Journal of Geophysical Research-Oceans最新文献

{"title":"Thirty-One Years of Warming and Oxygen Decline in Massachusetts Bay, a Well-Flushed Non-Eutrophic Temperate Coastal Waterbody","authors":"Daniel L. Codiga,&nbsp;Kenneth E. Keay,&nbsp;P. Scott Libby","doi":"10.1029/2024JC021589","DOIUrl":"https://doi.org/10.1029/2024JC021589","url":null,"abstract":"<p>Warming temperatures and declining oxygen are well-studied in eutrophic coastal systems. To help broaden understanding we investigate non-eutrophic Massachusetts Bay, a representative well-flushed temperate embayment with seasonal thermal stratification, minor river inputs, and residence time of about a month due to exchange with the Gulf of Maine. Long-term trends are computed from de-seasoned measurements over 31 years (1992–2022) at nine bay sites, each sampled at five depths from sea surface to seafloor six times annually. For averages across all stations and depths, the mean warming and oxygen decline rates are +0.0582 (95% C.I. +0.0410 to +0.0759) °C yr⁻¹ and −0.750 (−0.985 to −0.524) μmol kg⁻¹ yr⁻¹ [−0.0246 (−0.0323 to −0.0171) mg L⁻¹ yr⁻¹]. The observed warming reduces oxygen solubility, per seawater properties, at a rate about half the observed oxygen decline. Rates do not differ significantly by site, including near a seafloor outfall releasing treated wastewater effluent, nor at different depths. Because warming is comparable at all depths there is no significant trend in stratification. There is a significant trend of increasing salinity, similarly uniform across sites and depths. A strong hypothesis to explain the warming and salinity trends is advection of Gulf of Maine water into the bay, rather than local influences that could be expected to cause spatially differing rates contrary to those observed. Advection is also a plausible explanation for the observed oxygen decline beyond that due to the solubility decrease. This study highlights potential influence of external ocean forcing on long-term trends in a coastal waterbody.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021589","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the Response of the Labrador Sea to Greenland Meltwater Influx With High-Resolution Eddy-Rich NEMO Simulations","authors":"P. Hoshyar,&nbsp;C. Pennelly,&nbsp;P. G. Myers","doi":"10.1029/2024JC022102","DOIUrl":"https://doi.org/10.1029/2024JC022102","url":null,"abstract":"<p>The Greenland Ice Sheet has undergone substantial mass loss in recent decades primarily due to oceanic and atmospheric warming, contributing to global sea-level rise and enhanced ocean stratification. This study examines the Labrador Sea's response to increased Greenland freshwater influx using a very high-resolution, eddy-rich configuration of the NEMO ocean model. Two 9-year long experiments with identical setups, except one excluding Greenland runoff, suggest that freshwater influx leads to freshwater content increase (by up to 39%) and intensified stratification (enhanced convective resistance by up to 29%) in the Labrador Sea, whereas heat content remains mainly unchanged (up to 6% increase). Strengthened stratification weakens but does not entirely stop deep convection allowing continued water mass formation within the region (maximum mixed layer depth differences of up to 635 m). A sensitivity analysis indicates warmer, saltier surface waters and colder, fresher subsurface layers when Greenland meltwater is excluded likely driven by reduced lateral exchange from the West Greenland Current system and enhanced southward Arctic Water transport across Davis Strait. Offshore freshwater exchange in the Labrador Sea interior is not solely controlled by Greenland meltwater influx but also by air-sea fluxes and deepwater formation. Over longer timescales exceeding a decade, ongoing freshening and intensified stratification could further disrupt essential oceanic processes with potential consequences for deepwater formation and Atlantic Meridional Overturning Circulation. These findings underscore the importance of accurately representing Greenland meltwater and shelf-basin exchanges in models to improve the predictions of Labrador Sea under future warming.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022102","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics and Fluxes of Vertical and Lateral Particles in the Mesopelagic Northern South China Sea","authors":"Ziming Fang,&nbsp;Zeheng Lin,&nbsp;Binbin Guo,&nbsp;Weifeng Yang,&nbsp;Danyi Su,&nbsp;Mengya Chen,&nbsp;Andi Xu,&nbsp;Qianyong Liang","doi":"10.1029/2024JC022311","DOIUrl":"https://doi.org/10.1029/2024JC022311","url":null,"abstract":"<p>The lateral transport of sediments from the shelf to the ocean interior is ubiquitous on continental margins, exerting great impacts on the characteristics and flux of sinking particles in the mesopelagic ocean. In this study, we determined the biogenic components and stable carbon isotopes in sinking particles collected from the slope of the northern South China Sea using a time series sediment trap. Laterally derived particulate organic carbon (POC_lateral), which originated primarily from marine sources, as indicated by the ratio of POC to particulate nitrogen ratio and POC-δ¹³C, accounted for 31 ± 3% of the total POC flux during the one-and-a-half-year deployment. High fluxes of POC_lateral occurred in April and May 2021, comprising 69 ± 12% and 53 ± 9% of the total POC flux, respectively. This was likely due to the lateral input of shelf sediments entrained by a westward anticyclonic eddy. These allochthonous particles were mainly composed of small (&lt;53 μm) sediments and were depleted in biogenic components, such as POC and biogenic silica (bSi). In contrast, the flux of vertically derived POC (POC_vertical), that is, local biogenic POC, was strongly correlated with the surface Chl-<i>a</i> concentration (<i>R</i>² = 0.62, <i>p</i> &lt; 0.001) and bSi flux (<i>R</i>² = 0.83, <i>p</i> &lt; 0.001), indicating that the POC_vertical flux in the mesopelagic zone was governed by both primary productivity and the growth of diatoms, with the latter being the main controlling factor. Our results highlight that the POC_vertical flux was controlled by the seasonal variations in primary productivity and the phytoplankton community structure, whereas the POC_lateral flux was closely linked to hydrodynamic processes, such as mesoscale eddies.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Marine Heatwaves in the East Australian Current Modulated by Mesoscale Eddies","authors":"Christopher C. Chapman,&nbsp;Bernadette M. Sloyan,&nbsp;Thomas S. Moore II,&nbsp;John A. Reilly,&nbsp;Richard J. Matear","doi":"10.1029/2024JC021395","DOIUrl":"https://doi.org/10.1029/2024JC021395","url":null,"abstract":"<p>Marine heatwaves (MHWs), defined as periods of persistently elevated ocean temperatures, are investigated along the east coast of Australia. These events are shown to occur as a result of interactions between mesoscale eddies and the East Australian Current (EAC), a poleward flowing western boundary current that transports heat from warmer subtropical seas to cooler temperate latitudes. We show that mesoscale eddies are able to enhance the poleward transport of warm water by the EAC. By reinforcing the southward flow of the EAC, eddies induce strong north-south connectivity during MHW events, with swaths of the shelf and adjacent seas spanning up to 10<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> of latitude exposed to extreme temperatures simultaneously. The eddy signature of MHWs are detectable by as much as 40 days prior to the peak of any particular event. We discuss the implications of our results as a pathway toward early detection and prediction of extreme ocean conditions in boundary current regions.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021395","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in the Seasonal Cycle of Storm Surge Along the Global Coastline","authors":"A. Barroso,&nbsp;T. Wahl,&nbsp;A. Enriquez,&nbsp;J. Morim,&nbsp;S. Dangendorf","doi":"10.1029/2024JC022187","DOIUrl":"https://doi.org/10.1029/2024JC022187","url":null,"abstract":"<p>Storm surge events are a key driver of widespread flooding, particularly when combined with astronomical tides superimposed on mean sea level (MSL). Coastal storms exhibit seasonal variability which translates into a seasonal cycle in storm surge activity. Understanding changes in the seasonal storm surge cycle is critical as both changes in the amplitude and the phase may alter the flood potential, especially when compounded with changes in the MSL cycle. Here, a comprehensive analysis of the storm surge seasonal cycle and its links to the MSL seasonal cycle is performed using tide gauge observations from a quasi-global data set. Harmonic analysis is used to assess the mean and changing storm surge seasonal cycles over time. Extreme value analysis is applied to explore the effect of seasonal changes on storm surge return levels. We also quantify the influence of large-scale climate modes, and we compare how the seasonality of storm surge and MSL have changed relative to each other. The peak of the storm surge cycle typically occurs during winter for tide gauges outside of tropical cyclone regions, where there is also greater variability in the phase of the storm surge cycle. The timing of the peak varied by more than a month at 21% of the tide gauges analyzed. The MSL and storm surge cycles peaked at least once within 30 days over the historic records at 74% of tide gauges.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022187","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144117853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bottom-Up Control and Phytoplankton Succession in a Subtropical Upwelling System","authors":"Zhuyin Tong,&nbsp;Junbao Jiao,&nbsp;Wupeng Xiao,&nbsp;Kuanbo Zhou,&nbsp;Bangqin Huang","doi":"10.1029/2025JC022413","DOIUrl":"https://doi.org/10.1029/2025JC022413","url":null,"abstract":"<p>Diagnosing whether upwelling systems are governed by bottom-up or top-down control is critical for understanding marine ecosystem productivity and trophic interactions. While temperate upwelling systems are widely studied and generally characterized by bottom-up control, the dominant regulatory mechanism in subtropical upwelling systems remains unclear due to their unique physical and biogeochemical dynamics. This study investigated the Qiongdong upwelling system in the northwest South China Sea, aiming to elucidate the drivers of phytoplankton biomass, community composition, and trophic interactions across different upwelling phases. Three consecutive surveys conducted during the summer of 2023 revealed significant spatial and temporal variations in hydrological parameters, nutrient availability, and biological communities. Nutrient availability was closely linked to upwelling intensity, consistently supporting elevated phytoplankton and mesozooplankton biomass, indicating that bottom-up control plays a dominant role in this system. Phytoplankton community composition exhibited a distinct successional pattern: <i>Prochlorococcus</i> dominated during early upwelling stages, possibly influenced by vertical advection that transported it from subsurface waters to the surface. As upwelling intensified, diatoms prevailed, supported by increased nitrate availability and turbulent mixing. This succession highlights how physical and chemical processes interact to shape phytoplankton dynamics. Additionally, less abundant phytoplankton groups such as cryptophytes and prasinophytes enhanced community diversity and contributed to ecosystem stability under fluctuating environmental conditions. These findings highlight the Qiongdong upwelling system as a highly productive subtropical ecosystem that is governed by nutrient-driven processes, offering critical insights into the mechanisms regulating such systems and their potential responses to environmental variability.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144108813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seawater Carbonate Chemistry Along the Hawaiian-Emperor Seamount Chain in the North Pacific","authors":"T. L. Hicks,&nbsp;K. E. F. Shamberger,&nbsp;E. B. Roark,&nbsp;A. R. Baco,&nbsp;L. Watling,&nbsp;R. A. Feely","doi":"10.1029/2024JC021750","DOIUrl":"https://doi.org/10.1029/2024JC021750","url":null,"abstract":"<p>Below the aragonite saturation horizon (ASH), the aragonitic skeletons of deep-sea reef building corals are more susceptible to dissolution. Ocean acidification is causing the ASH to shallow worldwide, threatening the health and future of deep-sea coral reefs. Deep-sea reefs in the North Pacific already exist at or below the ASH, making them particularly vulnerable to future ocean acidification. Here we analyze multiple years (2014–2019) of seawater chemistry data from the Hawaiian-Emperor Seamount Chain (HESC), focusing particularly on intermediate depths (300–800 m) where deep-sea reefs have been found. Intermediate water masses were identified across the HESC based on characteristic temperature, salinity, and density ranges. We then characterize the corresponding carbonate chemistry of each water mass. North Pacific Intermediate Water (NPIW) dominates at intermediate depths for most of our sites. However, the influence of Pacific Subpolar Intermediate Water (PSIW) increases north of 29°N. PSIW has a shallower ASH and lower oxygen conditions than NPIW. The increasing influence of PSIW may thus play a role in restricting reef development, partially explaining why deep-sea reefs have not been found on seamounts north of Koko (34.8°N) in this region. In addition, topographic induced upwelling and temporal variability (seasonal, annual) have the potential to shift the ASH by &gt;100 m depth. As ocean acidification progresses, chronic exposure to corrosive waters may negatively affect reef development and persistence. Characterizing the current carbonate chemistry conditions and variability is critical for informed decision making and management efforts to preserve these valuable ecosystems under future climate change.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021750","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144108809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extrapolation of the Satellite Altimeter Record to Understand Regional Variations in Future Sea Level Change","authors":"A. Bellas-Manley,&nbsp;R. S. Nerem,&nbsp;B. D. Hamlington","doi":"10.1029/2024JC022094","DOIUrl":"https://doi.org/10.1029/2024JC022094","url":null,"abstract":"<p>We perform a quadratic extrapolation of sea level on a regional scale based on satellite altimeter observations spanning 1993.0–2023.0, including corrections for natural climate variability, vertical land motion, and a rigorous assessment of the uncertainties associated with serially correlated formal errors, glacial isostatic adjustment, and satellite altimeter measurement errors. The extrapolations are data-driven and show the trajectory of relative sea level (RSL) over the last 30 years extrapolated into the future. These extrapolations suggest that RSL rise in 2050 relative to 2020 will be 22 ± 5 cm in the North Pacific, 19 ± 6 cm in the North Atlantic, 17 ± 4 cm in the South Atlantic, 15 ± 5 cm in the Indian Ocean, 14 ± 5 cm in the South Pacific, 13 ± 5 cm in the Tropical Pacific, and 12 ± 4 cm in the Southern Ocean. The regional results may differ from each other by more than 80% and differ significantly from the extrapolated global mean sea level rise of 16 ± 4 cm in most cases. The errors in these regional extrapolations are relatively narrow, and we show significant overlap with the regional projections from the most recent IPCC Sixth Assessment Report. The results provide an additional line of evidence when considering how representative the range of climate model projections are in describing near-term sea level rise and highlight the significance of regional variations in estimates of future sea level.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrate-Nitrite Isotopic Exchange: Unveiling Its Influence on Isotope Effect Estimates in Nitrate Assimilation in the Cosmonaut Sea, Antarctica","authors":"Xueli Ba,&nbsp;Jun Zhao,&nbsp;Minfang Zheng,&nbsp;Mengya Chen,&nbsp;Jiawen Kang,&nbsp;Jiashun Hu,&nbsp;Shunan Cao,&nbsp;Jianfeng He,&nbsp;Min Chen","doi":"10.1029/2024JC021862","DOIUrl":"https://doi.org/10.1029/2024JC021862","url":null,"abstract":"&lt;p&gt;Recent insights into isotopic exchange between nitrate and nitrite have introduced complexities to our understanding of the nitrogen cycle in the Southern Ocean. This study highlights unusual isotopic compositions in the mixed layer of the Cosmonaut Sea characterized by notably low δ&lt;sup&gt;15&lt;/sup&gt;N and high δ&lt;sup&gt;18&lt;/sup&gt;O values in nitrite. These anomalies challenge our expectations regarding isotopic behavior within cycling pathways, highlighting the significant role of isotopic exchange between nitrate and nitrite. Interestingly, incorporating this exchange reaction significantly altered the estimated isotope effect of nitrate assimilation for both nitrogen and oxygen based on the Rayleigh model in the nitrate-only system. This raises questions about the reliability of previous estimates in assessing nitrate consumption in the Southern Ocean, suggesting that the nitrate + nitrite system may provide a more accurate representative of nitrate uptake. Additionally, spatial variations in the nitrate assimilation isotope effect (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;ε&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;NO&lt;/mtext&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;NO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${varepsilon }_{{text{NO}}_{3}+{text{NO}}_{2}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) both for nitrogen and oxygen were also observed, with higher &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mmultiscripts&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;ε&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;NO&lt;/mtext&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;NO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mprescripts&gt;&lt;/mprescripts&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;mn&gt;15&lt;/mn&gt;\u0000 &lt;/mmultiscripts&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${}^{15}{varepsilon }_{{text{NO}}_{3}+{text{NO}}_{2}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mmultiscripts&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;ε&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;NO&lt;/mtext&gt;\u0000 ","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scaling Estimation for Growth Rate and Horizontal Wavelength of Charney-Type Submesoscale Baroclinic Instabilities (C-SBCIs)","authors":"L. Feng,&nbsp;C. Liu,&nbsp;J. C. McWilliams,&nbsp;F. Wang","doi":"10.1029/2024JC022104","DOIUrl":"https://doi.org/10.1029/2024JC022104","url":null,"abstract":"<p>The Charney-type submesoscale baroclinic instabilities (C-SBCIs) originating from the mean ocean state are ubiquitous in the global ocean, characterized by a vertical structure that is surface-intensified and depth-decaying. In a companion study, we examined the geographic distribution and seasonal variation of C-SBCIs, focusing on growth rates, horizontal wavelengths, and Charney depth (or vertical scale). The Charney depth, defined as the depth range of quasi-geostrophic potential vorticity gradient necessary for the instability, serves as an important indicator for energy conversion. In the linear stage, phase change and lateral and vertical eddy buoyancy fluxes are significant above this depth but negligible below it. Based on this, a scaling formula for the growth rate of C-SBCIs is derived using the available potential energy averaged from the surface to the Charney depth; although a scaling formula for the horizontal wavelength of C-SBCIs is derived using the stratification averaged from the surface to the Charney depth. These scaling formulas are analogous to those for the Eady-type instabilities but rely on a self-selected Charney depth instead of the prescribed vertical scale in the Eady model, enhancing their applicability to the complex real ocean state. Additionally, the mechanism underlying phase speeds of C-SBCIs is investigated, which is predominantly controlled by the mean flow averaged from the surface to the Charney depth. The newly derived scaling formulas for the growth rates and horizontal wavelengths of C-SBCIs offer a potential framework for parameterizing the temporal and spatial scale of submesoscale turbulence associated with submesoscale eddies.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 5","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}