scholarly journals Revisiting the trend in the occurrences of the warm Arctic-cold Eurasian continent temperature pattern

2020 ◽  
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong ◽  
Cuijuan Sui ◽  
Bo Sun
Keyword(s):  
Surface Temperature ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Temperature Pattern ◽  
Self Organizing Map ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
The North ◽  
Eurasian Continent ◽  
Increasing Trend

Abstract. The recent increasing trend of warm Arctic, cold continents has attracted much attention, but it remains debatable as to what forces are behind this phenomenon. Here, we revisited surface-temperature variability over the Arctic and Eurasian continent by applying the Self-Organizing-Map (SOM) technique to gridded daily surface temperature data. Nearly 40 % of the surface temperature trends are explained by the nine SOM patterns that depict the switch to the current warm Arctic-cold Eurasia pattern at the beginning of this century from the reversed pattern that dominated the 1980s and the 90s. Further, no cause-effect relationship is found between the Arctic sea-ice loss and the cold spells in high-mid latitude Eurasian continent suggested by earlier studies. Instead, the increasing trend in warm Arctic-cold Eurasia pattern appears to be related to the anomalous atmospheric circulations associated with two Rossby wavetrains triggered by rising sea surface temperature (SST) over the central North Pacific and the North Atlantic Oceans. On interdecadal timescale, the recent increase in the occurrences of the warm Arctic-cold Eurasia pattern is a fragment of the interdecadal variability of SST over the Atlantic Ocean as represented by the Atlantic Multidecadal Oscillations (AMO), and over the central Pacific Ocean.

scholarly journals Revisiting the trend in the occurrences of the “warm Arctic–cold Eurasian continent” temperature pattern

2020 ◽  
Vol 20 (22) ◽  
pp. 13753-13770
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong ◽  
Cuijuan Sui ◽  
Bo Sun
Keyword(s):  
Surface Temperature ◽  
Atlantic Multidecadal Oscillation ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Temperature Pattern ◽  
Self Organizing Map ◽  
Central Pacific ◽  
The North ◽  
Eurasian Continent ◽  
Increasing Trend

Abstract. The recent increasing trend of “warm Arctic, cold continents” has attracted much attention, but it remains debatable as to what forces are behind this phenomenon. Here, we revisited surface temperature variability over the Arctic and the Eurasian continent by applying the self-organizing-map (SOM) technique to gridded daily surface temperature data. Nearly 40 % of the surface temperature trends are explained by the nine SOM patterns that depict the switch to the current warm Arctic–cold Eurasia pattern at the beginning of this century from the reversed pattern that dominated the 1980s and 1990s. Further, no cause–effect relationship is found between the Arctic sea ice loss and the cold spells in the high-latitude to midlatitude Eurasian continent suggested by earlier studies. Instead, the increasing trend in warm Arctic–cold Eurasia pattern appears to be related to the anomalous atmospheric circulations associated with two Rossby wave trains triggered by rising sea surface temperature (SST) over the central North Pacific and the North Atlantic oceans. On interdecadal timescale, the recent increase in the occurrences of the warm Arctic–cold Eurasia pattern is a fragment of the interdecadal variability of SST over the Atlantic Ocean as represented by the Atlantic Multidecadal Oscillation (AMO) and over the central Pacific Ocean.

scholarly journals Synoptic climatological approach associated with three recent summer heatwaves in the Canadian Arctic

2020 ◽  
Vol 11 (S1) ◽  
pp. 233-250 ◽  
Author(s):  
Farahnaz Fazel-Rastgar
Keyword(s):  
Sea Ice ◽  
Canadian Arctic ◽  
Arctic Region ◽  
Low Pressure ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
The North ◽  
Pressure Centre ◽  
Temperature Records ◽  
Arctic Temperature

Abstract The observed unusually high temperatures in the Arctic during recent decades can be related to the Arctic sea ice declines in summer 2007, 2012 and 2016. Arctic dipole formation has been associated with all three heatwaves of 2007, 2012 and 2016 in the Canadian Arctic. Here, the differences in weather patterns are investigated and compared with normal climatological mean (1981–2010) structures. This study examines the high-resolution datasets from the North American Regional Reanalysis model. During the study periods, the north of Alaska has been affected by the low-pressure tongue. The maximum difference between Greenland high-pressure centre and Alaska low-pressure tongue for the summers of 2012, 2016 and 2007 are 8 hPa, 7 hPa and 6 hPa, respectively, corresponding and matching to the maximum summer surface Canadian Arctic temperature records. During anomalous summer heatwaves, low-level wind, temperatures, total clouds (%) and downward radiation flux at the surface are dramatically changed. This study shows the surface albedo has been reduced over most parts of the Canadian Arctic Ocean during the mentioned heatwaves (∼5–40%), with a higher change (specifically in the eastern Canadian Arctic region) during summer 2012 in comparison with summer 2016 and summer 2007, agreeing with the maximum surface temperature and sea ice decline records.

Gridded Arctic sea ice concentration reconstruction for the first half of the 20th century based on different proxy data

2021 ◽  
Author(s):  
Vladimir Semenov ◽  
Tatiana Matveeva
Keyword(s):  
Sea Ice ◽  
20Th Century ◽  
Climate Model ◽  
Surface Air Temperature ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
The North ◽  
Arctic Sea ◽  
Ice Concentration

<p>Global warming in the recent decades has been accompanied by a rapid recline of the Arctic sea ice area most pronounced in summer (10% per decade). To understand the relative contribution of external forcing and natural variability to the modern and future sea ice area changes, it is necessary to evaluate a range of long-term variations of the Arctic sea ice area in the period before a significant increase in anthropogenic emissions of greenhouse gases into the atmosphere. Available observational data on the spatiotemporal dynamics of Arctic sea ice until 1950s are characterized by significant gaps and uncertainties. In the recent years, there have appeared several reconstructions of the early 20<sup>th</sup> century Arctic sea ice area that filled the gaps by analogue methods or utilized combined empirical data and climate model’s output. All of them resulted in a stronger that earlier believed negative sea ice area anomaly in the 1940s concurrent with the early 20<sup>th</sup> century warming (ETCW) peak. In this study, we reconstruct the monthly average gridded sea ice concentration (SIC) in the first half of the 20th century using the relationship between the spatiotemporal features of SIC variability, surface air temperature over the Northern Hemisphere extratropical continents, sea surface temperature in the North Atlantic and North Pacific, and sea level pressure. In agreement with a few previous results, our reconstructed data also show a significant negative anomaly of the Arctic sea ice area in the middle of the 20th century, however with some 15% to 30% stronger amplitude, about 1.5 million km<sup>2</sup> in September and 0.7 million km<sup>2</sup> in March. The reconstruction demonstrates a good agreement with regional Arctic sea ice area data when available and suggests that ETWC in the Arctic has been accompanied by a concurrent sea ice area decline of a magnitude that have been exceeded only in the beginning of the 21<sup>st</sup> century.</p>

scholarly journals Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 482 ◽  
Author(s):  
Przemyslaw Kowalczuk ◽  
Hassan Bouzahzah ◽  
Rolf Kleiv ◽  
Kurt Aasly
Keyword(s):  
Industrial Applications ◽  
The Arctic ◽  
Central Pacific ◽  
Massive Sulfides ◽  
Central Pacific Ocean ◽  
Polymetallic Nodules ◽  
Mid Ocean Ridge ◽  
Different Types ◽  
Loki’S Castle ◽  
Ocean Ridge

Simultaneous leaching of seafloor massive sulfides (SMS) from Loki’s Castle on the Arctic Mid-Ocean Ridge (AMOR) and polymetallic nodules (PN) from Clarion Clipperton Zone (CCZ) of the Central Pacific Ocean was studied. Leaching tests were conducted using sulfuric acid and sodium chloride, at a temperature of 80 °C for 48 h under reflux. The effect of PN-to-SMS ratio was examined. It was shown that simultaneous leaching of two different types of marine resources was possible resulting in high dissolution rates of metals. The proposed process has many advantages as it does not require pyrometallurgical pretreatment, and yields solid products (i.e., silica, barite, elemental sulfur, albite, microcline, muscovite), which might be utilized for various industrial applications.

scholarly journals The sensitivity of the Arctic sea ice to orbitally induced insolation changes: a study of the mid-Holocene Paleoclimate Modelling Intercomparison Project 2 and 3 simulations

2013 ◽  
Vol 9 (2) ◽  
pp. 969-982 ◽  
Author(s):  
M. Berger ◽  
J. Brandefelt ◽  
J. Nilsson
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Eastern Coast ◽  
Sea Ice Extent ◽  
The North ◽  
Arctic Sea ◽  
North Eastern ◽  
Intercomparison Project ◽  
Insolation Change

Abstract. In the present work the Arctic sea ice in the mid-Holocene and the pre-industrial climates are analysed and compared on the basis of climate-model results from the Paleoclimate Modelling Intercomparison Project phase 2 (PMIP2) and phase 3 (PMIP3). The PMIP3 models generally simulate smaller and thinner sea-ice extents than the PMIP2 models both for the pre-industrial and the mid-Holocene climate. Further, the PMIP2 and PMIP3 models all simulate a smaller and thinner Arctic summer sea-ice cover in the mid-Holocene than in the pre-industrial control climate. The PMIP3 models also simulate thinner winter sea ice than the PMIP2 models. The winter sea-ice extent response, i.e. the difference between the mid-Holocene and the pre-industrial climate, varies among both PMIP2 and PMIP3 models. Approximately one half of the models simulate a decrease in winter sea-ice extent and one half simulates an increase. The model-mean summer sea-ice extent is 11 % (21 %) smaller in the mid-Holocene than in the pre-industrial climate simulations in the PMIP2 (PMIP3). In accordance with the simple model of Thorndike (1992), the sea-ice thickness response to the insolation change from the pre-industrial to the mid-Holocene is stronger in models with thicker ice in the pre-industrial climate simulation. Further, the analyses show that climate models for which the Arctic sea-ice responses to increasing atmospheric CO2 concentrations are similar may simulate rather different sea-ice responses to the change in solar forcing between the mid-Holocene and the pre-industrial. For two specific models, which are analysed in detail, this difference is found to be associated with differences in the simulated cloud fractions in the summer Arctic; in the model with a larger cloud fraction the effect of insolation change is muted. A sub-set of the mid-Holocene simulations in the PMIP ensemble exhibit open water off the north-eastern coast of Greenland in summer, which can provide a fetch for surface waves. This is in broad agreement with recent analyses of sea-ice proxies, indicating that beach-ridges formed on the north-eastern coast of Greenland during the early- to mid-Holocene.

Unification of the Australian cratons before the formation of Nuna

2020 ◽  
Author(s):  
Uwe Kirscher ◽  
Ross Mitchell ◽  
Yebo Liu ◽  
Adam Nordsvan ◽  
Grant Cox ◽  
...  
Keyword(s):  
Building Blocks ◽  
Plate Motion ◽  
Central Pacific ◽  
Polar Wander ◽  
Central Pacific Ocean ◽  
The North ◽  
Rock Formations ◽  
Pine Creek ◽  
The Individual ◽  
Related Characteristic

<p>The paleogeography and chronology of the Paleoproterozoic supercontinent Nuna are highly debated. To further test the paleogeography of Australian cratons in the leadup to Nuna formation, we present new paleomagnetic results from two Paleoproterozoic rock formations in North Australia. First, we obtained paleomagnetic directions from the 1825±4 Ma, bimodal Plum Tree Creek Volcanics sequence located within the Pine Creek Inlier of the North Australian Craton. Second, we studied the 1855±2 Ma layered mafic-ultramafic ‘Toby’ intrusion from the Kimberley Craton (KC). Samples from both study areas reveal high quality, stable, magnetite related characteristic remanent magnetization directions. Combining within-site clustered mean directions, we obtained two paleopoles, which plot proximal to each other in the present day central Pacific Ocean, off the east coast of Australia. These results agree with previous interpretation that the Kimberly Craton was amalgamated with the rest of the North Australian Craton (NAC) prior to ca. 1.85 Ga. Comparing these new results with slightly younger poles from the NAC and slightly older, rotated poles form the West Australian Craton (WAC) reveal a high degree of clustering suggesting very minimal absolute plate motion between ca. 1.9-1.85 and 1.6 Ga before the final amalgamation of Nuna. All available paleomagnetic poles agree with an assembly, or close juxtaposition, of the two major Australian cratons (NAC and WAC) before 1.8 Ga. Furthermore, the individual virtual geomagnetic poles from the potentially slow cooled Toby intrusion show a non-fisherian distribution along a great circle. This spread might be related to previously interpreted major true polar wander events based on Laurentian data, which would be global if such an interpretation is correct. The assembly of proto-Australia prior to ca. 1.85 Ga roughly 250 to 300 Myr before the final stage of supercontinent Nuna’s amalgamation ca. 1.6 Ga suggests that assembling of major building blocks, such as Australia and Laurentia for the supercontinent Nuna and Gondwana for the supercontinent Pangea, is an important step in the formation of supercontinents.</p>

Predictable Patterns of Wintertime Surface Air Temperature in Northern Hemisphere and Their Predictability Sources in the SEAS5

2020 ◽  
Vol 33 (24) ◽  
pp. 10743-10754
Author(s):  
Hongdou Fan ◽  
Lin Wang ◽  
Yang Zhang ◽  
Youmin Tang ◽  
Wansuo Duan ◽  
...  
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Southern Oscillation ◽  
Arctic Sea Ice ◽  
Prediction Skill ◽  
The Arctic ◽  
The Tibetan Plateau ◽  
Central Pacific ◽  
The Pacific

AbstractBased on 36-yr hindcasts from the fifth-generation seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (SEAS5), the most predictable patterns of the wintertime 2-m air temperature (T2m) in the extratropical Northern Hemisphere are extracted via the maximum signal-to-noise (MSN) empirical orthogonal function (EOF) analysis, and their associated predictability sources are identified. The MSN EOF1 captures the warming trend that amplifies over the Arctic but misses the associated warm Arctic–cold continent pattern. The MSN EOF2 delineates a wavelike T2m pattern over the Pacific–North America region, which is rooted in the tropical forcing of the eastern Pacific-type El Niño–Southern Oscillation (ENSO). The MSN EOF3 shows a wavelike T2m pattern over the Pacific–North America region, which has an approximately 90° phase difference from that associated with MSN EOF2, and a loading center over midlatitude Eurasia. Its sources of predictability include the central Pacific-type ENSO and Eurasian snow cover. The MSN EOF4 reflects T2m variability surrounding the Tibetan Plateau, which is plausibly linked to the remote forcing of the Arctic sea ice. The information on the leading predictable patterns and their sources of predictability is further used to develop a calibration scheme to improve the prediction skill of T2m. The calibrated prediction skill in terms of the anomaly correlation coefficient improves significantly over midlatitude Eurasia in a leave-one-out cross-validation, implying a possible way to improve the wintertime T2m prediction in the SEAS5.

scholarly journals The role of local sea surface temperature pattern changes in shaping climate change in the North Atlantic sector

2018 ◽  
Vol 52 (1-2) ◽  
pp. 417-438 ◽  
Author(s):  
Ralf Hand ◽  
Noel S. Keenlyside ◽  
Nour-Eddine Omrani ◽  
Jürgen Bader ◽  
Richard J. Greatbatch
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Sea Surface ◽  
Temperature Pattern ◽  
Atlantic Sector ◽  
The North ◽  
The North Atlantic
Sign in / Sign up

Export Citation Format

Share Document