Latitudinal‑ and height‑dependent long‑term climatology of propagating quasi‑16‑day waves in the troposphere and stratosphere
Latitudinal‑ and height‑dependent long‑term climatology of propagating quasi‑16‑day waves in the troposphere and stratosphere
复制标题
对流层和平流层中传播准 16 日波的依赖于纬度和高度的长期气候学
DOI：
10.1186/s40623-021-01544-8
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Gan Q.
中科院分区：
文献类型：
--
作者：
Tang W.;Zhang S.;Huang C.;Huang K.;Gong Y.;Gan Q.
波数为1（Q16 W1）的向西向传播准16天波（16 DW）的全球振幅，是16 DW的最强分量，来自欧洲中期天气预报中心ERA-Interim再分析温度和纬向风数据集，从1979年2月到2018年1月。在温度和纬向风方面，Q16 W1在两半球中高纬度平流层上部都有较强的气候平均振幅，且北方半球（NH）的振幅强于南方半球（SH）。利用多元线性回归方法分别计算了Q16 W1温度和纬向风振幅对QBO（准两年振荡）、ENSO（厄尔尼诺-南方涛动）、太阳活动的响应以及Q16 W1振幅的线性趋势。Q16 W1温度和纬向风振幅的QBO特征主要位于平流层。Q16 W1在低纬地区具有显著的QBO响应。此外，只有温度振幅在其最强的气候振幅区呈现出较大的QBO特征。温度和纬向风幅值对ENSO和太阳活动的响应不显著。月平均Q16 W1温度和纬向风振幅的线性趋势一般为正，特别是在平流层中上部。这种趋势在赤道附近是不对称的，北半球的趋势明显强于南半球。研究了温度振幅变化趋势的季节变化，结果表明，温度振幅变化趋势冬季较强，春季和秋季较弱。进一步的研究表明，背景和局部不稳定趋势贡献了大部分的Q16 W1振幅的增加趋势。在南北半球冬季，东向纬向风的减弱趋势为Q16 W1的上升传播提供了更有利的背景风，在北半球秋冬季节和南半球春、秋、冬季节，局地不稳定度的增强趋势可能增强波浪的激发。
图形摘要
The global amplitude of the westward propagating quasi-16-day waves (16DW) with wavenumber 1 (Q16W1), the strongest component of 16DW, are derived from the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis temperature and zonal wind data sets from February 1979 to January 2018. In terms of temperature and zonal wind, strong climatologically average amplitudes of Q16W1 appear in the upper stratosphere at mid–high latitudes in both hemispheres, and the wave amplitude is stronger in the Northern Hemisphere (NH) than in the Southern Hemisphere (SH). Multivariate linear regression is separately applied to calculate the responses of the Q16W1 temperature and zonal wind amplitudes to the QBO (quasi-biennial oscillation), ENSO (El Niño-Southern Oscillation), solar activity and linear trends of the Q16W1 amplitude. The QBO signatures of the Q16W1 temperature and zonal wind amplitudes are mainly located in the stratosphere. The Q16W1 has significant QBO responses at low latitudes. In addition, only the temperature amplitude presents a larger QBO signature in its strongest climatological amplitude region. No significant responses to ENSO and solar activity are observed in temperature and zonal wind amplitudes. The linear trends of the monthly mean Q16W1 temperature and zonal wind amplitude are generally positive, especially in the mid-upper stratosphere. The trend is asymmetric about the equator and significantly stronger in the NH than in the SH. The seasonal variation in the trend of the temperature amplitude is studied and illustrated to be stronger in winter and weaker in spring and autumn. Further investigation suggests that the background and local instability trends contribute most of the increasing trend of the Q16W1 amplitude. In winter in both hemispheres, a weakening trend of eastward zonal wind provides more favourable background wind for Q16W1 upward propagation, in autumn and winter in the NH and in spring, autumn and winter in the SH, and the increasing trend of local instability may enhance wave excitation.
Graphical Abstract