Latitudinal and altitudinal variability of lower atmospheric inertial gravity waves revealed by U.S. radiosonde data
Latitudinal and altitudinal variability of lower atmospheric inertial gravity waves revealed by U.S. radiosonde data
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DOI：
10.1002/jgrd.50623
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
Shaodong Zhang;F. Yi;Chunming Huang;K. Huang;Q. Gan;Yehui Zhang;Yun Gong
中科院分区：
文献类型：
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作者：
Shaodong Zhang;F. Yi;Chunming Huang;K. Huang;Q. Gan;Yehui Zhang;Yun Gong
利用1998-2008年美国92个探空站（5°N ~ 75°N）11年的观测资料，采用宽谱数据分析方法，得到了2-25 km高度范围内惯性重力波（GW）参数的连续高度变率。据我们所知，这是第一次提出低层大气GW参数的纬向和连续高度变化。GW参数的纬度分布表明，对流层和平流层下部的波能量分别在中纬度和低纬度地区达到峰值，在低纬度地区，GW通常具有较大的固有频率与科里奥利参数的比值、较小的固有频率、较短的垂直波长和较长的水平波长。分析还揭示了大气重力波参数随高度的连续变化，其中大部分与背景温度场和风场密切相关，说明背景大气在大气重力波的激发和传播中起着重要作用。此外，我们的研究结果表明，深刻的气候影响的GWs的背景大气。在中纬度地区，GW诱导的力倾向于使纬向急流减速，并在对流层顶高度上方的偏北风中产生负垂直切变。GW热通量对对流层急流高度附近的大气有冷却作用，对中纬度对流层逆温的形成有重要贡献。此外，我们还证明了GW的能量密度，动量和热通量有明显的季节变化，特别是在中纬度地区。
We adopt a broad spectral data analyzing method to derive the continuous altitude variability of inertial gravity wave (GW) parameter properties in the altitude range of 2–25 km from 11 year (1998–2008) radiosonde observations over 92 United States stations locating in the latitude range from 5°N to 75°N. To our knowledge, this is the first time presenting latitudinal and continuous altitudinal variability of lower atmospheric GW parameters. The presented latitudinal distribution of GW parameters indicates that the wave energy in the troposphere and lower stratosphere peaks, respectively, at the middle and lower latitudes; and at lower latitudes, GWs usually have larger ratios of wave intrinsic frequency to Coriolis parameter, smaller intrinsic frequencies, shorter vertical wavelengths, and longer horizontal wavelengths. Our analyses also revealed continuous altitudinal variations of GW parameters, most of which are closely related to those of the background temperature and wind fields, indicating the important role of background atmosphere in excitation and propagation of GWs. Moreover, our results suggested the profound climatological impacts of GWs on background atmosphere. The GW‐induced force tends to decelerate the zonal jet at middle latitudes and produces a negative vertical shear in the northward wind closely above the tropopause altitude. The GW heat flux tends to cool the atmosphere around the tropospheric jet altitude and contributes significantly to the forming of tropospheric inversions at middle latitudes. Additionally, we demonstrated that GW energy densities, momentum, and heat fluxes have evident seasonal variations, especially at middle latitudes.