scholarly journals Arctic warming and associated sea ice reduction in the early 20th century induced by natural forcings in MRI‐ESM2.0 climate simulations and multi‐model analyses

2021 ◽  
Author(s):  
Takuro Aizawa ◽  
Masayoshi Ishii ◽  
Naga Oshima ◽  
Seiji Yukimoto ◽  
Hiroyasu Hasumi
Keyword(s):  
Sea Ice ◽  
20Th Century ◽  
Early 20Th Century ◽  
Arctic Warming ◽  
Climate Simulations ◽  
Sea Ice Reduction

scholarly journals Evaluation of Arctic warming in mid-Pliocene climate simulations

2020 ◽  
Author(s):  
Wesley de Nooijer ◽  
Qiong Zhang ◽  
Qiang Li ◽  
Qiang Zhang ◽  
Xiangyu Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Future Climate ◽  
The Arctic ◽  
Future Climate Change ◽  
Sea Ice Extent ◽  
Current Form ◽  
Arctic Warming ◽  
Amplification Ratio ◽  
Climate Simulations

Abstract. Palaeoclimate simulations improve our understanding of the climate, inform us about the performance of climate models in a different climate scenario, and help to identify robust features of the climate system. Here, we analyse Arctic warming in an ensemble of 16 simulations of the mid-Pliocene Warm Period (mPWP), derived from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The PlioMIP2 ensemble simulates Arctic (60–90° N) annual mean surface air temperature (SAT) increases of 3.7 to 11.6 °C compared to the pre-industrial, with a multi-model mean (MMM) increase of 7.2 °C. The Arctic warming amplification ratio relative to global SAT anomalies in the ensemble ranges from 1.8 to 3.1 (MMM is 2.3). Sea ice extent anomalies range from −3.0 to −10.4 × 06 km2 with a MMM anomaly of −5.6 × 106 km2, which constitutes a decrease of 53 % compared to the pre-industrial. The majority (11 out of 16) models simulate summer sea ice-free conditions (≤ 1 × 06 km2) in their mPWP simulation. The ensemble tends to underestimate SAT in the Arctic when compared to available reconstructions. The simulations with the highest Arctic SAT anomalies tend to match the proxy dataset in its current form better. The ensemble shows some agreement with reconstructions of sea ice, particularly with regards to seasonal sea ice. Large uncertainties limit the confidence that can be placed in the findings and the compatibility of the different proxy datasets. We show that, while reducing uncertainties in the reconstructions could decrease the SAT data-model discord substantially, further improvements are likely to be found in enhanced boundary conditions or model physics. Lastly, we compare the Arctic warming in the mPWP to projections of future Arctic warming and find that the PlioMIP2 ensemble simulates greater Arctic amplification, an increase instead of a decrease in AMOC strength compared to pre-industrial, and a lesser strengthening of northern modes of variability than CMIP5 future climate simulations. The results highlight the importance of slow feedbacks in equilibrium climate simulations, and that caution must be taken when using simulations of the mPWP as an analogue for future climate change.

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>

scholarly journals Evaluation of Arctic warming in mid-Pliocene climate simulations

2020 ◽  
Vol 16 (6) ◽  
pp. 2325-2341
Author(s):  
Wesley de Nooijer ◽  
Qiong Zhang ◽  
Qiang Li ◽  
Qiang Zhang ◽  
Xiangyu Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Meridional Overturning Circulation ◽  
Future Climate ◽  
The Arctic ◽  
Future Climate Change ◽  
Sea Ice Extent ◽  
Current Form ◽  
Arctic Warming ◽  
Climate Simulations

Abstract. Palaeoclimate simulations improve our understanding of the climate, inform us about the performance of climate models in a different climate scenario, and help to identify robust features of the climate system. Here, we analyse Arctic warming in an ensemble of 16 simulations of the mid-Pliocene Warm Period (mPWP), derived from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The PlioMIP2 ensemble simulates Arctic (60–90∘ N) annual mean surface air temperature (SAT) increases of 3.7 to 11.6 ∘C compared to the pre-industrial period, with a multi-model mean (MMM) increase of 7.2 ∘C. The Arctic warming amplification ratio relative to global SAT anomalies in the ensemble ranges from 1.8 to 3.1 (MMM is 2.3). Sea ice extent anomalies range from −3.0 to -10.4×106 km2, with a MMM anomaly of -5.6×106 km2, which constitutes a decrease of 53 % compared to the pre-industrial period. The majority (11 out of 16) of models simulate summer sea-ice-free conditions (≤1×106 km2) in their mPWP simulation. The ensemble tends to underestimate SAT in the Arctic when compared to available reconstructions, although the degree of underestimation varies strongly between the simulations. The simulations with the highest Arctic SAT anomalies tend to match the proxy dataset in its current form better. The ensemble shows some agreement with reconstructions of sea ice, particularly with regard to seasonal sea ice. Large uncertainties limit the confidence that can be placed in the findings and the compatibility of the different proxy datasets. We show that while reducing uncertainties in the reconstructions could decrease the SAT data–model discord substantially, further improvements are likely to be found in enhanced boundary conditions or model physics. Lastly, we compare the Arctic warming in the mPWP to projections of future Arctic warming and find that the PlioMIP2 ensemble simulates greater Arctic amplification than CMIP5 future climate simulations and an increase instead of a decrease in Atlantic Meridional Overturning Circulation (AMOC) strength compared to pre-industrial period. The results highlight the importance of slow feedbacks in equilibrium climate simulations, and that caution must be taken when using simulations of the mPWP as an analogue for future climate change.

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.

Early 20th century Arctic warming in retrospect

2009 ◽  
Vol 30 (9) ◽  
pp. 1269-1279 ◽  
Author(s):  
Kevin R. Wood ◽  
James E. Overland
Keyword(s):  
20Th Century ◽  
Early 20Th Century ◽  
Arctic Warming

scholarly journals External forcing of the early 20th century Arctic warming

2013 ◽  
Vol 65 (1) ◽  
pp. 20578 ◽  
Author(s):  
Lingling Suo ◽  
Odd Helge Otterå ◽  
Mats Bentsen ◽  
Yongqi Gao ◽  
Ola M. Johannessen
Keyword(s):  
20Th Century ◽  
Early 20Th Century ◽  
External Forcing ◽  
Arctic Warming
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