摘要
为了提高沙瓦特指数(SI)的计算精度,提出一种计算SI指数的新方案。在气块沿湿绝热线上升求解500 hPa气块温度过程中,当给定气压,温度变化很小时,假相当位温与温度近似为线性关系,利用这种线性关系可导出计算气块温度的显式公式。实例计算表明,该方案计算速度快且精度较高,最大误差和平均误差分别为0.69℃、0.51℃。
A new method is introduced to improve computational accuracy of Showalter Index.Calculating 500 hPa temperature of parcel which ascends along moist adiabat,if pressure is fixed and a small change of temperature is given,the relationship between potential pseudo-equivalent temperature and parcel temperature approximates linear one which can be used to educe explicit formula to calculate parcel temperature.The Showalter Index computed with the new method reaches a higher accuracy level with fast speed.The maximal error is 0.69 ℃ and average error is 0.51 ℃.
出处
《暴雨灾害》
2011年第4期379-382,共4页
Torrential Rain and Disasters
基金
国家自然科学基金项目"背风坡触发强对流天气的研究"(40705020)
关键词
沙瓦特指数
气块温度
假相当位温
Showalter index
parcel temperature
potential pseudo-equivalent temperature
