Holocene fluctuations in Arctic sea-ice cover: dinocyst-based reconstructions for the eastern Chukchi SeaThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.GEOTOP Publication 2008-0023.

2008 ◽  
Vol 45 (11) ◽  
pp. 1377-1397 ◽  
Author(s):  
J. L. McKay ◽  
A. de Vernal ◽  
C. Hillaire-Marcel ◽  
C. Not ◽  
L. Polyak ◽  
...  
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Chukchi Sea ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
Near Surface ◽  
The Holocene ◽  
Modern Analogue

Cores from site HLY0501-05 on the Alaskan margin in the eastern Chukchi Sea were analyzed for their geochemical (organic carbon, δ13Corg, Corg/N, and CaCO3) and palynological (dinocyst, pollen, and spores) content to document oceanographic changes during the Holocene. The chronology of the cores was established from 210Pb dating of near-surface sediments and 14C dating of bivalve shells. The sediments span the last 9000 years, possibly more, but with a gap between the base of the trigger core and top of the piston core. Sedimentation rates are very high (∼156 cm/ka), allowing analyses with a decadal to centennial resolution. The data suggest a shift from a dominantly terrigenous to marine input from the early to late Holocene. Dinocyst assemblages are characterized by relatively high concentrations (600–7200 cysts/cm3) and high species diversity, allowing the use of the modern analogue technique for the reconstruction of sea-ice cover, summer temperature, and salinity. Results indicate a decrease in sea-ice cover and a corresponding, albeit much smaller, increase in summer sea-surface temperature over the past 9000 years. Superimposed on these long-term trends are millennial-scale fluctuations characterized by periods of low sea-ice and high sea-surface temperature and salinity that appear quasi-cyclic with a frequency of about one every 2500–3000 years. The results of this study clearly show that sea-ice cover in the western Arctic Ocean has varied throughout the Holocene. More importantly, there have been times when sea-ice cover was less extensive than at the end of the 20th century.

scholarly journals Variations of the Mid-Pacific Trough and Their Relations to the Asian–Pacific–North American Climate: Roles of Tropical Sea Surface Temperature and Arctic Sea Ice

2018 ◽  
Vol 31 (6) ◽  
pp. 2233-2252 ◽  
Author(s):  
Kaiqiang Deng ◽  
Song Yang ◽  
Mingfang Ting ◽  
Chundi Hu ◽  
Mengmeng Lu
Keyword(s):  
United States ◽  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
The Arctic ◽  
Boreal Summer ◽  
Arctic Sea ◽  
Second Mode

The mid-Pacific trough (MPT), occurring in the upper troposphere during boreal summer, acts as an atmospheric bridge connecting the climate variations over Asia, the Pacific, and North America. The first (second) mode of empirical orthogonal function analysis of the MPT, which accounts for 20.3% (13.4%) of the total variance, reflects a change in its intensity on the southwestern (northeastern) portion of the trough. Both modes are significantly correlated with the variability of tropical Pacific sea surface temperature (SST). Moreover, the first mode is affected by Atlantic SST via planetary waves that originate from the North Atlantic and propagate eastward across the Eurasian continent, and the second mode is influenced by the Arctic sea ice near the Bering Strait by triggering an equatorward wave train over the northeast Pacific. A stronger MPT shown in the first mode is significantly linked to drier and warmer conditions in the Yangtze River basin, southern Japan, and the northern United States and wetter conditions in South Asia and northern China, while a stronger MPT shown in the second mode is associated with a drier and warmer southwestern United States. In addition, an intensified MPT (no matter whether in the southwestern or the northeastern portion) corresponds to more tropical cyclones (TCs) over the western North Pacific (WNP) and fewer TCs over the eastern Pacific (EP) in summer, which is associated with the MPT-induced ascending and descending motions over the WNP and the EP, respectively.

scholarly journals Extended Reconstructed Sea Surface Temperature, Version 5 (ERSSTv5): Upgrades, Validations, and Intercomparisons

2017 ◽  
Vol 30 (20) ◽  
pp. 8179-8205 ◽  
Author(s):  
Boyin Huang ◽  
Peter W. Thorne ◽  
Viva F. Banzon ◽  
Tim Boyer ◽  
Gennady Chepurin ◽  
...  
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
High Latitude ◽  
Sea Surface ◽  
Sea Ice Concentration ◽  
Near Surface ◽  
Analysis Technique ◽  
Observation Instruments ◽  
Data Source

Abstract The monthly global 2° × 2° Extended Reconstructed Sea Surface Temperature (ERSST) has been revised and updated from version 4 to version 5. This update incorporates a new release of ICOADS release 3.0 (R3.0), a decade of near-surface data from Argo floats, and a new estimate of centennial sea ice from HadISST2. A number of choices in aspects of quality control, bias adjustment, and interpolation have been substantively revised. The resulting ERSST estimates have more realistic spatiotemporal variations, better representation of high-latitude SSTs, and ship SST biases are now calculated relative to more accurate buoy measurements, while the global long-term trend remains about the same. Progressive experiments have been undertaken to highlight the effects of each change in data source and analysis technique upon the final product. The reconstructed SST is systematically decreased by 0.077°C, as the reference data source is switched from ship SST in ERSSTv4 to modern buoy SST in ERSSTv5. Furthermore, high-latitude SSTs are decreased by 0.1°–0.2°C by using sea ice concentration from HadISST2 over HadISST1. Changes arising from remaining innovations are mostly important at small space and time scales, primarily having an impact where and when input observations are sparse. Cross validations and verifications with independent modern observations show that the updates incorporated in ERSSTv5 have improved the representation of spatial variability over the global oceans, the magnitude of El Niño and La Niña events, and the decadal nature of SST changes over 1930s–40s when observation instruments changed rapidly. Both long- (1900–2015) and short-term (2000–15) SST trends in ERSSTv5 remain significant as in ERSSTv4.

scholarly journals Changes in sea-surface temperature and atmospheric circulation patterns associated with reductions in Arctic sea ice cover in recent decades

2018 ◽  
Vol 18 (19) ◽  
pp. 14149-14159 ◽  
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
The Arctic ◽  
Atmospheric Circulation Patterns ◽  
Arctic Sea

Abstract. In recent decades, the Arctic sea ice has been declining at a rapid pace as the Arctic warms at a rate of twice the global average. The underlying physical mechanisms for the Arctic warming and accelerated sea ice retreat are not fully understood. In this study, we apply a relatively novel statistical method called self-organizing maps (SOM) along with composite analysis to examine the trend and variability of autumn Arctic sea ice in the past three decades and their relationships to large-scale atmospheric circulation changes. Our statistical results show that the anomalous autumn Arctic dipole (AD) (Node 1) and the Arctic Oscillation (AO) (Node 9) could explain in a statistical sense as much as 50 % of autumn sea ice decline between 1979 and 2016. The Arctic atmospheric circulation anomalies associated with anomalous sea-surface temperature (SST) patterns over the North Pacific and North Atlantic influence Arctic sea ice primarily through anomalous temperature and water vapor advection and associated radiative feedback.

scholarly journals Seasonal to decadal predictions of regional Arctic sea ice by assimilating sea surface temperature in the Norwegian Climate Prediction Model

2020 ◽  
Vol 54 (9-10) ◽  
pp. 3863-3878 ◽  
Author(s):  
Panxi Dai ◽  
Yongqi Gao ◽  
François Counillon ◽  
Yiguo Wang ◽  
Madlen Kimmritz ◽  
...  
Keyword(s):  
Sea Ice ◽  
Prediction Model ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Prediction ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
Arctic Sea ◽  
Decadal Predictions

scholarly journals The Role of the Wind–Evaporation–Sea Surface Temperature (WES) Feedback as a Thermodynamic Pathway for the Equatorward Propagation of High-Latitude Sea Ice–Induced Cold Anomalies

2011 ◽  
Vol 24 (5) ◽  
pp. 1350-1361 ◽  
Author(s):  
Salil Mahajan ◽  
R. Saravanan ◽  
Ping Chang
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
High Latitude ◽  
Sea Surface ◽  
Specific Humidity ◽  
Near Surface ◽  
Wes Feedback ◽  
Northern Hemispheric

Abstract The role of the wind–evaporation–sea surface temperature (WES) feedback in the propagation of the high-latitude cooling signal to the tropical oceans using the NCAR atmospheric Community Climate Model (CCM3) coupled thermodynamically to a slab-ocean model (SOM) is studied. Abruptly imposed additional Northern Hemispheric sea ice cover equivalent to the Last Glacial Maximum (LGM; 18 kyr BP) in the model causes a Northern Hemisphere–wide cooling, as well as the generation and amplification of an anomalous cross-equatorial meridional SST dipole associated with a southward migration of the intertropical convergence zone (ITCZ) stabilizing within a period of 5 yr. In experiments where the WES feedback is switched off explicitly by modifying the sensible and latent heat flux bulk aerodynamic formulations over the oceans in CCM3, imposed Northern Hemispheric sea ice also results in widespread northern cooling at the same rate as the unmodified run, suggesting that the WES feedback is not essential in the propagation of the high-latitude cooling signal to the deep tropics. However, the WES-off experiment generates a weaker cross-equatorial SST dipole with a modest southward movement of the ITCZ, suggesting that the WES feedback is responsible for amplifying SST and atmospheric anomalies in the deep tropics during their transition to the new equilibrium state. The propagation of high-latitude cooling to the deep tropics is proposed to be caused by the decrease of near-surface specific humidity in the northern tropics.

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