Upscale effects in simulations of tropical convection on an equatorial beta-plane

摘要: Abstract A cloud-resolving model is configured to span the full meridional extent of tropical atmosphere and have sufficient zonal permit representation cloud super-clusters. This made computationally feasible by use anisotropic horizontal grids where one coordinate direction has over an order magnitude finer resolution than other direction. Typically, chosen coarser (40 km grid spacing) enough ‘permit’ crude convective squall line ascent (1 km spacing). The aim was run in (CRM) mode yet still capture equatorial trapped waves Hadley circulation. large-scale circulation driven imposed uniform tropospheric cooling conjunction with a fixed sea surface temperature distribution. At quasi-equilibrium flow characterized sub-tropical jetstreams, systems that form eastward-propagating super-clusters, depressions even hurricanes. Two scientific issues are briefly addressed simulations: what forces nature stratospheric appearing simulation. It found presence gradient not on its own force realistic though convection communicates underlying atmosphere. shown simulation accounts for observed time zonal-mean momentum forcing effect eddies (originating middle latitudes) heaviest precipitation concentrated near equator association moisture flux convergence Trade winds. spectral analysis using dispersion relation equatorially-trapped provides strong evidence existence domain-scale Kelvin wave together eastward westward propagating inertia-gravity waves. appear be part convectively coupled system travelling at about 15 ms −1 .