@article{guo_bishop_bryan_bachman_2023, title={Mesoscale Variability Linked to Interannual Displacement of Gulf Stream}, volume={50}, ISSN={["1944-8007"]}, url={https://doi.org/10.1029/2022GL102549}, DOI={10.1029/2022GL102549}, abstractNote={The impacts of interannual oscillations of the Gulf Stream (GS) on oceanic mesoscale variability are investigated using satellite observations of sea surface height (SSH) and sea surface temperature (SST) from 1993 to 2018. We show that variations in GS position, strength, and meandering status are the dominant spatiotemporal modes in regional SSH variability as they explain over 50% of the total variance. In particular, meridional shift of the GS associated with the large‐scale wind variation over the North Atlantic contributes to approximately 30% of SSH variability. We further find that this path displacement mode can drive approximately 15% of regional mesoscale variability in eddy kinetic energy and divergent eddy heat flux. This observational‐based evidence of ocean mesoscale response to GS shift infers a potentially important forcing mechanism that could drive eddy‐scale ocean variability and has far‐reaching implications for regional ocean and ecosystem dynamics in response to climate variation.}, number={7}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Guo, Yiming and Bishop, Stuart and Bryan, Frank and Bachman, Scott}, year={2023}, month={Apr} }
 @article{guo_bishop_bryan_bachman_2022, title={A Global Diagnosis of Eddy Potential Energy Budget in an Eddy-Permitting Ocean Model}, volume={52}, ISSN={["1520-0485"]}, url={http://dx.doi.org/10.1175/jpo-d-22-0029.1}, DOI={10.1175/JPO-D-22-0029.1}, abstractNote={Abstract We use an interannually forced version of the Parallel Ocean Program, configured to resolve mesoscale eddies, to close the global eddy potential energy (EPE) budget associated with temperature variability. By closing the EPE budget, we are able to properly investigate the role of diabatic processes in modulating mesoscale energetics in the context of other processes driving eddy–mean flow interactions. A Helmholtz decomposition of the eddy heat flux field into divergent and rotational components is applied to estimate the baroclinic conversion from mean to eddy potential energy. In doing so, an approximate two-way balance between the “divergent” baroclinic conversion and upgradient vertical eddy heat fluxes in the ocean interior is revealed, in accordance with baroclinic instability and the relaxation of isopycnal slopes. However, in the mixed layer, the EPE budget is greatly modulated by diabatic mixing, with air–sea interactions and interior diffusion playing comparable roles. Globally, this accounts for ∼60% of EPE converted to EKE (eddy kinetic energy), with the remainder being dissipated by air–sea interactions and interior mixing. A seasonal composite of baroclinic energy conversions shows that the strongest EPE to EKE conversion occurs during the summer in both hemispheres. The seasonally varying diabatic processes in the upper ocean are further shown to be closely linked to this EPE–EKE conversion seasonality, but with a lead. The peak energy dissipation through vertical mixing occurs ahead of the minimum EKE generation by 1–2 months.}, number={8}, journal={JOURNAL OF PHYSICAL OCEANOGRAPHY}, publisher={American Meteorological Society}, author={Guo, Yiming and Bishop, Stuart and Bryan, Frank and Bachman, Scott}, year={2022}, month={Aug}, pages={1731–1748} }
 @article{guo_bachman_bryan_bishop_2022, title={Increasing Trends in Oceanic Surface Poleward Eddy Heat Flux Observed Over the Past Three Decades}, volume={49}, ISSN={["1944-8007"]}, url={https://doi.org/10.1029/2022GL099362}, DOI={10.1029/2022GL099362}, abstractNote={Mesoscale processes make the largest contribution to ocean variability and are significant agents in ocean heat transport. In this investigation, we provide evidence based on satellite observations for an increasing trend in surface transient eddy heat flux (EHF) over the period 1993–2020. The enhanced EHF is particularly prominent in western boundary currents and their extensions at mid‐latitudes, with increases of 20%–40% per decade. Additionally, we decompose the EHF trend into contributions from velocity variance, temperature variance and a coherence parameter using a Cauchy–Schwarz inequality. We find that each contributes to the spatial pattern of the trend in EHF, with the contribution from enhanced temperature variance dominating the global zonal mean EHF trend over the past few decades.}, number={16}, journal={GEOPHYSICAL RESEARCH LETTERS}, publisher={American Geophysical Union (AGU)}, author={Guo, Yiming and Bachman, Scott and Bryan, Frank and Bishop, Stuart}, year={2022}, month={Aug} }
 @article{guo_bishop_2022, title={Surface Divergent Eddy Heat Fluxes and Their Impacts on Mixed Layer Eddy-Mean Flow Interactions}, volume={14}, ISSN={["1942-2466"]}, url={https://doi.org/10.1029/2021MS002863}, DOI={10.1029/2021MS002863}, abstractNote={In this study, the global surface divergent eddy heat flux (EHF) is estimated using remote sensing observations of sea surface height (SSH) and sea surface temperature (SST) over two decades (1993–2017). These results are used as a metric to assess model fidelity in a mesoscale eddy‐resolving version of the Community Earth System Model. The estimated EHFs show that the midlatitudes significantly contribute to the poleward transport of heat because of strong regional variability in SSH and SST. A Helmholtz decomposition is performed on the global EHFs to remove prominent nondynamic rotational wave‐like structures that appear in these fluxes. The dynamic divergent EHFs are responsible for driving cross‐frontal exchange and positive Baroclinic Conversion (BC) rates, suggesting a conversion of mean potential energy to eddy potential energy within the mixed layer. The results show that the model captures the same spatial patterns of EHFs and BC rates, but with relatively higher values in the midlatitudes than observations. The mixed layer geostrophic meridional eddy heat transport reaches maximums of 0.07 PW and 0.1 PW in the midlatitudes in the observations and climate model, respectively. The global integrated BC rate is 0.11 TW in the observations, which is ∼30% weaker than the climate model (0.16 TW). A cross‐spectral analysis further shows that the model has higher energy in low‐frequency bands for periods greater than 10 months in the northern hemisphere western boundary currents, but can capture the major spectral peaks in EHFs that are seen in observations.}, number={4}, journal={JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS}, publisher={American Geophysical Union (AGU)}, author={Guo, Yiming and Bishop, Stuart P.}, year={2022}, month={Apr} }
 @article{small_bryan_bishop_2022, title={Surface Water Mass Transformation in the Southern Ocean: The Role of Eddies Revisited}, volume={52}, ISSN={["1520-0485"]}, DOI={10.1175/JPO-D-21-0087.1}, abstractNote={
The water mass transformation (WMT) framework describes how water of one class, such as a discrete interval of density, is converted into another class via air-sea fluxes or interior mixing processes. This paper investigates how this process is modified at the surface when mesoscale ocean eddies are present, using a state-of-the-art high-resolution climate model with reasonable fidelity in the Southern Ocean. The method employed is to coarse-grain the high-resolution model fields to remove eddy signatures, and compare the results with those from the full model fields. This method shows that eddies reduced the WMT by 2 to 4 Sv (10% to 20%) over a wide range of densities, from typical values of 20Sv in the smoothed case. The corresponding water mass formation was reduced by 40% at one particular density increment, namely between 1026.4 kgm−3 and 1026.5 kgm−3, which corresponds to the lighter end of the range of Indian Ocean modewater in the model. The effect of eddies on surface WMT is decomposed into three terms: direct modulation of the density outcrops, then indirectly, by modifying the air-sea density flux, and the combined effect of the two, akin to a covariance. It is found that the first and third terms dominate, i.e. smoothing the outcrops alone has a significant effect, as does the combination of smoothing both outcrops and density flux distributions, but smoothing density flux fields alone has little effect. Results from the coarse-graining method are compared to an alternative approach of temporally averaging the data. Implications for climate model resolution are also discussed.}, number={5}, journal={JOURNAL OF PHYSICAL OCEANOGRAPHY}, author={Small, R. Justin and Bryan, Frank O. and Bishop, Stuart P.}, year={2022}, month={May}, pages={789–804} }
 @article{bishop_small_bryan_2020, title={The Global Sink of Available Potential Energy by Mesoscale Air-Sea Interaction}, volume={12}, ISSN={["1942-2466"]}, DOI={10.1029/2020MS002118}, abstractNote={Abstract}, number={10}, journal={JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS}, author={Bishop, Stuart P. and Small, R. Justin and Bryan, Frank O.}, year={2020}, month={Oct} }
 @article{small_bryan_bishop_larson_tomas_2020, title={What Drives Upper-Ocean Temperature Variability in Coupled Climate Models and Observations?}, volume={33}, ISSN={["1520-0442"]}, DOI={10.1175/JCLI-D-19-0295.1}, abstractNote={Abstract}, number={2}, journal={JOURNAL OF CLIMATE}, author={Small, R. Justin and Bryan, Frank O. and Bishop, Stuart P. and Larson, Sarah and Tomas, Robert}, year={2020}, month={Jan}, pages={577–596} }
 @article{small_bryan_bishop_tomas_2019, title={Air-Sea Turbulent Heat Fluxes in Climate Models and Observational Analyses: What Drives Their Variability?}, volume={32}, ISSN={["1520-0442"]}, DOI={10.1175/JCLI-D-18-0576.1}, abstractNote={Abstract}, number={8}, journal={JOURNAL OF CLIMATE}, author={Small, R. Justin and Bryan, Frank O. and Bishop, Stuart P. and Tomas, Robert A.}, year={2019}, month={Apr}, pages={2397–2421} }
 @article{bishop_gent_bryan_thompson_long_abernathey_2016, title={Southern Ocean Overturning Compensation in an Eddy-Resolving Climate Simulation}, volume={46}, ISSN={["1520-0485"]}, DOI={10.1175/jpo-d-15-0177.1}, abstractNote={Abstract}, number={5}, journal={JOURNAL OF PHYSICAL OCEANOGRAPHY}, author={Bishop, Stuart P. and Gent, Peter R. and Bryan, Frank O. and Thompson, Andrew F. and Long, Matthew C. and Abernathey, Ryan}, year={2016}, month={May}, pages={1575–1592} }
 @article{small_bacmeister_bailey_baker_bishop_bryan_caron_dennis_gent_hsu_et al._2014, title={A new synoptic scale resolving global climate simulation using the Community Earth System Model}, volume={6}, ISSN={1942-2466 1942-2466}, url={http://dx.doi.org/10.1002/2014MS000363}, DOI={10.1002/2014MS000363}, abstractNote={Abstract}, number={4}, journal={Journal of Advances in Modeling Earth Systems}, publisher={American Geophysical Union (AGU)}, author={Small, R. Justin and Bacmeister, Julio and Bailey, David and Baker, Allison and Bishop, Stuart and Bryan, Frank and Caron, Julie and Dennis, John and Gent, Peter and Hsu, Hsiao‐ming and et al.}, year={2014}, month={Dec}, pages={1065–1094} }