Climatic and atmospheric teleconnection indices and western Arctic sea ice variability

Abstract. Recent studies suggested significant impacts of boreal cryosphere changes on wintertime air stagnation and haze pollution extremes in China. However, the underlying mechanism of such a teleconnection relationship remains unclear. Here we used the Whole Atmosphere Community Climate Model (WACCM) to investigate dynamic processes leading to atmospheric circulation and air stagnation responses to Arctic sea ice changes. We conducted four climate sensitivity experiments by perturbing sea ice concentrations (SIC) and corresponding sea surface temperature (SST) in autumn and early winter over the whole Arctic and three sub-regions in the climate model. The results indicate different responses in the general circulation and regional ventilation to the region-specific Arctic changes, with the largest increase of both the probability (by 120 %) and the intensity (by 32 %) of air stagnation extreme events being found in the experiment driven by SIC and SST changes over the Pacific sector of the Arctic (the East Siberian and Chukchi Seas). The increased air stagnation extreme events are mainly driven by an amplified hemispheric-scale atmospheric teleconnection pattern that resembles the negative phase of the Eurasian (EU) pattern. Dynamical diagnostics suggest that convergence of transient eddy forcing in the vicinity of Scandinavia in winter is largely responsible for the amplification of the teleconnection pattern. Transient eddy vorticity fluxes dominate the transient eddy forcing and produce a barotropic anticyclonic anomaly near Scandinavia and wave-train propagation across Eurasia to the downstream regions in East Asia. The piecewise potential vorticity inversion analysis reveals that this long-range atmospheric teleconnection of the Arctic origin takes place primarily in the middle and upper troposphere. The anomalous ridge over East Asia in the middle and upper troposphere worsens regional ventilation conditions by weakening monsoon northwesterlies and enhancing temperature inversion near the surface, leading to more and stronger air stagnation and pollution extremes over eastern China in winter. Ensemble projections based on the state-of-the-art climate models in the Coupled Model Intercomparison Project Phase 6 (CMIP6) corroborate this teleconnection relationship between high-latitude environmental changes and middle-latitude weather extremes, though the tendency and magnitude vary considerably among each participating model.

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Eastern - Western Arctic Sea Ice Analysis 1987

10.21236/ada205477 ◽

1987 ◽

Author(s):

NAVAL POLAR OCEANOGRAPHY CENTER WASHINGTON DC

Keyword(s):

Sea Ice ◽

Arctic Sea Ice ◽

Arctic Sea ◽

Western Arctic

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Eastern-Western Arctic Sea Ice Analyses 1989

10.21236/ada236540 ◽

1989 ◽

Author(s):

NAVAL POLAR OCEANOGRAPHY CENTER WASHINGTON DC

Keyword(s):

Sea Ice ◽

Arctic Sea Ice ◽

Arctic Sea ◽

Western Arctic

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Regional differences in processes controlling Arctic sea ice floe size distribution in Chukchi Sea, East Siberian and Fram Strait during pre-ponding season

10.5194/egusphere-egu2020-5208 ◽

2020 ◽

Author(s):

Yanan Wang ◽

Byongjun Hwang ◽

Rajlaxmi Basu ◽

Jinchang Ren

Keyword(s):

Sea Ice ◽

Size Distribution ◽

Regional Difference ◽

Chukchi Sea ◽

Arctic Sea Ice ◽

Fram Strait ◽

East Siberian Sea ◽

Arctic Sea ◽

Before And After ◽

Western Arctic

<p>The floe size distribution (FSD) is important to the physical and biological processes in the marginal ice zone (MIZ). The FSD is controlled by ice advection, thermodynamics (lateral melting), and dynamics (winds, tides, currents and ocean swell). These thermodynamic and dynamic conditions are different between the western Arctic (e.g., Chukchi and Beaufort Seas) and the eastern Arctic (e.g., Fram Strait). For example, the MIZ in the western Arctic is strongly influenced by a warm ocean due to enhanced sea-ice albedo feedback, while the MIZ in the eastern Arctic is strongly influenced by ocean swell. We hypothesise that this regional difference can affect the FSD differently between the two regions. To address the hypothesis, we analysed the FSD data derived the images from MEDEA and synthetic aperture radar (SAR) TerraSAR-X in Chukchi Sea, East Siberian Sea and Fram Strait. Our results show that the FSD in Chukchi Sea the most dynamic as it contains a larger percentage of smaller floes and undergoes a greater interannual variability in the FSD compared to East Siberian Sea and Fram Strait. In particular, the FSD in Chukchi Sea shows a notable change before and after 2012. This change is likely attributed to the severe storm occurred in early August 2012 and the presence of thinner ice in this region.</p>

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Acceleration of western Arctic sea ice loss linked to the Pacific North American pattern

Nature Communications ◽

10.1038/s41467-021-21830-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhongfang Liu ◽

Camille Risi ◽

Francis Codron ◽

Xiaogang He ◽

Christopher J. Poulsen ◽

...

Keyword(s):

Sea Ice ◽

North American ◽

Arctic Sea Ice ◽

Model Simulations ◽

Pacific North American ◽

The Pacific ◽

Sea Ice Decline ◽

Arctic Sea ◽

Western Arctic ◽

Arctic Sea Ice Loss

AbstractRecent rapid Arctic sea-ice reduction has been well documented in observations, reconstructions and model simulations. However, the rate of sea ice loss is highly variable in both time and space. The western Arctic has seen the fastest sea-ice decline, with substantial interannual and decadal variability, but the underlying mechanism remains unclear. Here we demonstrate, through both observations and model simulations, that the Pacific North American (PNA) pattern is an important driver of western Arctic sea-ice variability, accounting for more than 25% of the interannual variance. Our results suggest that the recent persistent positive PNA pattern has led to increased heat and moisture fluxes from local processes and from advection of North Pacific airmasses into the western Arctic. These changes have increased lower-tropospheric temperature, humidity and downwelling longwave radiation in the western Arctic, accelerating sea-ice decline. Our results indicate that the PNA pattern is important for projections of Arctic climate changes, and that greenhouse warming and the resultant persistent positive PNA trend is likely to increase Arctic sea-ice loss.

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