On the Downward Progression of Stratospheric Temperature Anomalies Using Long‐Term SABER Observations
On the Downward Progression of Stratospheric Temperature Anomalies Using Long‐Term SABER Observations
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DOI：
10.1029/2022jd036487
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
B. Thurairajah;C. Cullens
中科院分区：
文献类型：
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作者：
B. Thurairajah;C. Cullens
平流层突然增温是平流层极涡与行星波相互作用的结果。SSW发生时，打破PWs减慢甚至逆转这种纬向风急流，并引起下沉运动，从而加热平流层，降低平流层顶。在本文中，我们使用18年（2003-2020年）的探测大气宽带辐射测量（SABER）观测平流层温度异常的这种向下进展的特点。每年1月和2月的SABER温度，派生的纬向风，PW活动和重力波（GW）活动表明每年的变化程度很高。在11次平流层增暖事件中（9次大事件和2次小事件），平流层顶高度下降速率变化范围为0.5 ~ 2km/d，平流层顶下降的最低高度变化范围为<20 ~ 1050 km（即，无下降）。温度和平方GW振幅异常的复合分析表明，从50到1025公里的温度异常的下降滞后于GW活动增加的向下进展。这增加GW活动与减弱和逆转的向西向纬向风与以前的研究一致。我们的研究表明，虽然PWs驱动30公里的SSW的发病，GW也发挥了作用，有助于温度异常的下降，从平流层顶到平流层中，低层。
It is well known that stratospheric sudden warmings (SSWs) are a result of the interaction between planetary waves (PWs) and the stratospheric polar vortex. SSWs occur when breaking PWs slow down or even reverse this zonal wind jet and induce a sinking motion that adiabatically warms the stratosphere and lowers the stratopause. In this paper we characterize this downward progression of stratospheric temperature anomalies using 18 years (2003–2020) of Sounding of the Atmosphere using Broadband Radiometry (SABER) observations. SABER temperatures, derived zonal winds, PW activity and gravity wave (GW) activity during January and February of each year indicate a high‐degree of year‐to‐year variability. From 11 stratospheric warming events (9 major and 2 minor events), the descent rate of the stratopause altitude varies from 0.5 to 2 km/day and the lowest altitude the stratopause descends to varies from <20 to ∼50 km (i.e., no descent). A composite analysis of temperature and squared GW amplitude anomalies indicate that the downward descent of temperature anomalies from 50 to ∼25 km lags the downward progression of increased GW activity. This increased GW activity coincides with the weakening and reversal of the westward zonal winds in agreement with previous studies. Our study suggests that although PWs drive the onset of SSWs at 30 km, GWs also play a role in contributing to the descent of temperature anomalies from the stratopause to the middle and lower stratosphere.