Interannual and decadal variability of Arctic summer sea ice associated with atmospheric teleconnection patterns during 1850-2017

Abstract

The interannual and decadal variability of summer Arctic sea ice is analyzed, using the longest reconstruction (1850-2017) of Arctic sea ice extent available, and its relationship with the dominant internal variabilities of the climate system is further investigated quantitatively. The leading empirical orthogonal function (EOF) mode of summer Arctic sea ice variability captures an in-phase fluctuation over the Arctic Basin. The second mode characterizes a sea ice dipolar pattern with out-of-phase variability between the Pacific Arctic and the Atlantic Arctic. Summer sea ice variability is impacted by the major internal climate patterns: the Atlantic Multidecadal Oscillation (AMO), North Atlantic Oscillation (NAO), Arctic Oscillation (AO), Pacific Decadal Oscillation (PDO) and Dipole Anomaly (DA), with descending order of importance based on the multiple regression analyses. The internal climate variability of the five teleconnection patterns accounts for up to 46% of the total variance in sea ice mode 1 (thermodynamical effect), and up to 30% of the total variance in mode 2 (dynamical effect). Furthermore, the variability of sea ice mode 1 decreased from 46% during 1953-2017 to 28% during 1979-2017, while the variability of mode 2 increased from 11% during 1953-2017 to 30% during 1979-2017. The increasingly greater reduction of Arctic summer sea ice during the recent four decades was enhanced with the positive ice/ocean albedo feedback loop being accelerated by the Arctic amplification, contributed in part by the atmospheric thermodynamical forcing from -AO, +NAO, +DA, +AMO, and –PDO and by the dynamical transpolar sea ice advection and outflow driven by +DA- and +AMO-derived strong anomalous meridional winds. Further analysis, using multiple large ensembles of climate simulations and single-forcing ensembles, indicates that the mode 1 of summer sea ice, dominated by the multidecadal oscillation, is partially a forced response to anthropogenic warming.

Unprecedented Arctic sea ice thickness loss and multiyear-ice volume export through Fram Strait during 2010–2011

“…The relationship with the atmospheric mode and the variability of the SIV export is broadly consistent with the mechanism outlined by Wu et al (2006), Wang et al (2009), Cai et al (2021aCai et al ( , 2021b and Wang et al (2021). The correlation coefficient between the DA (AO) index and the ice export anomalies was 0.58 (−0.35), reaching statistical significance at the 95% level.…”

“…Additionally, in March, the surface air temperature exhibited pronounced warming over the eastern Arctic, but less in the western Arctic (figure S4(d)). The positive AO and DA phase dynamically drove sea ice to be thinner, resulting in an enhanced heat flux from the ocean, while +AMO (0.15, slightly warm yr round) and −PDO (−1.23, very warm, yr round) were consistently warm, leading to thermodynamic melt (Rigor et al 2002, Cai et al 2021a, 2021b. The loss of MYI, together with warmer surface air temperatures, led to further loss of sea ice.…”

“…Based on the investigation conducted in this paper and previous studies, more absorbed solar radiation leads to more melting and more open water, which accelerates the decline of Arctic sea ice. Both dynamical and thermodynamical forcings of teleconnection pattern can speed up the ice/ocean-albedo positive feedback loop (Perovich et al 2008, Cai et al 2021a, 2021b. Hence the loss of MYI and the anomalies of cloud fraction played significant roles, whereas the albedo anomalies acted through an amplifying feedback process when the melting was already initiated.…”

A preliminary attempt on decadal prediction of the East Asian summer monsoon

“…S2). It is not surprised that the relationships between prediction and predictors have decadal shifts under the background of many decadal shifts occurred in the climate (Krishnamurthy and Krishnamurthy 2016;Notz 2017;Huang et al 2018;Xu et al 2019;Cai et al 2021).…”

Unveiling the role of tropical Pacific on the emergence of ice-free Arctic projections

“…The significance of these recovery events (positive SIC anomaly years) in a warming climate is that they could eventually slow down the rate of SIC loss. El Niño Southern Oscillation (ENSO; Clancy et al 2021), Arctic Oscillation (AO; Cai et al 2021), Atlantic multidecadal variability (Cai et al 2021), and Pacific Decadal Variability Francis 2016, Cai et al 2021), among others, modulate SIC fluctuations on interannual to multidecadal timescales.…”