Tropical Intraseasonal Variability in an "Aqua Planet" GCM

有强有力的理论证据表明，马登-朱利安（30-60 大气中的振荡是由于 对流和循环。 PI将研究 在一个完全非线性的大气环流中， 地球被海洋覆盖（“水行星”）。 初步 模型的实验表明，在 10-15天之间。 赤道上的振荡 在对流层上部被最大幅度捕获。 的 扰动似乎表现出开尔文波和罗斯贝波 特征，可能性表明干扰是 耦合开尔文-罗斯比波 假设已经提出 对流加热的垂直剖面定义了 在模型和真实的大气中观察到的传播速度。 研究表明，垂直场激发的相互作用垂直模 糖尿病加热导致传播波-CISK模式。 PI将 在“水行星”将军中批判性地审视这一假设 循环模型 最慢者的优先兴奋 在观测中最温暖的沃茨上的模态是不充分的 用假设来解释。 此外，私家侦探亦会研究 振荡对海面纬向不对称性的敏感性 温度 对流的空间尺度很小 而环流的振荡发生在行星上， 规模 最后，PI将研究分区尺度的选择， 旋转动能和发散动能之间的耦合， 作为一个模型的能量在波数域的分析 时间的函数。 预计拟议的研究将 更好地了解了 对流与大尺度大气相互作用 流通

There is strong theoretical evidence that the Madden-Julian (30-60 day) oscillation in the atmospheric is due to interactions between convection and circulation. The PI will study the characteristics of these interactions in a fully nonlinear general circulation model with an ocean covered earth ("aqua-planet"). Preliminary experiments with the model show strong eastward propagation at periods between 10-15-days. The oscillation is equatorially trapped with maximum amplitude in the upper troposphere. The disturbances appear to exhibit both Kelvin and Rossby wave characteristics, possibility suggesting that the disturbances are coupled Kelvin-Rossby waves. The hypothesis has been put forth that the vertical profile of convective heating defines the phase speed of propagation observed in the model and the real atmosphere. It is suggested that interacting vertical modes excited by the diabetic heating lead to propagating wave-CISK modes. The PI will critically examine this hypothesis in the "aqua-planet" general circulation model. The preferential excitement of the slowest modes over the warmest waters in the observations is inadequately explained by the hypothesis. The PIs will also study the sensitivity of oscillations to zonal asymmetries in the sea surface temperatures. The spatial scale of the convection is very small whereas the oscillations in the circulation occur on the planetary scale. Finally, the PIs will study the zonal scale selection and the coupling between the rotational and divergent kinetic energy by an analysis of the model energetics in the wave number domain as a function of time. It is expected that the proposed research will provide a better understanding of the characteristics of the interactions between convection and large scale atmospheric circulation.