利用1998~2003年6~8月的NCEP/NCAR再分析资料(1.0°×1.0°经纬度网格),以对流层中部500hPa高度层为重点,利用北半球夏季(6~8月)低纬度(0°~30°N)太平洋地区(160°E-120°W)各物理量(水平速度u,v,P-坐标垂直速度ω等)计算了水平运动方程中各分量的大小,通过比较对热带大尺度运动方程进行了简化,并给出了相应的简化方程,认为纬向风在除了赤道这一奇异带以外都是满足地转平衡的,而经向风则在离开赤道30°以外达到地转.由于热带太平洋地区是台风的重要发源地之一,因此弄清此地区的大气运动基本平衡关系有助于台风形成机制的研究。
By using the NCEP/NCAR reanalysis of daily with the horizontal resolution of 1.0°×1.0°(lat/ Ion grid), the general characteristics of the tropic motions in the north Pacific during 1998~2003 averaged for June-August, including the horizontal/vertical wind field, divergence and vorticity have been analysed. The main parts of the horizontal dynamical equations have been calculated and compared, according to which the force balance was investigated and the corresponding simplified equations were carried out. It is shown that the zonal wind (u) is geostrophic just outside the equator and the meridional wind (v) attains geostrophic beyond 30° N. For tropical cyclones are commonly generated in the tropical Pacific, the results may be attributed to the mechanism of the tropical cyclone genesis and development.