【摘要】 对 1998年 3月新疆强切变线天气的分析表明，蒙古阻塞高压对切变线形成起决定性作用，切变线是一个冷性结构的风辐合带，白天较弱，夜晚较强。在切变线上维持一个纬向的次级环流，该次级环流加强了切变线东部的降水。水汽在对流层中上层的切变线附近辐合，大降水落区与切变线相一致。更多还原

【Abstract】 Analyzed a case of severe shear line in Xinjiang in March in 1998, it is shown that Mongolia blocking anticyclone act decisively on the shear line; the shear line is a cold wind convergence zone, which is weaker in the day than at night. A longitudinal subcirculation keeps at the shear line and strengthens rainfall at eastern shear line. Water vapor converges near shear line of upper－ middle troposphere and the region of torrential rain is identical with that of shear line.更多还原