Low-level barotropic dynamics may help to explain the modulation of eastern and western North Pacific tropical cyclones by the Madden–Julian oscillation (MJO) during Northern Hemisphere summer. The MJO is characterized by alternating periods of westerly and easterly 850-mb zonal wind anomalies across the tropical Pacific Ocean. When MJO 850-mb wind anomalies are westerly, small-scale, slow-movi...

[1] Variability of the cloud population in the central equatorial Indian Ocean was observed in the context of the Madden-Julian Oscillation (MJO) during the Dynamics of the MaddenJulian Oscillation (DYNAMO) and Atmospheric Radiation Measurement Madden-Julian Investigation Experiment (AMIE) field campaigns. Radar observations from the polarimetric S-band radar on Addu Atoll in theMaldives charac...

The Madden-Julian Oscillation (MJO) is a tropical atmospheric phenomenon, associated with periods of active convection in the eastern hemisphere tropics.The MJOs temporal scale (22-90 days) coincides with a gap between weather (synoptic forecasts out to 10 days) and climate (seasonal and longer forecasts).Analysis of 35 years of daily rainfall data shows significant modulation of tropical and e...

The large-scale vertical moist thermodynamic structure of the Madden–Julian oscillation (MJO) was documented using the first 2.5 yr (2002–05) of version 4 atmospheric specific humidity and temperature profiles from the Atmospheric Infrared Sounder (AIRS). In this study, this issue is further examined using currently available 7-yr version 5 AIRS data (2002–09) to test its dependence on the AIRS...

The Madden–Julian oscillation (MJO) is the dominant mode of tropical intraseasonal variability, characterized by an eastward-propagating envelope of convective anomalies with a 30–70-day time scale. Here, the authors report changes in MJO activity across coupled simulations with a superparameterized version of the NCARCommunity Earth SystemModel. They find that intraseasonal OLR variance nearly...

This study examines the impacts of convective parameterization and moisture convective trigger on convectively coupled equatorial waves simulated by the Seoul National University (SNU) atmospheric general circulation model (AGCM). Three different convection schemes are used, including the simplified Arakawa–Schubert (SAS) scheme, the Kuo (1974) scheme, and the moist convective adjustment (MCA) ...

As a major mode of intraseasonal variability, which interacts with weather and climate systems on a near-global scale, the Madden–Julian Oscillation (MJO) is a crucial source of predictability for numerical weather prediction (NWP) models. Despite its global significance and comprehensive investigation, improvements in the representation of the MJO in an NWP context remain elusive. However, rec...

This study statistically investigates the timing and underlying processes of the shallow-to-deep convective transition (SDT) associated with Madden-Julian Oscillations (MJO) initiation over the Indian Ocean. Results show that SDT periods have a median value of 8–10 days with a wide spectrum of 2–20 days. SDTs lasting 10–20 days occurred nearly 50% of the time, consistent with gradual tropospher...

This study estimates MJO change under the A1B greenhouse gas emission scenario using the ECHAM5 AGCM whose coupled version (ECHAM5/MPI-OM) has simulated best MJO variance among fourteen CGCMs. The model has a horizontal resolution at T319 (about 40 km) and is forced by the monthly evolving SST derived from the ECHAM5/MPI-OM at a lower resolution of T63 (about 200 km). Two runs are carried out c...

In the equatorial troposphere, the Madden–Julian Oscillation (MJO) is a planetaryscale wave envelope of complex multi-scale convection (see Figure 1 for a schematic illustration). It begins as a standing wave in the Indian Ocean and propagates eastward across the western Pacific Ocean at a speed of ≈ 5 m/s. Due to its planetary-scale circulation anomalies, the MJO significantly affects monsoon ...