Ocean Science最新文献

{"title":"Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model","authors":"T. Kostadinov, L. Robertson Lain, C. Kong, Xiaodong Zhang, S. Maritorena, S. Bernard, H. Loisel, D. Jorge, E. Kochetkova, Shovonlal Roy, B. Jonsson, V. Martinez-Vicente, S. Sathyendranath","doi":"10.5194/os-19-703-2023","DOIUrl":"https://doi.org/10.5194/os-19-703-2023","url":null,"abstract":"Abstract. The particle size distribution (PSD) of suspended particles in near-surface seawater is a key property linking biogeochemical and ecosystem characteristics with optical properties that affect ocean color remote sensing. Phytoplankton size affects their physiological characteristics and ecosystem and biogeochemical roles, e.g., in the biological carbon pump, which has an important role in the global carbon cycle and thus climate. It is thus important to develop capabilities for measurement and predictive understanding of the structure and function of oceanic ecosystems, including the PSD, phytoplankton size classes (PSCs), and phytoplankton functional types (PFTs). Here, we present an ocean color satellite algorithm for the retrieval of the parameters of an assumed power-law PSD. The forward optical model considers two distinct particle populations: phytoplankton and non-algal particles (NAPs). Phytoplankton are modeled as coated spheres following the Equivalent Algal Populations (EAP) framework, and NAPs are modeled as homogeneous spheres. The forward model uses Mie and Aden–Kerker scattering computations, for homogeneous and coated spheres, respectively, to model the total particulate spectral backscattering coefficient as the sum of phytoplankton and NAP backscattering. The PSD retrieval is achieved via spectral angle mapping (SAM), which uses backscattering end-members created by the forward model. The PSD is used to retrieve size-partitioned absolute and fractional phytoplankton carbon concentrations (i.e., carbon-based PSCs), as well as particulate organic carbon (POC), using allometric coefficients. This model formulation also allows the estimation of chlorophyll a concentration via the retrieved PSD, as well as percent of backscattering due to NAPs vs. phytoplankton. The PSD algorithm is operationally applied to the merged Ocean Colour Climate Change Initiative (OC-CCI) v5.0 ocean color data set. Results of an initial validation effort are also presented using PSD, POC, and picophytoplankton carbon in situ measurements. Validation results indicate the need for an empirical tuning for the absolute phytoplankton carbon concentrations; however these results and comparison with other phytoplankton carbon algorithms are ambiguous as to the need for the tuning. The latter finding illustrates the continued need for high-quality, consistent, large global data sets of PSD, phytoplankton carbon, and related variables to facilitate future algorithm improvements.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82984244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving sea surface temperature in a regional ocean model through refined sea surface temperature assimilation","authors":"S. C. Iversen, A. Sperrevik, O. Goux","doi":"10.5194/os-19-729-2023","DOIUrl":"https://doi.org/10.5194/os-19-729-2023","url":null,"abstract":"Abstract. Infrared (IR) and passive microwave (PMW) satellite sea surface temperature (SST) retrievals are valuable to assimilate into high-resolution regional ocean forecast models. Still, there are issues related to these SSTs that need to be addressed to achieve improved ocean forecasts. Firstly, satellite SST products tend to be biased. Assimilating SSTs from different providers can thus cause the ocean model to receive inconsistent information. Secondly, while PMW SSTs are valuable for constraining models during cloudy conditions, the spatial resolution of these retrievals is rather coarse. Assimilating PMW SSTs into high-resolution ocean models will spatially smooth the modeled SST and consequently remove finer SST structures. In this study, we implement a bias correction scheme that corrects satellite SSTs before assimilation. We also introduce a special observation operator, called the supermod operator, into the Regional Ocean Modeling System (ROMS) four-dimensional variational data assimilation algorithm. This supermod operator handles the resolution mismatch between the coarse observations and the finer model. We test the bias correction scheme and the supermod operator using a setup of ROMS covering the shelf seas and shelf break off Norway. The results show that the validation statistics in the modeled SST improve if we apply the bias correction scheme. We also find improvements in the validation statistics when we assimilate PMW SSTs in conjunction with the IR SSTs. However, our supermod operator must be activated to avoid smoothing the modeled SST structures on spatial scales smaller than twice the PMW SST footprint. Both the bias correction scheme and the supermod operator are easy to apply, and the supermod operator can easily be adapted for other observation variables.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76547396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal and El Niño–Southern Oscillation-related ocean variability in the Panama Bight","authors":"Rafael R. Torres, Estefanía Giraldo, Cristian Muñoz, A. Caicedo, I. Hernández‐Carrasco, A. Orfila","doi":"10.5194/os-19-685-2023","DOIUrl":"https://doi.org/10.5194/os-19-685-2023","url":null,"abstract":"Abstract. In the Panama Bight, two different seasonal surface circulation patterns\u0000coincide with a strong mean sea level variation, as observed from 27 years\u0000of absolute dynamic topography (ADT) and the use of self-organizing maps.\u0000From January to April, a cyclonic gyre with a strong southwestward Panama\u0000Jet Surface Current (PJSC) dominates the basin circulation, forced by the\u0000Panama surface wind jet that also produces upwelling, reducing sea surface\u0000temperature (SST), increasing sea surface salinity (SSS) and causing an ADT\u0000decrease. From June to December, the Choco surface wind jet enhances SST,\u0000precipitation and river runoff, which reduces SSS, causing an ADT rise, which in turn forces a weak circulation in the bight, vanishing the PJSC. Interannual\u0000variability in the region is strongly affected by El Niño–Southern Oscillation (ENSO); however this\u0000climatic variability does not modify the seasonal circulation patterns in\u0000the Panama Bight. In contrast, the positive (negative) ENSO phase increases\u0000(decreases) SST and ADT in the Panama Bight, with a mean annual difference\u0000of 0.9 ∘C and 9.6 cm, respectively, between the two conditions,\u0000while its effect on SSS is small. However, as the strong seasonal SST, SSS\u0000and ADT ranges are up to 2.2 ∘C, 2.59 g kg−1 and 28.3 cm,\u0000the seasonal signal dominates over interannual variations in the bight.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77361652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica","authors":"E. Darelius, Vår Dundas, M. Janout, Sandra Tippenhauer","doi":"10.5194/os-19-671-2023","DOIUrl":"https://doi.org/10.5194/os-19-671-2023","url":null,"abstract":"Abstract. Around most of Antarctica, the Circumpolar Deep Water (CDW) shows a warming trend. At the same time, the thermocline is shoaling, thereby increasing the potential for CDW to enter the shallow continental shelves and ultimately increase basal melt in the ice shelf cavities that line the coast. Similar trends, on the order of 0.05 ∘C and 3 m per decade, have been observed in the Warm Deep Water (WDW), the slightly cooled CDW derivative found at depth in the Weddell Sea.\u0000Here, we report on a sudden, local increase in the temperature maximum of the WDW above the continental slope north of the Filchner Trough (74∘ S, 25–40∘ W), a region identified as a hotspot for both Antarctic Bottom Water formation (AABW) and potential changes in the flow of WDW towards the large Filchner–Ronne Ice Shelf. New conductivity–temperature–depth profiles, obtained in summer 2021, and recent (2017–2021) mooring records show that the temperature of the warm-water core increased by about 0.1 ∘C over the upper part of the slope (700–2750 m depth) compared with historical (1973–2018) measurements. The temperature increase occurred relatively suddenly in late 2019 and was accompanied by an unprecedented (in observations) freshening of the overlying winter water.\u0000The AABW descending down the continental slope from Filchner Trough is sourced by dense ice shelf water and consists to a large degree (60 %) of entrained WDW. The observed temperature increase can hence be expected to imprint directly on deep-water properties, increasing the temperature of newly produced bottom water (by up to 0.06 ∘C) and reducing its density.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75201527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-model analysis of the Adriatic dense-water dynamics","authors":"Petra Pranić, C. Denamiel, I. Janeković, I. Vilibić","doi":"10.5194/os-19-649-2023","DOIUrl":"https://doi.org/10.5194/os-19-649-2023","url":null,"abstract":"Abstract. This study aims to enhance our understanding of the bora-driven dense-water\u0000dynamics in the Adriatic Sea using different state-of-the-art modelling\u0000approaches during the 2014–2015 period. Practically, we analyse and compare\u0000the results of the following four different simulations: the latest reanalysis product for\u0000the Mediterranean Sea, a recently evaluated fine-resolution atmosphere–ocean\u0000Adriatic Sea climate model, and a long-time-running Adriatic Sea\u0000atmosphere–ocean forecast model used in both hindcast and data assimilation\u0000(with 4 d cycles) modes. As a first step, we evaluate the resolved physics\u0000in each simulation by focusing on the performance of the models. Then, we\u0000derive the general conditions in the ocean and the atmosphere during the\u0000investigated period. Finally, we analyse in detail the numerical\u0000reproduction of the dense-water dynamics as seen by the four simulations.\u0000The likely prerequisites for proper modelling of the ocean circulation in\u0000the Adriatic basin, including a kilometre-scale atmosphere–ocean approach,\u0000non-hydrostatic atmospheric models, fine vertical resolutions in both\u0000atmosphere and ocean, and the location and forcing of the open boundary\u0000conditions, are thus discussed in the context of the different simulations.\u0000In conclusion, a 31-year-long run of the fine-resolution Adriatic Sea\u0000climate model is found to be able to outperform most aspects of the\u0000reanalysis product, the short-term hindcast, and the data-assimilated\u0000simulation in reproducing the dense-water dynamics in the Adriatic Sea.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78276333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of the sea surface temperature to heatwaves during the France 2022 meteorological summer","authors":"T. Guinaldo, A. Voldoire, R. Waldman, S. Saux Picart, H. Roquet","doi":"10.5194/os-19-629-2023","DOIUrl":"https://doi.org/10.5194/os-19-629-2023","url":null,"abstract":"Abstract. The summer of 2022 was memorable and record-breaking, ranking as the second hottest summer in France since 1900, with a seasonal surface air temperature average of 22.7 ∘C. In particular, France experienced multiple record-breaking heatwaves during the meteorological summer. As the main heat reservoir of the Earth system, the oceans are at the forefront of events of this magnitude which enhance oceanic disturbances such as marine heatwaves (MHWs). In this study, we investigate the sea surface temperature (SST) of French maritime basins using remotely sensed measurements to track the response of surface waters to the atmospheric heatwaves and determine the intensity of such feedback. Beyond the direct relationship between SSTs and surface air temperatures, we explore the leading atmospheric parameters affecting the upper-layer ocean heat budget.\u0000Despite some gaps in data availability, the SSTs measured during the meteorological summer of 2022 were record-breaking, the mean SST was between 1.3 and 2.6 ∘C above the long-term average (1982–2011), and the studied areas experienced between 4 and 22 d where the basin-averaged SSTs exceeded the maximum recorded basin-averaged SSTs from 1982 to 2011. We found a significant SST response during heatwave periods with maximum temperatures measured locally at 30.8 ∘C in the north-western Mediterranean Sea.\u0000Our results show that in August 2022 (31 July to 13 August), France experienced above-average surface solar radiation correlated with below-average total cloud cover and negative wind speed anomalies. Our attribution analysis based on a simplified mixed-layer heat budget highlights the critical role of ocean–atmosphere fluxes in initiating abnormally warm SSTs, while ocean mixing plays a crucial role in the cessation of such periods. We find that the 2 m temperatures and specific humidity that are consistently linked to the advection of warm and moist air masses are key variables across all the studied regions. Our results reveal that the influence of wind on heatwaves is variable and of secondary importance. Moreover, we observe that the incident solar radiation has a significant effect only on the Bay of Biscay (BB) and the English Channel (EC) areas. Our study findings are consistent with previous research and demonstrate the vulnerability of the Mediterranean Sea to the increasing frequency of extreme weather events resulting from climate change. Furthermore, our investigation reveals that the recurring heatwave episodes during the summer of 2022 had an undeniable impact on all the surveyed maritime areas in France.\u0000Our study therefore provides valuable insights into the complex mechanisms underlying the ocean–atmosphere interaction and demonstrates the need for an efficient and sustainable operational system combining polar-orbiting and geostationary satellites to monitor the alterations that threaten the oceans in the context of climate change.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88737063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extension of the general unit hydrograph theory for the spread of salinity in estuaries","authors":"H. Cai, Bo Li, Junhao Gu, T. Zhao, E. Garel","doi":"10.5194/os-19-603-2023","DOIUrl":"https://doi.org/10.5194/os-19-603-2023","url":null,"abstract":"Abstract. From both practical and theoretical perspectives, it is\u0000essential to be able to express observed salinity distributions in terms of\u0000simplified theoretical models, which enable qualitative assessments to be\u0000made in many problems concerning water resource utilization (such as intake\u0000of fresh water) in estuaries. In this study, we propose a general and\u0000analytical salt intrusion model inspired by Guo's general unit hydrograph\u0000theory for flood hydrograph prediction in a watershed. To derive a simple,\u0000general and analytical model of salinity distribution, we first make four\u0000hypotheses on the longitudinal salinity gradient based on empirical\u0000observations; we then derive a general unit hydrograph for the salinity\u0000distribution along a partially mixed or well-mixed estuary. The newly\u0000developed model can be well calibrated using a minimum of three salinity\u0000measurements along the estuary axis and does converge towards zero when the\u0000along-estuary distance approaches infinity asymptotically. The theory has\u0000been successfully applied to reproduce the salt intrusion in 21 estuaries\u0000worldwide, which suggests that the proposed method can be a useful tool for\u0000quickly assessing the spread of salinity under a wide range of riverine and\u0000tidal conditions and for quantifying the potential impacts of\u0000human-induced and natural changes.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80674058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origins of mesoscale mixed-layer depth variability in the Southern Ocean","authors":"Yu Gao, I. Kamenkovich, Natalie Perlin","doi":"10.5194/os-19-615-2023","DOIUrl":"https://doi.org/10.5194/os-19-615-2023","url":null,"abstract":"Abstract. Mixed-layer depth (MLD) exhibits significant variability, which is important for atmosphere–ocean exchanges of heat and atmospheric gases. The origins of the mesoscale MLD variability in the Southern Ocean are studied here in an idealised regional ocean–atmosphere model (ROAM). The main conclusion from the analysis of the upper-ocean buoyancy budget is that, while the atmospheric forcing and oceanic vertical mixing, on average, induce the mesoscale variability of MLD, the three-dimensional oceanic advection of buoyancy counteracts and partially balances these atmosphere-induced vertical processes. The relative importance of advection changes with both season and average MLD. From January to May, when the mixed layer is shallow, the atmospheric forcing and oceanic mixing are the most important processes, with the advection playing a secondary role. From June to December, when the mixed layer is deep, both atmospheric forcing and oceanic advection are equally important in driving the MLD variability. Importantly, buoyancy advection by mesoscale ocean current anomalies can lead to both local shoaling and deepening of the mixed layer. The role of the atmospheric forcing is then directly addressed by two sensitivity experiments in which the mesoscale variability is removed from the atmosphere–ocean heat and momentum fluxes. The findings confirm that mesoscale atmospheric forcing predominantly controls MLD variability in summer and that intrinsic oceanic variability and surface forcing are equally important in winter. As a result, MLD variance increases when mesoscale anomalies in atmospheric fluxes are removed in winter, and oceanic advection becomes a dominant player in the buoyancy budget. This study highlights the importance of oceanic advection and intrinsic ocean dynamics in driving mesoscale MLD variability and underscores the importance of MLD in modulating the effects of advection on upper-ocean dynamics.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79655514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical processes and biological productivity in the upwelling regions of the tropical Atlantic","authors":"P Brandt, G. Alory, F. M. Awo, M. Dengler, S. Djakouré, Rodrigue Anicet Imbol Koungue, J. Jouanno, Mareike Körner, Marisa Roch, M. Rouault","doi":"10.5194/os-19-581-2023","DOIUrl":"https://doi.org/10.5194/os-19-581-2023","url":null,"abstract":"Abstract. In this paper, we review observational and modelling results on the\u0000upwelling in the tropical Atlantic between 10∘ N and 20∘ S. We focus on the physical processes that drive the seasonal variability of\u0000surface cooling and the upward nutrient flux required to explain the seasonality\u0000of biological productivity. We separately consider the equatorial upwelling\u0000system, the coastal upwelling system of the Gulf of Guinea and the tropical\u0000Angolan upwelling system. All three tropical Atlantic upwelling systems have\u0000in common a strong seasonal cycle, with peak biological productivity during\u0000boreal summer. However, the physical processes driving the upwelling vary\u0000between the three systems. For the equatorial regime, we discuss the wind\u0000forcing of upwelling velocity and turbulent mixing, as well as the underlying\u0000dynamics responsible for thermocline movements and current structure. The\u0000coastal upwelling system in the Gulf of Guinea is located along its northern\u0000boundary and is driven by both local and remote forcing. Particular emphasis\u0000is placed on the Guinea Current, its separation from the coast and the shape\u0000of the coastline. For the tropical Angolan upwelling, we show that this\u0000system is not driven by local winds but instead results from the combined\u0000effect of coastally trapped waves, surface heat and freshwater fluxes, and\u0000turbulent mixing. Finally, we review recent changes in the upwelling systems\u0000associated with climate variability and global warming and address possible\u0000responses of upwelling systems in future scenarios.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79595636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling the barotropic sea level in the Mediterranean Sea using data assimilation","authors":"M. Bajo, C. Ferrarin, G. Umgiesser, A. Bonometto, E. Coraci","doi":"10.5194/os-19-559-2023","DOIUrl":"https://doi.org/10.5194/os-19-559-2023","url":null,"abstract":"Abstract. This paper analyses the variability of the sea level barotropic components in the Mediterranean Sea and their\u0000reproduction using a hydrodynamic model with and without data assimilation.\u0000The impact of data assimilation is considered both in reanalysis and short-forecast simulations.\u0000We used a two-dimensional finite element model paired with an ensemble Kalman\u0000filter, which assimilated hourly sea level data from 50 stations in the Mediterranean basin. The\u0000results brought about a significant improvement given by data assimilation in the reanalysis of\u0000the astronomical tide, the surge, and the barotropic total sea level, even in coastal areas\u0000and far from the assimilated stations (e.g. the southeastern Mediterranean Sea).\u0000As with the reanalysis simulations, the forecast simulations, which start from analysis states,\u0000improve, especially on the first day (37 % average error reduction) and when\u0000seiche oscillations are triggered.\u0000Since seiches are free barotropic oscillations that depend only on the initial state, their\u0000reproduction improves very effectively with data assimilation. Finally, we estimate the\u0000periods and the energy of these oscillations by means of spectral analysis, both in the Adriatic Sea,\u0000where they have been extensively studied, and in the Mediterranean Sea, where the present\u0000documentation is scarce. While the periods are well reproduced by the model even without\u0000data assimilation, their energy shows a good improvement when using it.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77822810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}