Using the physical decomposition method to study the effects of Arctic factors on wintertime temperatures in the Northern Hemisphere and China

• Main Authors: Cuijuan, Sui, Zhanhai, Zhang, Yi, Cai, Huiding, Wu
• Format: Article in Journal/Newspaper
• Language: English
• Published: Polar Research Institute of China - PRIC 2014
• Subjects: Atmosphere; Advances in Polar Science; Arctic; Bering Strait; Greenland; Polar Science; Siberia
• Online Access: http://library.arcticportal.org/2542/; http://library.arcticportal.org/2542/1/A20140401.pdf

The physical decomposition method separates atmospheric variables into four parts, correlating each with solar radiation, land–sea distribution, and inter-annual and seasonal internal forcing, strengthening the anomaly signal and increasing the correlation between variables. This method was applied to the reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), to study the effects of Arctic factors (Arctic oscillation (AO) and Arctic polar vortex) on wintertime temperatures in the Northern Hemisphere and China. It was found that AO effects on zonal average temperature disturbance could persist for 1 month. In the AO negative phase in wintertime, the temperatures are lower in the mid–high latitudes than in normal years, but higher in low latitudes. When the polar vortex area is bigger, the zonal average temperature is lower at 50°N. Influenced mainly by meridional circulation enhancement, cold air flows from high to low latitudes; thus, the temperatures in Continental Europe and the North American continent exhibit an antiphase seesaw relationship. When the AO is in negative phase and the Arctic polar vortex larger, the temperature is lower in Siberia, but higher in Greenland and the Bering Strait. Influenced by westerly troughs and ridges, the polar air disperses mainly along the tracks of atmospheric activity centers. The AO index can be considered a predictor of wintertime temperature in China. When the AO is in negative phase or the Asian polar vortex is intensified, temperatures in Northeast China and Inner Mongolia are lower, because under the influence of the Siberia High and northeast cold vortex, the cold air flows southwards.