LAM output for: The excitation of the Madden-Julian Oscillation as part of atmospheric adjustment to equatorial heating

We study the adjustment of the tropical atmosphere to localized surface heating using a Lagrangian atmospheric model(LAM) that simulates a realistic Madden-Julian Oscillation (MJO) – the dominant, eastward-propagating mode of tropical intraseasonal variability modulating atmospheric convection. Idealized warm sea surface temperature (SST) anomalies of different aspect ratios and magnitudes are imposed in the equatorial Indian Ocean during MJO-neutral conditions and then maintained for 15 days. Throughout these experiments, we observe a robust generation of an MJO event, evident inprecipitation, velocity, temperature and moisture fields, which becomes a key element of atmospheric adjustment along with the expected Kelvin and Rossby waves. The MJO circulation pattern gradually builds up during the first week, and then starts to propagate eastward at a speed of 5-7m/s. The upper-level quadrupole circulation characteristic of the MJObecomes evident around day 14, with two anticyclonic gyres...

我们使用拉格朗日大气模型（Lagrangian atmospheric model，LAM）研究热带大气对局部地表加热的调整，该模型能模拟真实的马登-朱利安振荡（Madden-Julian Oscillation，MJO）——热带季节内变率中主导的东传模态，调控大气对流。在MJO中性条件下，我们在赤道印度洋施加不同纵横比和强度的理想化暖海表温度（sea surface temperature，SST）异常，并维持15天。在这些实验中，我们观测到MJO事件的稳定生成，这在降水、风速、温度和湿度场中均有体现；该事件与预期的开尔文波和罗斯贝波一同，成为大气调整的关键要素。MJO环流型在第一周逐渐形成，随后以5-7米/秒的速度开始东传。MJO特有的高层四极环流在第14天左右变得明显，伴随两个反气旋涡旋……