The Kinetic Energy Budget and Circulation Characteristics of the Tropical Storm Irma during AMEX Phase Ⅱ

By using the data from observation on the Chinese research vessel Xiang Yang Hong No.5 and other sources during AMEX phase II, the kinetic energy budget and circulation characteristics of the tropical storm Irma were analyzed.Irma formed on the ITCZ of the Southern Hemisphere. During the formative stage of the storm, the SE trades and monsoon westerlies on both sides of the ITCZ strengthened, and more importantly, there was a strong divergent flow in upper troposphere. These contributed to the intensification of Irma. At the time when Irma formed, the Richardson number (Ri) in middle and lower troposphere was much smaller than that prior to and post the formation.When Irma intensified rapidly, the area-averaged kinetic energy in the general flow increased in the whole troposphere . The largest contribution came from kinetic energy generation term, -[v.(?)(?)] .indicates that there existed a strong ageostrophic accetration. As to the generation term , the conversion of available potential energy to kinet     

AMEX期间一个热带风暴发展的动能收支及环流特征

利用中、美、澳联合进行的澳大利亚季风试验(AMFX)第二阶段观测资料,对南半球热 带风暴Irma的发展,进行了环流背景和动能收支的分析。 Irma发生于南半球的ITCZ上,生成时的环流条件是ITCZ两侧偏东信风、偏西季风都在加强,尤其是对流层上部气流散开区移近,辐散强烈增加。同时,对流层下半部的R_1数出现最小值。 Irma迅速增加时,总动能增加主要来自制造项,说明这时有很强的非地转加速。而对制造的最大贡献者,是有效位能的释放。由此表明了内源和积云对流总体影响的重要性。 而Irma迅速增强时涡动能的增加,最重要的源是较小尺度运动或次网格尺度动能,主要贡献在对流层上部。少量的贡献来目区域平均气流动能的转换。因此,扰动的发展,从较大、较小两种尺度运动中都取得能量,但后者重要得多。制造项也有重要作用,但主要贡献在对流层下部。此外,扰动还向周围大气输出涡动动能,因此起着祸动动能制造并输出的作用。