Sea-level Field Research Articles

Space Panoramic Radio Altimeter Model: Imaging of the Developing Tsunami Wave Field in a Bistatic Quasi-Mirror Radar

A model of the formation of the gradient sea-level field by the space bi-static radar measurements is developed. An interferometer radar with cross-sectional base is used as a receiver. The relatively small antenna 5–10 m of cross-sectional base gives a huge gain in energy when working for quasi-mirror scattering in the range of short wind waves. The efficiency of the system is evaluated by converting the dynamical model of tsunami wave evolution for the case of the Kuril earthquake (October 4, 1994) into a panoramic radar image of the sea level. The panoramic image of the front wave allows predicting the direction, amplitude and, finally, the expected time of tsunami arrival to a given point. The obtained radar image confirms the main feature of the quasi-mirror method: the fluctuation-level sensitivity varies within the radar swath (~2000 km) and is the worst near the mirror point. For the chosen radar parameters, the average sensitivity in the swath is ~5 cm for a site (15 × 15) km. Without accounting the time required to transmit information from the receiver to the tsunami–prone sites, the minimal time interval between the appearance of the wave front and the tsunami alert is determined by the number of sequentially launched small tandem spacecrafts. For a single tandem this time is about 45 min.

Next generation of Bluelink ocean reanalysis with multiscale data assimilation: BRAN2020

Abstract. BRAN2020 (2020 version of the Bluelink ReANalysis) is an ocean reanalysis that combines observations with an eddy-resolving, near-global ocean general circulation model to produce a four-dimensional estimate of the ocean state. The data assimilation system employed is ensemble optimal interpolation, implemented with a new multiscale approach that constrains the broad-scale ocean properties and the mesoscale circulation in two steps. There is a separation in the scales that are corrected in the two steps: the high-resolution step corrects the mesoscale dynamics in the same way as previous versions of BRAN, while the extra coarse step is effective at correcting biases that develop at large scales. The reanalysis currently spans January 1993 to December 2019 and assimilates observations of in situ temperature and salinity, as well as of satellite sea-level anomaly and sea surface temperature. BRAN2020 is planned to be updated to within months of real time after this initial release, until an updated version of BRAN is available. Reanalysed fields from BRAN2020 generally show much closer agreement to observations than all previous versions with misfits between reanalysed and observed fields reduced by over 30 % for some variables, for subsurface temperature and salinity in particular. The BRAN2020 dataset is comprised of daily averaged fields of temperature, salinity, velocity, mixed-layer depth and sea level. Reanalysed fields realistically represent all of the major current systems within 75∘ S and 75∘ N, excluding processes relating to sea ice but including boundary currents, equatorial circulation, Southern Ocean variability and mesoscale eddies. BRAN2020 is publicly available at https://doi.org/10.25914/6009627c7af03 (Chamberlain et al., 2021b) and is intended for use by the research community.

Performance of the Adriatic early warning system during the multi-meteotsunami event of 11–19 May 2020: an assessment using energy banners

Abstract. This study quantifies the performance of the Croatian meteotsunami early warning system (CMeEWS) composed of a network of air pressure and sea level observations, a high-resolution atmosphere–ocean modelling suite, and a stochastic surrogate model. The CMeEWS, which is not operational due to a lack of numerical resources, is used retroactively to reproduce the multiple events observed in the eastern Adriatic between 11 and 19 May 2020. The performances of the CMeEWS deterministic models are then assessed with an innovative method using energy banners based on temporal and spatial spectral analysis of the high-pass-filtered air pressure and sea level fields. It is found that deterministic simulations largely fail to forecast these extreme events at endangered locations along the Croatian coast, mostly due to a systematic northwestward shift of the atmospheric disturbances. Additionally, the use of combined ocean and atmospheric model results, instead of atmospheric model results only, is not found to improve the selection of the transects used to extract the atmospheric parameters feeding the stochastic meteotsunami surrogate model. Finally, in operational mode, the stochastic surrogate model would have triggered the warnings for most of the observed events but also set off some false alarms. Due to the uncertainties associated with operational modelling of meteotsunamigenic disturbances, the stochastic approach has thus proven to overcome the failures of the deterministic forecasts and should be further developed.

A Relocatable Ocean Modeling Platform for Downscaling to Shelf-Coastal Areas to Support Disaster Risk Reduction

High-impact ocean weather events and climate extremes can have devastating effects on coastal zones and small islands. Marine Disaster Risk Reduction (DRR) is a systematic approach to such events, through which the risk of disaster can be identified, assessed and reduced. This can be done by improving ocean and atmosphere prediction models, data assimilation for better initial conditions and developing an efficient and sustainable impact forecasting methodology for Early Warnings Systems. A common user request during disaster remediation actions is for high-resolution information, which can be derived from easily deployable numerical models nested into operational larger-scale ocean models. The Structured and Unstructured Relocatable Ocean Model for Forecasting (SURF) enables users to rapidly deploy a nested high-resolution numerical model into larger-scale ocean forecasts. Rapidly downscaling the currents, sea level, temperature, and salinity fields is critical in supporting emergency responses to extreme events and natural hazards in the world’s oceans. The most important requirement in a relocatable model is to ensure that the interpolation of low-resolution ocean model fields (analyses and reanalyses) and atmospheric forcing is tested for different model domains. The provision of continuous ocean circulation forecasts through the Copernicus Marine Environment Monitoring Service (CMEMS) enables this testing. High-resolution SURF ocean circulation forecasts can be provided to specific application models such as oil spill fate and transport models, search and rescue trajectory models, and ship routing models requiring knowledge of meteo-oceanographic conditions. SURF was used to downscale CMEMS circulation analyses in four world ocean regions, and the high-resolution currents it can simulate for specific applications are examined. The SURF downscaled circulation fields show that the marine current resolutions affect the quality of the application models to be used for assessing disaster risks, particularly near coastal areas where the coastline geometry must be resolved through a numerical grid, and high-frequency coastal currents must be accurately simulated.

Численное моделирование сгонно-нагонных колебаний в заливе Донузлав (Черное море)

Surge oscillations in the coastal zone of the seas can have a significant impact on the infrastructure and safety of navigation in bays and bays. The purpose of this work is to study the surge oscillations in the Donuzlav Bay located on the western coast of the Crimean Peninsula and connected to the sea by a narrow strait. The Advanced Circulation Model for Shelves Coasts and Estuaries (ADCIRC) is used for this. The numerical algorithm of the model is based on the finite element method using triangular elements and linear basis functions. The input data of the ADCIRC model were the surface wind velocity and atmospheric pressure fields over the Black Sea. Numerical modeling was performed on two nested unstructured grids. The first grid included the entire Black Sea, the second grid included the bay and the adjacent sea area. To graphically display the simulation results, the Generic Mapping Tools (GMT) mapping package was used. Analysis of the simulation results for different wind directions showed that when the wind acts on the water area of the Donuzlav Bay, seiche-like oscillations occur in the fields of sea level and currents. The intensity of these fluctuations is determined by how quickly the wind speed reaches its maximum value. Owing to the narrowness of the strait outside the bay, fluctuations do not appear. Modeling of an extreme storm situation that occurred in the Black Sea on November 11, 2007 was carried out. During the storm, a rapid change in wind direction from southeast to west occurred with a simultaneous increase in wind speed to 15–21 m/s. This caused a rise in sea level at the top of the bay to 0.5 m and an increase in the current velocity in the strait to 0.6 m/s.

Rising sea level and its implications on coastal tourism development in Cape Town, South Africa

While there is agreement among tourism role-players on tourism's potential to contribute to socio-economic and environmental development, the industry is under severe threat from the increased impact of climate variability and change. This study examines the implications of rising sea level on coastal tourism in Cape Town, South Africa. Making use of mean sea level data from permanent sea level markers, remote sensing and field observations, supported by key informant interviews, the study found that coastal tourism is under threat from rising sea level. Current and projected rising sea level, as well as other extreme weather events such as the increased storm intensity trigger massive waves and tides that result in storm surges, which overtop and encroach into the land surface area. At least 80% of the city's 2019/2020 Blue Flag beaches are now under threat from rising sea level and coastal erosion. The study also found that some of the iconic tourist attractions such as the Cape Point, V&A Waterfront, Robben Island and several beaches along the False Bay area are under the same threat. Other tourism facilities under threat of weather extremes from climate change include servitudes, coastal roads, railway facilities and tidal pools: all threatening the attractiveness of some resorts. Management implicationsRising sea level is a huge challenge that requires innovative solutions for the city of Cape Town. Given the threat that the industry is facing, there is a need for a public-private partnership aimed at ensuring that there are sufficient resources to help the tourism sector is capable of adapting to climate change. Increase insurance cover is a must to protect businesses from anticipated increased damage from rising sea levels and associated weather extreme events. Continued risk assessment is a must to ensure the industry is abreast with the continued changes which are threats to coastal tourism resorts and infrastructure.

Modelling seasonal and intraseasonal variations of circulation,temperature, salinity and sea level in the Bellingshausen Seaand on the Antarctic Peninsula shelf

The objective of the study is to simulate using numerical methods the seasonal and intraseasonal variations of circula-tion, sea level, temperature and salinity in the Bellingshausen Sea and on the shelf of the western part of the Antarctic Penin-sula (WAP). The Semi-implicit Cross-scale Hydroscience Integrated System Model with an unstructured triangular horizontal grid and a vertical local sigma coordinate system and ice dynamic-thermodynamic Finite-Element Sea Ice Model were applied. Heat, momentum and salt fluxes were set on the ocean surface using the ERA5 reanalysis data. At the open boundaries, the vertical distribution of temperature and salinity was determined according to the COPERNICUS reanalysis. At the western open boundary of the computational domain, the vertical distribution of velocity of currents from COPERNICUS was also specified, whereas at the open eastern boundary the level deviations were specified. Time variability analysis of sea level wasperformed using wavelet analysis. The results of modelling of the sea level, temperature, and salinity fields for 2014–2015 were compared with the available observational data on the shelf of the WAP, including data from the Ukrainian Antarctic Expedition. The simulated horizontal and vertical distributions of the subsurface layer with minimum of potential temperature Tmin (Winter Water) are given. The depth of the Tmin varies in the range of 10–100 m increasing to the north. The values of minimum of po-tential temperature Tmin also increase to the north from –1.8 to 1.2 °C. The intraseasonal oscillations of sea level computed by the model for 2014—2015 were analysed together with data of observations at the tidal stations Faraday/Akademik Vernadsky and Rothera located at the coast of WAP. In the range 1–150 days the largest amplitudes of the level scalegrams were found for a period of approximately 100 days in 2014 and 120 days in 2015 at both stations. The largest amplitudes of modelled level scale-grams were observed with a period of approximately 88 days in 2014 and 80 days in 2015 at both stations. The largest amplitudesof scalegrams for Antarctic Oscillation (AAO) were found for a period of 105 days in 2014 and 123 days in 2015. The corresponding correlation coefficients between observed sea level scalegrams and AAO for 2014 were 0.84 and 0.86, respectively, whereas for 2015 they were 0.87 and 0.90, respectively. It was concluded that the relationship between intraseasonal processes in the ocean in West Antarctica and AAO existed at a time scale of about 100 days.

Sensitivity of results of Black Sea level modeling to the choice of boundary conditions on the free surface

This work is devoted to an analysis of the influence of sea surface boundary conditions on results of Black Sea level modeling. Two numerical experiments are carried out by using a z-coordinate model of the Marine Hydrophysical Institute, RAS. A linear kinematic condition on the free surface is used for calculating a level rise in the first experiment and a nonlinear one – in the second experiment. The analysis shows that both experiments reconstruct the Black Sea surface dynamics in accordance with altimetry data. It is found that the sea level near the western boundary of the basin decreases under the nonlinear kinematic condition in cases of storm winds. The greatest differences in the structure of the sea level fields are observed during weakening of the RIM Current in the evolution zones of Sevastopol and Batumi anticyclones. The minimal and maximal values of the level are almost identical in both experiments, but the locations do not match. The discrepancies in the spatial positions of raising/lowering levels are due to a mismatch in the motion phases of anticyclones and mesoscale eddies along the periphery of the RIM Current.

Putnikovye dannye dlya issledovaniya dinamiki poverkhnostnogo sloya Chernogo morya: al'timetriya na regulyarnoy setke i IK-izobrazheniya vysokogo razresheniya

Purpose. During more than 20 years, very detailed notions of the sea level variability in the World Ocean and its particular parts have been obtained based on satellite altimetry observations. Their advantage consists in possibility of a fairly rapid assessment of the surface currents’ velocities at synoptic scales. The alternative method for studying surface dynamics is estimation of the motions using a sequence of visible/infrared (IR) satellite images of the sea surface. The purpose of the present study is to compare the results obtained from application of two described methods used to analyze general circulation of the Black Sea surface layer. Methods and Results. The structure of the current fields in the northwestern Black Sea in winter, 1999 is investigated using the results of analysis of the IR image sequence from the NOAA/AVHRR sensors, as well as the gridded sea level anomaly data (processing level L4) and the along-track measurements (level processing L3) from the Copernicus Marine Environment Monitoring Service. The surface currents’ velocities are estimated based on the sea level field, which is calculated using two versions of mean dynamic topography. To compare the gridded altimetry and the results of the image sequence processing, a simple procedure is proposed for reconstructing the sea level using the current velocities’ components. The results of reconstructing the surface circulation features by two methods were compared and demonstrated, in particular, the anticyclonic eddy locations in the northwestern part of the Black Sea. It is noted that the locations of the eddy center in the sea level fields reconstructed from the altimetry data and by processing of the IR image sequence are different. Evolution of the eddy is investigated using the sea level anomaly data. It is shown that its motion is rather intermittent in time that can be a result of applying the procedure of optimal interpolation. Conclusions. It is noted that the gridded satellite altimetry product from the CMEMS, being applied to the Black Sea basin, should be used with due regard for the provided information on the mapping errors.

Basin- to mesoscale surface circulation of the Western Mediterranean manifested by satellite-derived data products

In this article, there is an overview of the potential of different (mostly altimetry-derived) products for manifesting features of basin- and mesoscale circulation of the Western Mediterranean Basin. In terms of detection of mesoscale eddies and larger gyres, the comparison was performed between eddy statistics extracted directly from fields of sea surface temperature (SST), on the one hand, and reconstructed from different scalar and vector altimetry-derived fields, on the other hand. Among the products being analysed, there are fields of (i) sea level anomaly (SLA), (ii) geostrophic currents, and (iii) finite size Lyapunov exponents (FSLE). Comparison of the eddy statistics provided by such different data sources revealed that altimetry-based techniques tended to overestimate the number of big cyclones and thus failed to reproduce cyclonic/anticyclonic eddy asymmetry which was shown by fields of SST. Defining the spatial scale of eddies via altimetry-based techniques seemed particularly problematic. FSLE product analysed in the study showed significant disagreements with vortical structures observed in fields of SST both in terms of the spatial scale and the sign of rotation. In order to scrutinize basin-scale features of surface circulation in the region of interest, fields of (i) geostrophic currents, (ii) total currents reconstructed by the GlobCurrent project, and (iii) surface currents provided by the reanalysis technique were analysed. As a result of the comparison performed, a conclusion was made on the complementarity of the datasets analysed.

Computing complex for modeling the Black Sea

This paper presents a description of a computing complex and results of its use for modeling the Black Sea. The complex is created on the basis of a circulation model and contains blocks of hydrodynamics, energy, and pollutant transport. A numerical experiment is carried out with the Skiron reanalysis data of 2016 as atmospheric forcing. Fields of sea level, velocities of currents, temperature, and salinity are calculated. Comparison of the simulated temperature, salinity, and velocity with contact observations shows good qualitative and quantitative agreement with the in-situ data. The seasonal variability of a basin-scale circulation is reproduced in the velocity field. Mesoscale eddies are reconstructed, and an analysis of the mean current energy and the eddy energy is performed. The most intensive mesoscale variability was observed near the Crimean and Turkish coasts in 2016. The mean current kinetic energy is decreasing during the year, and the formation of mesoscale eddies is associated with baroclinic instability. A test calculation of the radioactive beryllium distribution is also carried out in this experiment. Comparison with real measurements shows that the complex simulates pollutant transport with high degree of accuracy.

Eddies in the Western Mediterranean seen in thermal infrared imagery and SLA fields

ABSTRACTIn this article, daily fields of sea surface temperature (SST) and sea level anomaly (SLA) of the Western Mediterranean Sea obtained in 2011–2013 are being co-analysed. The study is aimed at assessing potentials of the fields of SLA for manifestation of mesoscale eddies in the region of interest. First, the SST imagery was inspected visually and locations of mesoscale eddies noticed in the images were detected. After that, closed contours were extracted in the fields of SLA and their locations were compared with locations of eddies directly seen in the SST images. Such a comparison showed that among anticyclonic eddies found in SST, about 56.3% had corresponding closed contours of SLA; the percentage was increasing with increasing eddy diameter. For cyclonic eddies, supposedly due to their smaller spatial and time scales, such percentage was only about 20.2%. During the warm season, when the mixed layer is particularly shallow and the turbulence is closer to the two-dimensional model, the correspondence between eddies seen in SST and closed contours of SLA was higher than during the cold period.

Bias in Estimates of Global Mean Sea Level Change Inferred from Satellite Altimetry

Estimates of regional and global average sea level change remain a focus of climate change research. One complication in obtaining coherent estimates is that geodetic datasets measure different aspects of the sea level field. Satellite altimetry constrains changes in the sea surface height (SSH; or absolute sea level), whereas tide gauge data provide a measure of changes in SSH relative to the crust (i.e., relative sea level). The latter is a direct measure of changes in ocean volume (and the combined impacts of ice sheet melt and steric effects), but the former is not since it does not account for crustal deformation. Nevertheless, the literature commonly conflates the two estimates by directly comparing them. We demonstrate that using satellite altimetry records to estimate global ocean volume changes can lead to biases that can exceed 15%. The level of bias will depend on the relative contributions to sea level changes from the Antarctic and Greenland Ice Sheets. The bias is also more sensitive to the detailed geometry of mass flux from the Antarctic Ice Sheet than the Greenland Ice Sheet due to rotational effects on sea level. Finally, in a regional sense, altimetry estimates should not be compared to relative sea level changes because radial crustal motions driven by polar ice mass flux are nonnegligible globally.

Euro-Atlantic winter storminess and precipitation extremes under 1.5 °C vs. 2 °C warming scenarios

Abstract. Severe winter storms in combination with precipitation extremes pose a serious threat to Europe. Located at the southeastern exit of the North Atlantic's storm track, European coastlines are directly exposed to impacts by high wind speeds, storm floods and coastal erosion. In this study we analyze potential changes in simulated winter storminess and extreme precipitation, which may occur under 1.5 or 2 ∘C warming scenarios. Here we focus on a first simulation suite of the atmospheric model CAM5 performed within the HAPPI project and evaluate how changes of the horizontal model resolution impact the results regarding atmospheric pressure, storm tracks, wind speed and precipitation extremes. The comparison of CAM5 simulations with different resolutions indicates that an increased horizontal resolution to 0.25∘ not only refines regional-scale information but also improves large-scale atmospheric circulation features over the Euro-Atlantic region. The zonal bias in monthly pressure at mean sea level and wind fields, which is typically found in low-resolution models, is considerably reduced. This allows us to analyze potential changes in regional- to local-scale extreme wind speeds and precipitation in a more realistic way. Our analysis of the future response for the 2 ∘C warming scenario generally confirms previous model simulations suggesting a poleward shift and intensification of the meridional circulation in the Euro-Atlantic region. Additional analysis suggests that this shift occurs mainly after exceeding the 1.5 ∘C global warming level, when the midlatitude jet stream manifests a strengthening northeastward. At the same time, this northeastern shift of the storm tracks allows an intensification and northeastern expansion of the Azores high, leading to a tendency of less precipitation across the Bay of Biscay and North Sea. Regions impacted by the strengthening of the midlatitude jet, such as the northwestern coasts of the British Isles, Scandinavia and the Norwegian Sea, and over the North Atlantic east of Newfoundland, experience an increase in the mean as well as daily and sub-daily precipitation, wind extremes and storminess, suggesting an important influence of increasing storm activity in these regions in response to global warming.

Current variability by wave propagation in Todos Santos Bay, Baja California, Mexico

The temperature, velocity, and sea level fields for a summer climatological month (August) were analyzed using tridimensional and baroclinic model outputs in Todos Santos Bay (TSB), Baja California, Mexico. The numerical model was forced with wind (nonstationary), heat flux, and California Current System climatology on the open boundary. The 3- to 5-day current variability is related to a baroclinic wave traveling towards the northwest of the bay. Wave travel periodicity was due to the release of accumulated water from the Ensenada–Punta Banda Estuary (E–PBE) region. Local wind stress causes southeastward water flow and, given the TSB geometry, water accumulates in the E–PBE region. Weakening wind stress was the main cause of water release. In addition, complex empirical orthogonal function analysis found that outer TSB disturbances cause sea level variability.

Modeling Black Sea circulation with high resolution in the coastal zone

We present a numerical model of Black Sea circulation based on primitive equations with improved spatial resolution in the coastal zone. The model equations are formulated in a two-pole orthogonal coordinate system with arbitrary locations of the poles and a vertical σ coordinate. Increased horizontal resolution is gained by displacing the pole into the vicinity of the separated subdomain. The problem is solved over a grid with a variable step. The northern coordinate pole is displaced to the vicinity of Gelendzhik; the grid step varies from 150 m in the coastal zone to 4.6 km in the main basin. We simulated the fields of currents, sea level, temperature, and salinity under the given atmospheric forcing in 2007. The model is capable of reproducing the large-scale Black Sea circulation and submesoscale variations in the coastal currents.

Tsunami-induced magnetic fields detected at Chichijima Island before the arrival of the 2011 Tohoku earthquake tsunami

Magnetic field disturbances associated with the tsunami caused by the 2011 Tohoku earthquake were observed at Chichijima Island, 1200 km south of the epicenter. The vertical component of the magnetic field showed a periodic signal at approximately 20 min before the tsunami arrived. This study investigated the mechanism of the magnetic field signal using simulation studies. First, we derived a tsunami source model that explained the tide gauge records and sea-level changes at Chichijima Island. Using this model, we then computed the electric current induced by the tsunami and the resulting secondary magnetic field. The computed changes in sea level and magnetic field are consistent with their respective observed waveforms, including the timing of the magnetic field signals. In our interpretation, the tsunami flow induced an electric current along the tsunami wave front, which in turn generated a secondary induced magnetic field ahead of the tsunami wave. Hence, magnetic variations preceding the tsunami were observed at Chichijima Island. This suggests that imminent arrivals of tsunamis can be detected by observations of the magnetic field.

Application of the Multi-Adaptive Regression Splines to Integrate Sea Level Data from Altimetry and Tide Gauges for Monitoring Extreme Sea Level Events

This article determines sea level fields with nonlinear components along the northern coast of Australia using a state-of-the-art approach of the Multi-Adaptive Regression Splines (MARS). The 20 years of data from multi-missions of satellite altimetry (e.g., Topex, Jason-1, Jason-2) and 14 tide gauges are combined to provide a consistent view of sea levels. The MARS is chosen because it is capable of dividing measured sea levels into distinct time intervals where different linear relationships can be identified, and of weighting individual tide gauge according to the importance of their contributions to predicted sea levels. In the study area, the mean R-squared (R2) of 0.62 and Root Mean Squared (RMS) error of 6.73 cm are obtained from modelling sea levels by MARS. The comparison of the MARS with the multiple-regression shows an improved sea level prediction, as MARS can explain 62% of sea level variance while multiple-regression only accounts for 44% of variance. The predicted sea levels during six tropical cyclones are validated against sea level observations at three independent tide-gauge sites. The comparison results show a strong correlation (˜99%) between modelled and observed sea levels, suggesting that the MARS can be used for efficiently monitoring sea level extremes.

Numerical model of the hydrodynamics of the Black Sea and the Sea of Azov with variational initialization of temperature and salinity

A numerical primitive-equation model of the hydrodynamics of the Black Sea and the Sea of Azov in σ-coordinates is proposed. The model has a resolution of ∼4 × 4 km in horizontal coordinates with 40-σ levels in the vertical and includes the four-dimensional variational initialization of temperature and salinity fields. A numerical initialization algorithm combines splitting methods and adjoint equations. Flow, temperature, sea level, and salinity fields driven by atmospheric forcing are calculated for the year 2008. The calculations are made in a variational initialization — prediction regime. Temperature and salinity fields are initialized at the end of each month. The optimality system includes forward and adjoint transport-diffusion equations for heat and salt that are linearized on the assimilation interval. Results of three numerical experiments with different sets of assimilated data in comparison with the prediction obtained from the forward model are discussed.

Effects of tropical instability wave (TIW)-induced surface wind feedback in the tropical Pacific Ocean

Tropical instability waves (TIWs) arise from oceanic instability in the eastern tropical Pacific and Atlantic Oceans, having a clear atmospheric signature that results in coupled atmosphere-ocean interactions at TIW scales. In this study, the extent to which TIW-induced surface wind feedback influences the ocean is examined using an ocean general circulation model (OGCM). The TIW-induced wind stress (sTIW) part is diagnostically determined using an empirical sTIW model from sea surface temperature (SST) fields simulated in the OGCM. The interactively represented TIW wind tends to reduce TIW activity in the ocean and influence the mean state, with largest impacts during TIW active periods in fall and winter. In December, the interactive sTIW forcing induces a surface cooling (an order of -0.1 to -0.3 C), an increased heat flux into the ocean, a shallower mixed layer and a weakening of the South Equatorial Current in the eastern equatorial Pacific. Additionally, the TIW wind effect yields a pronounced latitudinal asymmetry of sea level field across the equator, and a change to upper thermal structure, characterized by a surface cooling and a warming below in the thermocline, leading to a decreased temperature gradient between the mixed layer and the thermocline. Pro- cesses responsible for the sTIW-induced cooling effects are analyzed. Vertical mixing and meridional advection are the two terms in the SST budget that are dominantly affected by the TIW wind feedback: the cooling effect from the vertical mixing on SST is enhanced, with the maximum induced cooling in winter; the warming effect from the meridional advection is reduced in July-October, but enhanced in November-December. Additional experiments are per- formed to separate the relative roles the affected surface momentum and heat fluxes play in the cooling effect on SST. This ocean-only modeling work indicates that the effect of TIW-induced wind feedback is small but not negligible, and may need to be adequately taken into account in large-scale climate modeling.