Investigation of Low Frequency Atmospheric Oscillations Based on Satellite Data

大气的低频振荡（LFO）是一种时间尺度为一到两个月的现象，引起了全世界研究人员的兴趣。很多工作都集中在热带地区，那里是最初发现这种影响的地方。这个研究项目将集中在高纬度地区，特别是平流层，这个小组是第一个研究LFO的。该研究包括四个部分：1)将对平流层中上层的红外SSU数据计算与MSU微波分析（90mb温度）相似的全球相关图。2)利用位势高度场和SSU数据，利用相干性（波数的同相和非相相关）研究LFO垂直结构和从对流层到平流层上层的传播。滞后相关Hovmoller研究将用于研究波包行为。将利用热带微波数据与高纬度/高纬度位势高度和SSU场之间的相关性来评估热带-高纬度联系。3)通过Eliassen-Palm通量散度计算，研究LFO能量传播及其对平均流量的影响。e矢量公式将用于强基流分区不对称区域。将与模型预测进行比较。4)牛津大学将利用最近重新处理的中间层辐射数据场来寻找平流层顶以上LFO的存在。这项研究很重要，因为它寻求高层大气过程与地球表面附近气候之间的关系。这样的关系将增强我们对气候的理解和预测气候变化的能力。

Low frequency oscillations (LFO) of the atmosphere, a phenomenon with one-to two-month time scales, have captured the interest of researchers worldwide. Much work has been concentrated on the tropics where the effects were initially discovered. This research project will focus on higher latitudes and, in particular, the stratosphere where this group has been the first to study LFO. The research has four components: 1) Global correlation maps similar to those obtained with MSU microwave analyses (90 mb temperatures) will be calculated for infrared SSU data in the middle and upper stratosphere. 2) LFO vertical structure and propagation from the troposphere to the upper stratosphere will be studied with coherencies (in- and out-of phase correlations by wavenumber) using geopotential height fields and SSU data. Lag-correlation Hovmoller studies will be used to investigate wavepacket behavior. Tropics-higher latitude connections will be assessed with correlations between tropical microwave data and higher latitude/altitude geopotential height and SSU fields. 3) LFO energy propagation and effect on the mean flow will be investigated with Eliassen-Palm flux divergence calculations. An E-vector formulation will be used in regions of strong basic flow zonal asymmetry. Comparison will be made with model predictions. 4) Recently reprocessed mesospheric radiance data fields will be used at Oxford University to search for the existence of LFO above the stratopause. This research is important because it seeks relationships between processes in the high atmosphere and climate as manifested near the surface of the earth. Such relationships should enhance our understanding of climate and our ability to predict its variations.