Interannual and day-to-day variations of gravity wave activity in the lower stratosphere over the ea
Interannual and day-to-day variations of gravity wave activity in the lower stratosphere over the ea
复制标题
东亚地区平流层低层重力波活动的年际和日变化
DOI：
10.2151/jmsj1965.77.2_413
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发表时间：
1999
影响因子：
3.1
通讯作者：
S. Fukao
中科院分区：
文献类型：
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作者：
S. Ogino;M. Yamanaka;S. Fukao
利用1989- 1995年日本东部（27°N-45°N，大致沿沿着东经140°）上空的探空资料，研究了平流层下部重力波活动的年际和逐日变化。重力波的活动是由温度和纬向风波动的变化与垂直尺度为2- 6公里量化。在连续7年的时间里，每年冬季在秋田（北纬40°）20 km高度附近都有活跃的重力波出现。结果表明，该地区观测到的重力波活动具有明显的年际和逐日变化。冬季秋田上空20 km高度层温度距平的年际变化在1990/91 ~ 1994/95年间随背景纬向风的增加而增加了1.5倍。另一方面，温度变化和背景Vaisala-Brunt数之间没有观察到明确的关系。同一地区（冬季秋田上空20 km左右）重力波活动的日变化特征是间歇性出现，周期为几天。各高度层的温度方差与背景纬向风速度的互相关分析表明，当近地面纬向风强时，20 km层附近的重力波活动增强。在日本东北部和北方的其他观测站也发现了类似的特征。结果表明，每年冬季日本东北部和北方上空约20 km处出现的波动是由南北走向的山脉上的强纬向风激发的山波引起的。
Interannual and day-to-day variations of gravity wave activities in the lower stratosphere were examined using operational rawinsonde data over eastern part of Japan (27°N-45°N, roughly along ∼140°E) during 1989-95. The gravity-wave activities were quantified by variances of temperature and zonal wind fluctuations with vertical scales of 2--6 km. Active gravity waves were confirmed to appear around the 20 km altitude level over Akita (∼40°N) every winter throughout the seven year period. It was found that the gravity wave activities observed in this region have remarkable interannual and day-to-day variations. The interannual variation of temperature variance at about the 20 km level over Akita in winter shows ∼1.5 times increase from 1990/91 to 1994/95 together with the increase in the background zonal wind. On the other hand, a clear relationship was not observed between the temperature variance and the background Vaisala-Brunt number. The day-to-day variation of the gravity wave activity in the same region (around the 20 km level over Akita in winter) is characterized by intermittent appearance with a periodicity of several days. Cross-correlation analyses between the temperature variance and the background zonal win velocity at each altitude level, showed clearly that gravity wave activity around the 20 km level was intensified when zonal wind near the surface is strong. The similar features were also found at other stations over the northeastern and northern part of Japan. The results suggest that the fluctuations that appear around 20 km over northeastern and northern Japan every winter, are due to mountain waves excited by strong zonal wind flowing over north-south running mountain ranges.
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山中医学博士：“重力波动量和能量通量通过中层大气转移到高层大气的简单模型”J.Atmos.Terr.Phys.(1993)
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