Journal of the Atmospheric Sciences: Recent submissions
Now showing items 4041-4060 of 13215
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Genesis of Tropical Storm Eugene (2005) from Merging Vortices Associated with ITCZ Breakdowns. Part II: Roles of Vortex Merger and Ambient Potential Vorticity
(American Meteorological Society, 2009)In this study, the roles of merging midlevel mesoscale convective vortices (MCVs) and convectively generated potential vorticity (PV) patches embedded in the intertropical convergence zone (ITCZ) in determining tropical ... -
Can the Frequency of Blocking Be Described by a Red Noise Process?
(American Meteorological Society, 2009)The frequency of persistent atmospheric blocking events in the 40-yr ECMWF Re-Analysis (ERA-40) is compared with the blocking frequency produced by a simple first-order Markov model designed to predict the time evolution ... -
Theoretical Studies of Convectively Forced Mesoscale Flows in Three Dimensions. Part I: Uniform Basic-State Flow
(American Meteorological Society, 2009)Convectively forced mesoscale flows in three dimensions are theoretically investigated by examining the transient response of a stably stratified atmosphere to convective heating. Solutions for the equations governing ... -
The Influence of Entrainment and Mixing Assumption on Aerosol–Cloud Interactions in Marine Stratocumulus
(American Meteorological Society, 2009)This study uses large-eddy simulation with bin microphysics to investigate the influence of entrainment and mixing on aerosol?cloud interactions in the context of idealized, nocturnal, nondrizzling marine stratocumulus ... -
Longitudinally Dependent Ozone Increase in the Antarctic Polar Vortex Revealed by Balloon and Satellite Observations
(American Meteorological Society, 2009)The horizontal structure of processes causing increases in ozone in the Antarctic polar vortex was examined using data measured in 2003 from an ozonesonde observation campaign at Syowa Station (39.6°E, 69.0°S) and from the ... -
The Role of Boundary Layer Processes in Limiting PV Homogenization
(American Meteorological Society, 2009)A ?-plane multilevel quasigeostrophic channel model with interactive static stability and a simplified parameterization of atmospheric boundary layer physics is used to study the role of different boundary layer processes ... -
Backscatter Lidar Observations of Lower Tropospheric Dynamics during Southern California Wildfires
(American Meteorological Society, 2009)Wavelike features suggesting gravity waves were revealed by lidar observations (from El Segundo, California) of smoke layers produced by large wildfires in the Southern California region during a Santa Ana event. Unique ... -
Regimes of Dry Convection above Wildfires: Idealized Numerical Simulations and Dimensional Analysis
(American Meteorological Society, 2009)Wildfires are capable of inducing atmospheric circulations that result predominantly from large temperature anomalies produced by the fire. The fundamental dynamics through which a forest fire and the atmosphere interact ... -
Lee-Wave Resonances over Double Bell-Shaped Obstacles
(American Meteorological Society, 2009)Lee-wave resonance over double bell-shaped obstacles is investigated through a series of idealized high-resolution numerical simulations with the nonhydrostatic Coupled Ocean?Atmosphere Mesoscale Prediction System (COAMPS) ... -
Scales of Linear Baroclinic Instability and Macroturbulence in Dry Atmospheres
(American Meteorological Society, 2009)Linear stability analyses are performed on a wide range of mean flows simulated with a dry idealized general circulation model. The zonal length scale of the linearly most unstable waves is similar to the Rossby radius. ... -
Energy–Vorticity Theory of Ideal Fluid Mechanics
(American Meteorological Society, 2009)Nambu field theory, originated by Névir and Blender for incompressible flows, is generalized to establish a unified energy?vorticity theory of ideal fluid mechanics. Using this approach, the degeneracy of the corresponding ... -
Ocean–Atmosphere Coupling on Different Spatiotemporal Scales: A Mechanism for Intraseasonal Instabilities
(American Meteorological Society, 2009)The possibility of interactions between oceanic and atmospheric oscillations with different temporal and spatial scales is examined with analytical solutions to idealized linear governing equations. With a reasonable choice ... -
Instability of Surface Quasigeostrophic Vortices
(American Meteorological Society, 2009)The instability of circular vortices is studied numerically in the surface quasigeostrophic (SQG) model, and their evolutions are compared with those of barotropically unstable 2D vortices. The growth rates in the SQG model ... -
A Climatology of the Gravest Waves in the Equatorial Lower and Middle Stratosphere: Method and Results for the ERA-40 Re-Analysis and the LMDz GCM
(American Meteorological Society, 2009)A climatology of the three-dimensional life cycle of the gravest waves in the tropical lower and middle stratosphere is presented. It shows that at periods around 10 days the gravest waves correspond to Kelvin and ... -
Cloud Microphysics Impact on Hurricane Track as Revealed in Idealized Experiments
(American Meteorological Society, 2009)Analyses of tropical cyclones created in an idealized environment reveal how and why cloud microphysical assumptions can influence storm motion, including speed and direction. It is well known that in the absence of a mean ... -
Average Predictability Time. Part II: Seamless Diagnoses of Predictability on Multiple Time Scales
(American Meteorological Society, 2009)This paper proposes a new method for diagnosing predictability on multiple time scales without time averaging. The method finds components that maximize the average predictability time (APT) of a system, where APT is defined ... -
Seasonal Cycle–El Niño Relationship: Validation of Hypotheses
(American Meteorological Society, 2009)The present paper examines ways in which the seasonal cycle influences the evolution of El Niño in the tropical Pacific. The following hypotheses and associated physical mechanisms are investigated: (i) Hypothesis 1 (H1)?the ... -
Internal Waves at an Interface between Two Layers of Differing Stability
(American Meteorological Society, 2009)Internal waves in a two-layer fluid are considered. The layers have different values of the buoyancy frequency, assumed to be constant in each layer. The density profile is chosen to be continuous across the interface and ... -
Baroclinic Rossby Wave Forcing and Barotropic Rossby Wave Response to Stratospheric Vortex Variability
(American Meteorological Society, 2009)An analysis is performed on the dynamical coupling between the variability of the extratropical stratospheric and tropospheric circulations during the Northern Hemisphere winter. Obtained results provide evidence that in ... -
Average Predictability Time. Part I: Theory
(American Meteorological Society, 2009)This paper introduces the average predictability time (APT) for characterizing the overall predictability of a system. APT is the integral of a predictability measure over all lead times. The underlying predictability ...