scholarly journals Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability

2017 ◽  
Vol 114 (24) ◽  
pp. 6227-6232 ◽  
Author(s):  
Hiroki Tokinaga ◽  
Shang-Ping Xie ◽  
Hitoshi Mukougawa
Keyword(s):  
Phase Shift ◽  
20Th Century ◽  
North Atlantic ◽  
Interdecadal Variability ◽  
The Arctic ◽  
Positive Phase ◽  
Northern Eurasia ◽  
Early 20Th Century ◽  
Arctic Warming ◽  
The Pacific

With amplified warming and record sea ice loss, the Arctic is the canary of global warming. The historical Arctic warming is poorly understood, limiting our confidence in model projections. Specifically, Arctic surface air temperature increased rapidly over the early 20th century, at rates comparable to those of recent decades despite much weaker greenhouse gas forcing. Here, we show that the concurrent phase shift of Pacific and Atlantic interdecadal variability modes is the major driver for the rapid early 20th-century Arctic warming. Atmospheric model simulations successfully reproduce the early Arctic warming when the interdecadal variability of sea surface temperature (SST) is properly prescribed. The early 20th-century Arctic warming is associated with positive SST anomalies over the tropical and North Atlantic and a Pacific SST pattern reminiscent of the positive phase of the Pacific decadal oscillation. Atmospheric circulation changes are important for the early 20th-century Arctic warming. The equatorial Pacific warming deepens the Aleutian low, advecting warm air into the North American Arctic. The extratropical North Atlantic and North Pacific SST warming strengthens surface westerly winds over northern Eurasia, intensifying the warming there. Coupled ocean–atmosphere simulations support the constructive intensification of Arctic warming by a concurrent, negative-to-positive phase shift of the Pacific and Atlantic interdecadal modes. Our results aid attributing the historical Arctic warming and thereby constrain the amplified warming projected for this important region.

scholarly journals Eurasian autumn snow link to winter North Atlantic Oscillation is strongest for Arctic warming periods

2020 ◽  
Vol 11 (2) ◽  
pp. 509-524 ◽  
Author(s):  
Martin Wegmann ◽  
Marco Rohrer ◽  
María Santolaria-Otín ◽  
Gerrit Lohmann
Keyword(s):  
North Atlantic Oscillation ◽  
Snow Cover ◽  
20Th Century ◽  
North Atlantic ◽  
The Arctic ◽  
Atmospheric Conditions ◽  
Sea Ice Concentration ◽  
Stratospheric Polar Vortex ◽  
Winter Climate ◽  
Arctic Warming

Abstract. In recent years, many components of the connection between Eurasian autumn snow cover and wintertime North Atlantic Oscillation (NAO) have been investigated, suggesting that November snow cover distribution has strong prediction power for the upcoming Northern Hemisphere winter climate. However, the non-stationarity of this relationship could impact its use for prediction routines. Here we use snow products from long-term reanalyses to investigate interannual and interdecadal links between autumnal snow cover and atmospheric conditions in winter. We find evidence for a negative NAO-like signal after November with a strong west-to-east snow cover gradient, which is valid throughout the last 150 years. This correlation is consistently linked to a weak stratospheric polar vortex state. Nevertheless, decadal evolution of this link shows episodes of decreased correlation strength, which co-occur with episodes of low variability in the November snow index. By contrast, periods with high prediction skill for winter NAO are found in periods of high November snow variability, which co-occur with the Arctic warming periods of the 20th century, namely the early 20th-century Arctic warming between 1920 and 1940 and the ongoing anthropogenic global warming at the end of the 20th century. A strong snow dipole itself is consistently associated with reduced Barents–Kara sea ice concentration, increased Ural blocking frequency and negative temperature anomalies in eastern Eurasia.

Solar radiation in the Arctic during the Early Twentieth Century Warming period (1921–50)

2020 ◽  
Author(s):  
Rajmund Przybylak ◽  
Pavel Sviashchennikov ◽  
Joanna Uscka-Kowalkowska ◽  
Przemysław Wyszyński
Keyword(s):  
Twentieth Century ◽  
Solar Radiation ◽  
20Th Century ◽  
Solar Irradiance ◽  
Research Work ◽  
The Arctic ◽  
Early 20Th Century ◽  
Solar Forcing ◽  
Arctic Warming ◽  
Early Twentieth Century

<p>The Early Twentieth Century Warming (ETCW) period includes a time when a clear increase in actinometric observations was noted in the Arctic, which is defined for the purpose of the present paper after Atlas Arktiki (Treshnikov ed., 1985). Nevertheless, available information about energy balance, and its components, for the Arctic for the study period is still very limited, and therefore solar forcing cannot be reliably determined. As a result, the literature contains large discrepancies between estimates of solar forcing. For example, reconstructions of the increase of terrestrial solar irradiance (TSI) during the ETCW period range from 0.6 Wm<sup>-2</sup> (CMIP5, Wang et al., 2005), through 1.8 Wm<sup>-2</sup> (Crowley et al., 2003), to 3.6 Wm<sup>-2</sup> (Shapiro et al., 2011). Suo et al. (2013) concluded that the collection and processing of solar data is of paramount and central importance to the ability to take solar forcing into account, especially in modelling work.</p><p>            Having in mind the weaknesses of our knowledge described above, we decided to present in the paper a summary of our research concerning the availability of solar data in the Arctic (including measurements taken during land and marine expeditions). A detailed inventory of data series for the ETCW period (1921–50) also containing all available metadata will be an important part of this work. Based on the gathered data, a preliminary analysis will be presented of the general solar conditions in the Arctic in this time in terms of global, diffuse and direct solar radiation, and their changes from the ETCW period to present times (mainly 1981–2010).</p><p>            The research work in this paper was supported by a grant entitled “Causes of the Early 20th Century Arctic Warming”, funded by the National Science Centre, Poland (grant no. 2015/19/B/ST10/02933).</p><p>References:</p><p>Crowley T.J., Baum S.K., Kim K., Hegerl G.C. and Hyde W.T., 2003. Modeling ocean heat content changes during the last millennium. Geophys. Res. Lett. 30, 1932</p><p>Shapiro A.I., Schmutz W., Rozanov E., Schoell M., Haberreiter M. and co-authors, 2011. A new approach to the long-term reconstruction of the solar irradiance leads to large historical solar forcing. Astron. Astrophys. 529, A67.</p><p>Suo L., Ottera O.H., Bentsen M., Gao Y. and Johannessen O.M., 2013. External forcing of the early 20th century Arctic warming, Tellus A 2013, 65, 20578, http://dx.doi.org/10.3402/tellusa.v65i0.20578</p><p>Treshnikov A.F. (ed.), 1985. Atlas Arktiki. Glavnoye Upravlenye Geodeziy i Kartografiy: Moscow.</p><p>Wang Y.M., Lean J.L. and Sheeley Jr. N.R., 2005. Modeling the sun’s magnetic field and irradiance since 1713. Astroph. J. 625, 522.</p>

Meridional Tripole Mode of Winter Precipitation over the Arctic and Continental North Africa–Eurasia

2021 ◽  
pp. 1
Author(s):  
Xiaolin Liu ◽  
Jianhua Lu ◽  
Yimin Liu ◽  
Guoxiong Wu
Keyword(s):  
Time Series ◽  
North Africa ◽  
North Atlantic ◽  
Hadley Cell ◽  
The Arctic ◽  
Positive Phase ◽  
The North ◽  
Ferrel Cell ◽  
The North Atlantic ◽  
Westerly Jets

AbstractWintertime precipitation is vital to the growth of glaciers in the northern hemisphere. We find a tripole mode of precipitation (PTM), with each pole of the mode extending zonally over the eastern hemisphere roughly between 30°W and 120°E, and the positive/negative/positive structure for its positive phase extending meridionally from the Arctic to the continental North Africa–Eurasia. The large-scale dynamics associated with the PTM is explored. The positive phase of the PTM is associated with the negative while eastward-shifted phase of the North Atlantic Oscillation (NAO) and a zonal band of positive SST anomaly in the tropics, together with a narrowed Hadley cell and weakened Ferrel cell. While being north-eastward tilted and separated from their North Africa-Eurasia counterpart in the climatological mean, the upper-tropospheric westerly jets over the east Pacific and north Atlantic become extending zonally and shifting southward and hence form a circumpolar subtropical jet as a whole by connecting with the westerly jets over the North Africa-Eurasia. The enhanced zonal winds over the north Atlantic promote more synoptic-scale transient eddies which are waveguided by the jet streams. The polar vortex weakens and cold air dips southward from the North Pole. Further diagnosis of the E-vectors suggests that transient eddies have a positive feedback on the weakening of Ferrel cell. Opposite features are associated with the negative phase of the PTM. The reconstructed time series using multiple linear regression on the NAO index and the tropical SST averaged over 20°S– 20°N, can explain 62.4% of the variance of the original the original precipitation time series.

Climate Variability in the Context of Climate Change: El Niño and Other Oscillations

2008 ◽  
Author(s):  
Cynthia Rosenzweig ◽  
Daniel Hillel
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Global Climate ◽  
Climate System ◽  
The Arctic ◽  
The Pacific ◽  
Earth’S Climate

The climate system envelops our planet, with swirling fluxes of mass, momentum, and energy through air, water, and land. Its processes are partly regular and partly chaotic. The regularity of diurnal and seasonal fluctuations in these processes is well understood. Recently, there has been significant progress in understanding some of the mechanisms that induce deviations from that regularity in many parts of the globe. These mechanisms include a set of combined oceanic–atmospheric phenomena with quasi-regular manifestations. The largest of these is centered in the Pacific Ocean and is known as the El Niño–Southern Oscillation. The term “oscillation” refers to a shifting pattern of atmospheric pressure gradients that has distinct manifestations in its alternating phases. In the Arctic and North Atlantic regions, the occurrence of somewhat analogous but less regular interactions known as the Arctic Oscillation and its offshoot, the North Atlantic Oscillation, are also being studied. These and other major oscillations influence climate patterns in many parts of the globe. Examples of other large-scale interactive ocean–atmosphere– land processes are the Pacific Decadal Oscillation, the Madden-Julian Oscillation, the Pacific/North American pattern, the Tropical Atlantic Variability, the West Pacific pattern, the Quasi-Biennial Oscillation, and the Indian Ocean Dipole. In this chapter we review the earth’s climate system in general, define climate variability, and describe the processes related to ENSO and the other major systems and their interactions. We then consider the possible connections of the major climate variability systems to anthropogenic global climate change. The climate system consists of a series of fluxes and transformations of energy (radiation, sensible and latent heat, and momentum), as well as transports and changes in the state of matter (air, water, solid matter, and biota) as conveyed and influenced by the atmosphere, the ocean, and the land masses. Acting like a giant engine, this dynamic system is driven by the infusion, transformation, and redistribution of energy.

scholarly journals CMIP5 Projections of Arctic Amplification, of the North American/North Atlantic Circulation, and of Their Relationship

2015 ◽  
Vol 28 (13) ◽  
pp. 5254-5271 ◽  
Author(s):  
Elizabeth A. Barnes ◽  
Lorenzo M. Polvani
Keyword(s):  
North Atlantic ◽  
Climate Models ◽  
Coupled Model ◽  
Arctic Region ◽  
The Arctic ◽  
Cmip5 Models ◽  
Arctic Amplification ◽  
Arctic Warming ◽  
The North ◽  
Sequence Of Events

Abstract Recent studies have hypothesized that Arctic amplification, the enhanced warming of the Arctic region compared to the rest of the globe, will cause changes in midlatitude weather over the twenty-first century. This study exploits the recently completed phase 5 of the Coupled Model Intercomparison Project (CMIP5) and examines 27 state-of-the-art climate models to determine if their projected changes in the midlatitude circulation are consistent with the hypothesized impact of Arctic amplification over North America and the North Atlantic. Under the largest future greenhouse forcing (RCP8.5), it is found that every model, in every season, exhibits Arctic amplification by 2100. At the same time, the projected circulation responses are either opposite in sign to those hypothesized or too widely spread among the models to discern any robust change. However, in a few seasons and for some of the circulation metrics examined, correlations are found between the model spread in Arctic amplification and the model spread in the projected circulation changes. Therefore, while the CMIP5 models offer some evidence that future Arctic warming may be able to modulate some aspects of the midlatitude circulation response in some seasons, the analysis herein leads to the conclusion that the net circulation response in the future is unlikely to be determined solely—or even primarily—by Arctic warming according to the sequence of events recently hypothesized.

scholarly journals The Occurrence and Properties of Long-Lived Liquid-Bearing Clouds over the Greenland Ice Sheet and Their Relationship to the North Atlantic Oscillation

2018 ◽  
Vol 57 (4) ◽  
pp. 921-935 ◽  
Author(s):  
Jonathan Edwards-Opperman ◽  
Steven Cavallo ◽  
David Turner
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
The Arctic ◽  
Positive Phase ◽  
Cloud Base ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractStratiform liquid-bearing clouds (LBCs), defined herein as either pure liquid or mixed-phase clouds, have a large impact on the surface radiation budget across the Arctic. LBCs lasting at least 6 h are observed at Summit, Greenland, year-round with a maximum in occurrence during summer. Mean cloud-base height is below 1 km for 85% of LBC cases identified, 59% have mean liquid water path (LWP) values between 10 and 40 g m−2, and most produce sporadic light ice-phase precipitation. During their occurrence, the atmosphere above the ice sheet is anomalously warm and moist, with southerly winds observed over much of the ice sheet, including at Summit. LBCs that occur when the North Atlantic Oscillation (NAO) is in the negative phase correspond to strong ridging centered over the Greenland Ice Sheet (GIS), allowing for southwesterly flow over the GIS toward Summit. During the positive phase of the NAO, the occurrence of LBCs corresponds to a cyclone located off the southeastern coast of the ice sheet, which leads to easterly-to-southeasterly flow toward Summit. Furthermore, air parcels at Summit frequently originate from below the elevation of Summit, indicating that orographic lift along the ice sheet is a factor in the occurrence of LBCs at Summit. LBCs are more frequently observed during the negative NAO, and both the LWP and precipitation rate are larger in LBCs occurring during this phase. Mean LWP in LBCs occurring during the negative NAO is 15 g m−2 larger than in LBCs occurring during the positive phase.

scholarly journals Long-term variations of the seasonal snow cover in Nordland, Norway: the influence of the North Atlantic Oscillation

2013 ◽  
Vol 54 (62) ◽  
pp. 25-34 ◽  
Author(s):  
Wilfred H. Theakstone
Keyword(s):  
North Atlantic Oscillation ◽  
Snow Cover ◽  
20Th Century ◽  
North Atlantic ◽  
Temporal Trends ◽  
The Arctic ◽  
Simple Task ◽  
Seasonal Snow ◽  
Synoptic Conditions ◽  
Seasonal Snow Cover

AbstractTemporal and spatial variations of the seasonal snow cover at 40 sites in Nordland county, Norway, since the last decade of the 19th century are examined. Nordland lies across the Arctic Circle. Annual maximum snow depths there have varied, reflecting the interaction of synoptic conditions, temperature and terrain. North/south and coastal/inland differences are evident, but common temporal trends are identified. Maximum snow depths are strongly related to the winter North Atlantic Oscillation index. Early in the 20th century, the index was positive and the associated stormy conditions resulted in a deep, prolonged snow cover. As the index declined in the 1920s, snow depths decreased sharply. Through much of the second half of the 20th century they increased as the index tended to become more positive. The start and duration of the period of continuous snow cover is influenced by the autumn NAO index. A decrease of duration around 1990 was particularly evident at low-lying stations and those in northern Nordland. The NAO has varied considerably over the past 120 years. Because of its influence, forecasting future trends of snow depth and snow-cover duration is not a simple task.

scholarly journals Scientific Research in the European Part of the Arctic Territories in the Second Half of the 19th – Early 20th Century as a Part of the North of European Russia Modernization Program

2020 ◽  
pp. 774-785
Author(s):  
Anna K. Gagieva ◽  
◽  
Nikolay N. Gagiev ◽  
Keyword(s):  
20Th Century ◽  
Scientific Research ◽  
European Part ◽  
European Russia ◽  
Transport Infrastructure ◽  
The Arctic ◽  
Early 20Th Century ◽  
Historical Sources ◽  
The North ◽  
Stage Of Development

The article discusses main stages of scientific research of the arctic territories of the European North in the second half of the 19th – early 20th century. Drawing on historical sources and published literature, it concludes that the nature of research changed due to requirements of the time. It is known that the second half of the 19th – early 20th century was a time when society faced the task of expanding its reproduction base, which stimulated development of new spaces, introduction of new means of transport, and active inclusion of population and regions in production relations. The speed and efficiency of the developing commercial interactions between the territories came to the fore. Overcoming institutional and technical backwardness of the country and its territories involved a consistent expansion of the “effective national territory” by means of market development, spatial mobility of the main factors of production, capital, labor, and transport infrastructure improvement. The spatial expansion played a special part. The arctic zone of the North of European Russia presented great opportunities due its unique natural resources, and also prospects of solving geopolitical problems. This should have contributed to a new qualitative growth of production and transition to a new stage of development. Scientific research of the European part of the arctic territories, which was carried out at the time, was a part of the program of modernization of the North of European Russia, which unfolded on the pan-European scale. It was supported by the reorganization of administrative-territorial structure based on traditional structures of grass-roots management and prompted growing interest in the periphery as a source of resources for the growing economy; scientific research of the arctic territories intensified, as it became practical. Thanks to scientific research, the development of the Arctic territories became dynamic, which speeded up the integration of the region (in our case, the Komi krai) into the national space.

scholarly journals How does the Arctic affect North Atlantic climate? Fresh perspectives on a long-standing question.

2021 ◽  
Author(s):  
Marilena Oltmanns ◽  
N. Penny Holliday ◽  
James Screen ◽  
D. Gwyn Evans ◽  
Simon A. Josey ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Heat Waves ◽  
Rapid Change ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Weather Extremes ◽  
Arctic Warming ◽  
The North ◽  
Arctic Ice

<p>Recent decades have been characterised by amplified Arctic warming and increased occurrence of extreme weather events in the North Atlantic region. While earlier studies noticed statistical links between high-latitude warming and mid-latitude weather extremes, the underlying dynamical connections remained elusive. Combining different data products, I will demonstrate a new mechanism linking Arctic ice losses with cold anomalies and storms in the subpolar region in winter, and with heat waves and droughts over Europe summer. Considering feedbacks of the identified mechanism on the Arctic Ocean circulation, I will further present new support for the potential of Arctic warming to trigger a rapid change in climate.</p>

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