Regional Model Studies of the Madden and Julian Oscillation

该项目将通过区域模型和协调诊断研究的数值实验，促进对热带地区马登-朱利安振荡（MJO）变化的理解和建模。 实验的目的是测试各种假设MJO成因，特别是那些有关的内部机制和特定的边界强迫。 重点将放在赤道印度洋和西太平洋海盆上空季节内对流的开始和发展上。 Weare和Chen博士（加州大学戴维斯分校）将使用区域模式（MM 5，WRF）进行一系列数值实验，其中可以操纵边界条件以选择性地抑制一种或多种假设机制。 PI希望对20-70天变率的“控制”和“扰动”模拟进行比较，以揭示在正常和ENSO气候条件下MJO发展的主导机制。 MJO变率的模拟提出了一个巨大的挑战：最先进的大气GCM和耦合气候模型（例如，NCAR的社区大气模型和社区气候系统模型）目前无法模拟这一现象及其对热带和中纬度的影响。 因此，该项目将导致更好的理解，并可能更准确地模拟MJO的变化，及其对长期天气和季节到年际气候变化的影响。

The project will advance the understanding and modeling of Madden-Julian Oscillation (MJO) variability in the tropics from numerical experiments with a regional model and coordinated diagnostic studies. The experiments are designed to test various hypotheses for MJO genesis, particularly those related to internal mechanisms and specific boundary forcing. The focus will be on initiation and development of intra-seasonal convection over the equatorial Indian and western Pacific ocean basins. Drs. Weare and Chen (University of California, Davis) will conduct a suite of numerical experiments with regional models (MM5, WRF) in which boundary conditions can be manipulated to selectively suppress one or more of the hypothesized mechanisms. The PIs expect comparisons of "control" and "perturbed" simulations of 20-70 day variability to reveal the dominant mechanism of MJO development in both normal and ENSO climate conditions. Simulation of MJO variability poses a great challenge: The state-of-the-art atmospheric GCMs and coupled climate models (e.g., NCAR's Community Atmospheric Model and Community Climate System Model) are presently unable to simulate this phenomenon and its tropical and midlatitude impacts. The project will thus lead to greater understanding and, potentially, more accurate modeling of MJO variability, and its influence on long-term weather and seasonal-to-interannual climate variability.