Research Highlights

Observations Show That Smaller/Faster Falling Convective Ice Particles Improve GCM Simulations
Nov 27, 2016       
Aircraft observations from multiple ARM field campaigns show that ice particles detrained from deep convective clouds are smaller and fall faster than previously assumed. We have used this new knowledge to improve the representation of convective ice in the NASA GISS global climate model (GCM), and as a result, our GCM simulation of ice [...]

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Efficient Formation of Organic Particles from Isoprene Oxidation by a New Pathway
Nov 22, 2016       
New research showed that photooxidation of isoprene, copiously emitted from many plants, forms organic aerosol more efficiently than previously believed. The study identified new compounds with real-time mass spectrometry (MS) techniques and proposed a new chemical mechanism to explain the compounds’ formation.

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Exploiting Mie Scattering in KAZR Radial Velocities to Retrieve Air Motion and DSDs
Nov 18, 2016       
In order to improve our modeling of raindrop breakup and coalescence processes, we need innovative retrieval techniques that convert ARM radar observations into vertical columns of air motion and raindrop size distributions (DSDs). A new retrieval technique (Williams et al. 2016) exploits the Mie scattering signatures in KAZR (Ka-band ARM Zenith Radar) to estimate air [...]

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Potential of Higher-order Radar Moments and Slopes for Observing Arctic Ice Clouds
Nov 15, 2016       
Classical radar observations of clouds are partially ambiguous for deriving micro-physical ice cloud characteristics such as water content and particle size. Here, we investigate whether additional information contained in the higher moments (Spectrum Width, Skewness, Kurtosis) and the slopes (left and right) of the radar Doppler spectrum (that can be easily derived from modern zenith-pointing [...]

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Deep Convective Vertical Velocity Insights from ARM Profilers in the Amazon
Nov 14, 2016       
Profilers have been underutilized for their unique insights into deep convective storm vertical velocity and precipitation distributions. ARM Radar Wind Profilers (RWP) in the Amazon are used to inform Global Climate Model (GCM) deep convection parameterizations. This is accomplished by characterizing the relationship between storm environment and intensity in terms of vertical velocity, convective area [...]

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Impacts of the Manaus Pollution Plume on the Microphysical Properties of Amazonian Warm-Phase C
Nov 07, 2016       
We compare cloud properties in regions affected or not by the pollution from Manaus city, in the Amazon. Cloud formed under the pollution effect present different microphysical properties, with more numerous and smaller droplets.

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A Radiation Closure Study at Both Surface and TOA Using RTM
Oct 26, 2016       
Cloud macrophysical and microphysical properties have a significant impact on the radiative energy budgets at both the surface and top of atmosphere (TOA). The cloud-radiative interactions in the Arctic are even more complex due to large solar zenith angles, highly reflective snow and ice surfaces, and multiple reflections of solar radiation between the cloud [...]

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New DSD Parameterization and SR QPE from Aircraft and Surface Distrometer
Oct 26, 2016       
The characteristics of stratiform rainfall in Deep Convective Systems (DCSs) have been intensively investigated through a variety of platforms, including satellite, ground-based radar, surface rain gauge network, and airborne remote measurements. Because aircraft in situ measurements have better collocations with radar observations and larger sample volumes than surface disdrometer measurements, aircraft can provide more [...]

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4D (Space-time) Ice Cloud Microphysical Properties of DCSs Retrieved from NEXRAD
Oct 26, 2016       
Obtaining an accurate representation of convective processes in numerical models is a challenge for improving current and future simulations of the Earth’s climate system. A primary unresolved issue is the lack of understanding of the detailed cloud microphysical properties of deep convective systems (DCSs). Although these properties can be measured by research aircraft, such [...]

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Sub-micrometre Particulate Matter Is Primarily in Liquid Form over Amazon Rainforest
Oct 25, 2016       
The rebound of submicrometer PM was studied in central Amazonia during the wet and dry seasons using a particle-impaction apparatus equipped with RH adjustment. Rebound can indicate whether a particle is liquid or non-liquid. Physical state can affect particle growth and reactivity and hence particle number, size, and composition, with important tie-ins to the connections [...]

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Estimation of Cloud Fraction Profile in Shallow Convection Using a Scanning Cloud Radar
Oct 13, 2016       
Shallow convection plays a critical role in the heat and moisture transfer between the boundary layer and free atmosphere above about 2 km. However, with an average spatial scale of 0.5–1.5 km, shallow cumuli are not resolved in weather forecast and climate models, and their broken cloud coverage results in uncertainties in estimations of domain-averaged [...]

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New Method Tracks Diverse Cloud Characteristics and Evolution
Oct 04, 2016       
Cloud fields composed of clouds in a wide range of sizes and at different stages of their lifetimes are difficult to compare. A new method that combines tracking individual clouds and projecting cloud populations onto the space of the cloud center of gravity altitude versus cloud mass (CvM) offers a new way to characterize the [...]

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New Instrument to Study Ice Crystal Residuals
Oct 04, 2016       
A new instrument that allows separation of cloud elements to examine the physical and chemical properties of ice crystals is necessary to further our understanding of aerosol-cloud interactions.

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Unraveling the Layers of Aerosols in the Atmosphere
Oct 04, 2016       
Previous studies have shown that there are large errors in the characteristics of simulated aerosol particle layers in global models that subsequently contribute to uncertainties in radiative forcing calculations. Understanding the processes that contribute to the vertical distribution of aerosols is the necessary first step to better represent the relevant atmospheric processes in climate models.

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