A Global Morphology of Gravity Wave Activity in the Stratosphere Revealed by the GPS Occultation Data (GPS/MET)
A Global Morphology of Gravity Wave Activity in the Stratosphere Revealed by the GPS Occultation Data (GPS/MET)
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DOI：
10.1029/1999jd901005
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发表时间：
2000-03
影响因子：
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通讯作者：
T. Tsuda;M. Nishida;C. Rocken;R. Ware
中科院分区：
文献类型：
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作者：
T. Tsuda;M. Nishida;C. Rocken;R. Ware
使用GPS/MET（GPS气象学）实验从1995年4月至1997年2月获得的温度分布，我们提取了中尺度温度扰动的垂直波长范围从2到10公里和背景Brunt-Vaisala频率平方，N2。对于每一个掩星事件，我们可以估计一个势能Ep，它被认为是由大气重力波引起的。日本附近15-20 km处Ep的月平均值呈年际变化，冬季有所增强，这与1985 ~ 1989年MU（34.9°N，136.0°E）雷达观测到的重力波动能的气候特征相一致。然后我们导出了北方半球冬季（11月至次年2月）20-30公里处Ep的全球分布。我们的分析表明，最大的Ep值一般集中在赤道附近25°N和25°S之间，有相当大的经度变化。本文还分析了30° ~ 60 ° N纬度范围内20-30 km处Ep的经向变化，结果表明大陆Ep值大于太平洋Ep值。利用GPS/MET资料，在不加反欺骗的情况下，测定了15-45 km范围内Ep的纬向变化。虽然大的Ep值集中在赤道附近20-30公里处，但在30-40公里处的中纬度地区和更高海拔地区，Ep往往变得更大。在中纬度地区，Ep在两个半球的冬季月份都较大。Ep的高度变化表明，在25-30公里处减少，30公里以上单调增加。
Using temperature profiles obtained by the GPS/MET (GPS Meteorology) experiment from April 1995 to February 1997, we have extracted mesoscale temperature perturbations with vertical wavelengths ranging from 2 to 10 km and background Brunt-Vaisala frequency squared, N2. For each occultation event, we can evaluate a potential energy Ep which is assumed to be caused by atmospheric gravity waves. The monthly mean values of Ep at 15–20 km around Japan showed an annual variation with an enhancement in winter, which is consistent with the climatological behavior of the kinetic energy of gravity waves observed with the MU (middle and upper atmosphere) radar (34.9°N, 136.0°E) from 1985 to 1989. We have then derived the global distribution of Ep at 20–30 km during Northern Hemisphere winter (from November to February). Our analysis shows that the largest Ep values are generally centered around the equator between 25°N and 25°S with considerable longitude variations. Longitudinal variations of Ep at 20–30 km in a latitude range of 30°–60°N are also analyzed, resulting in larger Ep values over the continents than over the Pacific Ocean. Using GPS/MET data without antispoofing, latitudinal variations of Ep are determined in 15–45 km. Although large Ep values are concentrated near the equator at 20–30 km, Ep tends to become larger at midlatitudes at 30–40 km and higher-altitude regions. At midlatitudes, Ep is found to be larger in winter months in both hemispheres. Height variations of Ep indicate a decrease at 25–30 km and a monotonic increase above 30 km.