AMERICAN METEOROLOGICAL SOCIETY | 425 W eather prediction is typically concerned with lead times of hours to days, while seasonal-tointerannual climate prediction is concerned with lead times of months to seasons. Recently, there has been growing interest in “subseasonal” forecasts—those that have lead times on the order of weeks (e.g., Schubert et al. 2002; Waliser et al. 2003; Waliser et al. ...

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 variability of rainfall and drop size distributions (DSDs) as a function of large-scale atmospheric conditions and storm characteristics is investigated using measurements from the Atmospheric Radiation Measurement Program (ARM) facility at Darwin, Australia. Observations are obtained from an impact disdrometer with a near continuous record of operation over five consecutive wet seasons (20...

The simulation of the Madden–Julian Oscillation (MJO) and convectively coupled equatorial waves (CCEWs) is considered in 13 state-of-the-art models from phase 6 Coupled Model Intercomparison Project (CMIP6). We use frequency–wavenumber power spectra observations for Outgoing Longwave Radiation (OLR) zonal winds at 250 hPa (U250), consider historical simulations end twenty-first century projecti...

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...

Spontaneous transition to superrotation in warm climates simulated by CAM3" (2010). [1] Recent paleoclimate proxy reconstructions show that tropical surface temperatures may have been as high as 35°–40°C in the Early Cenozoic. Here, we study the tropical atmospheric circulation's response to temperatures in this range using a full‐complexity atmospheric general circulation model (AGCM). We find...

In this study, we model extreme rainfall to study the high events in province of South Sulawesi, Indonesia. We investigated effect El Nino Oscillation (ENSO), Indian Ocean Dipole Mode (IOD), and Madden–Julian (MJO) on events. also assume that a location are affected by other nearby locations. Using data from results showed related IOD MJO.