Cold‐Season Arctic Amplification Driven by Arctic Ocean‐Mediated Seasonal Energy Transfer

Chung, Eui‐Seok; Ha, Kyung‐Ja; Timmermann, Axel; Stuecker, Malte F.; Bódai, Tamás; Lee, Sang Ki

doi:10.1029/2020ef001898

Cited by 49 publications

(67 citation statements)

References 63 publications

(186 reference statements)

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“…Despite reduced seasonal ocean heat storage, the winter lapse-rate feedback remains similarly strong in the No ice, set albedo experiment compared to the Ice experiment. In contrast to the hypothesis of Dai et al (2019) and Chung et al (2021), these results suggest that seasonal heat transfer related to sea-ice insulation loss is not necessary for a strong wintertime lapse-rate feedback.…”

Section: Mechanisms Linking Sea Ice To Seasonality In Arctic Warmingcontrasting

confidence: 99%

“…As a result, a more-positive lapse-rate feedback in winter could result from any process that promotes stronger bottom-heavy atmospheric warming, including the ice-albedo feedback (Feldl et al, 2017;Graversen et al, 2014). Dai et al (2019) and Chung et al (2021) further suggest that seasonal ocean heat storage and sea-ice insulation loss are necessary to kickstart the winter lapse-rate feedback via increased turbulent heat release to the atmosphere over newly opened ocean. Separating these potentially interdependent icealbedo, seasonal ocean heat storage, and insulation effects of sea-ice loss and their impact on the lapse-rate feedback remains a challenge in comprehensive climate models.…”

Section: Introductionmentioning

confidence: 99%

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Seasonality in Arctic Warming Driven By Sea Ice Effective Heat Capacity

Hahn¹,

Armour²,

Battisti³

et al. 2021

Preprint

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Arctic surface warming under greenhouse gas forcing peaks in early winter and reaches its minimum during summer in both observations and model projections. Many mechanisms have been proposed to explain this seasonal asymmetry, but disentangling these processes remains a challenge in the interpretation of general circulation model (GCM) experiments. To isolate these mechanisms, we use an idealized single-column sea ice model (SCM) which captures the seasonal pattern of Arctic warming. SCM experiments demonstrate that as sea ice melts and exposes open ocean, the accompanying increase in effective surface heat capacity can alone produce the observed pattern of peak early winter warming by slowing the seasonal heating and cooling rate, thus delaying the phase and reducing the amplitude of the seasonal cycle of surface temperature. To investigate warming seasonality in more complex models, we perform GCM experiments that individually isolate sea-ice albedo and thermodynamic effects under CO2 forcing. These also show a key role for the effective heat capacity of sea ice in promoting seasonal asymmetry through suppressing summer warming, in addition to precluding summer climatological inversions and a positive summer lapse-rate feedback. Peak winter warming in GCM experiments is further supported by a positive winter lapse-rate feedback that persists with only the albedo effects of sea-ice loss prescribed, due to cold initial surface temperatures and strong surface-trapped warming. While many factors support peak early winter warming as Arctic sea ice declines, these results highlight changes in effective surface heat capacity as a central mechanism contributing to this seasonality.

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Section: Mechanisms Linking Sea Ice To Seasonality In Arctic Warmingcontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Seasonality in Arctic Warming Driven By Sea Ice Effective Heat Capacity

Hahn¹,

Armour²,

Battisti³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…For example, the strength of the lapse-rate feedback may be impacted by the amount of surface warming contributed by the albedo feedback (Graversen et al, 2014;Feldl et al, 2017) and mixed-phase cloud changes (Tan and Storelvmo, 2019), but the warming contribution method diagnoses the contributions of surface albedo, cloud, and lapse-rate changes separately. Others have argued that a strong winter lapse-rate feedback additionally requires seasonal ocean heat storage and sea-ice insulation loss in order to increase surface turbulent heat fluxes and upward longwave radiation, promoting warming in the lower-troposphere (Dai et al, 2019;Feldl et al, 2020;Chung et al, 2021). As demonstrated by these studies, experiments isolating specific mechanisms in climate models are needed to fully address the interconnected feedbacks promoting polar amplification.…”

Section: Discussionmentioning

confidence: 99%

Contributions to Polar Amplification in CMIP5 and CMIP6 Models

et al. 2021

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As a step towards understanding the fundamental drivers of polar climate change, we evaluate contributions to polar warming and its seasonal and hemispheric asymmetries in Coupled Model Intercomparison Project phase 6 (CMIP6) as compared with CMIP5. CMIP6 models broadly capture the observed pattern of surface- and winter-dominated Arctic warming that has outpaced both tropical and Antarctic warming in recent decades. For both CMIP5 and CMIP6, CO2 quadrupling experiments reveal that the lapse-rate and surface albedo feedbacks contribute most to stronger warming in the Arctic than the tropics or Antarctic. The relative strength of the polar surface albedo feedback in comparison to the lapse-rate feedback is sensitive to the choice of radiative kernel, and the albedo feedback contributes most to intermodel spread in polar warming at both poles. By separately calculating moist and dry atmospheric heat transport, we show that increased poleward moisture transport is another important driver of Arctic amplification and the largest contributor to projected Antarctic warming. Seasonal ocean heat storage and winter-amplified temperature feedbacks contribute most to the winter peak in warming in the Arctic and a weaker winter peak in the Antarctic. In comparison with CMIP5, stronger polar warming in CMIP6 results from a larger surface albedo feedback at both poles, combined with less-negative cloud feedbacks in the Arctic and increased poleward moisture transport in the Antarctic. However, normalizing by the global-mean surface warming yields a similar degree of Arctic amplification and only slightly increased Antarctic amplification in CMIP6 compared to CMIP5.

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“…S4), exhibits preferential warming of the eastern relative to the western equatorial Pacific, Arctic amplification, and a pronounced warming hole over the subpolar North Atlantic. These features are associated with the known mechanisms of the enhanced equatorial warming pattern (33), and more positive polar feedbacks (34) including the Arctic heat capacitor (35), and the slowdown of the AMOC (36,37), respectively. For precipitation (Fig 2, central; fig.…”

Section: Mean State Changesmentioning

confidence: 93%

Ubiquity of human-induced changes in climate variability

Rodgers¹,

Lee²,

Rosenbloom³

et al. 2022

Preprint

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While climate change mitigation targets necessarily concern maximum mean state changes, understanding impacts and developing adaptation strategies will be largely contingent on how climate variability responds to increasing anthropogenic perturbations. Here we present a new 100-member large ensemble of climate change projections conducted with the Community Earth System Model version 2 to examine the sensitivity of internal climate fluctuations to greenhouse warming. Our unprecedented simulations reveal that changes in variability, considered broadly in terms of probability distribution, amplitude, frequency, phasing, and patterns, are ubiquitous and span a wide range of physical and ecosystem variables across many spatial and temporal scales. Greenhouse warming will in particular alter variance spectra of Earth system variables that are characterized by non-Gaussian probability distributions, such as rainfall, primary production or fire occurrence. Our modeling results have important implications for climate adaptation efforts, resource management, and for seasonal predictions.

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Cold‐Season Arctic Amplification Driven by Arctic Ocean‐Mediated Seasonal Energy Transfer

Cited by 49 publications

References 63 publications

Seasonality in Arctic Warming Driven By Sea Ice Effective Heat Capacity

Seasonality in Arctic Warming Driven By Sea Ice Effective Heat Capacity

Contributions to Polar Amplification in CMIP5 and CMIP6 Models

Ubiquity of human-induced changes in climate variability

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