scholarly journals Mechanisms of Stratospheric and Tropospheric Circulation Response to Projected Arctic Sea Ice Loss*

2015 ◽  
Vol 28 (19) ◽  
pp. 7824-7845 ◽  
Author(s):  
Lantao Sun ◽  
Clara Deser ◽  
Robert A. Tomas
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Arctic Sea Ice ◽  
Climate Impacts ◽  
Negative Phase ◽  
Surface Boundary ◽  
Arctic Sea ◽  
Tropospheric Circulation ◽  
Arctic Sea Ice Loss ◽  
The Impact

Abstract The impact of projected Arctic sea ice loss on the atmospheric circulation is investigated using the Whole Atmosphere Community Climate Model (WACCM), a model with a well-resolved stratosphere. Two 160-yr simulations are conducted: one with surface boundary conditions fixed at late twentieth-century values and the other with identical conditions except for Arctic sea ice, which is prescribed at late twenty-first-century values. Their difference isolates the impact of future Arctic sea ice loss upon the atmosphere. The tropospheric circulation response to the imposed ice loss resembles the negative phase of the northern annular mode, with the largest amplitude in winter, while the less well-known stratospheric response transitions from a slight weakening of the polar vortex in winter to a strengthening of the vortex in spring. The lack of a significant winter stratospheric circulation response is shown to be a consequence of largely cancelling effects from sea ice loss in the Atlantic and Pacific sectors, which drive opposite-signed changes in upward wave propagation from the troposphere to the stratosphere. Identical experiments conducted with Community Atmosphere Model, version 4, WACCM’s low-top counterpart, show a weaker tropospheric response and a different stratospheric response compared to WACCM. An additional WACCM experiment in which the imposed ice loss is limited to August–November reveals that autumn ice loss weakens the stratospheric polar vortex in January, followed by a small but significant tropospheric response in late winter and early spring that resembles the negative phase of the North Atlantic Oscillation, with attendant surface climate impacts.

scholarly journals The impact of Arctic sea ice loss on mid-Holocene climate

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Hyo-Seok Park ◽  
Seong-Joong Kim ◽  
Kyong-Hwan Seo ◽  
Andrew L. Stewart ◽  
Seo-Yeon Kim ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Holocene Climate ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss ◽  
The Impact

Transient climate response to Arctic sea-ice loss with two ice-constraining methods

2021 ◽  
pp. 1-50
Author(s):  
Amélie Simon ◽  
Guillaume Gastineau ◽  
Claude Frankignoul ◽  
Clément Rousset ◽  
Francis Codron
Keyword(s):  
Thermal Conductivity ◽  
Sea Ice ◽  
North Atlantic ◽  
Arctic Sea Ice ◽  
Climate Impacts ◽  
The Arctic ◽  
The North ◽  
Arctic Sea ◽  
The North Atlantic ◽  
Arctic Sea Ice Loss

AbstractThe impact of Arctic sea-ice loss on the ocean and atmosphere is investigated focusing on a gradual reduction of Arctic sea-ice by 20% on annual mean, occurring within 30 years, starting from present-day conditions. Two ice-constraining methods are explored to melt Arctic sea-ice in a coupled climate model, while keeping present-day conditions for external forcing. The first method uses a reduction of sea-ice albedo, which modifies the incoming surface shortwave radiation. The second method uses a reduction of thermal conductivity, which changes the heat conduction flux inside ice. Reduced thermal conductivity inhibits oceanic cooling in winter and sea-ice basal growth, reducing seasonality of sea-ice thickness. For similar Arctic sea-ice area loss, decreasing the albedo induces larger Arctic warming than reducing the conductivity, especially in spring. Both ice-constraining methods produce similar climate impacts, but with smaller anomalies when reducing the conductivity. In the Arctic, the sea-ice loss leads to an increase of the North Atlantic water inflow in the Barents Sea and Eastern Arctic, while the salinity decreases and the gyre intensifies in the Beaufort Sea. In the North Atlantic, the subtropical gyre shifts southward and the Atlantic meridional overturning circulation weakens. A dipole of sea-level pressure anomalies sets up in winter over Northern Siberia and the North Atlantic, which resembles the negative phase of the North Atlantic Oscillation. In the tropics, the Atlantic Intertropical Convergence Zone shifts southward as the South Atlantic Ocean warms. In addition, Walker circulation reorganizes and the Southeastern Pacific Ocean cools.

scholarly journals Isolating the Atmospheric Circulation Response to Arctic Sea Ice Loss in the Coupled Climate System

2017 ◽  
Vol 30 (6) ◽  
pp. 2163-2185 ◽  
Author(s):  
Russell Blackport ◽  
Paul J. Kushner
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Arctic Sea Ice ◽  
Low Latitude ◽  
Stratospheric Polar Vortex ◽  
Sea Level Pressure ◽  
Surface Warming ◽  
Arctic Sea ◽  
Pressure Anomaly ◽  
Arctic Sea Ice Loss

Abstract In this study, coupled ocean–atmosphere–land–sea ice Earth system model (ESM) simulations driven separately by sea ice albedo reduction and by projected greenhouse-dominated radiative forcing are combined to cleanly isolate the sea ice loss response of the atmospheric circulation. A pattern scaling approach is proposed in which the local multidecadal mean atmospheric response is assumed to be separately proportional to the total sea ice loss and to the total low-latitude ocean surface warming. The proposed approach estimates the response to Arctic sea ice loss with low-latitude ocean temperatures fixed and vice versa. The sea ice response includes a high northern latitude easterly zonal wind response, an equatorward shift of the eddy-driven jet, a weakening of the stratospheric polar vortex, an anticyclonic sea level pressure anomaly over coastal Eurasia, a cyclonic sea level pressure anomaly over the North Pacific, and increased wintertime precipitation over the west coast of North America. Many of these responses are opposed by the response to low-latitude surface warming with sea ice fixed. However, both sea ice loss and low-latitude surface warming act in concert to reduce subseasonal temperature variability throughout the middle and high latitudes. The responses are similar in two related versions of the National Center for Atmospheric Research Earth system models, apart from the stratospheric polar vortex response. Evidence is presented that internal variability can easily contaminate the estimates if not enough independent climate states are used to construct them.

scholarly journals Impact of Ural Blocking on Winter Warm Arctic–Cold Eurasian Anomalies. Part I: Blocking-Induced Amplification

2016 ◽  
Vol 29 (11) ◽  
pp. 3925-3947 ◽  
Author(s):  
Dehai Luo ◽  
Yiqing Xiao ◽  
Yao Yao ◽  
Aiguo Dai ◽  
Ian Simmonds ◽  
...  
Keyword(s):  
Sea Ice ◽  
High Latitude ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Height Anomaly ◽  
Arctic Sea ◽  
Cold Anomaly ◽  
Arctic Sea Ice Loss ◽  
The Impact ◽  
Sea Ice Reduction

Abstract In Part I of this study, the impact of Ural blocking (UB) on the warm Arctic–cold Eurasian (WACE) pattern associated with the winter (DJF) arctic sea ice loss during 1979–2013 is examined by dividing the arctic sea ice reduction region into two dominant subregions: the Barents and Kara Seas (BKS) and the North American high-latitude (NAH) region (Baffin and Hudson Bay, Davis Strait, and Labrador Sea). It is found that atmospheric response to arctic sea ice loss resembles a negative Arctic response oscillation with a dominant positive height anomaly over the Eurasian subarctic region. Regression analyses of the two subregions further show that the sea ice loss over the BKS corresponds to the UB pattern together with a positive North Atlantic Oscillation (NAO+) and is followed by a WACE anomaly, while the sea ice reduction in the NAH region corresponds to a negative NAO (NAO−) pattern with a cold anomaly over northern Eurasia. Further analyses reveal that the UB pattern is more persistent during the period 2000–13 (P2) than 1979–99 (P1) because of the reduced middle-to-high-latitude mean westerly winds over Eurasia associated with the intense BKS warming. During P2 the establishment of the UB becomes a slow process because of the role of the BKS warming, while its decay is slightly rapid. In the presence of the long-lived UB that often occurs with the NAO+, the BKS-warming-induced DJF-mean anticyclonic anomaly is intensified and widened and then expands southward during P2 to amplify the WACE pattern and induce the southward displacement of its cold anomaly and the further loss of the BKS sea ice. Thus, midlatitude Eurasian cold events should be more frequent as the sea ice loss continues over the BKS.

scholarly journals Weak Stratospheric Polar Vortex Events Modulated by the Arctic Sea‐Ice Loss

2019 ◽  
Vol 124 (2) ◽  
pp. 858-869 ◽  
Author(s):  
Kazuhira Hoshi ◽  
Jinro Ukita ◽  
Meiji Honda ◽  
Tetsu Nakamura ◽  
Koji Yamazaki ◽  
...  
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Stratospheric Polar Vortex ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss

scholarly journals Weakening of the stratospheric polar vortex by Arctic sea-ice loss

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Baek-Min Kim ◽  
Seok-Woo Son ◽  
Seung-Ki Min ◽  
Jee-Hoon Jeong ◽  
Seong-Joong Kim ◽  
...  
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Arctic Sea Ice ◽  
Stratospheric Polar Vortex ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss

Model and state dependence of the atmospheric response to Arctic sea-ice loss

2020 ◽  
Author(s):  
Amber Walsh ◽  
James Screen ◽  
Adam Scaife ◽  
Doug Smith ◽  
Rosie Eade
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Horizontal Resolution ◽  
Arctic Sea Ice ◽  
Atmospheric Response ◽  
Model Resolution ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss

<p>The climate response to Arctic sea-ice loss is highly uncertain. There exists considerable disagreement between observational and modelling studies, and between models, for reasons that remain poorly understood. To make progress, the Polar Amplification Model Intercomparison Project (PAMIP) was designed to provide coordinated experiments, with consistent sea-ice loss applied in multiple models. Results from the PAMIP are presented, focussing on the robustness of the atmospheric response to Arctic sea-ice loss across models and, within individual models, the dependence of the response on the mean state.</p><p>In the troposphere, the mid-latitude jet is either weakened and/or shifted towards the equator in all models, albeit with varying magnitudes. We hypothesise that the magnitude of the jet response is sensitive to the atmospheric model resolution. To test this, and to more broadly identify the aspects of the atmospheric response that are sensitive to model resolution, we compare like-for-like experiments with two versions of the HadGEM3 model at low (N96) and high (N216) horizontal resolution.</p><p>The stratospheric polar vortex response to Arctic sea-ice loss is not consistent between models, and appears to be influenced by both the size of the ensemble for each model and the phase of the Quasi-Biennial Oscillation (QBO). The possible modulating effect of the QBO is further explored using new simulations with background atmospheric states representing the easterly and westerly QBO phases.</p><p>A surprising early result from the PAMIP simulations were sizeable changes in the Southern Hemisphere in response to Arctic sea-ice loss and significant changes in the Northern Hemisphere in response to Antarctic sea-ice loss, even in atmosphere-only model experiments. The robustness of such apparent interhemispheric connections across models, ensemble sizes and mean states is investigated.</p><p> </p><p> </p><p> </p>

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