Abstract:Based on daily temperature data in winter, the relationship between number of extreme low temperature (NELT) and Arctic Oscillation (AO) in Beijing-Tianjin-Hebei Region in winter is analyzed, the AO-related interdecadal atmospheric circulation anomalies in late winter (February) is explored. The results show that NELT in winter in Beijing-Tianjin-Hebei Region has been decreasing since 1961. The correlation is weakening between NELT and AO after the middle 1980s compared to that before the middle 1980s, but strengthening in early winter, and that remains weak in late winter after early 2000s. Furthermore, the interdecadal variation in the relationship between NELT and AO in late winter in Beijing-Tianjin-Hebei Region is largely attributed to the AO-related atmospheric circulation anomalies under different interdecadal backgrounds. When significant correlation exists between NELT and AO, through impacting the Siberian high, Aleutian low, Ural blocking high and East Asian trough, a positive AO phase is associated with less frequency of extreme low temperature, and vice versa. In contrast, AO displays a more zonal symmetry structure, and the climate circulation system in mid-high latitudes is weak, which confines the influence of winter AO on NELT and leads to an insignificant late winter AO-NELT relationship.