Observations of Quasi‐Two‐Day wave by TIMED/SABER and TIMED/TIDI
Observations of Quasi‐Two‐Day wave by TIMED/SABER and TIMED/TIDI
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DOI：
10.1002/jgrd.50191
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
Sheng‐yang Gu;Tao Li;X. Dou;Qian Wu;M. Mlynczak;J. Russell
中科院分区：
文献类型：
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作者：
Sheng‐yang Gu;Tao Li;X. Dou;Qian Wu;M. Mlynczak;J. Russell
利用2002-2012年期间的全球温度和风场数据集研究了准两日波s = −3（W3）和s = −4（W 4）模态的季节和年际变化，这些数据集分别由热层电离层和中间层电动力学（TIMED）卫星上的宽带发射辐射测量大气探测（SABER）和TIMED多普勒成像仪（TIDI）仪器观测到。W_3和W_4的振幅分别在南半球夏季和北半球夏季显著增强。2006年1月，在温度、纬向风和纬向风的所有三个分量中都观察到了强W3振幅。这很可能与冬季强烈的行星波活动有关，导致了强烈的平流层突然变暖（SSW）事件。10年来，W 4的最大温度、纬向和纬向分量振幅分别为~8-9 K、~40 m/s和~20 m/s，约为W3的~15 K、~65 m/s和~35 m/s的一半。在2008年和2009年1月，观测到异常弱的W3振荡，但强的W 4振荡，对应于夏季东风急流（向西）比其他年份弱得多。这表明，相对较弱的夏季东风可能无法提供足够强的正压/斜压不稳定放大W3，但有利于W 4的放大。与W3相比，W 4的较弱的震级值、较低的峰值高度和较长的寿命间隔表明W 4可能比W3遭受更大的阻尼率。W 4的观测结果与Rossby重力（4，0）模吻合得很好，因为它的群速度比Rossby重力（3，0）模低，更容易在纬度和高度上被捕获。
Seasonal and interannual variations of the Quasi‐Two‐Day wave s = −3 (W3) and s = −4 (W4) modes were studied with global temperature and wind data sets during 2002–2012, observed respectively by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and TIMED Doppler Imager (TIDI) instruments onboard the Thermosphere Ionosphere and Mesosphere Electric Dynamics (TIMED) satellite. The amplitudes of W3 and W4 are significantly enhanced during austral and boreal summer respectively. Strong W3 amplitudes are observed during January 2006 in all three components of temperature, meridional wind, and zonal wind. This is most likely related to the intensive winter planetary wave activity that led to a strong sudden stratosphere warming (SSW) event. The maximum amplitudes of W4 during the 10 years are ~8–9 K, ~40 m/s, and ~20 m/s for temperature, meridional, and zonal components respectively, nearly half as large as those of W3, with ~15 K, ~65 m/s, and ~35 m/s. In January 2008 and 2009, unusually weak W3 but strong W4 oscillations were observed, corresponding to the much weaker summer easterly jets (westward wind) than those in other years. This suggests that relatively weak summer easterly may not be able to provide sufficiently strong barotropic/baroclinic instability to amplify W3 but is favorable for the amplification of W4. The weaker magnitude values, lower peak heights, and longer life intervals of W4 than those of W3 suggest that the W4 may suffer a greater damping rate than the W3. The observations of W4 show good agreement with Rossby‐gravity (4, 0) mode, which is more easily trapped in both latitude and altitude because of its lower group velocity than that of Rossby‐gravity (3, 0) mode.