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An overview of the Regional Atmospheric Modeling System (RAMS) is presented. We focus on new developments in the RAMS physics and computational algorithms since 1992. We also summarize some of the recent applications of RAMS that includes synoptic-scale weather systems and climate studies, to small-scale research using RAMS configured as a large eddy(More)
The microphysics module of the version of the Regional Atmospheric Modeling System (RAMS) maintained at Colorado State University has undergone a series of improvements, including the addition of a large-cloud-droplet mode from 40 to 80 ␮m in diameter and the prognostic number concentration of cloud droplets through activation of cloud condensation nuclei(More)
A new cloudy boundary layer single-column model is presented. It is designed to be flexible enough to represent a variety of cloudiness regimes—such as cumulus, stratocumulus, and clear regimes—without the need for case-specific adjustments. The methodology behind the model is the so-called assumed probability density function (PDF) method. The(More)
In this paper we review observational and modeling studies of cloud venting by a wide variety of cloud types ranging from ordinary cumuli, to ordinary cumulonimbi, mesoscale convective systems and tropical and extratropical cyclones. We have used explicit cloud-resolving simulations with RAMS to illustrate the nature of the process of venting of boundary(More)
The impact of giant and ultragiant cloud condensation nuclei (Ͼ5-␮m radius) on drizzle formation in stra-tocumuli is investigated within a number of modeling frameworks. These include a simple box model of collection, a trajectory ensemble model (comprising an ensemble of Lagrangian parcel models), a 2D eddy-resolving model, and a 3D large-eddy simulation(More)
Toward the end of the Cirrus Regional Study of Tropical Anvils and Cirrus Layer–Florida Area Cirrus Experiment (CRYSTAL–FACE) field campaign held during July 2002, high concentrations of Saharan dust, which can serve as cloud condensation nuclei (CCN), giant CCN (GCCN), and ice-forming nuclei (IFN) were observed over the peninsula of Florida. To investigate(More)
[1] Numerical simulations of a cloudy marine boundary layer (MBL) observed during the Atlantic Stratocumulus Transition Experiment were performed to study the influence of entrainment of free tropospheric cloud condensation nuclei (CCN) on cloud microphysics, dynamics, and radiative properties. The initial CCN concentration is 100 cm À3 in one simulation,(More)
A storm-resolving version of the Regional Atmospheric Modeling System is executed over St. Louis, Missouri, on 8 June 1999, along with sophisticated boundary conditions, to simulate the urban atmosphere and its role in deep, moist convection. In particular, surface-driven low-level convergence mechanisms are investigated. Sensitivity experiments show that(More)
The hypothesis that inertial instability plays a role in the upscale development of mesoscale convective systems (MCSs) is explored by sampling environments that supported the growth of MCSs in the Preliminary Regional Experiment for STORM (Stormscale Operational and Research Meteorology) (PRE-STORM) network with high quality special soundings. Secondary(More)
A critique of one-and two-dimensional models of boundary layer clouds with a binned representations of drop microphysics Abstract A variety of models of boundary layer turbulence are increasingly being coupled to binned representation of cloud-drop spectra for the purpose of studying cloudy boundary layers and aerosol-cloud-drop interactions. A critique of(More)