Research Highlights

Diagnosing Raindrop Evaporation, Breakup, and Coalescence in Vertical Radar Observations
Apr 27, 2016       
In our quest to better understand precipitating cloud systems, we must realize that radars do not directly observe microphysical processes. Rather, radars observe raindrops and the changes in the number and size of those observed raindrops over time and space provide us with clues to the microphysical processes acting upon those raindrops. Thus, evaporation and [...]

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Quasi-Vertical Profiles – a New Way to Look at Polarimetric Radar Data
Apr 26, 2016       
A novel methodology is introduced for processing and presenting polarimetric radar data collected by scanning weather radars. It involves azimuthal averaging of polarimetric radar variables at high antenna elevation and presenting resulting quasi-vertical profiles (QVPs) in a height-versus-time format.

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Saggy Bright Bands
Apr 26, 2016       
A new technique for viewing radar observations allows for analyzing the evolution of the melting layer “bright band,” a signature associated with melting snowflakes. Radar and aircraft data demonstrate that transient bright band sagging provides information about the ice particles falling into the layer from above.

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Dependence of Entrainment in Shallow Cumulus Convection on Vertical Velocity and Distance to Cloud Edge
Apr 17, 2016       
How entrainment rates of shallow cumuli depend on environmental conditions is quantified by applying a novel Lagrangian tracking analysis on the response of shallow cumuli to an imposed small large-scale temperature perturbation, leading to a simple formulation that relates entrainment rates to vertical velocity and distance to cloud edge (or cloud size).

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The Midlatitude Continental Convective Clouds Experiment (MC3E)
Apr 11, 2016       
The DOE ARM Climate Research Facility and the NASA Global Precipitation Measurement (GPM) satellite mission collaborated for the 2011 Midlatitude Continental Convective Clouds Experiment (MC3E) to collect ground- and aircraft-based measurements characterizing the four-dimensional properties of convective storms at the Southern Great Plains. Over the course of the six-week campaign, a number of storms were [...]

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Birth and Growth of an Aerosol
Apr 06, 2016       
Tiny atmospheric aerosols are some of the most highly studied particles connected with Planet Earth, yet questions remain on how they are formed and how they affect climate. Now Pacific Northwest National Laboratory scientists have developed new approaches to accurately model the birth and growth of these important aerosols. "Most atmospheric climate models either neglect [...]

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Cloud Droplet Spectral Shape Sheds New Light on Aerosol-Cloud-Interaction Regimes
Mar 24, 2016       
Despite decades of research, aerosol indirect effects remain among the most uncertain climate forcings according to the latest Intergovernmental Panel on Climate Change report. Furthermore, climate models tend to overestimate the cooling of aerosol indirect effects and are more susceptible than observations to aerosols. Two microphysical factors have been proposed to be partially responsible for [...]

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Back to Basics: Theoretical Studies on Storm Clouds and Implications for Modeling
Mar 24, 2016       
Storms associated with deep convection are a key component of weather and climate. For example, they produce a large share of precipitation that falls to the Earth’s surface, and their anvil shields act as a thermal blanket on the planet.

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An Ensemble-Constrained Variational Analysis of Atmospheric Forcing Data and Its Application
Mar 15, 2016       
Clouds represent one of the largest uncertainties in current General Circulation Models (GCM) simulations. Studies have shown that the model discrepancies can come from deficiencies in the physical parameterization and uncertainties in the large-scale atmospheric condition. However, it is still unclear how each of them contributes to the model errors. The ensemble ARM [...]

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