Impact of Ocean–Atmosphere Current Feedback on Ocean Mesoscale Activity: Regional Variations and Sensitivity to Model Resolution

Jullien, Swen; Masson, Sébastien; Oerder, Véra; Samson, Guillaume; Colas, François; Renault, Lionel

doi:10.1175/jcli-d-19-0484.1

Cited by 26 publications

(29 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, it allows better isolation of the oceanic mesoscale signal from large-scale currents that can have a duration of, for example, less than 1 month (e.g., wind-driven current). Nevertheless, similar results can be found using a temporal filter and by estimating difference between a simulation with CFB and a simulation without CFB (Jullien et al, 2020).…”

Section: Sink Of Oceanic Energy By the Mesoscale Cfbsupporting

confidence: 75%

Recipes for How to Force Oceanic Model Dynamics

Renault

Masson

Arsouze

et al. 2020

J Adv Model Earth Syst

Self Cite

View full text Add to dashboard Cite

The current feedback to the atmosphere (CFB) contributes to the oceanic circulation by damping eddies. In an ocean‐atmosphere coupled model, CFB can be correctly accounted for by using the wind relative to the oceanic current. However, its implementation in a forced oceanic model is less straightforward as CFB also enhances the 10‐m wind. Wind products based on observations have seen real currents that will not necessarily correspond to model currents, whereas meteorological reanalyses often neglect surface currents or use surface currents that, again, will differ from the surface currents of the forced oceanic simulation. In this study, we use a set of quasi‐global oceanic simulations, coupled or not with the atmosphere, to (i) quantify the error associated with the different existing strategies of forcing an oceanic model, (ii) test different parameterizations of the CFB, and (iii) propose the best strategy to account for CFB in forced oceanic simulation. We show that scatterometer wind or stress are not suitable to properly represent the CFB in forced oceanic simulation. We furthermore demonstrate that a parameterization of CFB based on a wind‐predicted coupling coefficient between the surface current and the stress allows us to reproduce the main characteristics of a coupled simulation. Such a parameterization can be used with any forcing set, including future coupled reanalyses, assuming that the associated oceanic surface currents are known. A further assessment of the thermal feedback of the surface wind in response to oceanic surface temperature gradients shows a weak forcing effect on oceanic currents.

show abstract

Section: Sink Of Oceanic Energy By the Mesoscale Cfbsupporting

confidence: 75%

Recipes for How to Force Oceanic Model Dynamics

Renault

Masson

Arsouze

et al. 2020

J Adv Model Earth Syst

Self Cite

View full text Add to dashboard Cite

show abstract

“…Most studies on CFB (e.g: Jullien et al, 2020;Renault et al, 2016bRenault et al, , 2017b use the geostrophic Sw and Sτ (i.e: the slope of the linear regression between of the curl of the geostrophic currents and the curl of the surface wind/stress). However, no significant differences are found between geostrophic Sτ and Sw and the total Sτ and Sw in our simulations.…”

Section: Current Feedback In Coupled and Forced Modesmentioning

confidence: 99%

“…In coupled models, the wind can adjust and a positive linear relationship is found between the surface wind and current curls (Renault et al, 2016b), which partially re-energizes the ocean, leading to more realistic EKE levels (Renault et al, 2016b(Renault et al, , 2019Jullien et al, 2020). This atmospheric response that re-energizes the ocean is called "Wind Current FeedBack" (CFB_wind).…”

Section: Introductionmentioning

confidence: 99%

“…In coupled mode, the "Total Current FeedBack" (CFB_tot) is the sum of CFB_stress and CFB_wind, which are the oceanic and atmospheric retroaction loops, respectively. The kinetic energy damping caused by the current feedback exhibits a strong regional variability and is related to both mean wind intensity and EKE (Jullien et al, 2020). A proper representation of the current feedback improves the realism of simulated structures such as the Gulf-Stream separation and post-separation at Cape Hatteras (Renault et al, 2016a) or the position of the Agulhas current retroflection (Renault et al, 2017a), therefore influencing the regional and global climate systems.…”

Section: Introductionmentioning

confidence: 99%

“…Correct current feedback representation (i.e. representing CFB_tot instead of CFB_stress only) necessitates both an ocean models resolving mesoscale fields and an atmosphere model at the ocean model effective resolution (Jullien et al, 2020), but the computational cost of such configurations remains limiting for long term analysis and operational perspectives.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Impact of the current feedback on kinetic energy over the North-East Atlantic from a coupled ocean/atmospheric boundary layer model

Brivoal

Samson

Giordani

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. A one-dimensional Atmospheric Boundary Layer (ABL1D) is coupled with the NEMO ocean model and implemented over the Iberian–Biscay–Ireland (IBI) area at 1/36° resolution to investigate the retroactions between the surface currents and the atmosphere, namely the Current FeedBack (CFB) in this region of low mesoscale activity. The ABL1D-NEMO coupled model is forced by a large-scale atmospheric reanalysis (ERA-Interim) and integrated over the period 2016–2017. The mechanisms of eddy kinetic energy damping and ocean upper-layers re-energization are realistically simulated, meaning that the CFB is properly represented by the model. In particular, the dynamical coupling coefficients between the curls of surface stress/wind and current are in agreement with the literature. The effects of CFB on the kinetic energy (KE) are then investigated through a KE budget. We show that the KE decrease induced by the CFB is significant down to 1500 m. Near the surface (0–300 m), most of the KE decrease can be explained by a reduction of the surface wind work by 4 %. At depth (300–2000 m), the CFB induce a reduction of the pressure work (i.e: the PE to KE conversion) associated with a reduction of KE which is significant down to 1500 m. We show that this reduction of KE at depth can be explained by CFB-induced Ekman pumping above eddies that weakens the mesoscale activity and this over the whole water column.

show abstract

The East Asian Summer Monsoon Response to Global Warming in a High Resolution Coupled Model: Mean and Extremes

Liu

Lee

Nellikkattil

et al. 2022

Asia-Pac J Atmos Sci

View full text Add to dashboard Cite

Current climate models still have considerable biases in the simulation of the East Asian summer monsoon (EASM), which in turn reduces their reliability of monsoon projections under global warming. We hypothesize that a higher-resolution coupled climate model with atmospheric and oceanic components at horizontal resolutions of 0.25° and 0.1°, respectively, will better capture regional details and extremes of the EASM. Present-day (PD), 2 × CO2 and 4 × CO2 simulations are conducted with the Community Earth System Model (CESM1.2.2) to evaluate PD simulation performance and quantify future changes. Indeed, our PD simulation well reproduces the climatological seasonal mean and intra-seasonal northward advancement of the monsoon rainband, as well as climate extremes. Compared with the PD simulation, the perturbed CO2 experiments show an intensified EASM response to CO2-induced warming. We find that the precipitation increases of the Meiyu-Baiu-Changma band are caused by comparable contributions from the dynamical and thermodynamical components in 2 × CO2, while they are more driven by the thermodynamical component in 4 × CO2 due to stronger upper atmospheric stability. The regional changes in the probability distribution of the temperature show that extreme temperatures warm faster than the most often temperatures, increasing the skewness. Fitting extreme precipitation values with a generalized Pareto distribution model reveals that they increase significantly in 4 × CO2. Changes of temperature extremes scale with the CO2 concentrations over the monsoon domain but not for precipitation extreme changes. The 99th percentile of precipitation over the monsoon region increases at a super Clausius-Clapeyron rate, ~ 8% K–1, which is mainly caused by increased moisture transport through anomalous southerly winds.

show abstract

Impact of Ocean–Atmosphere Current Feedback on Ocean Mesoscale Activity: Regional Variations and Sensitivity to Model Resolution

Cited by 26 publications

References 83 publications

Recipes for How to Force Oceanic Model Dynamics

Recipes for How to Force Oceanic Model Dynamics

Impact of the current feedback on kinetic energy over the North-East Atlantic from a coupled ocean/atmospheric boundary layer model

The East Asian Summer Monsoon Response to Global Warming in a High Resolution Coupled Model: Mean and Extremes

Contact Info

Product

Resources

About