摘要
利用云迹风并结合实测风，从涡度方程出发，对１９９８年南海和西太平洋的几个热带气旋进行诊断计算。结果反映，涡度局地变率((/(ｔ对热带气旋移动有指示意义，它既可指示热带气旋的正常路径，在引导气流不明显的情况下，也能对热带气旋的转折路径有较明显的反映，热带气旋常朝涡度局地变率最大的方向移动。当热带气旋周围有数个((/(ｔ中心时，矢量合成法确定了气旋的最大可能移动方向。此外，正如引导气流一样，热带气旋周围的((/(ｔ场存在着有效作用半径，在此半径范围内场对热带气旋运动有最直接的影响。
ased on the cloud track winds and the upper sounding winds,the first three terms ofright hand side of the fractionless barotropic vorticity equation, e. g. the relative vorticity advection, the planetary vorticity advection and the divergent term were calculated. The sum ofthese three terms gave an estimate of the local vorticity variation rate. Computations werecarried out to some tropical cyclone cases for the year 1998 over the region of the South China Sea and the Western Pacific. Results show that the local vorticity variation rate hasspecial significance in indicating tropical cyclone movement,and it can indicate obviously botha steady track of tropical cyclone motion and a sudden turning on tropical cyclone movement.Tropical cyclones move generally toward the direction of maximum local vorticity variationrate. If has several maxima in the vicinity of tropical cyclone center, vector compositionmethod may give a mostly probable direction of tropical cyclone motion. In addition, just asthe steering current, there is an effective radius of interaction in U field,within the effectiveradius the changes in field may have a direct influence to tropical cyclone motion.
出处
《气象》
CSCD
北大核心
1999年第12期11-16,共6页
Meteorological Monthly
关键词
云迹风
热带气候
路径预报
气旋预报
: cloud track wind tropical cyclone track prediction
