2008年低温雨雪天气扰动能量的积累和传播

利用NCEP/NCAR再分析资料,通过波包传播的诊断方法,对2008年1月我国南方地区大范围低温雨雪天气期间波包传播和积累进行了分析与研究.分析表明,中低层500hPa和700hPa高度场的波包传播特征能够较好地反映期间出现的4次低温雨雪天气过程.4次雨雪过程基本上产生于波包扰动能量积累的高值时段或处于低压系统持续稳定阶段,雨雪天气处于波包大值区控制下.波包值的经向和纬向传播特征表明2008年1月我国南方地区持续低温雨雪天气过程,主要受到青藏高原南缘系统异常活跃的影响,南支槽活动频繁有利于来自印度洋和孟加拉湾的暖湿气流沿云贵高原不断向我国输送,继而为我国长江中下游以及其南部地区低温雨雪天气提供了充足的水汽来源.偏北路径的冷空气,副高西南侧偏东气流的扰动能量的传播和积累,在波包传播图上都有一定的反映.该研究对进一步利用波包传播图预报天气过程提供了有意义的一种思路.

Propagation and Accumulation of Perturbation Energy in the Severe Cold Surge, Ice-snow and Frozen Disaster in South China During January 2008

By using the NCEP/NCAR reanalysis data and the diagnosis analysis meth od of wave packet propagation (WPD), wave packet propagation and accumulation du ring the extreme lowtemperature, heavy snowstorm and frost disasters occurred i n South China were analyzed. Results show that the characteristic of wave packe t propagation at 500 hPa and 700 hPa can better display four processes of rainst orm weather.Accumulated perturbation energy has been maintaining high value when these four processes occur. Frozen weather appears in the high value region of wave packet. The characteristic of wave packet propagation shows that the pe rsistent processes of severe weathers with cold surge, ice snow and frozen rain on January 2008 are influenced by the Indian and Burma trough (IBT) in the south side of the Qinghai Xizang Plateau. Because it is quite active, it also favors to the moisture transportation to China along the Yunnan Guizhou Plateau from th e Indian Ocean and Bay of Bengal. Perturbation energies of cold air in the north ward path and in the eastward side of western Pacific subtropical high (WPSTH) a re certainly reflected on the wave packet map. It indicates that the diagnosis a nalysis of wave packet propagation (WPD) is meaningful to predict the weather pr ocess.