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arxiv: 2603.28481 · v2 · submitted 2026-03-30 · ⚛️ physics.ao-ph

Remote Influences of Land Surface Temperature and their Implications for Sea Surface Temperature Patterns

Bosong Zhang , Timothy M. Merlis This is my paper

Pith reviewed 2026-05-14 00:39 UTC · model grok-4.3

classification ⚛️ physics.ao-ph
keywords land surface temperaturesea surface temperaturetropical PacificRossby wavesLa Niña-like statenudging experimentsremote climate influences
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0 comments X

The pith

Warming land over South America strengthens the tropical Pacific zonal SST gradient, yielding a more La Niña-like mean state.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper uses a coupled ocean-land-atmosphere model to test how regional land surface temperature changes affect ocean patterns far away. Warming imposed over South America increases the contrast in diabatic heating, which excites stationary Rossby waves that strengthen alongshore winds and coastal upwelling in the eastern Pacific. This cools the east relative to the west, shifting the tropical Pacific toward a La Niña-like state. Similar but region-specific responses appear for North America and Central Africa, while warming over the Maritime Continent or Tibetan Plateau produces little change. Nudged historical runs show southeast Pacific cooling, suggesting land temperature uncertainty may contribute to model SST biases.

Core claim

LST warming over South America strengthens the tropical Pacific zonal SST gradient, yielding a more La Niña-like mean state. Enhanced LST increases the zonal contrast in diabatic heating and excites stationary Rossby wave responses, which reinforce alongshore winds and coastal upwelling in the eastern Pacific. This provides a dynamical pathway linking regional land warming to changes in the equatorial Pacific mean state.

What carries the argument

Stationary Rossby wave responses to enhanced zonal diabatic heating contrast from regional LST warming, which alter alongshore winds and coastal upwelling.

If this is right

  • LST warming over North America is accompanied by North Pacific cooling.
  • Warming over Central Africa is coupled with tropical Atlantic cooling.
  • Warming over the Maritime Continent or the Tibetan Plateau does not induce significant SST pattern changes.
  • Nudged historical simulations exhibit cooling in the tropical southeast Pacific, suggesting LST uncertainty may contribute to model-simulated SST biases.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The mechanism could be tested by running free simulations with prescribed land-use changes to check persistence without nudging.
  • This pathway implies that historical or future land temperature shifts might influence the baseline for ENSO events.
  • Similar remote effects might appear in other ocean basins if analogous land-ocean heating contrasts are imposed.

Load-bearing premise

The imposed regional LST perturbations through nudging in the coupled model accurately represent real-world remote influences without introducing significant model-specific artifacts or violating energy balances.

What would settle it

If independent observations or reanalysis show no strengthening of the Pacific zonal SST gradient during periods of South American land warming, the proposed dynamical link would be falsified.

read the original abstract

The spatial pattern of sea surface temperature (SST) plays a central role in shaping the climate system, yet the influence of land surface temperature (LST) remains poorly understood. Using a state-of-the-art coupled ocean--land--atmosphere model, we examine the model's response to regional LST perturbations imposed through LST nudging and idealized time-dependent ramp warming simulations. We find that LST warming over South America strengthens the tropical Pacific zonal SST gradient, yielding a more La Ni\~na--like mean state. Enhanced LST increases the zonal contrast in diabatic heating and excites stationary Rossby wave responses, which reinforce alongshore winds and coastal upwelling in the eastern Pacific. This provides a dynamical pathway linking regional land warming to changes in the equatorial Pacific mean state. Similar responses are found for warming over North America, accompanied by North Pacific cooling, and for warming over Central Africa, coupled with tropical Atlantic cooling. In contrast, warming over the Maritime Continent or the Tibetan Plateau does not induce significant SST pattern changes. Historical simulations nudged toward observed LST exhibit cooling in the tropical southeast Pacific, with the tentative implication that uncertainty in LST may contribute to model-simulated SST biases during the historical period.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper claims that regional land surface temperature (LST) warming, particularly over South America, strengthens the tropical Pacific zonal sea surface temperature (SST) gradient through enhanced diabatic heating contrasts and stationary Rossby wave responses that reinforce eastern Pacific upwelling, leading to a more La Niña-like mean state. This is demonstrated using a coupled climate model with LST nudging experiments and idealized ramp warming simulations. Similar but region-specific responses are reported for other land areas, and nudged historical simulations suggest LST uncertainty contributes to southeast Pacific cooling biases.

Significance. If the mechanism is robust, this provides a new dynamical pathway connecting land warming to equatorial Pacific SST patterns, with potential to explain and mitigate biases in climate models' representation of the tropical mean state. The multi-region perturbation approach adds value by showing specificity of the response.

major comments (2)
  1. [Methods (LST nudging experiments)] The central results rely on imposing LST perturbations via nudging (as described in the experimental setup), which adds a relaxation term to the surface energy budget. This term can directly influence near-surface diabatic heating rates, potentially driving the reported zonal heating contrast and Rossby wave excitation rather than reflecting physical remote influences. The manuscript should provide diagnostics separating the nudging contribution from turbulent and radiative fluxes to confirm the physical nature of the response.
  2. [Results (South American warming case)] While the abstract mentions consistent responses across experiments, there is no reported quantification of robustness to nudging strength, perturbation amplitude, or ensemble variability. This weakens the support for the mechanism as a general feature rather than model-specific.
minor comments (2)
  1. [Abstract] The La Niña symbol is rendered as 'La Ni~na'; ensure proper typesetting in the final version.
  2. [Discussion] Additional references to existing literature on land-atmosphere-ocean teleconnections would strengthen the context.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments, which help clarify the interpretation of our nudging experiments and strengthen the robustness assessment. We address each major comment below and will incorporate revisions accordingly.

read point-by-point responses

  1. Referee: [Methods (LST nudging experiments)] The central results rely on imposing LST perturbations via nudging (as described in the experimental setup), which adds a relaxation term to the surface energy budget. This term can directly influence near-surface diabatic heating rates, potentially driving the reported zonal heating contrast and Rossby wave excitation rather than reflecting physical remote influences. The manuscript should provide diagnostics separating the nudging contribution from turbulent and radiative fluxes to confirm the physical nature of the response.

    Authors: We agree that the nudging relaxation term is part of the surface energy budget and could in principle contribute to near-surface heating. However, because nudging is applied only to land surface temperature (not directly to atmospheric heating), the resulting diabatic heating contrast and Rossby wave response arise from the adjusted turbulent and radiative fluxes at the land-atmosphere interface. To demonstrate this separation explicitly, we will add new diagnostics in the revised manuscript that isolate the nudging heat flux from the turbulent sensible/latent heat fluxes and radiative fluxes. These diagnostics will be shown for the South American warming case and confirm that the physical flux changes dominate the reported mechanism. revision: yes

  2. Referee: [Results (South American warming case)] While the abstract mentions consistent responses across experiments, there is no reported quantification of robustness to nudging strength, perturbation amplitude, or ensemble variability. This weakens the support for the mechanism as a general feature rather than model-specific.

    Authors: We acknowledge that the current manuscript does not include quantitative sensitivity tests or ensemble statistics for the South American case. In the revised version we will add (i) experiments with varied nudging relaxation timescales and perturbation amplitudes, (ii) results from an ensemble of at least three realizations per experiment, and (iii) a brief quantification of the range in the Pacific SST gradient response. These additions will provide a clearer assessment of robustness while preserving the overall conclusions. revision: yes

Circularity Check

0 steps flagged

No significant circularity: results emerge from forward coupled-model simulations with imposed LST perturbations

full rationale

The paper's derivation consists of running a state-of-the-art coupled ocean-land-atmosphere model under externally imposed regional LST perturbations (via nudging and idealized ramp warming). The reported SST gradient strengthening, diabatic heating contrasts, stationary Rossby wave responses, and alongshore wind changes are model outputs, not quantities fitted to match target SST patterns or defined in terms of themselves. No load-bearing steps reduce by construction to the inputs, no self-citations justify uniqueness theorems or ansatzes, and no renaming of known results occurs. The chain is self-contained forward modeling whose validity can be assessed against external benchmarks or alternative forcing methods.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim depends on the fidelity of the coupled model physics and the assumption that nudging imposes realistic land temperature anomalies without major side effects. No explicit free parameters or new entities are introduced in the abstract.

axioms (1)
  • domain assumption The state-of-the-art coupled ocean-land-atmosphere model faithfully represents physical interactions between land surface temperature and atmospheric circulation.
    Invoked when using model responses to imposed LST perturbations to infer real-world remote influences.

pith-pipeline@v0.9.0 · 5507 in / 1249 out tokens · 43698 ms · 2026-05-14T00:39:20.616367+00:00 · methodology

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Reference graph

Works this paper leans on

17 extracted references · 17 canonical work pages

  1. [1]

    Chadwick, D

    Ackerley, D., R. Chadwick, D. Dommenget, and P. Petrelli, 2018: An ensemble of amip simulations with prescribed land surface temperatures.Geoscientific Model Development,11 (9), 3865–3881. Ackerley, D., and D. Dommenget, 2016: Atmosphere-only gcm (access1

    work page 2018

  2. [2]

    Alessi, M

    simulations with prescribed land surface temperatures.Geoscientific Model Development,9 (6), 2077–2098. Alessi, M. J., and M. A. Rugenstein, 2023: Surface temperature pattern scenarios suggest higher warming rates than current projections.Geophysical Research Letters,50 (23), e2023GL105

    work page 2077

  3. [3]

    Andrews, T., C. J. Smith, G. Myhre, P. M. Forster, R. Chadwick, and D. Ackerley, 2021: Effective radiative forcing in a gcm with fixed surface temperatures.Journal of Geophysical Research: Atmospheres,126 (4), e2020JD033

    work page 2021

  4. [4]

    Bloch-Johnson, J., and Coauthors, 2024: The Green’s Function Model Intercomparison Project (GFMIP) Protocol.Journal of Advances in Modeling Earth Systems,16 (2), e2023MS003

    work page 2024

  5. [5]

    D., and Coauthors, 1990: Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models.J

    Cess, R. D., and Coauthors, 1990: Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models.J. Geophys. Res.,95, 16 601–16

    work page 1990

  6. [6]

    23 Chen, Y.-T., T. M. Merlis, T. Dinh, S. M. Griffies, J. P. Krasting, R. Dussin, N. Zadeh, and S. Fueglistaler, 2025: Assessing Earth’s energy imbalance trend in the early 21st century in two high-resolution coupled models.Authorea Preprints. Clement, A. C., R. Seager, M. A. Cane, and S. E. Zebiak, 1996: An ocean dynamical thermostat. J. Climate,9, 2190–...

    work page 2025

  7. [7]

    Proistosescu, K

    Dong, Y., C. Proistosescu, K. C. Armour, and D. S. Battisti, 2019: Attributing historical and future evolution of radiative feedbacks to regional warming patterns using a Green’s function approach: The preeminence of the western Pacific.Journal of Climate,32 (17), 5471–5491. Emanuel, K. A., J. D. Neelin, and C. S. Bretherton, 1994: On large-scale circulat...

    work page 2019

  8. [8]

    Meyssignac, 2025: Quantifying the influence of the sea surface temperature pattern effect on transient global warming.Journal of Climate

    24 Guillaume-Castel, R., and B. Meyssignac, 2025: Quantifying the influence of the sea surface temperature pattern effect on transient global warming.Journal of Climate. G¨ unther, M., S. M. Kang, and Y. Kaspi, 2025: Heating the land cools the eastern and equatorial pacific. Harris, I., T. J. Osborn, P. Jones, and D. Lister, 2020: Version 4 of the cru ts ...

    work page 2025

  9. [9]

    L., 2022: The antarctic ozone hole and the pattern effect on climate sensitivity

    Hartmann, D. L., 2022: The antarctic ozone hole and the pattern effect on climate sensitivity. Proceedings of the National Academy of Sciences,119 (35), e2207889

    work page 2022

  10. [10]

    Hersbach, H., and Coauthors, 2020: The era5 global reanalysis.Quarterly journal of the royal meteorological society,146 (730), 1999–2049. Kang, S. M., D. A. Putrasahan, N. G. Brizuela, H. Haak, J. Kr¨oger, J. Marotzke, B. Stevens, and J.- S. von Storch, 2026: Km-scale coupled simulation and model–observation sst trend discrepancy. Proceedings of the Natio...

    work page 2020

  11. [11]

    Ceppi, 2025: Responses to lower-tropospheric stability dominate in- termodel differences in the historical pattern effect.Geophysical Research Letters,52 (17), e2025GL117

    Kawaguchi, K., and P. Ceppi, 2025: Responses to lower-tropospheric stability dominate in- termodel differences in the historical pattern effect.Geophysical Research Letters,52 (17), e2025GL117

    work page 2025

  12. [12]

    Kim, H., S. M. Kang, J. E. Kay, and S.-P. Xie, 2022: Subtropical clouds key to southern ocean tele- connections to the tropical pacific.Proceedings of the National Academy of Sciences,119 (34), e2200514

    work page 2022

  13. [13]

    R., and S

    Knutson, T. R., and S. Manabe, 1995: Time-mean response over the tropical Pacific to increased CO2 in a coupled oc ean-atmosphere model.J. Climate,8, 2181–2199. Liu, Y., G. Wu, and R. Ren, 2004: Relationship between the subtropical anticyclone and diabatic heating.Journal of Climate,17 (4), 682–698. Merlis, T. M., 2025: Perturbing the surface energy balan...

    work page 1995

  14. [14]

    Meteorological Monographs,59, 14–1

    Ramaswamy, V., and Coauthors, 2019: Radiative forcing of climate: The historical evolution of the radiative forcing concept, the forcing agents and their quantification, and applications. Meteorological Monographs,59, 14–1. Rodwell, M. J., and B. J. Hoskins, 2001: Subtropical anticyclones and summer monsoons.Journal of Climate,14 (15), 3192–3211. Rohde, R...

    work page 2019

  15. [15]

    Wills, R. C., Y. Dong, C. Proistosecu, K. C. Armour, and D. S. Battisti, 2022: Systematic climate model biases in the large-scale patterns of recent sea-surface temperature and sea-level pressure change.Geophysical Research Letters,49 (17), e2022GL100

    work page 2022

  16. [16]

    Zhang, B., B. J. Soden, H. He, and R. J. Kramer, 2026: Decoupling land surface effects from co 2 effective radiative forcing in a climate model.Journal of Climate,39 (1), 65–76. Zhang, B., M. Zhao, and Z. Tan, 2023: Using a Green’s function approach to diagnose the pattern effect in GFDL AM4 and CM4.Journal of Climate,36 (4), 1105–1124. Zhang, L., and T. ...

    work page 2026

  17. [17]

    Zhou, C., M

    model description, sensitivity studies, and tuning strategies.Journal of Advances in Modeling Earth Systems,10 (3), 735–769. Zhou, C., M. D. Zelinka, and S. A. Klein, 2017: Analyzing the dependence of global cloud feedback on the spatial pattern of sea surface temperature change with a Green’s function approach.Journal of Advances in Modeling Earth System...

    work page 2017