Research Highlights

Members of ARM's science team are major contributors to radiation and cloud research. ARM investigators publish about 150 refereed journal articles per year, and ARM data are used in many studies published by other scientific organizations. These documented research efforts represent tangible evidence of ARM's contribution to advances in almost all areas of atmospheric radiation and cloud research. Below is a selection of summaries highlighting recently-published ARM research. The entire collection of ARM Research Highlights can be accessed using the sorting buttons at right.

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Stereo Photogrammetry Reveals Substantial Drag on Cloud Thermals

Jun 25, 2015 Funded By: ASR

Fast updrafts within clouds can generate hail, lightning, and tornadoes at the surface, as well as clear-air turbulence that pose hazards for aircraft aloft. Despite these important impacts of fast updrafts, there is surprisingly large uncertainty about the forces that generate these updraft speeds. For example, do these cloud updrafts experience drag? If so, what [...]

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Sticky Thermals: Evidence for a Dominant Balance Between Buoyancy and Drag in Cloud Updrafts

Jun 25, 2015 Funded By: ASR

Quickly rising clouds are associated with many important phenomena, including hail, turbulence, and lightning. But, what sets the speeds of these rising clouds? In other words, what is the balance of forces giving rise to the observed cloud updraft speeds? Here, we answer this question by studying thousands of cloud thermals in a high-resolution large-eddy [...]

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Regime Analysis to Identify the Contribution of Clouds to Surface Temperature Errors in GCMs

Jun 16, 2015 Funded By: ARM

Many Global Circulation Models (GCMs) exhibit a persistent bias in the 2m-temperature (T2m) over the midlatitude continents, present in weather forecasts and climate simulations. A number of hypotheses have been proposed, from deficiencies in the soil-vegetation-atmosphere energy exchange, to poorly resolved boundary-layer clouds to misrepresentations of deep convection. This paper presents a new method to [...]

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Bimodal CCN Spectra

May 23, 2015 Funded By: ARM ASR

Aerosol spectra under marine stratus are often bimodal and attributable to cloud processes. Sizes at the minima between the modes have inferred supersaturations (S) of nearby clouds (Hoppel et al. 1985, 1994). This was based on the principle that the lower critical S (Sc) particles that produced cloud droplets were increased by 1) chemical reactions [...]

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Assessing Impact of Shattered Artifacts on Measured Size Distributions

May 12, 2015 Funded By: ARM ASR

Model parameterizations of ice clouds have typically been derived from observations of ice particle size distributions (PSDs), collected by optical array probes, mounted on the wings of aircraft. Many recent studies have shown PSDs can potentially be contaminated by particles shattering on the tips of these probes, with shattered artifacts subsequently entering the probe sample [...]

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