【摘要】 2018年1月6日河北省出现一次低槽冷锋天气系统,利用两次云粒子垂直探测资料分析层状云结构特征和演化规律,探讨冬季低槽冷锋系统层状云催化条件和催化时机。结果表明:天气系统初期西南风风速中心发生在6500 m高空时,风速随高度呈不连续分布,层状云云顶温度为-29.2℃,中低云层稀薄; 3000 m以上云层粒子基本被冰化,云内过冷水含量小于0.05 g·m^-3,固态含水量为0.1 g·m^-3左右,3000 m以下云层有大量自然冰晶,过冷水低于0.15 g·m^-3,不具备催化条件。700—3000 m高度层西南风加强,云内过冷水含量普遍大于0.1 g·m^-3; 2200 m风速中心风速达16 m·s^-1,该高度最大液态水含量达0.38 g·m^-3,冰晶浓度为6 L^-1,温度为-9℃,适宜催化。低槽冷锋天气系统层状云结构特征和催化条件受槽前西南风强弱和风速中心高度影响,天气系统初期层状云云顶过高、温度过低时,层状云为不可播云。随槽线东移,风速中心高度降低,3000 m以下西南风加强,层状云转变为可播云。更多还原

【Abstract】 A lowtrough cold front precipitation process occurred on January 6,2018,in Hebei province.Based on two sets of aircraft detection data,macro and micro cloud structure and cloud development process were analyzed,and the catalytic condition and seeding opportunity for the stratiform cloud in lowtrough cold front system in winter were investigated.The results showthat when the wind center of southwest wind occurred at an altitude of6500 m at the beginning of the weather system,the wind speed was discontinuously distributed with the height,the cloud top temperature of stratiform cloud was around-29.2 ℃,and the lowand middle clouds were thin.At the same time,cloud particles above 3000 m were glaciated,the supercooled water content in the cloud was less than 0.05 g·m^-3,and the solid water content was about 0.1 g·m^-3.Meanwhile,there were a lot of natural ice crystals in the cloud below3000 m,and the supercooled water content was less than 0.15 g·m^-3,which was not available for seeding.At the height of 700-3000 m,the southwesterly wind was strengthened,the supercooled water content in the cloud was generally larger than 0.1 g·m^-3,and the wind speed at the wind center at 2200 m was 16 m·s^-1,and the maximum liquid water content at this height was 0.38 g·m^-3,and ice crystal concentration was 6 L^-1,and the temperature was-9 ℃,which was suitable for seeding.The structure characteristics and seeding conditions of stratiform clouds in this lowcold front weather system were affected by the intensity of the southwest wind ahead of the trough and the height of the wind center.Because the top of the stratiform cloud was too high and the temperature was too lowin the early stage of the weather system,this cloud system was not in favor of seeding.As the trough line moved eastward,the wind center height decreased and the southwesterly wind below3000 m was intensified,this stratiform cloud was transformed into the cloud available for seeding.更多还原