Attribution of the Recent Winter Sea Ice Decline over the Atlantic Sector of the Arctic Ocean

Park, Doo‐Sun R.; Lee, Sukyoung; Feldstein, Steven B.

doi:10.1175/jcli-d-15-0042.1

Cited by 159 publications

(153 citation statements)

References 36 publications

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“…Contributing to the enhanced high-latitude warming are the sea ice-albedo effect, the lapse rate feedback (Pithan and Mauritsen, 2014), atmospheric heat and moisture advection (Park et al, 2015), ocean heat transport (Chylek et al, 2009), aerosol effects, and potentially others, all linked in complex relations. Particularly clouds are known as a major contributor to Arctic amplification (Curry et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Twenty-five years of cloud base height measurements by ceilometer in Ny-Ålesund, Svalbard

Maturilli

Ebell

2018

Earth Syst. Sci. Data

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Abstract. Clouds are a key factor for the Arctic amplification of global warming, but their actual appearance and distribution are still afflicted by large uncertainty. On the Arctic-wide scale, large discrepancies are found between the various reanalyses and satellite products, respectively. Although ground-based observations by remote sensing are limited to point measurements, they have the advantage of obtaining extended time series of vertically resolved cloud properties. Here, we present a 25-year data record of cloud base height measured by ceilometer at the Ny-Ålesund, Svalbard, Arctic site. We explain the composition of the three sub-periods with different instrumentation contributing to the data set, and show examples of potential application areas. Linked to cyclonic activity, the cloud base height provides essential information for the interpretation of the surface radiation balance and contributes to the understanding of meteorological processes. Furthermore, it is a useful auxiliary component for the analysis of advanced technologies that provide insight into cloud microphysical properties, like the cloud radar. The long-term time series also allows derivation of an annual cycle of the cloud occurrence frequency, revealing the more frequent cloud cover in summer and the lowest cloud cover amount in April. However, as the use of different ceilometer instruments over the years potentially imposed inhomogeneities onto the data record, any long-term trend analysis should be avoided.

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Section: Introductionmentioning

confidence: 99%

Twenty-five years of cloud base height measurements by ceilometer in Ny-Ålesund, Svalbard

Maturilli

Ebell

2018

Earth Syst. Sci. Data

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“…Recently, many studies have addressed the mechanism of SIC change in winter [10,11]. The roles of radiation and sensible heat [8,12], moisture transport [13,14], wind-driven sea ice drifting [15,16] and other factors [17] have been examined in many previous studies.…”

Section: Introductionmentioning

confidence: 99%

Effects of Northern Hemisphere Atmospheric Blocking on Arctic Sea Ice Decline in Winter at Weekly Time Scales

2018

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Abstract:In this study, the effects of the Northern Hemisphere atmospheric blocking circulation on Arctic sea ice decline at weekly time scales are examined by defining four key regions based on observational data analysis. Given the regression analysis, the frequently occurring atmospheric patterns related to the sea ice decline in four key sea regions (Baffin Bay, Barents-Kara Seas, Okhotsk Sea and Bering Sea) are found to be Greenland blocking (GB), Ural blocking (UB), western Pacific blocking (PB-W) and eastern Pacific blocking (PB-E), respectively. The results show that the regional blocking frequency is higher (lower) in lower (higher) sea ice winters for each key region. Moreover, composite analysis indicates that blocking evolution is usually accompanied by significant sea ice decline at weekly time scales during the blocking life cycle for each key region. In addition, the intensified surface downward infrared radiation (IR) anomaly and the precipitable water for the entire atmosphere (PWA) in each key region are found to make significant contributions to the positive surface air temperature (SAT) anomaly, which is beneficial for the reduction in sea ice. The approximate quantitative analysis of different surface energy fluxes induced by blocking is also applied. Further analysis shows that the blocking event and the associated changes in SAT and radiation anomalies for each key region lead the sea ice decline by approximately 3~6 days. This result indicates that regional blocking can contribute to regional sea ice decline at weekly time scales through surface warming associated with enhanced water vapor and associated IR variations. Further quantitative estimates indicate that regional blocking can reduce regional sea ice cover (SIC) by 49.6%, 49.4%, 52.2% and 49.5% for Baffin Bay, Barents-Kara Seas, Okhotsk Sea and Bering Sea, respectively, during the blocking life cycle. Finally, a physical process diagrammatic sketch is given to illustrate how blocking affects SIC decline.

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“…However, the recent Arctic changes that occurred during winter in association with the effect of clouds remain poorly understood. For example, the role of downward longwave radiation on the relationship between clouds and sea ice during the freezing season has been recently examined (Park et al, 2015). Extremely cold, dry and windy conditions in Arctic winter lead to large detection errors in cloud observation and large uncertainties in the proper modelling of Arctic clouds.…”

Section: Introductionmentioning

confidence: 99%

Recent changes in winter Arctic clouds and their relationships with sea ice and atmospheric conditions

Jun

Jeong

et al. 2016

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C T Changes in Arctic clouds during boreal winter (December through February) and their relationship with sea ice and atmospheric conditions in recent decades have been examined using satellite and reanalysis data, and they are compared with output data from atmospheric general circulation model (AGCM) experiments. All the datasets used in this study consistently show that cloud amount over the Arctic Ocean (north of 678N) decreased until the late 1990s but rapidly increased thereafter. Cloud increase in recent decade was a salient feature in the lower troposphere over a large part of the Arctic Sea, in association with obvious increase of lower tropospheric temperature and moisture. The comparison between the two periods before and after 1997 indicates that interannual covariability of Arctic clouds and lower tropospheric temperature and moisture was significantly enhanced after the late 1990s. Large reduction of sea ice cover during boreal winter decreased lower tropospheric static stability and deepened the planetary boundary layer. These changes led to an enhanced upward moisture transport and cloud formation, which led to considerable longwave radiative forcing and, as a result, strengthened the cloudÁmoistureÁtemperature relationship in the lower troposphere. AGCM experiments under reduced sea ice conditions support those results obtained by satellite and reanalysis datasets reproducing the increases in cloud amount and lower tropospheric temperature and their enhanced covariability.

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Attribution of the Recent Winter Sea Ice Decline over the Atlantic Sector of the Arctic Ocean

Cited by 159 publications

References 36 publications

Twenty-five years of cloud base height measurements by ceilometer in Ny-Ålesund, Svalbard

Twenty-five years of cloud base height measurements by ceilometer in Ny-Ålesund, Svalbard

Effects of Northern Hemisphere Atmospheric Blocking on Arctic Sea Ice Decline in Winter at Weekly Time Scales

Recent changes in winter Arctic clouds and their relationships with sea ice and atmospheric conditions

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