The Madden–Julian oscillation (MJO) is an equatorial planetary-scale circulation system coupled with a multiscale convective complex, and it moves eastward slowly (about 5 m s) with a horizontal quadrupole vortex and vertical rearward-tilted structure. The nature and role of scale interaction (SI) is one of the elusive aspects of the MJO dynamics. Here a prototype theoretical model is formulate...

We discuss recent eruptions from Ruang, Semeru and Rabaul, and some mysterious aircraft encounters over Micronesia, in the context of current Darwin VAAC operations. Ruang was generally monitored successfully, with some qualifications such as a high level, eastward moving SO2 cloud that was only clear in post-analysis, and the complete lack of aviation 'SIGMETs'. Rabaul and Semeru are both long...

We present the first coordinated observations of quasi-periodic (QP) radar echoes from sporadic-E (Es) field-aligned irregularities (FAIs), OI 557.7-nm airglow, and neutral winds in a common volume over Shigaraki, Japan (34.9 N, 136.1 E) on the night of 5 August 2002 during the SEEK-2 campaign. QP echo altitudes of 90–110 km were lower than usual by 10 km, enabling us to make a detailed compari...

The eastward propagating Madden-Julian Oscillation (MJO) typically exhibits complex behavior during its passage over the Maritime Continent, sometimes slowly propagating eastward and other times stalling and even terminating there with large amounts of rainfall. This is a huge challenge for present-day numerical models to simulate. One possible reason is the inadequate treatment of the diurnal ...

A meteotsunami with a wave height of 0.1–0.9 m and period 60 min was observed at tide gauges along the Korea Strait on 7 April 2019, while train two to four atmospheric pressure disturbances disturbance heights 1.5–3.9 hPa moved eastward from Yellow Sea Strait. Analysis observational data indicated that isobar lines had angles 75–83° counterclockwise due east propagated velocity 26.5–31.0 m/s. ...