仇永炎. 1979. 动能的周期变化和动能转换率对动能增衰的作用[J]. 气象学报, 37(3):13-21, doi:10.11676/qxxb1979.025
动能的周期变化和动能转换率对动能增衰的作用
PERIODIC VARIATION OF KINETIC ENERGY AND THE CONTRIBUTION OF KINETIC CONVERSION RATE TO THE INTENSIFICATION AND DECAY OF KINETIC ENERGY
投稿时间:1979-01-26  
DOI:10.11676/qxxb1979.025
中文关键词:  
英文关键词:
基金项目:
作者单位
仇永炎 北京大学地球物理系 
摘要点击次数: 1770
全文下载次数: 1912
中文摘要:
      利用1976~1977年冬季四个月北半球500mb资料,对北半球平均动能和涡动动能波谱的中期变化、动能转换率对平均动能的增衰和对波动增衰的作用进行了研究,得到一些初步结果。指出:北半球平均动能、涡动动能以及涡动动能和平均动能之间的转换率,有准两周的周期振动。涡动动能先于动能转换率一天达到峰值,而后再过两天平均动能达到峰值。在k=3波时,动能也存在准两周的周期振动,它是对涡动动能总值贡献最大的波动,同涡动动能总值具有同位相的振动。对动能转换率总值贡献最大的还是k=3波,其转换率具有同转换率总值同位相的准两周振动。动能转换率对平均动能整个增长阶段的贡献,大于衰退阶段,在平均动能增长阶段,动能转换率近似于同平均动能变化率平衡。这意味着平均动能的增长,正压过程在起作用。文中还研究了动能转换率对k=1~6波增衰的作用,结果表明:它对波动的增长不起作用,但对波动的衰退起到足够的贡献。最后,对波动的增衰同平均动能和涡动动能的中期变化之间的联系进行了讨论。
英文摘要:
      By the use of 500 mb northern hemispheric data of four months during the winter season of 1976-77 medium range variations of northern hemispheric mean kinetic energy, eddy kinetic energy spectra and the spectra of kinetic conversion rate are studied.Through the qualitative analysis and power spectral analysis of these time series, some preliminary results are obtained. Mean energy, total eddy energy and total value of conversion rate all show a quasi-two-week oscillation. But, there are phase differences among them. The total eddy energy leads the total conversion rate by about one day, and leads the mean energy by about 3 days. The values of eddy energy and conversion rate of wave number three all show a quasi-two-week variation. The eddy energy of wave number three is not only in approximate phase with the total eddy energy, but also the most significant contribution among the waves. The wave number 3 also gives the most significant contribution to the total conversion rate. The contributions of conversion rate to the intensification and decay of mean energy and eddy energy for various wave numbers are investigated. It is found that the rates of change of mean energy throughout its intensification are almost balanced by the conversion rates. It suggests that barotropic process plays a more important role in the intensifying stage of mean energy. As far as individual wave numbers are concerned, the decay of kinetic energies for k=3-6 is, say the least, partly due to losing energy through barotropic conversion process.Finally,the relationship between the medium range variations of mean and eddy kinetic energies and their intensifiction and decay is discussed.
HTML   查看全文   查看/发表评论  下载PDF阅读器
分享按钮