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Why Do General Circulation Models Overestimate the Aerosol Cloud Lifetime Effect?
Mar 21, 2017 [ Research Highlights ]       
Traditionally, aerosols have been thought to lengthen cloud lifetime by increasing droplet number and reducing droplet size, thereby delaying and reducing the formation of rain in clouds. These longer-lived clouds would then increase cloud cover and reflect more sunlight. Yet observational evidence for these lifetime effects is limited and contradictory. Moreover, observations of ship tracks [...]

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Low-aerosol Conditions over the Azores Occur During Marine Cold Air Outbreaks.
Mar 20, 2017 [ Research Highlights ]       
Current estimates suggest that between one-quarter and two-thirds of all cloud condensation nuclei in the atmosphere may be a direct result of human activities. Climate models suggest that brighter clouds are masking a significant fraction of the global warming that the Earth would be experiencing if aerosol particle concentrations had not increased. These aerosol-cloud interactions [...]

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High-resolution Photos of Clouds from the Surface Reveal Structure Down to Centimeter Level.
Mar 10, 2017 [ Research Highlights ]       
Even thin clouds exert strong radiative influences that must be accurately represented in models. This study examines optical depth of thin clouds at unprecedentedly high resolution to examine this important cloud property at scales down to a few centimeters.

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Seasonal and Diurnal Variations of Large-scale Budgets Observed in the GoAmazon2014/15 Experiment
Mar 10, 2017 [ Research Highlights ]       
Amazonia is one of the major tropical convective regions in the global climate system, providing moisture to the global hydrological cycle and energy to drive the global atmospheric circulation.  This study aims to improve our understanding of the seasonal and diurnal variation of convective systems over the Amazon region and their associated large-scale structures through [...]

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Gone with the Wind: the Trans-Pacific Journey of Atmospheric Particles
Mar 08, 2017 [ Research Highlights ]       
Dust particles from African and Asian deserts can travel long distances through the atmosphere, but a lack of integrated observations has made it difficult to assess the complex and size-dependent processes associated with dust emission, transport, and removal.

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Looking at Clouds from Both Sides Now
Jan 25, 2017 [ Research Highlights ]       
The impact of clouds on the reflection of sunlight to space depends on two key properties: cloud optical depth and droplet effective radius. Satellites provide nearly global coverage of these cloud properties, but the accuracy of the retrievals has not been evaluated. This study used ground-based retrievals to evaluate the satellite retrievals, and found good [...]

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To Evaporate or Not to Evaporate: the Question of Secondary Organic Particulate Matter Lability
Jan 07, 2017 [ Research Highlights ]       
New research highlights a nonlabile-to-labile transition for material representative of anthropogenic secondary organic particulate matter at a threshold humidity range. This behavior differs markedly from materials representing biogenic aerosol sources, which lack such a transition.

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Less Is More: Low Aerosol Concentrations Produce High Variability in Cloud Droplet Sizes
Jan 07, 2017 [ Research Highlights ]       
Clouds form when water vapor in the atmosphere condenses around airborne particles, or aerosols, but the exact details of the process remain relatively unknown. Researchers used large-eddy simulations (LES) to model cloud droplets that formed in Michigan Technological University’s cloud chamber by injecting various amounts of aerosols. They found that high concentrations of aerosols decreased [...]

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Daily Cycle of Cloudiness over Maritime Continent Disrupt the Madden-Julian Oscillation
Jan 06, 2017 [ Research Highlights ]       
Every month or two, a large complex of clouds forms over the Indian Ocean and moves eastward, a pattern known as the Madden-Julian Oscillation (MJO). The MJO exhibits hard-to-predict behaviors, often weakening, as it moves across the Maritime Continent (MC; Indonesia-Malaysia and New Guinea)—so-called because of its combination of shallow seas and scattered land masses. [...]

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