【摘要】 从沙氏指数的物理定义出发,给出了计算沙氏指数的4种方案并进行了误差分析。A方案没有考虑水汽凝结潜热,计算结果误差大;B方案虽然考虑水汽凝结潜热,但计算方法没有考虑湿绝热线的曲率等问题,计算结果虽优于A方案,但误差仍较大;C方案不仅考虑水汽凝结潜热,并从计算方法上作了改进,不仅考虑了湿绝热线的曲率等问题,同时避免了由气压直接求取气温造成误差较大的问题,计算结果优于A、B方案,比较理想,可在实际工作中使用;D方案由假绝热方程经过转化求得上升气块的温度,然后算出沙氏指数,虽然精确,但计算复杂,实际应用较困难。更多还原

【Abstract】 According to the physical definition of Showalter Index(SI),four Calculation Schemes are proposed.Scheme A does not consider water vapor latent heat,resulting in large calculation errors.Although Scheme B considers the condensation latent heat,the curvature of wet adiabat is not considered in the computational method.Scheme B is superior to Scheme A,but the errors are still large.Scheme C not only considers the condensation latent heat,but also improves the computational method,considering the curvature of wet adiabat and the errors resulted from the derived temperature directly from pressure,with the result being superior to both Scheme A and B plan.Scheme D obtains the temperature of ascending air parcels through transformation by the pseudo-adiabatic equation,and then figures out SI index.It is more precise,but its calculation is very complex,difficult to be used widely.Therefore Scheme C is preferred,can be put to operational use.更多还原