We investigate the connection between the equatorial Madden-Julian Oscillation (MJO) and different types of the Northern Hemisphere mid-winter major stratospheric sudden warmings (SSWs), i.e., vortex-displacement and vortex-split SSWs. The MJO-SSW relationship for vortex-split SSWs is stronger than that for vortex-displacement SSWs, as a result of the stronger and more coherent eastward propaga...

In the Indo-Pacific region, mesoscale convective systems (MCSs) occur in a pattern consistent with the eastward propagation of the large-scale convective envelope of the Madden–Julian oscillation (MJO). MCSs are major contributors to the total precipitation. Over the open ocean they tend to be merged or connected systems, while over the Maritime Continent area they tend to be separated or discr...

The Madden–Julian Oscillation (MJO) is the dominant component of intraseasonal (30–90 days) variability in the tropical atmosphere. Here, traveling wave solutions are presented for the MJO skeleton model of Majda and Stechmann. The model is a system of nonlinear partial differential equations that describe the evolution of the tropical atmosphere on planetary (10,000– 40,000 km) spatial scales....

Radar data from the Tropical Rainfall Measuring Mission show the evolution of echo tops of convective elements over the Indian Ocean and Maritime Continent during the Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign of 2011–2012. Echo top heights exhibited a bimodal distribution wherein cumulonimbi of moderate height constituted a “congestus mode” while vertically extensive cum...

Gene flow through dispersal has traditionally been thought to function as a force opposing evolutionary differentiation. However, directional gene flow may actually reinforce divergence of populations in close proximity. This study documents the phenotypic differentiation over more than two decades in body size (tarsus length) at a very short spatial scale (1.1 km) within a population of pied f...

The authors report a significant increase in Madden–Julian oscillation (MJO)–like variability in a superparameterized version of the NCARCommunity AtmosphereModel run with high sea surface temperatures (SSTs). A series of aquaplanet simulations exhibit a tripling of intraseasonal outgoing longwave radiation variance as equatorial SST is increased from 268 to 358C. The simulated intraseasonal va...

The Madden Julian Oscillation is a large-scale atmospheric phenomenon that is generated above the tropical Indian Ocean. It is associated with large convective systems that propagate eastward across the Pacific Ocean. Since it is an atmospheric event limited to the equatorial domain, it was believed that it has little effect on non-tropical regions. However, recent research found correlations b...

5 We present a simple semi-empirical model to explore the hypothesis that the Madden-Julian 6 oscillation can be represented as a moisture mode destabilized by surface flux and cloud7 radiative feedbacks. The model is one-dimensional in longitude; vertical and meridional 8 structure are entirely implicit. The only prognostic variable is column water vapor, W. The 9 zonal wind field is an instan...