Increasing occurrence of heat waves in the terrestrial Arctic

Environmental Research Letters, Год журнала: 2019, Номер 15(2), С. 024022 - 024022

Опубликована: Дек. 18, 2019

Abstract Heat waves in the Arctic may strongly impact environment and local communities. Recently several indices have been proposed for monitoring environmental changes Arctic, but heat not addressed. By applying a structured approach evaluating occurrences of periods with exceptionally high temperatures, this study demonstrates that last decades there was an increase wave over terrestrial Arctic. The is mainly Canadian Archipelago Greenland are surrounded by ocean undergoing sea-ice melting trend, while Eurasian shows no significant change occurrence. Since 2002 probability experiencing has similar or even higher than middle low latitudes already started to increasingly threaten vegetation, ecology, human health economy.

Язык: Английский

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Sea surface temperature variability in the Arctic Ocean and its marginal seas in a changing climate: Patterns and mechanisms

Global and Planetary Change, Год журнала: 2020, Номер 193, С. 103265 - 103265

Опубликована: Июль 8, 2020

Язык: Английский

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Observed Antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Фев. 16, 2021

The Antarctic sea ice area expanded significantly during 1979-2015. This is at odds with state-of-the-art climate models, which typically simulate a receding cover in response to increasing greenhouse forcing. Here, we investigate the hypothesis that this discrepancy between models and observations occurs due simulation biases drift velocity. As control use Community Earth System Model (CESM) Large Ensemble, has 40 realizations of past future change all undergo retreat recent decades. We modify CESM replace simulated velocity field satellite-derived estimate observed motion, 3 change. find expands these realizations, spatial structure expansion bearing resemblance observations. results suggest reason failed capture velocity, implying an improved representation motion crucial for more accurate projections.

Язык: Английский

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A Connection of Winter Eurasian Cold Anomaly to the Modulation of Ural Blocking by ENSO

Geophysical Research Letters, Год журнала: 2021, Номер 48(17)

Опубликована: Авг. 27, 2021

Abstract This study investigates how El Niño‐Southern Oscillation (ENSO) modulates winter cold anomalies over central Eurasia (CE) using reanalysis data during 1950–2019. It is found that ENSO can significantly influence air temperature CE mainly through modulating the strength and location of cyclonic anomaly Ural blocking (UB) or long‐lived UB events. A strong (weak) on southeastern (eastern) side Mountains tends to occur midlatitude (high‐latitude) La Niña (El Niño) winters. Such anomalous circulation leads a CE, especially East Asia, due enhanced (weakened) advection toward Niño). The UB‐related in (high latitude) shown be related weakened (enhanced) eastward extension westerly winds

Язык: Английский

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Antarctic skin temperature warming related to enhanced downward longwave radiation associated with increased atmospheric advection of moisture and temperature

Environmental Research Letters, Год журнала: 2021, Номер 16(6), С. 064059 - 064059

Опубликована: Май 17, 2021

Abstract We investigate linear trends in Antarctic skin temperatures (temperatures from about the top millimeter of surface) over four seasons using ERA5 ensemble mean reanalysis data. During 1950–2020, statistically significant warming occurred East and West Antarctica spring, autumn winter, Peninsula winter. A surface energy budget analysis revealed that increases downward longwave radiation related to air temperature total column integrated cloud had a key role warming. There were negative sea level pressure around periphery throughout year, associated circulation contributed warm advection middle latitudes Peninsula. Over interior Antarctica, increase moisture lower enhanced low-level cover. two-dimensional parameter diagram showed for time segments longer than 30 years starting before 1960 exhibited winter In also long segments. summer, cooling less years. For all studied intervals, when positive trends, more 70% vice versa. This result demonstrates on space scales, changes with variations atmospheric loading play dominant controlling temperatures.

Язык: Английский

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Temperature and precipitation projections for the Antarctic Peninsula over the next two decades: contrasting global and regional climate model simulations

Climate Dynamics, Год журнала: 2021, Номер 56(11-12), С. 3853 - 3874

Опубликована: Фев. 8, 2021

Язык: Английский

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Record low sea ice extent in the Weddell Sea, Antarctica in April/May 2019 driven by intense and explosive polar cyclones

npj Climate and Atmospheric Science, Год журнала: 2022, Номер 5(1)

Опубликована: Март 18, 2022

Abstract Sea ice extent (SIE) in the Weddell attained exceptionally low levels April (1.97 million km 2 ) and May (3.06 2019, with values being ~22% below long-term mean. Using in-situ, satellite atmospheric reanalysis data, we show large negative SIE anomalies were driven by passage of a series intense explosive polar cyclones (with record pressure), also known as ‘bombs’, which had rivers on their eastern flanks. These storms led to poleward propagation record-high swell wind waves (~9.6 m), resulting southward advection (~50 km). Thermodynamic processes played part, including anomalous heat (>138 W m −2 moisture (>300 kg −1 s fluxes from midlatitudes, along ocean mixed-layer warming (>2 °C). The circulation associated an amplified wave number three pattern leading enhanced meridional flow between midlatitudes Antarctic.

Язык: Английский

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Trends in the tropospheric general circulation from 1979 to 2022

Weather and Climate Dynamics, Год журнала: 2022, Номер 3(3), С. 777 - 809

Опубликована: Июль 21, 2022

Abstract. Atmospheric general circulation changes from March 1979 to February 2022 are examined using the ERA5 reanalysis. Maps of linear trends and time series for specific areas presented. Attention is concentrated on monthly, seasonal annual means, but shorter-timescale variability also considered, including extremes. Changes in near-tropopause winds main focus, related temperature, wind other variables throughout troposphere discussed. Middle- upper-tropospheric warming larger subtropics outer tropics than deep tropics, except over Pacific. This linked with a strengthening meridional expansion tropical easterlies that has received little previous attention. The change occurs predominantly first half period. Warming several mid-latitude subtropical land comes close matching large Arctic, some seasons at least. Westerly upper-level weaken Arctic winter strengthen northern middle latitudes, contrary arguments based due solely amplified warming. jet-stream region eastern North Atlantic western Europe shifts southward. Westerlies band stretching south-eastwards Pacific southern Australia, as well polar-jet-stream surrounds Antarctica. Extreme increase Atlantic. Net kinetic energy increases, mostly associated sub-monthly along storm tracks Available potential less. Geopotential height shows distinct pattern stationary long-wave structures. There increases surface pressure mid-latitudes decreases Ocean offshore Several comparisons made between JRA-55 reanalysis observations it assimilated. They show reassuring agreement, regional differences require further investigation.

Язык: Английский

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A recent weakening of winter temperature association between Arctic and Asia

Environmental Research Letters, Год журнала: 2022, Номер 17(3), С. 034030 - 034030

Опубликована: Янв. 13, 2022

Abstract Arctic warming and its association with the mid-latitudes has been a hot topic over past two decades. Although many studies have explored these issues, it is not clear how their linkage changed time. The results show that winter low tropospheric temperatures in Asia experienced phases Phase I (2007/2008–2012/2013) was characterized by warm cold Eurasia, phase II Eurasia (2013/2014–2018/2019). A strengthened temperature between occurred during I, followed weakened II. Simulation experiments forced observed sea ice variability largely reproduce patterns, suggesting loss contributes to phasic (or low-frequency) variations atmosphere makes Arctic–Asia fluctuate weakening of post-2012/2013 associated amplified expanded warming. corresponding anomalies level pressure resembled positive-phase North Atlantic Oscillation This study implies Arctic—cold Arctic—warm patterns would alternately happen context loss, which increases difficulty correctly predicting Asian temperature.

Язык: Английский

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Decoding the dynamics of poleward shifting climate zones using aqua-planet model simulations

Climate Dynamics, Год журнала: 2022, Номер 58(11-12), С. 3513 - 3526

Опубликована: Янв. 5, 2022

Abstract Growing evidence indicates that the atmospheric and oceanic circulation experiences a systematic poleward shift in warming climate. However, complexity of climate system, including coupling between ocean atmosphere, natural variability land-sea distribution, tends to obfuscate causal mechanism underlying shift. Here, using an idealised coupled aqua-planet model, we explore shifting circulation, by isolating contributing factors from direct CO $$_2$$ 2 forcing, indirect surface warming, wind-stress feedback dynamics. We find that, contrast particular enhanced subtropical plays important role driving This emerges background Ekman convergence anomalous heat absence dynamical change. It expands tropical warm water zone, causes mid-latitude temperature gradient, hence forces corresponding associated wind pattern. The wind, turn drives circulation. Our simulations, despite being idealised, capture main features observed changes, for example, patterns near-surface sea level pressure, storm tracks, precipitation large-scale implying increase greenhouse gas concentrations not only raises temperature, but can also systematically zones poleward.

Язык: Английский

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