Dynamics of the Tropical Intraseasonal Oscillation

题目：热带季节内振荡动力学。本研究的目的是进一步发展对热带季节内扰动（TIS）复杂行为的物理认识。从这项研究中获得的结果有望对MJO和相关气候变化的未来预测有用。将进行三个相互关联的研究项目。1. 本文将采用一个描述赤道湿润波和时间平均流的三层热带大气模式，研究三维平均流对波发展和传播的影响，以及与波活动相关的动量和热输送（或E-P通量）引起的平均流的变化。2. 为了在季节内时间尺度上了解大气-海洋相互作用的性质，太平洋太平洋指数将(a)利用一个热带海洋中间模式进行数值实验，以了解季节内强迫对ENSO循环的可能影响；(b)对海温和MJO的季节内变化关系进行实证研究，以了解海温和MJO之间的耦合程度。c)分析与暖海区有关的大气和海洋的热力学耦合可能引起的耦合不稳定性。3. 项目将利用小波分析等有效手段，研究MJO的多尺度时空结构及其与云团、热带气旋和温带强迫的关系。采用理论分析、数值分析和实证分析相结合的策略。实证分析用于揭示新的事实和提出假设，而理论和数值模拟用于解释现象和验证假设。这项研究很重要，因为它试图了解季节内时间尺度上的变化。

Abstract ATM-9400759 Wang, Bin University of Hawaii Title: Dynamics of the Tropical Intraseasonal Oscillation The goal of this proposed research is to futher develop physical understanding of the complex behavior of tropical intraseasonal disturbances (TIS). The results gained from the study are expected to be useful for future predictions of MJO and related climate variations. Three interrelated research projects will be undertaken. 1. Interaction of TIDS and mean tropical circulations A three-layer tropical atmospheric model describing both the moist equatorial waves and time-mean flows will be used to investigate the effects of a three-dimensional mean flow on wave development and propagation, and the change of mean flow caused by momentum and heat transports (or E-P flux) associated with wave activities. 2. Interaction of MJO and tropical ocean To understand the nature of atmosphere-ocean interaction on intraseasonal time scales, the PI will (a) perform numerical experiments with an intermediate tropical ocean model to access the possible influences of an ensemble of intraseasonal forcing on the ENSO cycle, (b) conduct an empirical study of the relation between intraseasonal variation of SST and MJO to access the degree of the coupling between SST and MJO, and c) analyze coupled instability possibly arising from the thermodynamic coupling of the atmosphere and ocean relevant to warm ocean regions. 3. Multi-scale structure of MJO and higher-frequency disturbances The PI will investigate the multi-scale temporal and spatial structure of the MJO and its relation to cloud clusters, tropical cyclones, and extratropical forcing, using wavelet analysis and other effective means. A strategy of combining theoretical, numerical, and empirical analyses is adopted. Empirical analysis is used for revealing new facts and formulating hypotheses, while theoretical and numerical modeling are used to explain the phenomenon and te st the hypotheses. This research is important because it seeks to understand variability on intraseasonal time scales.