重力波波包在向上传播过程中的破碎

采用二维全隐欧拉（FICE）格式对具有高斯分布的重力波波包在可压大气中传播时的饱和过程进行数值模拟和分析．数值计算结果表明，波振幅首先随高度增加而增加，但当波振幅接近于线性不稳定性给出的阈值时，不再增加，重力波波包达到饱和进而破碎．破碎出现的高度（86．50km）比线性理论预言的结果（84．59km）要高一些，并且一般都在波包的下游出现．波破碎过程能使波能量在空间重新分配，并对重力波能量有明显的耗散作用．并且波破碎会使波相关能量传输方向偏离线性射线理论的射线路径．

BREAKING OF A UPWARD PROPAGATING GRAVITY WAVE PACKET

NUmerical simulation of breaking of gravity wave packets with Gaussiandistribution propapare upward in a compressible atmosphere is presented by using 2-DFICE scheme. The numerical analyses show that wave-associatod distUrbance velocihesincrease with the height until close to the threshold value given by the linear theory,the gravity wave Packet is satUrate and then breaking. The height （86.50km） wavebreaking occurs is a bit higher than the height （84.59km） given by the linear theory,and wave breakng often occurs at the downstream region of wave packet. The wavebreding can redistribute the wave-associated energy in space and obviously dissipatethe wave-associated energy. Furthermore the wave breaking can differ the propagationdirechon of wave-associated energy from the ray path given by linear theory.