scale resolution, developed within the European Union's Destination Earth initiative. Using three coupled Earth system models and selected impact-sector applications, we have built end-to-end workflows for both regular and on-demand climate projections on two EuroHPC supercomputers, LUMI and MareNostrum5. These workflows produced the first-ever multi-decadal simulations at 5 km resolution across all major Earth system components, using the same output parameters and grid, and achieving a production throughput of 0.6 simulated years per day and a climate data portfolio of 6.6 petabytes. We demonstrate the scalability of two of these Earth system models across both CPU and GPU-based systems at global resolutions up to 1 km, across atmosphere, ocean, land, and sea-ice, and report record-breaking full-machine performance on LUMI and MareNostrum5 of up to 97 simulated days per day at 1 km resolution.

The Arctic sea ice is vanishing at an alarming pace, far outstripping the predictions of many current climate models (Shu et al., 2020). This growing discrepancy suggests that vital oceanic processes—especially (sub)mesoscale eddies responsible for heat transport to the sea ice—are not being fully captured. In this study, we leverage a cutting-edge, coupled ocean-sea ice model with an unprecedented 2 km eddy-resolving resolution, spanning 1980 to 2100, to explore how oceanic eddies are driving the dramatic loss of Arctic sea ice. Our findings reveal that eddy-driven processes are playing an increasingly dominant role in sea ice decline, with their most profound impact occurring in the final decades of the 21st century. The main driver of this intensifying trend is the transport of heat to the ice-ocean interface by oceanic eddies, particularly in the marginal ice zones. We further propose that a self-amplifying feedback loop between sea ice loss and eddy dynamics is at play, accelerating the melting process. These results highlight the urgent need to integrate eddy dynamics into future Arctic sea ice models, especially as the region undergoes rapid transformation in a warming climate.

The Canary/Iberia region (CIR), part of the Canary Current Upwelling System, is well-known for its coastal productivity and crucial role in enriching the oligotrophic open ocean through the offshore transport of the upwelled coastal waters. Given its significant ecological and socio-economic importance, it is essential to assess the impact of climate change on this area. Therefore, the goal of this study is to analyze the climate change signal over the CIR using a high-resolution regional climate system model driven by the Earth system model MPI-ESM-LR under RCP8.5 scenario. This modelling system presents a regional atmosphere model coupled to a global ocean model with enough horizontal resolution at CIR to examine the role of the upwelling favourable winds and the ocean stratification as key factors in the future changes. CIR exhibits significant latitudinal and seasonal variability in response to climate change under RCP8.5 scenario, where ocean stratification and wind patterns will play both complementary and competitive roles. Ocean stratification will increase from the Strait of Gibraltar to Cape Juby by the end of the century, weakening the coastal upwelling all year long. This increase in stratification is associated with a freshening of the surface layers of the North Atlantic. However, modifications in the wind pattern will play a primary role in upwelling source water depth changes in the southernmost region of the CIR in winter and in the north of the Iberian Peninsula in summer. Wind pattern changes are related to the intensification of the Azores High in winter and to a deepening of the Iberian thermal low in summer months.

The observation-based analysis of drought development in the Chorotega region showed that, despite the area being relatively small, agricultural drought exhibits high spatial variability across the region. However, the lack of net radiation data hinders the capacity to provide reliable estimates of evapotranspiration (ET), affecting the assessment of drought occurrence, since its propagation across the hydrological system is very sensitive to the ET estimation method. The coarse resolution of satellite-derived Normalized Difference Vegetation Index (NDVI) products and the lack of information on irrigation in agricultural areas limits the ability to properly establish a relationship between drought and vegetation response. Based on the observations, the most prominent precipitation deficits occur between September and October (–100 mm on average), showing that changes in the large-scale circulation are responsible for the impact of severe drought in the region. In agreement with previous studies, El Niño-Southern Oscillation (ENSO) is the main modulator of the drought severity, with the warm ENSO phase favoring an enhanced drought development and its influence being more significant between August and October, displaying correlations greater than –0.6. The climate change projections under RCP4.5 and RCP8.5 scenarios suggest the intensification of drought events in the Chorotega region at mid-century, with the Tempisque-Bebedero basin being the most affected area in terms of precipitation decrease and warming. The projected scenarios correspond to an increase of 1 oC for mean temperature and more of 2 oC for minimum and maximum temperature in the 2050 horizon, as well as a decrease of 400 to 800 mm for annual precipitation under both RCPs.

This study examines the future climate change in the South Asia region during 2070–2099 with respect to the historical period (1975–2004) under RCP8.5 scenario using a high-resolution regional earth system model. We found substantial changes in the key climatic parameters over the South Asia region including ocean biological productivity, however, the magnitude of response varies spatially. A substantial increase (> 2.5 °C) in the projected annual-mean sea surface temperature (SST) was found over the Indian Ocean with the highest increase (~ 3.4 °C) locally in the northern part of the Arabian Sea and in the Persian Gulf, SST changes being significant throughout the study area with 95% confidence level. The changes in the sea surface salinity showed strong spatial variability with the highest freshening over northern Bay of Bengal and highest salinity in the Persian Gulf followed by northern Arabian Sea. The amount of annual-mean precipitation will substantially increase over the eastern coast of the Bay of Bengal (up to 1.5–2.0 mm/day) and along the equator in the band 10° S–10° N (0.5–1.5 mm/day), while it will decrease over the western part of the Bay of Bengal and in the northern states of India (− 0.5 to 1.0 mm/day). The most pronounced increase of precipitation rate in the future climate will occur over India (3–5 mm/day) and the eastern coasts of the Bay of Bengal (> 5 mm/day) during the monsoon period, and over the equatorial band (2–3 mm/day) during the post-monsoon period, with all precipitation changes indicated above being significant at 95% confidence level.

In this study, a future projection of marine cold spells (MCSs) over the tropical Indian Ocean is made using a fully coupled regional Earth system model, namely ROM, under two representative concentration pathways (RCPs): RCP4.5 and RCP8.5. In both RCPs, the future MCS properties have been estimated across three distinct time intervals: the near future (NF; 2010-2039), the middle future (MF; 2040-2069), and the far future (FF; 2070-2099). The future MCS computations were examined with respect to fixed historical baseline periods and varying baseline periods. MCSs were frequent, intense, and prolonged during the historical period. ROM effectively simulated these historical MCS metrics and their trends and outperformed the forcing general circulation model as well as the multimodel ensemble mean of Coupled Model Intercomparison Project phase 5 models. In the future, MCSs will cease to occur in similar to 13% (4%), similar to 56% (66%) and similar to 69% (93%) of the area of the tropical Indian Ocean in the NF, MF, and FF respectively under the RCP4.5 (RCP8.5) scenario using a fixed historical baseline period. This departure of MCSs led to the disappearance of events, first identified over the Arabian Sea in both RCPs. The decrease in net heat flux and increase in wind speed contribute to the genesis and severity of MCS events. Further, during the El Nino regime, the MCS events dramatically decrease due to the basin-wide warming, but during the La Nina phase, the MCS intensity and spatial range increase. This study further investigates the sensitivity of MCSs with the choice of baseline period. Adopting varying baseline periods over time does not result in the disappearance of MCSs but does produce declining trends in MCS activity, highlighting the need for careful consideration in choosing a baseline period. Future projections of marine cold spells (MCSs) are defined relative to fixed and varying baseline periods, under two representative concentration pathways, RCP4.5 and RCP8.5, over the tropical Indian Ocean. Dissolution of MCSs occurs with a fixed baseline period, whereas a varying baseline period produces declining trends in MCS activity. MCS events dramatically decrease during El Nino, whereas the La Nina phase increases MCS intensity and spatial range. image

There is an urgent need to enhance climate projections for Central Equatorial Africa (CEA), given the region's high vulnerability to climatic hazards and its economy's heavy dependence on climate-sensitive sectors. This study aims to evaluate the performance of the regional earth system model ROM, composed of the atmosphere-only regional climate model (RCM) REMO coupled with the global Max Planck Institute for Meteorology Ocean Model (MPIOM), in reproducing the precipitation climatology over CEA. ROM results are compared to those of REMO in two sets of experiments, one driven by the ERA-Interim reanalysis and the other by the MPI-ESM-LR earth system model (ESM), both at similar to 25-km horizontal resolution. Results show that ocean coupling improves rainfall climatology thanks to a better representation of the physical processes and mechanisms underlying the rainfall system. In particular, an improved sea surface temperature (SST) results in a more realistic simulation of land-atmosphere-ocean interactions, and subsequently the atmospheric baroclinicity. Specifically, the coupling reduces the positive SST bias inherited by the driving ESM across the entire Guinea Gulf and Benguela-Angola coastal seas. This leads to better simulated land-ocean thermal and pressure contrasts. Improvements in land-ocean contrasts, in turn, enhance the representation of the regional atmospheric circulation, and thus precipitation. Interestingly, the coupling is more beneficial when ROM is driven by the ESM than the reanalysis. This study emphasizes the advantage of dynamically downscaling ESMs using regional earth system models rather than atmosphere-only RCMs, with the potential to enhance confidence in future climate projections. Designing timely and relevant societal responses to climate-related impacts and risks to humans and natural systems requires reliable information about climate variability and projected change, especially at regional scales. For this purpose, considerable efforts were devoted to the improvement of the numerical models used to represent the climate system, including better formulation of the models' physical and dynamical components and the inclusion of feedback between different components of the climate systems, such as those between the ocean and the atmosphere. In this study we aim at investigating whether the use of a regional climate model which includes an explicit representation (coupling) of the ocean is able to better simulate (i.e., adds value) the main mechanisms responsible for precipitation over Central Equatorial Africa. The results show that the coupled model is indeed able to simulate more realistically the complex physical processes and mechanisms underpinning the rainfall system. Our findings advocate for the use of the global ocean-regional atmosphere coupling approach for regional climate change projection analyses. The global ocean-regional atmosphere coupling improves the rainfall climatology compared to its atmosphere-only counterpart model The added value resulting from the coupling is plausible, as associated with improvements in the processes underpinning the rainfall system The added value is modulated by the boundary conditions, with better suitability under the imperfect forcing mode

This study employed a regional earth system model, namely ROM over the CORDEX-SA domain, to investigate the future changes in the Marine heatwaves (MHWs) with respect to the historical baseline period (1976–2005) in the three time-slices, explicitly, near future (NRF; 2010–2039), middle future (MDF;2040–2069), and far future (FRF; 2070–2099) under two emission scenarios, Representative Concentration Pathway (RCP4.5 and RCP8.5). For the historical period, ROM showed a reasonable agreement with observed MHWs metrics and their trends and outperformed the forcing General Circulation Model and Multi-Model Ensemble of CMIP5 models. The future MHWs are expected to increase in intensity and duration. The continuous lengthening of MHWs duration leads to a permanent MHW state condition with strong spatial variability in its appearance. The first permanent MHW will emerge in both RCPs, while the absolute permanent MHW state is mainly visible in RCP8.5. The genesis and augmentation in the MHWs intensity is associated with local air-sea fluxes, however, in the long term, the increase in the mean SST in the future led to the rise of MHWs activity. The diagnosis of El Niño Southern Oscillation teleconnection and Indian Ocean Dipole on the MHWs is investigated. During the El Niño regime, not only did the proportion of the Tropical Indian Ocean experiencing MHWs increase but also an increase in the intensity is evident. IOD controls the MHWs metrics in the proximity of the western box and eastern box during its positive and negative phases.

Abstract Changes in Mediterranean circulation patterns due to global warming may have strong socio‐economic and environmental impacts. We analyze the future evolution of the Mediterranean surface circulation under different levels of global warming by using 28 multi‐decadal simulations from a set of fully coupled and high‐resolution regional climate models of the Med‐CORDEX multi‐model initiative. There is no model agreement for a significant basin‐scale modification of the surface circulation. However significant and robust local circulation changes are identified. In particular, the circulation is expected to shift from cyclonic to predominantly anticyclonic in the northern Balearic, while a strengthening of the cyclonic circulation is expected in the southern Adriatic. Furthermore, our results show an increase in the Mediterranean circulation variability primarily associated with a general increase of meso‐scale activity. Generally, we find a linear increase of the identified changes with global warming levels.

Unraveling plausible future rainfall change (Delta Pr) patterns is crucial for tailoring societies' responses to climate change-induced hazards. This study compares rainfall projections from the regionally coupled ocean model (ROM) and its atmospheric component, the regional atmospheric model REMO, over Central Equatorial Africa (CEA). Both models are forced by the Earth system model MPI-ESM-LR following the Representative Concentration Pathway 8.5. Results reveal increased rainfall across most of CEA, with ROM projecting more widespread and intensified wetting than REMO, although REMO produces more precipitation under future conditions, underscoring the influence of historical biases on REMO's projection. Examining processes underpinning changes unveils strong controls of sea and land surface temperature changes in Delta Pr differences between the two models. Specifically, ROM mitigates warming more over the Atlantic than over CEA landmass compared to REMO, inducing enhancement of the Congo Basin cell and increased precipitable water content through specific humidity, affecting deep convection. Both models project enhanced Sahel and Kalahari thermal lows, with ROM better depicting the Kalahari low's warmer nature than the Sahel low. The resulting temperature gradients strengthen the northern and southern shallow meridional Hadley overturning circulation. ROM simulates the wetter conditions than REMO, attributed to its weaker northern Hadley Cell, which restricts the likelihood of northward moisture divergence toward the Sahel. Additionally, differences in mid-tropospheric moisture convergence differentiate between ROM and REMO's wetness relative to the historical period and under future conditions. ROM projections are more plausible, in association with the reliability of its added value under the historical climate and mechanisms underlying Delta pr.

We evaluate the benefits of the use of a regional coupled model over its stand-alone atmospheric component when forced by reanalysis data in the simulation of the South American climate. We find that the coupling allows for a better simulation of important features of the atmospheric circulation and surface temperature. The simulated 2 meters air temperature is improved over most of the continent, the sea level pressure over the South Pacific Anticyclone area is better represented in the coupled simulation and the location of the ITCZ is improved during the austral winter. The precipitation, especially over the Andes, benefits less from the coupling, although a more realistic humidity transport leads to a reduction of the precipitation biases over extensive regions. The austral summer precipitation bias is reduced in areas such as eastern Colombia, northern Bolivia, eastern Brazil and central Argentina. For austral winter, the coupled model has a better performance in a large part of the Amazon region, in areas such as east of Peru, west Brazil, north Bolivia and south Argentina. Moreover, the regionally coupled model not only improves the simulation of important features of the observed atmospheric fields but also demonstrates good skills in reproducing the Humboldt upwelling system. Therefore, our study highlights the advantages of regional coupled models for the simulation of the South American climate, as the ocean-atmosphere interaction is of utmost importance for the circulation mechanisms that determine the climate of the region.

Regional winds are caused by small-scale pressure differences in a way that important air flows can arise in a very small and specific region. Sometimes an orographic feature, such as a channel like the Ebro Valley or the Strait of Gibraltar, lead the wind, due to mass conservation, to acquire a certain specific range of directions and considerable speed. For some regional winds in the Iberian Peninsula, such as Cierzo, Levante and Poniente, there are quantitative works on their properties through high-resolution reanalyses, but their possible changes under the influence of climate change have not been studied with models. This work proposes to investigate the capacity of several climate models, validated against reanalysis, to study Cierzo, Levante and Poniente main characteristics in the common period 1995-2011. To this end, regional wind algorithms to detect the flows have been proposed. Three models (REMO, MPIOM-REMO and CNRM-RCSM4) have been selected based on evaluation results. Then, a study of Cierzo, Levante and Poniente future changes under RCP 8.5 emissions scenario (2006-2099) has been carried out. This has been compared with its historical period (1950-2005). Results suggest that spatial resolution is key to detecting these winds, especially in inland flows such as Cierzo, but that the internal physics of each model are also a source of variation beyond 10-km spatial resolution. Low temporal resolutions introduce errors in regional wind days calculation, while coupling effects will depend on each flow. In general, all models are capable of simulating historical Cierzo (100-130 days), Levante and Poniente (150-160 days) frequencies similar to observations. Trend study suggests that Cierzo extension could decrease by 1.5% in a statistically significant manner by the end of the century. Results also show a strong increase of 10-20 annual Levante events depending on the model. Levante extension will vary significantly, although the models do not agree on trend sign. Poniente shows a weakening of its characteristics for all models. Specifically, a decrease in the number of annual Poniente events of 5-20 days is detected.

Interannual oscillations in the surface temperature of the Arctic Ocean and the North Atlantic with the southern boundary (instead “border”) at latitude 55° 25′ N between 1949 and 2007 are investigated based on the MPIOM (Max Planck Institute Ocean Model) solution. It is a free surface ocean model based on primitive equations in the Boussinesq and incompressibility approximations. High-resolution spectra were estimated via fast Fourier transform with a maximum resolution (Welch’s method). Factor analysis method, which makes it possible to identify areas with highly correlated oscillations and reduce the study of the characteristics in question to their analysis in local points, is used to minimize the significant amount of the initial information about monthly average sea surface temperature fields. Аnalysis of the main factors made it possible to identify 10 areas with quasi-synchronous variability of temperature anomalies by including the points correlated with relevant factors with correlation exceeding 0.6. Spectral structure compliance classification revealed that the areas of the Chukchi Sea, the Hudson Bay, the Irminger Sea, and the Labrador Sea have oscillation peak similarities for the periods of 5–6 years and 8–9 years. Central and western areas of the Norwegian Sea, the area affected by the North Atlantic Current, the eastern part of the Norwegian Sea, and some areas of the Kara Sea have similar spectral structure defined by the peaks at the 11-year and 6-year periods. The Baffin Bay with two main peaks at the 16-year and 5–6-year periods, and the central and the western parts of the Barents Sea, where oscillations are similar to the ones in the Chukchi Sea at short periods, and to the ones in the south-eastern part of the Barents Sea and in the eastern part of the Norwegian Sea at 7–8-year periods, stand out significantly. In some cases, spectrum peaks in different areas appear shifted and attenuated, so presumably the frequency characteristics of the temperature signal change as it moves across the water area.