Lidar Observations of Stratospheric Gravity Waves From 2011 to 2015 at McMurdo (77.84°S, 166.69°E), Antarctica: 2. Potential Energy Densities, Lognormal Distributions, and Seasonal Variations
Lidar Observations of Stratospheric Gravity Waves From 2011 to 2015 at McMurdo (77.84°S, 166.69°E), Antarctica: 2. Potential Energy Densities, Lognormal Distributions, and Seasonal Variations
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DOI：
10.1029/2017jd027386
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发表时间：
2018-08
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通讯作者：
X. Chu;Jian Zhao;Xian Lu;V. Harvey;R. Jones;E. Becker;Cao Chen;W. Fong;Zhibin Yu;B. Roberts;A. Dörnbrack
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作者：
X. Chu;Jian Zhao;Xian Lu;V. Harvey;R. Jones;E. Becker;Cao Chen;W. Fong;Zhibin Yu;B. Roberts;A. Dörnbrack
利用麦克默多站2011 - 2015年5年的Fe Boltzmann激光雷达瑞利温度数据，对平流层30-50 km的重力波位能质量密度（Epm）、位能体积密度（Epv）、垂直波数谱和静态稳定度N2进行了表征。Epm（Epv）廓线随海拔升高而增大（减小），Epv的尺度高度表明冬季波浪耗散较夏季强。海拔平均E <$pm和E <$pv服从对数正态分布，夏季小值集中，冬季大值分布广泛。E <$pm和E <$pv在不同的观测中变化很大，但表现出重复的季节性模式，夏季最小，冬季最大。2012年和2015年冬季最大值高于其他年份，表明年际变化。海拔平均N2 <$从仲冬的最大值到10月左右的最小值变化约30-40%，并呈现出近双峰分布。5-20 km垂直波长的月平均垂直波数功率谱密度从夏季到冬季逐渐增加。使用现代研究和应用回顾分析第2版数据，我们发现，当麦克默多位于极涡内部时，冬季的E ′ pm值会很大。月平均E ′ pm与风旋转角呈负相关，但与3 km和30 km风速呈正相关。相应的相关系数分别为-0.62、+0.87和+0.80。结果表明，Epm的夏冬不对称主要是由临界水平滤波引起的，该滤波在夏季耗散了大部分重力波。冬季E ′ pm的变化主要是由于对流层和平流层重力波产生的变化以及平流层平均风的多普勒频移。
Five years of Fe Boltzmann lidar's Rayleigh temperature data from 2011 to 2015 at McMurdo are used to characterize gravity wave potential energy mass density (Epm), potential energy volume density (Epv), vertical wave number spectra, and static stability N2 in the stratosphere 30–50 km. Epm (Epv) profiles increase (decrease) with altitude, and the scale heights of Epv indicate stronger wave dissipation in winter than in summer. Altitude mean E¯pm and E¯pv obey lognormal distributions and possess narrowly clustered small values in summer but widely spread large values in winter. E¯pm and E¯pv vary significantly from observation to observation but exhibit repeated seasonal patterns with summer minima and winter maxima. The winter maxima in 2012 and 2015 are higher than in other years, indicating interannual variations. Altitude mean N2¯ varies by ~30–40% from the midwinter maxima to minima around October and exhibits a nearly bimodal distribution. Monthly mean vertical wave number power spectral density for vertical wavelengths of 5–20 km increases from summer to winter. Using Modern Era Retrospective Analysis for Research and Applications version 2 data, we find that large values of E¯pm during wintertime occur when McMurdo is well inside the polar vortex. Monthly mean E¯pm are anticorrelated with wind rotation angles but positively correlated with wind speeds at 3 and 30 km. Corresponding correlation coefficients are −0.62, +0.87, and +0.80, respectively. Results indicate that the summer‐winter asymmetry of E¯pm is mainly caused by critical level filtering that dissipates most gravity waves in summer. E¯pm variations in winter are mainly due to variations of gravity wave generation in the troposphere and stratosphere and Doppler shifting by the mean stratospheric winds.