利用COSMIC掩星资料分析大气重力波参数的全球分布特征
Analysis of the Global Distribution of the Atmospheric Gravity Wave Parameters Using COSMIC Radio Occultation Data
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摘要: 本文介绍了从单一温度廓线提取重力波的水平波长、垂直波长、势能和动量通量的方法,利用2007~2008年COSMIC干温廓线数据计算得到了可以表征中尺度重力波活动特征的相关参数值在各年夏季和冬季的全球分布。结果与国内外已有的相关结果在形态分布上符合较好。结果表明,在20~30 km大气层,重力波在北半球处于冬季时的活动明显强于夏季,重力波的活动呈现纬向分布特征,夏半球高纬地区的重力波活动有明显的季节性变化,重力波的活动主要受地形和对流作用影响。COSMIC数据计算的动量通量分布大致与势能分布趋于一致。Abstract: This paper introduces a method to retrieve the vertical and the horizontal wavelength, the potential energy and the momentum flux of the gravity waves in the atmosphere from single temperature profiles. Using GPS RO dry temperature profiles from the COSMIC mission, we obtain the global distributions of the gravity wave parameters during the summer and winter of 2007 to 2008, regarded as the characteristics of the mesoscale atomosphere gravity wave activities. Our results show that the distribution form of the gravity wave is in good agreement with those found in the latest references. Our study shows that at the altitudes of 20~30 km, the atmospheric gravity wave activities are apparently stronger in NH winters than in NH summers. Gravity wave activities have zonal distribution characteristics. In the high latitudes of the hemisphere during summer, gravity wave activities have significant seasonal variations. Gravity wave activities are affected by topography and convections. The distributions of the momentum flux and potential energy derived from COSMIC RO data show similar characteristics.