January temperature anomalies over Northeast China and precursors

This paper analyzes the large-scale atmospheric circulation characteristics of anomalous cases of January temperatures that occurred in Northeast China during 1960–2008 and precursory oceanic conditions. The January monthly mean surface air temperature (SAT) anomalies and the duration of low temperature are used to define temperature anomaly cases. The anomalous cyclonic circulation over northeast Asia strengthens the northerly flow in cold Januarys, while the anomalous anticyclonic circulation weakens the northerly flow in the warm Januarys. The negative (positive) North Pacific sea surface temperature anomaly (SSTA) and increased (decreased) sea ice concentration in the Barents-Kara seas in the preceding month are probably linked to the cyclonic (anticyclonic) circulation pattern over northeast Asia in the cold (warm) cases. Further analyses indicate that the preceding oceanic conditions play distinct roles in the SAT anomalies over Northeast China on different time scales. Strong relationships exist between North Pacific SSTA and the SAT in Northeast China on the interannual time scale. On the other hand, the sea ice concentration is more closely associated with the interdecadal variations of SAT in Northeast China.