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Year‐to‐year forecasts of the Arctic climate conditions have drawn much interest in recent decades. This study investigates the primary drivers responsible for interannual variations (without multi‐decadal trends) of air temperature at 2 m (T2m) and sea ice concentration (SIC) over the Barents‐Kara Seas (BKS) during September from 1950 to 2021. The Arctic Dipole (AD), a leading factor in the BKS variability, plays an important role via influencing large‐scale atmospheric circulations and local thermodynamical feedbacks (i.e., vapor and albedo feedbacks). During a negative AD phase, the positive surface air temperature advection anomalies warm up the BKS region and promote sea ice melting, which in turn maintains the below‐normal sea ice and warmer‐than‐normal conditions via positive vapor and albedo feedbacks. Moreover, our results suggest that the sea surface temperature (SST) variability in the midlatitudes of the North Atlantic in the preceding month could also be an important driver of the SIC variability over the BKS area. The anomalous temperature advections from the surface to the upper troposphere are accompanied by a Rossby wave‐type atmospheric response, which intensifies the energy exchanges between the ocean and the atmosphere. Local SST anomalies associated with the surface heat flux anomalies further persist in the following month and influence sea ice variations due to their long‐lasting memory. A better understanding of the mechanisms of interannual climate variabilities over the BKS region in boreal early autumn is helpful to improving the Arctic regional climate predictions. Key Points: Understanding primary drivers of the interannual climate variabilities over the Arctic is essential to improve the regional prediction skillsThe Arctic Dipole is mainly responsible for driving the Barents‐Kara Seas (BKS) surface air temperature interannual variability in SeptemberThe North Atlantic sea surface temperature variability at 1‐month lead is associated with the early autumn sea ice cover variability in the BKS region [ABSTRACT FROM AUTHOR]

Under global warming, surface air temperature has risen rapidly and sea ice has decreased markedly in the Arctic. These drastic climate changes have brought about various severe impacts on the vulnerable environment and ecosystem there. Thus, accurate prediction of Arctic climate becomes more important than before. Here we examine the seasonal to interannual predictive skills of 2-m air temperature (2-m T) and sea ice cover (SIC) over the Arctic region (70°–90°N) during 1980–2014 with a high-resolution global coupled model called the Met Office Decadal Prediction System, version 3 (DePreSys3). The model captures well both the climatology and interannual variability of the Arctic 2-m T and SIC. Moreover, the anomaly correlation coefficient of Arctic-averaged 2-m T and SIC shows statistically significant skills at lead times up to 16 months. This is mainly due to the contribution of strong decadal trends. In addition, it is found that the peak warming trend of Arctic 2-m T lags the maximum decrease trend of SIC by 1 month, in association with the heat flux forcing from the ocean surface to lower atmosphere. While the predictive skill is generally much lower for the detrended variations, we find a close relationship between the tropical Pacific El Niño–Southern Oscillation and the Arctic detrended 2-m T anomalies. This indicates potential seasonal to interannual predictability of the Arctic natural variations. [ABSTRACT FROM AUTHOR]