From CMIP3 to CMIP6: Northern Hemisphere Atmospheric Blocking Simulation in Present and Future Climate

Journal of Climate, Год журнала: 2020, Номер 33(23), С. 10021 - 10038

Опубликована: Авг. 17, 2020

Abstract A comprehensive analysis of the representation winter and summer Northern Hemisphere atmospheric blocking in global climate simulations both present future is presented. Three generations models are considered: CMIP3 (2007), CMIP5 (2012), CMIP6 (2019). All show common extended underestimation frequencies, but a reduction negative biases successive model observed. However, some specific regions seasons such as European sector, even not yet able to achieve observed frequency. For decades vast majority simulate decrease frequency summer, with exception over Urals western North America. Winter predicted decreases may be larger than currently estimated considering that hence generally smaller errors, reduction. Nonetheless, trends computed historical period weak often contrast observations: this particularly worrisome for Greenland where observations significantly disagree. Finally, intensity warming related changes: wintertime Pacific expected following mean temperatures, while Ural increase.

Язык: Английский

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How do intermittency and simultaneous processes obfuscate the Arctic influence on midlatitude winter extreme weather events?

Environmental Research Letters, Год журнала: 2021, Номер 16(4), С. 043002 - 043002

Опубликована: Янв. 14, 2021

Abstract Pronounced changes in the Arctic environment add a new potential driver of anomalous weather patterns midlatitudes that affect billions people. Recent studies these Arctic/midlatitude linkages, however, state inconsistent conclusions. A source uncertainty arises from chaotic nature atmosphere. Thermodynamic forcing by rapidly warming contributes to events through changing surface heat fluxes and large-scale temperature pressure gradients. But internal shifts atmospheric dynamics—the variability location, strength, character jet stream, blocking, stratospheric polar vortex (SPV)—obscure direct causes effects. It is important understand associated processes differentiate Arctic-forced natural variability. For example early winter, reduced Barents/Kara Seas sea-ice coverage may reinforce existing teleconnections between North Atlantic/Arctic central Asia, downstream East Asia. Reduced sea ice Chukchi Sea can amplify ridging high near Alaska, influencing across America. In late winter southward displacement SPV, coupled troposphere, leads extremes Eurasia Combined tropical conditions modulate SPV. Observational evidence for linkages continues accumulate, along with understanding connections pre-existing climate states. Relative variability, loss alone has played secondary role linkages; full influence amplification remains uncertain.

Язык: Английский

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Seasonal Cumulative Effect of Ural Blocking Episodes on the Frequent Cold events in China during the Early Winter of 2020/21

Advances in Atmospheric Sciences, Год журнала: 2022, Номер 39(4), С. 609 - 624

Опубликована: Янв. 7, 2022

Abstract Starting in mid-November, China was hit by several cold events during the early winter of 2020/21. The lowest temperature observed at Beijing station on 7 January reached −19.6°C. In this paper, we show that outbreak record-breaking extreme event can be attributed to a huge merging Ural blocking (UB) ridge over Eurasian region. sea-ice cover Kara and East Siberia Seas (KESS) autumn its value since 1979, which could have served as precursor signal. Further analysis shows successive UB episodes occurred from 1 September 2020 10 2021. persistent late September/early October may made an important contribution historical minimum sea ice KESS Our results also that, after each episode winter, significant upward propagation wave activity around 60°E, resulted weakening stratospheric vortex. Meanwhile, caused reduction extent westerly jet mid–high-latitude Eurasia. Results suggest Arctic vortex, is supposed enhance seasonally, became weaker more unstable than climatic mean under seasonal cumulative effects episodes, warming, long-lasting negative-phase North Atlantic Oscillation (NAO–). Those effects, combined with impact La Niña led frequent occurrence events.

Язык: Английский

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Eurasian Cooling Linked to the Vertical Distribution of Arctic Warming

Geophysical Research Letters, Год журнала: 2020, Номер 47(10)

Опубликована: Апрель 24, 2020

Abstract Observations show that deep Arctic winter warming, extending from surface to mid‐troposphere, has concurred with below‐average temperature over central Eurasia. Modeling studies focusing on the response sea ice loss have shown warming but no consistent atmospheric changes at midlatitude. Using a large number of simulations coupled and uncoupled climate models, we Eurasian temperatures are more frequent in winters compared shallow, near‐surface Barents‐Kara Seas. Dramatic weakening midlatitude jet stream increase Ural blocking frequency likely occur warming. Deep is independent forcing follows increased poleward energy moisture advection North Atlantic Arctic, indicating internal natural variability not main driving for warming‐cold Eurasia pattern historical simulations.

Язык: Английский

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Northern hemisphere cold air outbreaks are more likely to be severe during weak polar vortex conditions

Communications Earth & Environment, Год журнала: 2021, Номер 2(1)

Опубликована: Июль 23, 2021

Abstract Severe cold air outbreaks have significant impacts on human health, energy use, agriculture, and transportation. Anomalous behavior of the Arctic stratospheric polar vortex provides an important source subseasonal-to-seasonal predictability Northern Hemisphere outbreaks. Here, through reanalysis data for period 1958–2019 climate model simulations preindustrial conditions, we show that weak conditions increase risk severe in mid-latitude East Asia by 100%, contrast to only 40% moderate Such a disproportionate is also found Europe, with elevated persisting more than three weeks. By analysing stream mass, affects modifying inter-hemispheric transport mass. Using novel method assess Granger causality, predictive information regarding over multiple regions Hemisphere, which may help mitigating their impact.

Язык: Английский

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Extreme Cold Events from East Asia to North America in Winter 2020/21: Comparisons, Causes, and Future Implications

Advances in Atmospheric Sciences, Год журнала: 2021, Номер 39(4), С. 553 - 565

Опубликована: Авг. 9, 2021

Язык: Английский

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Impact of Pacific blocking on the intraseasonal winter sea ice seesaw between the Bering and Okhotsk Seas

Atmospheric Research, Год журнала: 2024, Номер 300, С. 107227 - 107227

Опубликована: Янв. 6, 2024

Язык: Английский

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On the role of Ural Blocking in driving the Warm Arctic–Cold Siberia pattern

Quarterly Journal of the Royal Meteorological Society, Год журнала: 2020, Номер 146(730), С. 2138 - 2153

Опубликована: Март 13, 2020

Abstract We use reanalysis data to substantiate the role of Ural blocking (UB) in driving Warm Arctic–Cold Siberia (WACS) pattern, which represents an anti‐correlation surface temperature between Barents–Kara Seas and central Asia. confirm a robust link UB WACS pattern on daily subseasonal time‐scales. controls pace pattern; warming over cooling Asia peak 3–5 days after onset. The observed sea ice deficit weeks prior onset is not statistically significant when long‐term trend removed. Thus, may have direct impact occurrence but it develops as delayed response UB. interannual variability also strongly linked identify upward wintertime recent decades that accounts for rate 1°C/decade Over Seas, trends explain small fraction warming, dominated by Arctic amplification. Finally, ERA‐Interim period weaker during 1990s lowest activity was observed.

Язык: Английский

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Impact of Ural Blocking on Early Winter Climate Variability Under Different Barents‐Kara Sea Ice Conditions

Journal of Geophysical Research Atmospheres, Год журнала: 2023, Номер 128(6)

Опубликована: Март 8, 2023

Abstract Ural blocking (UB) is a prominent mode of variability the Northern Hemisphere atmospheric circulation, particularly in fall. It can persist for several days and exert lagged influence on wintertime NH providing predictability at subseasonal time scale. Using two models, we explore how early winter circulation responds to 2‐week persistent UB anomaly imposed November. Experiments are carried out with different configurations Barents‐Kara (BK) sea‐ice concentration examine whether it plays role impacts variability. In both followed by weakening stratospheric polar vortex negative phase North Atlantic Oscillation (NAO), which lasts up 2 months after forcing released. Interestingly, response more under low BK conditions, that is, sea ice modulates UB. Additional experiments prescribed anomalies alone suggest exerts limited The involves persists longer ice, explains configuration. Our study highlights November robust precursor NAO/polar stratosphere anomalies, this may be relevant context declining Arctic extent. Provided climate models accurately capture teleconnection, has potential improve predictions climate.

Язык: Английский

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The role of Barents–Kara sea ice loss in projected polar vortex changes

Weather and Climate Dynamics, Год журнала: 2020, Номер 1(2), С. 715 - 730

Опубликована: Ноя. 20, 2020

Abstract. The Northern Hemisphere stratospheric polar vortex (SPV) plays a key role in mid-latitude weather and climate. However, what way the SPV will respond to global warming is not clear, with climate models disagreeing on sign magnitude of projected strength change. Here we address potential Barents Kara (BK) sea ice loss this. We provide evidence for non-linear response mean temperature change, which coincident time BK seas become ice-free. Using causal network approach, demonstrate that show some partial support previously proposed link between low autumn weakened winter but this effect plausibly very small relative internal variability. Yet, given expected dramatic decrease future, even can explain all ensemble-mean weakening, approximately one-half ensemble spread middle 21st century, one-third at end century. Finally, note most have unrealistic amounts ice, meaning their unrealistic. Bias adjusting leads pronounced differences individual both ends spectrum has no strong consequences overall spread. Overall, our results indicate importance exploring plausible implications changing Arctic regional risk assessments.

Язык: Английский

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