polar front jet (stream)

The meso scale structure of the systems associated the two rainbands are diagnosed in this paper by using the high resolution modeling data and the Sawyer Eliassen equation,revealing the special contribution of the jet frontogenesis to the formation and maintenance of the rain belts.

通过模式输出资料进行数值求解，揭示了急流锋生在两支雨带形成和维持中的特殊贡献。

Then,500hPa and 100hPa fields of height and its departure in winter over Northern Hemisphere,also the intensities and positions of polar frontal zone over Xinjiang are calculated corresponding to the two kinds of abnormal years.

使用 NCEP/NCAR 1979～ 1995年 17年全球旬平均网格点资料及北疆 8个站 1979～ 1995年 17年冬季（ 12～ 2月）降水资料，选取了 3个降水偏多年， 4个降水偏少年，分别计算了偏多、偏少年对应北半球范围内 500、 100hPa冬季平均高度场及距平场，分别计算了对应新疆范围内极锋锋区的强度和位置。