Journal of the Atmospheric Sciences: Recent submissions
Now showing items 3861-3880 of 13215
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Dynamical Feedbacks and the Persistence of the NAO
(American Meteorological Society, 2010)The persistence of the North Atlantic Oscillation (NAO) is studied using observations of the three-dimensional vorticity budget in the Atlantic sector. Analysis of the relative vorticity tendency equation shows that ... -
Observed Patterns of Month-to-Month Storm-Track Variability and Their Relationship to the Background Flow
(American Meteorological Society, 2009)Month-to-month storm-track variability is investigated via EOF analyses performed on ERA-40 monthly-averaged high-pass filtered daily 850-hPa meridional heat flux and the variances of 300-hPa meridional wind and 500-hPa ... -
Numerical Investigation of Collision-Induced Breakup of Raindrops. Part II: Parameterizations of Coalescence Efficiencies and Fragment Size Distributions
(American Meteorological Society, 2010)Results of numerically investigated binary collisions of 32 drop pairs presented in Part I of this study are used to parameterize coalescence efficiencies and size distributions of breakup fragments of large raindrops. In ... -
Do Undiluted Convective Plumes Exist in the Upper Tropical Troposphere?
(American Meteorological Society, 2010)Using a passive tracer, entrainment is studied in cloud-resolving simulations of deep convection in radiative?convective equilibrium. It is found that the convective flux of undiluted parcels decays with height exponentially, ... -
The Dimensional Characteristics of Ice Crystal Aggregates from Fractal Geometry
(American Meteorological Society, 2010)Ice crystal aggregates imaged by aircraft particle imaging probes often appear to be fractal in nature. As such, their dimensional properties, mass, and projected area can be related using fractal geometry. In cloud ... -
Eddy-Induced Instability for Low-Frequency Variability
(American Meteorological Society, 2009)Synoptic eddy?mean flow interaction has been recognized as one of the key sources for extratropical low-frequency variability. In this paper, the underlying dynamics of this interaction are examined from the perspective ... -
Aircraft Microphysical and Surface-Based Radar Observations of Summertime Arctic Clouds
(American Meteorological Society, 2009)Updated analyses of in situ microphysical properties of three Arctic cloud systems sampled by aircraft in July 1998 during the Surface Heat Budget of the Arctic Ocean (SHEBA)/First International Satellite Cloud Climatology ... -
The Echo Size Distribution of Precipitating Shallow Cumuli
(American Meteorological Society, 2010)S-band radar surveillance scans of precipitating shallow convection are analyzed. The scans are complied from 52 days of near-continuous measurements in the winter trades of the North Atlantic during the Rain in Cumulus ... -
Distribution and Radiative Forcing of Tropical Thin Cirrus Clouds
(American Meteorological Society, 2009)To understand the radiative impact of tropical thin cirrus clouds, the frequency of occurrence and optical depths of these clouds have been derived. ?Thin? cirrus clouds are defined here as being those that are not detected ... -
Spatial and Temporal Scales of Boundary Layer Wind Predictability in Response to Small-Amplitude Land Surface Uncertainty
(American Meteorological Society, 2010)Predictability experiments with the Weather Research and Forecast (WRF) model as a proxy for the atmosphere are analyzed to quantify the spatial and temporal scales of boundary layer wind response to land surface perturbations. ... -
Breakdown and Reformation of the Intertropical Convergence Zone in a Moist Atmosphere
(American Meteorological Society, 2009)The effects of moisture on the intertropical convergence zone (ITCZ) over the eastern Pacific on the synoptic time scale are investigated using an intermediate complexity atmospheric circulation model, the quasi-equilibrium ... -
Quantifying the Eddy Feedback and the Persistence of the Zonal Index in an Idealized Atmospheric Model
(American Meteorological Society, 2009)An idealized atmospheric model is employed to quantify the strength of the eddy feedback and the persistence of the zonal index. The strength of the surface frictional damping on the zonal index is varied, and an external ... -
A Nonlinear Perspective on the Dynamics of the MJO: Idealized Large-Eddy Simulations
(American Meteorological Society, 2009)The 30?60-day intraseasonal atmospheric oscillation in the equatorial atmosphere, the Madden?Julian oscillation (MJO), is most visible in its signature of outgoing longwave radiation and associated convective centers. ... -
Numerical Investigation of Collision-Induced Breakup of Raindrops. Part I: Methodology and Dependencies on Collision Energy and Eccentricity
(American Meteorological Society, 2010)Binary collisions of large raindrops moving with terminal fall velocity are numerically investigated using FS3D, a direct numerical simulation (DNS) code based on the ?volume of fluid? method. The result of this process ... -
Low-Frequency Variability in a Turbulent Baroclinic Jet: Eddy–Mean Flow Interactions in a Two-Level Model
(American Meteorological Society, 2010)The origin of low-frequency variability in the midlatitude jet is investigated using a two-level baroclinic channel model. The model state fields are separated into slow and fast components using intermediate time- scale ... -
Evaporation of Nonequilibrium Raindrops as a Fog Formation Mechanism
(American Meteorological Society, 2010)To gain insights into the poorly understood phenomenon of precipitation fog, this study assesses the evaporation of freely falling drops departing from equilibrium as a possible contributing factor to fog formation in rainy ... -
Do High-Frequency Eddies Contribute to Low-Frequency Teleconnection Tendencies?
(American Meteorological Society, 2010)An isentropic potential vorticity (PV) budget analysis is employed to examine the role of synoptic transients, advection, and nonconservative processes as forcings for the evolution of the low-frequency PV anomalies locally ... -
A Hybrid Bulk–Bin Approach to Model Warm-Rain Processes
(American Meteorological Society, 2010)This paper presents a hybrid approach to model warm-rain processes, merging the diverse schemes of bulk and detailed (bin) microphysics. In the bulk scheme, the key assumption is that the exact saturation is maintained ... -
Formation of Jets through Mixing and Forcing of Potential Vorticity: Analysis and Parameterization of Beta-Plane Turbulence
(American Meteorological Society, 2010)Formation of multiple jets in forced beta-plane turbulence is studied from the perspective of nonuniform nonconservative arrangement of potential vorticity (PV). Numerical simulations are analyzed to show that mixing and ... -
Inferring Cirrus Size Distributions through Satellite Remote Sensing and Microphysical Databases
(American Meteorological Society, 2009)Since cirrus clouds have a substantial influence on the global energy balance that depends on their microphysical properties, climate models should strive to realistically characterize the cirrus ice particle size distribution ...