Gravity wave sources and spectra appearing in a mesoscale model simulation of the Maritime Continent

The Maritime Continent, consisting of north Australia, New Guinea, and the Indonesian archipelago has emerged as an important source region for atmospheric gravity waves (GWs). It is generally thought that in this region the GWs are generated primarily by deep cumulus convection. Simulations with cloud-resolving models have associated deep convection with waves characterized by high frequencies and long vertical wavelengths. Ray-tracing techniques have shown that these waves are favored to reach high altitudes where their influence may be very significant on spatial and temporal scales consistent with their generation. Recent space-based observations have correlated wave variances in the middle atmosphere with the convective zones in the tropics. The Maritime Continent in particular showed high variances during the wet season, suggesting wave generation by deep convection. Next generation numerical weather prediction models can strongly aid the fast improving satellite measurements by providing important source information and resolving gravity wave source spectra. The synergy between remote sensing platforms and next generation mesoscale models holds much promise for a more complete description of gravity wave source spectra, source distributions, and propagation properties directly relevant to middle atmospheric studies of gravity wave effects. This paper presents a simulation of the Maritime Continent on 17 November 2001 using the Weather Research and Forecasting model to investigate the organization and spectra of potential GW sources in this convectively active system of complex land-sea interactions.