Analysis of the Causes for a Strong Cold-air Outbreak in Guangdong in December 2023

JIANG Xiaocen; HU Yamin; HUANG Feng; MO Weiqiang

doi:10.3969/j.issn.1007-6190.2025.02.004

Abstract：To learn what caused anomalously cold temperatures in Guangdong during a cold-air out-break on December 16-25,2023,this paper used the NCEP/NCAR reanalysis data,sea surface tempera-tures from NOAA and air temperatures from 86 national stations across the province to analyze possible cau-ses for the process.The results are shown as follows.On the large-scale circulation field,an upper-level jet stream moved eastward and was relatively strong,conducive to the strengthening of a Siberian high and an A-leutian low.A polar vortex was positioned southeastward and phase-superimposed with a trough in eastern Europe,a blocking high in the Ural Mountains and a main trough in East Asia were strong,favoring the me-ridional increase of circulation above the Eurasian continent and the southward progression of cold air.A subtropical high was northward in the western Pacific and relatively strong,beneficial for the main East Asi-an trough to move slowly.An East Asian monsoon was stronger than usual for that particular section of the life cycle,making it the most immediate cause for the strong cold-air outbreak studied.Meanwhile,sea sur-face temperatures were high in the northern and southwestern parts of the North Atlantic and a wavetrain propagated eastward in the northern part of the North Atlantic,which was one of the possible causes for the anomalous circulation patterns at the mid-and higher-latitudes of the Eurasian continent.