Research Highlights

Simulating the MJO: Everybody Into the (Cold) Pool!
Aug 11, 2015       
Most general circulation models (GCMs) continue to have difficulty simulating the Madden-Julian Oscillation (MJO), the most important source of tropical precipitation variability on time scales shorter than seasons. In recent years, evidence has grown for viewing the MJO as a “moisture mode.” Moisture modes differ from other equatorial waves in that they depend explicitly on [...]

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Observed Relations Between Snowfall Microphysics and Triple-Frequency Radar Observations
Aug 05, 2015       
Recent theoretical and observational studies indicated that triple-frequency measurements (e.g., combining Ku, Ka, and W band) bear the potential to derive important snowfall microphysical parameters like median mass diameter, fractal dimension, or particle habit. These observations further revealed that naturally occurring snowflakes exhibit scattering signatures that are in some cases consistent with spheroidal particle models [...]

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Liquid Water the Key to Arctic Cloud Radiative Closure
Jul 21, 2015       
Consistent with our growing understanding of Arctic liquid water clouds, it is not surprising that proper identification and characterization of cloud liquid water is important for accurately representing Arctic radiative fluxes. This conclusion is one of the primary findings resulting from the development and evaluation of a comprehensive cloud retrieval suite, called ShupeTurner, which is [...]

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A Lidar View of Clouds in Southeastern China
Jul 15, 2015       
From May 2008 to December 2009, a suite of instruments, including a micropulse lidar, were installed at a site along Lake Taihu, China, located in the center of the Yangtze Delta region. This was part of an effort to characterize aerosols, clouds, and their interactions in heavily polluted southeastern China. The seasonal patterns and diurnal [...]

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ARM Data Used to Evaluate Reanalysis Results
Jul 06, 2015       
Atmospheric reanalysis data sets have been used for a variety of applications, such as providing forcing data for single-column and cloud resolving models (Xie et al. 2004; Kennedy et al. 2011), investigating extreme weather and climatic events (Dong et al. 2011 and 2014), and examining forecast skill. These reanalysis data sets also provide an essential [...]

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DCS Ice Cloud Microphysical Properties Derived from Aircraft Data During MC3E
Jul 06, 2015       
Particle size distributions (PSDs) play an important role in the study of ice clouds because most of bulk ice cloud microphysical properties, including ice water contents (IWC), bulk density, median mass diameter (Dm), etc., are determined from the PSD measurements. Furthermore, the PSD should have a strong relationship to ice formation and growth processes, including [...]

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MBL Cloud and CCN Properties Under Coupled and Decoupled Conditions
Jul 06, 2015       
Marine boundary layer (MBL) stratocumuli are turbulently mixed from the top-downward due to negative buoyancy through a combination of longwave (LW) radiative cooling and evaporative cooling at the cloud top (Wood 2012; Shin and Ha 2009). The vertical and horizontal structures of stratocumulus are strongly tied to the vertical structure of the boundary layer. The [...]

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Stereo Photogrammetry Reveals Substantial Drag on Cloud Thermals
Jun 25, 2015       
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       
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       
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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