Abstract:Based on the conventional surface observation data and NECP 25°×25° reanalysis dataset, the planetary-scale characteristics of the persistent freezing events over Jiangxi province for the period of 1959—2008 have been investigated. The results show that the 500 hPa pattern with the blocking high in high-latitude, the trough in middle latitude and the splintering trough in lower latitude is favorable to freezing rain event occurrences in Jiangxi. The surface strong cold air invading along middle and east China, offers a favorable thermal condition for freezing rain. At 700 hPa, there are stable “moist tongue” and southwesterly jet stream from lower latitude, which are propitious to the formation and maintenance of temperature inversion structure at middle level, and also are the major mechanisms of vapor transportation. The results of anomaly correlation (AC) analysis reveal that during the persistent freezing rains, the ACs of sea level pressure, 1 000—925 hPa thickness and 1 000—500 hPa thickness are larger than 07, most of which are larger than 08, which indicates that during the persistent freezing rains, the influencing systems at upper and lower levels are stable and unchangeable.