A stochastic barotropic model linearized about the 850-mb flow is used to investigate the relationship between wind variations associated with the Madden–Julian oscillation (MJO) and eddy kinetic energy variations in the Tropics. Such a model is successful in predicting the observed location of eddy kinetic energy maxima during the westerly phase of the MJO and the suppression of eddy activity ...

The connections between the Madden–Julian Oscillation (MJO) and Arctic (AO) are examined in both observations model forecasts. In observations, time-lag composites carried out for AO indices anomalies of 1,000-hPa geopotential height after an active or inactive initial MJO. results show that when is its positive (negative) phase at time, activity generally enhanced (weakened) Reforecast data 11...

Abstract This study investigates the intraseasonal change in diurnal cycle of rainfall over Sumatra terms Madden Julian oscillation (MJO) phases. Change peak time mean accumulation (PA), frequency (PF), and intensity (PI) precipitation from Integrated Multi-Satellite Retrievals GPM (IMERG) final run product version 06 data during 2016-2019 was investigated. Data were classified into active (2,3...

A significant sign reversal in the meridional potential vorticity gradient was found during the summer of 1991 on the 310-K isentropic surface (near 700 mb) over the Caribbean Sea. The Charney–Stern necessary condition for instability of the mean flow is met in this region. It is speculated that the sign reversal permits either invigoration of African waves or actual generation of easterly wave...

The effect of the Madden–Julian oscillation (MJO) in the eastern Pacific on the North American monsoon is documented using NCEP–NCAR reanalysis and daily mean precipitation data from 1958 to 2003. It is found that positive zonal wind anomalies in the eastern tropical Pacific lead to above-normal precipitation in northwest Mexico and Arizona from several days to over a week later. This connectio...

Internal gravity waves influence a variety of phenomena in Earth’s stratosphere and upper troposphere, including aviation weather turbulence and circulations that set high-altitude distributions of ozone and greenhouse gases. Here coupling between the dominant mode of subseasonal variability of the equatorial atmosphere—the Madden-Julian oscillation (MJO)—and subtropical stratospheric gravity w...

The influence of the Madden–Julian oscillation (MJO) on precipitation over Tibetan Plateau (TP) during boreal summer is investigated using observational and reanalysis data 1980–2020. results show that most areas eastern TP increases (decreases) in MJO Phases 1–2 (5–6), especially when eastward-propagating active convection located Indian Ocean (Western Pacific) Phase 2 (6). significant negativ...

The “Vertical structure and physical processes of the Madden-Julian oscillation (MJO)” project comprises three experiments, designed to evaluate comprehensively the heating, moistening, and momentum associated with tropical convection in general circulation models (GCMs). We consider here only those GCMs that performed all experiments. Some models display relatively higher or lower MJO fidelity...

Boreal-wintertime hindcasts in the Unified Forecast System with tropics nudged toward reanalysis improve United States (US) West Coast precipitation forecasts at Weeks 3–4 lead times when compared to those without nudging. To diagnose origin of these improvements, a multivariate k-means clustering method is used group into subsets by their initial conditions. One cluster characterized an initia...

A new model of the Madden-Julian oscillation (MJO) is presented. Cloudradiation interactions in this model make the tropical atmosphere susceptible to large-scale radiative-convective overturning. The modeled MJO takes the form of such an instability, though its behavior is substantially modified by the effects of surface heat flux variability. The dynamics of the disturbance in the model are q...