About

Alexey Fedorov is a Professor of Oceanic and Atmospheric Sciences in the Department of Earth and Planetary Sciences at Yale University and serves as a Senior Visiting Scientist at the LOCEAN/IPSL at Sorbonne University. His research aims to advance understanding of climate, ocean, and atmospheric dynamics in the context of contemporary global warming and past climate changes. He specializes in the problems of ocean and atmospheric general circulation, large-scale ocean-atmosphere interactions, climate predictability, and mechanisms of long-term climate variations. His group employs modern observational and numerical methodologies, including state-of-the-art general circulation models (GCMs), advanced theoretical methods, statistical data analysis, and conceptual climate models, to investigate physical processes that control climate and improve climate prediction. Fedorov's work encompasses a broad range of topics such as El Niño phenomena, Atlantic meridional overturning circulation (AMOC), ocean circulation and thermal structure, tropical cyclones, and the impacts of climate change on these systems. His contributions include investigating the effects of climate change on El Niño, understanding rapid climate shifts related to ocean circulation reorganizations, and studying the ocean's thermal structure through Lagrangian models. He has been recognized with awards such as the Packard Fellowship in Science and Engineering, the Guggenheim Fellowship, and the Presidential climate change research award from the 'Make our planet great again' program. Fedorov leads a research group that actively explores climate variability on timescales from decades to millennia, aiming to deepen scientific understanding and enhance predictive capabilities of Earth's climate system.

Research topics

• Oceanography
• Geology
• Environmental science
• Climatology

Selected publications

• A Revised Temperature-Dependent Remineralization Scheme for the Community Earth System Model (v1.2.2)

  2025-09-16 · 1 citations

  preprintOpen access

  Abstract. Export of carbon from the euphotic zone to intermediate and deep water plays a critical role in the ocean’s feedback response to a warming climate. However, as water temperature increases so does the rate of bacterial respiration at the base of the biological pump, resulting in more efficient recycling of carbon in the upper ocean, less efficient export of carbon to depth, and a diminished net negative feedback on climate. Therefore, to better predict climate response associated with changes in ocean carbon storage in warming scenarios, it is imperative to incorporate temperature-sensitive mechanisms, such as bacterial respiration (remineralization), into Earth system models. Here, we employ a new temperature-dependent parameterization for remineralization (Tdep) in the Community Earth System Model version 1 (CESM1) applied to gravitationally sinking particulate organic carbon (POC) in a preindustrial control simulation. We find that the inclusion of Tdep in both low and high-resolution model configurations more accurately captures regional heterogeneity in POC transfer efficiency while preserving the overall trends in nutrient distribution and attenuation of sinking particulate matter when compared with modern empirical data. Inclusion of this parametrization will allow for improved predictions of temperature-sensitive mechanisms impacting carbon storage in the warming ocean.

  PublisherOA PDFDOI

• Supplementary material to "A Revised Temperature-Dependent Remineralization Scheme for the Community Earth System Model (v1.2.2)"

  2025-09-16

  preprintOpen access
  PublisherDOI

• Observed Pacific Gradient Strengthening Remains Rare in Climate Models Despite Corrected ENSO Variability

  2025-10-23

  articleOpen access

  Observations show a strengthening of the equatorial Pacific zonal sea surface temperature (SST) gradient since the 1980s, in contrast with climate models that generally project a weakening or no change. Using the full CMIP6 archive, we find that fewer than 1% of simulations match the observed trend—a stronger mismatch than reported previously. Models rarely simulate extreme El Niño events; too-low Niño3 SST skewness captures this bias and correlates (~0.65) with interdecadal gradient internal variability. Applying an observational constraint based on this relation enhances simulated variability and raises the fraction of simulations matching or exceeding the observed trend to ~5%. Yet over 95% of simulations project a ~15% zonal gradient reduction once global mean surface warming exceeds +1.7°C. These findings support the view that the recent strengthening is a transient forced signal missed by most models, while the long-term weakening is a robust feature across simulations.

  PublisherOA PDFDOI

• Atmospheric Nonlinearity Controls ENSO Asymmetry in a Hybrid Statistical‐Dynamical Climate Model

  Geophysical Research Letters · 2025-10-16 · 1 citations

  articleOpen accessSenior author

  Abstract The El Niño Southern Oscillation (ENSO) phases are asymmetrical, with El Niño exhibiting greater sea surface temperature (SST) anomalies compared to La Niña, though La Niña can persist for longer. This asymmetry results in a positive skewness of SST variations in the eastern equatorial Pacific—a feature that climate models struggle to replicate. To understand the roles of oceanic and atmospheric nonlinearities in this asymmetry, we use a hybrid statistical‐dynamical model, based on the Community Earth System Model version 2 (CESM2), that couples the ocean component of CESM2 to a partially statistical atmospheric component. We find that without the nonlinear atmospheric wind‐stress response to SST anomalies, ENSO exhibits stronger La Niñas than El Niños and negative skewness, contrary to observations, which is caused by oceanic nonlinearities. Only by incorporating the observed wind‐stress nonlinearities can the model reproduce the observed ENSO asymmetry, highlighting the atmosphere's critical role within this framework.

  PublisherOA PDFDOI

• Atmospheric nonlinearity controls ENSO asymmetry in a hybrid statistical-dynamical model

  2025-06-26

  preprintOpen accessSenior author

  The El Niño Southern Oscillation (ENSO) phases are asymmetrical, with El Niño exhibiting greater sea surface temperature (SST) anomalies compared to La Niña. La Niña conditions can also persist longer, often lasting two-to-three years. This asymmetry results in a positive skewness of SST variations in the eastern equatorial Pacific – a feature that climate models struggle to replicate. To understand the roles of oceanic and atmospheric nonlinearities in this asymmetry, we use a hybrid statistical-dynamical model, based on the Community Earth System Model version 2 (CESM2), that couples the ocean of CESM2 to a partially statistical atmospheric component. We find that without the nonlinear atmospheric wind-stress response to SST anomalies, ENSO exhibits stronger La Niñas than El Niños and negative skewness, contrary to observations, which is caused by oceanic nonlinearities. Only by incorporating the observed wind-stress nonlinearities can the model reproduce the observed ENSO asymmetry, highlighting the atmosphere’s critical role.

  PublisherOA PDFDOI

• Warm Equatorial Upper Ocean Thermal Structure During the Mid‐Pliocene Warm Period: A Data‐Model Comparison

  Geophysical Research Letters · 2025-08-21 · 5 citations

  articleOpen access

  Abstract The tropical Pacific climate has an outsized impact on global climate, yet future projections are poorly constrained. Data‐model comparisons from the mid‐Pliocene warm period (3.3 million years ago) can help investigate warm climate dynamics and evaluate model behavior. Here we compare proxy records to PlioMIP2 models and a model with modified cloud albedo. Relative to modern, the mid‐Pliocene warm period records show subsurface warming across the tropical Pacific, strong eastern Pacific surface warming and weak western Pacific surface warming. Using clustering analyses to group model behavior relative to the proxy data, we find the model cluster with the best fit with the proxy data has enhanced warming in mid‐latitude thermocline source water regions which connect to the equator through the ventilated thermocline. Our study shows tropical ocean heat content during the mid‐Pliocene warm period was higher than today and has broad implications for the ocean's ability to absorb anthropogenic heat.

  PublisherOA PDFDOI

• Tipping points in ocean and atmosphere circulations

  Earth System Dynamics · 2025-10-08 · 4 citations

  articleOpen access

  Abstract. Continued anthropogenic pressures on the Earth system hold the potential to disrupt established circulation patterns in the ocean and atmosphere. In this narrative review, we investigate tipping points in these systems by assessing scientific evidence for feedbacks that may drive self-sustained change beyond critical forcing thresholds, drawing on insights from expert elicitation. The literature provides multiple strands of evidence for oceanic tipping points in the Atlantic Meridional Overturning Circulation (AMOC), the North Atlantic subpolar gyre (SPG), and the Antarctic Overturning Circulation, which may collapse under warmer and “fresher” (i.e. less salty) conditions. A slowdown or collapse of these oceanic circulations would have far-reaching consequences for the rest of the climate system and could lead to strong impacts on human societies and the biosphere. Among the atmospheric circulation systems considered, a few lines of evidence suggest the West African monsoon (WAM) as a tipping system. Its abrupt changes in the past have led to vastly different vegetation states of the Sahara (e.g. “green Sahara” states). Despite multiple potential sources of destabilization, evidence about tipping of the monsoon systems over South America and Asia is limited. Although theoretically possible, there is currently little indication for tipping points in tropical clouds or mid-latitude atmospheric circulations. Similarly, tipping towards a more extreme or persistent state of the El Niño–Southern Oscillation (ENSO) is currently not fully supported by models and observations. While the tipping thresholds for many of these systems are uncertain, tipping could have severe socio-environmental consequences. Stabilizing Earth's climate (along with minimizing other environmental pressures, such as aerosol pollution and ecosystem degradation) is critical for reducing the likelihood of reaching tipping points in the ocean–atmosphere system.

  PublisherOA PDFDOI

• Climate Models Exaggerate the Enhanced Double‐ITCZ in the Warming Tropical Pacific Due To Preexisting Precipitation Bias

  Geophysical Research Letters · 2025-05-29 · 3 citations

  articleOpen accessSenior author

  Abstract Future greenhouse warming projections from the CMIP6 multi‐model ensemble indicate increased precipitation in the southeastern Pacific Ocean and a reduction in interhemispheric precipitation asymmetry, suggesting an enhanced double‐Intertropical Convergence Zone (ITCZ) in the tropical Pacific. However, these models exhibit a persistent annual‐mean double‐ITCZ bias in preindustrial and historical simulations, casting doubt on their projections. Indeed, models with the smallest preexisting double‐ITCZ bias—aside from a few outliers—typically show the least enhancement of the double‐ITCZ feature under global warming. To investigate this further, we use CESM2 and conduct flux‐adjusted simulations that nearly eliminate the precipitation bias in preindustrial experiments, followed by CO 2 ‐doubling simulations. Our bias‐reduced simulations show a much smaller reduction in the precipitation asymmetry index and only half the increase in rainfall in the southeastern Pacific compared to the original model. We conclude that climate models likely overestimate the enhanced double‐ITCZ feature under global warming due to the preexisting precipitation bias.

  PublisherOA PDFDOI

• Realistic ENSO Dynamics Requires a Damped Nonlinear Recharge Oscillator

  ArXiv.org · 2025-06-12

  preprintOpen access

  The dynamics of the El Niño-Southern Oscillation (ENSO) are succinctly captured by the Recharge Oscillator (RO) framework. However, to simulate ENSO realistically, careful choices must be made regarding the RO's key parameters. In particular, nonlinear parameters govern how well the model reproduces ENSO asymmetries-El Niño events tend to be stronger but relatively short, often transitioning into La Niña, whereas La Niña events are typically weaker but may last longer. While amplitude asymmetry has been studied within the RO framework, duration and transition asymmetries remain less explored and their causes are debated. In this study, by systematically exploring the RO parameter space-rather than relying on commonly used fitting methods-we identify optimal parameter values that successfully capture key linear and nonlinear ENSO characteristics. In doing so, we revisit several foundational elements of the RO framework. First, we analytically derive the phase relationship between temperature and heat content anomalies, showing that it depends on the signs of the Bjerknes feedback and the ocean damping timescale. We show that self-sustained oscillations fail to reproduce the observed kurtosis of Niño indices. We further derive an analytical expression for the power spectrum and argue that incorporating red noise forcing, rather than white noise, introduces unnecessary complexity. The most realistic yet simplest RO configuration is a strongly damped oscillator, with a decay timescale shorter than the dominant period, forced by multiplicative white noise and influenced by weak deterministic nonlinearities. Identifying these minimal components preserves the RO framework's clarity and isolates the core physical processes underlying ENSO behavior.

  PublisherOA PDFDOI

• Stratospheric Control of the Linkage between the AMOC and Atlantic Multidecadal Variability

  Journal of Climate · 2025-05-02 · 2 citations

  articleOpen access

  Abstract The ocean’s role in Atlantic multidecadal variability (AMV) remains intensely debated. The core issue is whether AMV, as an internal climate mode, is driven by variations in the Atlantic meridional overturning circulation (AMOC) or by atmospheric processes. Climate models exhibit a wide range of AMOC–AMV linkages, producing temporal correlations between 0.3 and 0.8, but no robust explanation for these differences exists. Here, using both multimodel intercomparison and perturbation experiments, we propose a dynamical mechanism relating the strength of AMOC–AMV linkage in climate models to stratospheric temperature. This mechanism includes 1) tropospheric midlatitude jet response to stratospheric mean-state temperature anomalies in midlatitudes and 2) resulting ocean surface density changes that alter the spatial structure of deep-water formation in the subpolar North Atlantic and hence AMOC–AMV connection. Specifically, colder stratospheric temperatures produce tighter linkage through a northward jet shift and a stronger AMOC, with enhanced deep-water formation in the Labrador and Irminger Seas relative to the Nordic seas. Models with a warm stratospheric bias tend to produce weaker linkage. Perturbation experiments imposing stratospheric cooling at mid- to high latitudes within two independent climate models support these conclusions. Furthermore, we find that models with stronger AMOC–AMV linkage predict a stronger North Atlantic “warming hole” and weaker twenty-first-century Arctic amplification. We conclude that these results have significant implications for climate prediction and projections.

  PublisherOA PDFDOI

Recent grants

• P2C2: Understanding Mean Patterns, Gradients, Variability and Mechanisms of Early Pliocene Warmth: The Role of Cloud Albedo

  NSF · $368k · 2014–2017

• Collaborative Research: Examining the links between Atlantic Meridional Overturning Circulation and Atlantic Multidecadal Variability

  NSF · $289k · 2018–2021

• Collaborative research: Quantifying Global and Regional Impacts of the Atlantic Meridional Overturning Circulation (AMOC) Slowdown in the 21st (twenty-first) Century

  NSF · $324k · 2021–2026

• The Arctic ocean control of the Atlantic meridional overturning circulation on multi-decadal and longer timescales

  NSF · $480k · 2018–2021

• Net energy dissipation in the tropical ocean and ENSO dynamics: modeling and theoretical study.

  NSF · $384k · 2006–2010

Frequent coauthors

• Brady Ferster

  Centre National de la Recherche Scientifique

  206 shared

• Éric Guilyardi

  Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques

  168 shared

• Emmanuel Mignot

  Stanford University

  155 shared

• Chris Brierley

  60 shared

• K. T. Lawrence

  Providence College

  53 shared

• Zhonghui Liu

  University of Hong Kong

  52 shared

• Yong Sun

  China Southern Power Grid (China)

  51 shared

• Timothy D. Herbert

  51 shared

Education

• Ph.D., Scripps Institution of Oceanography

  University of California San Diego

Awards & honors

• Packard Fellowship in Science and Engineering (2007-2014)
• Guggenheim Fellowship (2018)
• Presidential climate change research award of the “Make our…