Research Highlights

Sensitivity of Arctic Mixed-Phase Stratocumulus to Surface-Layer and Cloud-Top Moisture Sources
Jan 09, 2015       
Arctic mixed-phase stratocumulus cloud systems (AMPS) play an important role in determining the structure of the Arctic atmospheric boundary layer and magnitudes of surface energy budget terms, due to the presence of radiatively important supercooled cloud liquid water. AMPS occur in significantly different environments than subtropical stratocumuli. For example, AMPS are observed above both stable [...]

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A Comprehensive Parameterization of Heterogeneous Ice Nucleation of Dust Surrogate
Dec 30, 2014       
Reducing uncertainty in predicting climate change requires understanding ice clouds. At supercooled temperatures, many kinds of airborne aerosol particles can promote ice nucleation. In this paper, researchers, including scientists at DOE’s Pacific Northwest National Laboratory, developed and tested a new heterogeneous ice nucleation parameterization that covers a wide temperature range.

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Water Vapor Turbulence Statistics in the Convective Boundary Layer
Dec 09, 2014       
Turbulence is a process that redistributes water vapor and other atmospheric gases, sensible heat, and momentum in the atmosphere. It is a stochastic process, and is best represented by statistics of various moments. It has been shown that the Atmospheric Radiation Measurement (ARM) Raman lidar has the accuracy and noise level to measure the second- [...]

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Validating Water Vapor Turbulence Measurements from Lidar
Dec 08, 2014       
Turbulence in the convective boundary layer is important for redistributing water vapor and other atmospheric gases, sensible heat, and momentum. Turbulent mixing works over a wide range of scales from kilometers down to millimeters. The horizontal and vertical resolutions of most atmospheric models, such as general circulation and cloud resolving models, are too coarse to [...]

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Hail Generation and Melting in Deep Convective Clouds from the Perspective of Dual-polarization
Dec 02, 2014       
Large hail is generated in vigorous convective updrafts which are commonly associated with columnar regions of enhanced differential reflectivity (ZDR columns) often capped with the depression of the cross-correlation coefficient ρhv measured by dual-polarization radars. After hailstones fall below the freezing level, they melt and produce large raindrops making a hail/rain mixture, which is characterized [...]

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On the Right Track for Tropical Clouds
Nov 27, 2014       
Researchers at Pacific Northwest National Laboratory and collaborators are hot on the trail of a large and lumbering atmospheric wave. Originating in the tropics, the intra-seasonal force wields influence on weather patterns around the world. Using high-resolution regional modeling along with field data, the scientists found that the frequency of the wave’s shallow-to-deep convective cloud [...]

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Double Bonus: Win-Win for Atmospheric Particles
Nov 18, 2014       
It’s a slam dunk for scientists measuring atmospheric particle properties. Typically calculated from their chemical composition and size distribution data, the larger particles often escape characterization. Scientists at Pacific Northwest National Laboratory and the University of Colorado developed a new method that simultaneously connects two critical properties: real refractive index, a measure of how much [...]

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Observing Warm Clouds in 3D Using ARM Scanning Cloud Radars and a Novel Ensemble Method
Nov 05, 2014       
Boundary-layer clouds make a significant contribution to the planetary albedo and thus are fundamentally important to the Earth’s radiation budget. Due to their complex turbulent structures, coupled with a strong susceptibility to aerosol, they remain a key source of uncertainty in climate projections. While Atmospheric Radiation Measurement Climate Research Facility (ARM)’s long-term observations from vertically [...]

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