On the Mechanism of Arctic Climate Oscillation with a Period of About 15 Years According to Data of the INM RAS Climate Model

2020 ◽  
Vol 56 (2) ◽  
pp. 112-122
Author(s):  
E. M. Volodin
2020 ◽  
Author(s):  
Evgeny Volodin

<p>Natural variability of Arctic climate is studied on the basis of preindustrial run with climate model INM-CM5-0.  The length of run is 1200 years. Temperature in Arctic shows significant peaks at periods of 60 and 15 years. Model climate oscillations are studied using technique of calculation of energy generation and impact to phase change.</p><p>60-year oscillation is generated mainly by advection of Atlantic water to Arctic ocean. Anomaly of oceanic currents associated with the oscillation are generated by gradients of density. Before warm phase there is negative anomaly of density near coasts and continental slope. This leads to enhancing of Atlantic water inflow to Arctic ocean, warming, increasing of density near slope and turning to negative phase of oscillation. Cyclonic vorticity over warm Bartents and Kara seas leads to wind currents that enhance inflow of Atlantic water to Arctic.</p><p>15-year oscillation is also generated by advection of Atlantic water to Arctic ocean, but anomalies of currents are generated mainly by wind stress. Before warm Arctic we have cold and fresh North Atlantic, that leads to positive NAO, it induces wind currents that transport more Atlantic water to Arctic ocean. This leads to Arctic warming, decrease of NAO and turn to opposite phase of oscillation. Warming of North Atlantic happens 3-4 years after maximum of Arctic warming. The response of Atlantic meridional streamfunction to the oscillation is studied.</p><p>"Ideal model" potential predictability experiments started from synthetic state preceding warm Arctic (cold and fresh North Atlantic) show that this oscillation can be predicted for time interval up to 10 years.</p>


Author(s):  
Xiying Liu ◽  
Chenchen Lu

Abstract To get insights into the effects of sea ice change on the Arctic climate, a polar atmospheric regional climate model was used to perform two groups of numerical experiments with prescribed sea ice cover of typical mild and severe sea ice. In experiments within the same group, the lateral boundary conditions and initial values were kept the same. The prescribed sea ice concentration (SIC) and other fields for the lower boundary conditions were changed every six hours. 10-year integration was completed, and monthly mean results were saved for analysis in each experiment. It is shown that the changes in annual mean surface air temperature have close connections with that in SIC, and the maximum change of temperature surpasses 15 K. The effects of SIC changes on 850 hPa air temperature is also evident, with more significant changes in the group with reduced sea ice. The higher the height, the weaker the response in air temperature to SIC change. The annual mean SIC change creates the pattern of differences in annual mean sea level pressure. The degree of significance in pressure change is modulated by atmospheric stratification stability. In response to reduction/increase of sea ice, the intensity of polar vortex weakens/strengthens.


2021 ◽  
Author(s):  
Karen Smith ◽  
Sarah Maleska ◽  
John Virgin

<p>Stratospheric ozone depletion in the Antarctic is well known to cause changes in Southern Hemisphere tropospheric climate; however, because of its smaller magnitude in the Arctic, the effects of stratospheric ozone depletion on Northern Hemisphere tropospheric climate are not as obvious or well understood. Recent research using both global climate models and observational data has determined that the impact of ozone depletion on ozone extremes can affect interannual variability in tropospheric circulation in the Northern Hemisphere in spring. To further this work, we use a coupled chemistry–climate model to examine the difference in high cloud between years with anomalously low and high Arctic stratospheric ozone concentrations. We find that low ozone extremes during the late twentieth century, when ozone-depleting substances (ODS) emissions are higher, are related to a decrease in upper tropospheric stability and an increase in high cloud fraction, which may contribute to enhanced Arctic surface warming in spring through a positive longwave cloud radiative effect. A better understanding of how Arctic climate is affected by ODS emissions, ozone depletion, and ozone extremes will lead to improved predictions of Arctic climate and its associated feedbacks with atmospheric fields as ozone levels recover.</p>


AMBIO ◽  
2004 ◽  
Vol 33 (4) ◽  
pp. 211-220 ◽  
Author(s):  
Colin G. Jones ◽  
Klaus Wyser ◽  
Anders Ullerstig ◽  
Ulrika Willén

2018 ◽  
Vol 33 (6) ◽  
pp. 359-366 ◽  
Author(s):  
Evgenii M. Volodin

Abstract Using the data of pre-industrial experiment with the INM-CM5 climate model for the period of 1200 years, we study the mechanism of natural oscillations of Arctic climate with the period of about 60 years. It is shown that for a quarter of the period prior to the Arctic warming there is a flow of Atlantic water into the Arctic ocean (AO) being more intense than usual, the salinity and density are less than usual near the coast and shelf border. As the result of advection of Atlantic water after Arctic warming, the water near the coast and shelf border becomes more salty and heavy, which leads to a weakening of the flow of Atlantic water and the change of oscillation phase. The conclusions are confirmed by calculations of the generation of anomalies of temperature, salinity, and velocity of currents by different terms, as well as estimation of the contribution of various components to the change of oscillation phase.


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