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

Atmospheric Research, Journal Year: 2024, Volume and Issue: 300, P. 107227 - 107227

Published: Jan. 6, 2024

Language: Английский

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Recent European drying and its link to prevailing large-scale atmospheric patterns

Scientific Reports, Journal Year: 2023, Volume and Issue: 13(1)

Published: Dec. 8, 2023

Abstract The extreme 2018 and 2022 droughts pose as recent examples of a series drought events that have hit Europe over the last decades with wide ranging social, environmental economic impacts. Although link between atmospheric circulation meteorological is clear often highlighted during major events, there lack in-depth studies linking historical changes in indices prevailing large-scale patterns Europe. To meet this shortfall, we investigated relation drought, indicated by geopotential height at 500mb (Z500) Standardised Precipitation-Evapotranspiration Index (SPEI), respectively. Calculations were done separately for four climate regions (North, West, Central-East Mediterranean) growing season (March–September). Coherent significant towards higher pressure (increasing Z500) drier conditions (decreasing SPEI) 1979–2021 are found West spring summer. Z500 SPEI strongly linked, reflected both (1979–2021) correlations high co-occurrences (69-96%) high-pressure anomaly occurrences since 1900. North shows most heterogeneous trend weakest links, but constitutes hotspot significantly increasing September. Finally, performed an ensemble-based, European analysis future Z500, based on CMIP6 low-end (SSP126) high-end (SSP585) 21st century emission scenarios. According to projected changes, anomalously systems will be new normal regardless scenario, well exceeding levels case scenario. However, due limitations model ensemble represent spatial heterogeneity variability trends (1979–2014), circulation, associated droughts, highly uncertain. This paper provides insight into Europe, their strong links observed drying trends, inability reproduce changes.

Language: Английский

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Underestimated Ural blocking events lead to weakened spring Arctic warming in CMIP6 simulations

Climate Dynamics, Journal Year: 2025, Volume and Issue: 63(3)

Published: Feb. 26, 2025

Language: Английский

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Influence of high-latitude blocking and the northern stratospheric polar vortex on cold-air outbreaks under Arctic amplification of global warming

Environmental Research Climate, Journal Year: 2024, Volume and Issue: 3(4), P. 042004 - 042004

Published: Nov. 18, 2024

Abstract It is widely accepted that Arctic amplification (AA)—enhanced warming relative to global warming—will increasingly moderate cold-air outbreaks (CAOs) the midlatitudes. Yet, some recent studies also argue AA over last three decades rest of present century may contribute more frequent severe winter weather including disruptive cold spells. To prepare society for future extremes, it necessary resolve whether and midlatitude are coincidental or physically linked. Severe events in northern continents often related a range stratospheric polar vortex (SPV) configurations atmospheric blocking, but these dynamical drivers complex still not fully understood. Here we review research advances paradigms nonlinear theory blocking helps explain location, timing duration AA/midlatitude connections, vortex’s zonal asymmetric intra-seasonal variations, its southward migration continents, surface impacts. We highlight novel understanding SPV variability—polar stretching stratosphere–troposphere oscillation—that have remained mostly hidden predominant focus on sudden warmings. A physical explanation two-way vertical coupling process between highs, taking into account local conditions, remains elusive. conclude evidence exists tropical preconditioning Arctic-midlatitude climate linkages. Recent using very large-ensemble modelling provides an emerging opportunity robustly quantify internal variability when studying potential response CAOs sea-ice loss.

Language: Английский

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Strengthened Impact of Late Autumn Arctic Sea Ice on Asian Winter Cold Extremes after 1999/2000

Environmental Research Letters, Journal Year: 2024, Volume and Issue: 19(7), P. 074045 - 074045

Published: June 13, 2024

Abstract Winter cold extremes (WCEs) frequently plague densely populated areas of Asia, leading to substantial economic losses and even fatalities. It has been found that the late autumn sea ice concentration (SIC) anomalies in northern (SICN) southern Arctic (SICS) are significantly positively negatively correlated with occurrence frequency WCE respectively (Wang Su 2024). Our study demonstrates impacts SICN SICS have strengthened after 1999/2000. Specifically, before 1999/2000, influences on Asian (AWCE) were relatively weak, possibly related weak intensity limited correlation between SICS. After interannual variability became larger anti-correlated SICN, resulting a stronger teleconnection SIC AWCE. is revealed greater loss modified atmospheric stability through changes surface heat fluxes upward longwave radiation fluxes. This alteration weakened magnitudes westerly winds increased blocking events over Eurasian continent, directly higher Asia. These interdecadal differences influence AWCE may be associated long-term climate change.

Language: Английский

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Effect of stratospheric temperature perturbation on the onset of Ural blocking events in winter

Quarterly Journal of the Royal Meteorological Society, Journal Year: 2025, Volume and Issue: unknown

Published: May 2, 2025

Abstract The impact of stratospheric temperature uncertainty on ural blocking (UB) onset is investigated by utilizing the Open Integrated Forecasting System model. results reveal that optimal initial perturbation obtained conditional nonlinear (CNOP) approach could obviously suppress UB onset, leading to weakening or even collapse UB. This contains multiple‐scale signals mainly located in upper stratosphere and upstream sector. Further diagnosis indicates develops causes anomalous Eliassen–Palm (E‐P) flux propagating downward into troposphere. planetary wave activity further contributes tropospheric energy divergence. Then, an enhanced meridional gradient zonal winds appear Ural its adjacent sectors. Moreover, sector dominated increased potential vorticity gradient. Eventually, weakened during phase. different scales explored. Numerical show perturbations at calculated via CNOP method clearly onset. It noted these have similar effects shows with spatial distributions tend evolve specific planetary‐scale perturbations. above are key factors explaining analogous These emphasize notable role which deepens our understanding stratosphere–troposphere coupling. contribute implementation targeted observations improve predictions.

Language: Английский

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Observed winter Barents Kara Sea ice variations induce prominent sub-decadal variability and a multi-decadal trend in the Warm Arctic Cold Eurasia pattern

Environmental Research Letters, Journal Year: 2024, Volume and Issue: 19(2), P. 024018 - 024018

Published: Jan. 8, 2024

Abstract The observed winter Barents-Kara Sea (BKS) sea ice concentration (SIC) has shown a close association with the second empirical orthogonal function (EOF) mode of Eurasian surface air temperature (SAT) variability, known as Warm Arctic Cold Eurasia (WACE) pattern. However, potential role BKS SIC on this WACE pattern variability and its long-term trend remains elusive. Here, we show that from 1979 to 2022, is most prominent statistically significant for at sub-decadal time scale 5–6 years. We also critical multi-decadal in principal component explaining overall over same period. Furthermore, large multi-model ensemble atmosphere-only experiments 2014, without forcing, suggests variations induce WACE. Additionally, analyse model simulated first or leading EOF SAT which observations, closely relates Oscillation (AO). find weaker AO positive our simulation, opposite found observation. This contrasting nature reflects excessive hemispheric warming models, partly contributed by modelled loss.

Language: Английский

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Weather whiplash events in Europe and North Atlantic assessed as continental-scale atmospheric regime shifts

npj Climate and Atmospheric Science, Journal Year: 2023, Volume and Issue: 6(1)

Published: Dec. 21, 2023

Abstract The term “weather whiplash” describes abrupt transitions from one persistent weather regime to another substantially different one, such as a frigid cold spell anomalous warmth. Weather whiplash events (WWEs) are often highly disruptive agriculture, ecosystems, infrastructure, and human activities. While no consistent definition exists, we identify WWEs based on substantial shifts in the continental-scale, upper-atmosphere circulation. As first demonstrated our earlier study focused NE Pacific/North American region, WWE is detected when persistent, large-scale pattern 500 hPa height anomalies distinctly one. Patterns identified using self-organizing maps (SOMs), which create matrix of representative patterns data. In present study, apply this approach North Atlantic/European sector. We analyze occurrence originating with long-duration (four or more days) each pattern. A two days following event different, measured distance thresholds internal matrix. Changes frequency, past future, assessed objectively reanalysis output climate model simulations. find that future changes under RCP 8.5 forcing exhibit distinct trends, especially summer months, while those less clear. featuring positive high latitudes projected produce exhibiting negative fewer. Shifts temperature precipitation extremes associated these diagnosed.

Language: Английский

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Different influences of La Niña types on the winter sub-seasonal Eurasian cold anomalies linked to Ural blocking

Atmospheric Research, Journal Year: 2023, Volume and Issue: 299, P. 107172 - 107172

Published: Dec. 13, 2023

Language: Английский

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Arctic springtime temperature and energy flux interannual variability is driven by 1- to 2-week frequency atmospheric events

Weather and Climate Extremes, Journal Year: 2024, Volume and Issue: 43, P. 100650 - 100650

Published: Feb. 9, 2024

The Arctic is experiencing amplified climate warming, decreasing sea ice extent, increasingly earlier springtime snowmelt, and a related increase in fire activity. transition from cold to warm season the strongly varies between years, but our understanding of temperature surface energy budget changes over limited. Here we investigate intraseasonal variability components their interannual trends 40 years (1981–2020) across terrestrial (above 60° N) using ERA5-Land reanalysis data. We found central western Siberian regions have highest spring anomaly among all during 40-year period. Also this region, discovered strength increased for heat extremes decreased when comparing first last 20 study. Peaks composited extreme anomalies were observed occur concurrently, indicating are not driven by components. Lastly, utilizing power spectrum analyses, identified primary driver be operating at 1- 2-week frequency. Based on findings observations recent literature, hypothesize that can attributed decline an frequency associated atmospheric blocking events.

Language: Английский

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