New insight into the disappearing Arctic sea ice

Francis, Jennifer A.; Hunter, Elias

doi:10.1029/2006eo460001

Cited by 175 publications

(144 citation statements)

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“…The reconstructed September Arctic SIE explains ∼56% of the total variance. Various nonlinear feedbacks, such as the ice infrared feedback (11,12) and ice albedo feedback (13)(14)(15), might contribute to the residual variance not explained by the multiple regression model.…”

Section: Multiple Regression and Spatial Patternmentioning

confidence: 99%

“…Various mechanisms have been proposed separately for the observed recent summer Arctic sea ice decline, such as the positive ice infrared feedback, i.e., enhanced downward longwave radiative flux due to increased air temperature, water vapor, cloudiness, and reduced sea ice (11,12); the positive ice albedo feedback (13)(14)(15); the warming of the Atlantic water in the Arctic (16)(17)(18); the increase in Bering Strait ocean heat fluxes (19); the influence of wind forcing over the central Arctic associated with the Arctic Oscillation (AO) (20,21) and the nonlinear positive feedback (22) among Pacific inflow, Beaufort Gyre (23), and AO at interannual time scale; and the interaction between the Arctic Dipole (AD) and transpolar ice drift (24)(25)(26)(27)(28). The previous studies are often based on short observational records.…”

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confidence: 99%

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Mechanisms for low-frequency variability of summer Arctic sea ice extent

Zhang

2015

Proc. Natl. Acad. Sci. U.S.A.

185

174

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Satellite observations reveal a substantial decline in September Arctic sea ice extent since 1979, which has played a leading role in the observed recent Arctic surface warming and has often been attributed, in large part, to the increase in greenhouse gases. However, the most rapid decline occurred during the recent global warming hiatus period. Previous studies are often focused on a single mechanism for changes and variations of summer Arctic sea ice extent, and many are based on short observational records. The key players for summer Arctic sea ice extent variability at multidecadal/ centennial time scales and their contributions to the observed summer Arctic sea ice decline are not well understood. Here a multiple regression model is developed for the first time, to the author's knowledge, to provide a framework to quantify the contributions of three key predictors (Atlantic/Pacific heat transport into the Arctic, and Arctic Dipole) to the internal low-frequency variability of Summer Arctic sea ice extent, using a 3,600-y-long control climate model simulation. The results suggest that changes in these key predictors could have contributed substantially to the observed summer Arctic sea ice decline. If the ocean heat transport into the Arctic were to weaken in the near future due to internal variability, there might be a hiatus in the decline of September Arctic sea ice. The modeling results also suggest that at multidecadal/centennial time scales, variations in the atmosphere heat transport across the Arctic Circle are forced by anticorrelated variations in the Atlantic heat transport into the Arctic.Arctic sea ice | internal variability | ocean heat transport O bservations reveal multidecadal variations in Arctic surface air temperature (SAT), and amplified Arctic warming similar to that observed in recent decades also occurred during 1930-1940 (1-3). Both observations and climate modeling results suggest that the reduced Arctic sea ice is crucial for the early twentieth century Arctic warming, and internal variability is a very likely cause for that event (3). In recent decades, satellite observations reveal a substantial decline in September Arctic sea ice extent (4). This observed recent Arctic sea ice decline is also found to have played a leading role in causing the observed amplified Arctic surface warming in recent decades (5, 6).The summer Arctic was projected to become ice-free within a few decades by some climate models used in Coupled Model Intercomparison Project Phase 5 (CMIP5) due to the increase in anthropogenic greenhouse gases (7, 8), or even within the next decade if extrapolating the observed trend (9). These future projections imply enormous social and economic impacts, such as the potential for trans-Arctic shipping. However, the most rapid decline in summer Arctic sea ice actually occurred during the recent global warming hiatus period. The CMIP5 multimodel mean response to changes in anthropogenic radiative forcings exhibits much less decline in September Arctic sea ice extent (SIE)...

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Section: Multiple Regression and Spatial Patternmentioning

confidence: 99%

mentioning

confidence: 99%

Mechanisms for low-frequency variability of summer Arctic sea ice extent

Zhang

2015

Proc. Natl. Acad. Sci. U.S.A.

185

174

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“…More importantly, the changes in sea ice extent affect the vertical heat fluxes between the Arctic Ocean and the overlying atmosphere (Serreze et al 2009;Screen and Simmonds 2010). Considering the impact of the extended open water surface on the latent heat fluxes, related changes in cloud cover and atmospheric water vapour content affect the downward longwave (LW) radiation flux (Francis and Hunter 2006;Schweiger et al 2008). Moreover, circulation changes also increase the meridional transport of water vapour to the Arctic with impact on the LW radiation (Doyle et al 2011;Park et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Arctic warming, moisture increase and circulation changes observed in the Ny-Ålesund homogenized radiosonde record

Maturilli

Kayser

2016

Theor Appl Climatol

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Radiosonde measurements obtained at the Arctic site Ny-Ålesund (78.9°N, 11.9°E), Svalbard, from 1993 to 2014 have been homogenized accounting for instrumentation discontinuities by correcting known errors in the manufacturer provided profiles. The resulting homogenized radiosonde record is provided as supplementary material at http://doi. pangaea.de/10.1594/PANGAEA.845373. From the homogenized data record, the first Ny-Ålesund upper-air climatology of wind, temperature and humidity is presented, forming the background for the analysis of changes during the 22-year period. Particularly during the winter season, a strong increase in atmospheric temperature and humidity is observed, with a significant warming of the free troposphere in January and February up to 3 K per decade. This winter warming is even more pronounced in the boundary layer below 1 km, presumably amplified by mesoscale processes including e.g. orographic effects or the boundary layer capping inversion. Though the largest contribution to the increasing atmospheric water vapour column in winter originates from the lowermost 2 km, no increase in the contribution by specific humidity inversions is detected. Instead, we find an increase in the humidity content of the large-scale background humidity profiles. At the same time, the tropospheric flow in winter is found to occur less frequent from northerly directions and to the same amount more frequent from the South. We conclude that changes in the atmospheric circulation lead to an enhanced advection of warm and moist air from lower latitudes to the Svalbard region in the winter season, causing the warming and moistening of the atmospheric column above Ny-Ålesund, and link the observations to changes in the Arctic Oscillation.

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“…Atmospheric moisture transport has an important role in sea ice extent variations. The increase in cloud cover or water vapour over the Arctic have been suggested as one of the main causes of the downwelling longwave flux [29,30], which is considered to be closely related with sea ice extent [29,31]. The relation between the amplified moisture transport toward norther latitudes and its influence on river discharge was demonstrated by Zhang et al [32].…”

Section: Introductionmentioning

confidence: 97%

“…For this purpose, we employed the Lagrangian FLEXible PARTicle dispersion (FLEXPART) model [37,38] to assess variations in arctic moisture sources, and to observe how the moisture contribution from these sources into the Arctic varied for 2007 and 2012, as a means of investigating the possible relationship between variations in moisture supply over the main arctic Atmospheric moisture transport has an important role in sea ice extent variations. The increase in cloud cover or water vapour over the Arctic have been suggested as one of the main causes of the downwelling longwave flux [29,30], which is considered to be closely related with sea ice extent [29,31]. The relation between the amplified moisture transport toward norther latitudes and its influence on river discharge was demonstrated by Zhang et al [32].…”

Section: Introductionmentioning

confidence: 97%

Extreme Sea Ice Loss over the Arctic: An Analysis Based on Anomalous Moisture Transport

2017

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Abstract:The Arctic system has experienced in recent times an extreme reduction in the extent of its sea ice. The years 2007 and 2012 in particular showed maxima in the loss of sea ice. It has been suggested that such a rapid decrease has important implications for climate not only over the system itself but also globally. Understanding the causes of this sea ice loss is key to analysing how future changes related to climate change can affect the Arctic system. For this purpose, we applied the Lagrangian FLEXible PARTicle dispersion (FLEXPART) model to study the anomalous transport of moisture for 2006/2007 and 2011/2012 in order to assess the implications for the sea ice. We used the model results to analyse the variation in the sources of moisture for the system (backward analysis), as well as how the moisture supply from these sources differs (forward analysis) during these years. The results indicate an anomalous transport of moisture for both years. However, the pattern differs between events, and the anomalous moisture supply varies both in intensity and spatial distribution for all sources.

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New insight into the disappearing Arctic sea ice

Cited by 175 publications

References 14 publications

Mechanisms for low-frequency variability of summer Arctic sea ice extent

Mechanisms for low-frequency variability of summer Arctic sea ice extent

Arctic warming, moisture increase and circulation changes observed in the Ny-Ålesund homogenized radiosonde record

Extreme Sea Ice Loss over the Arctic: An Analysis Based on Anomalous Moisture Transport

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