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The Spectroscopic Foundation of Radiative Forcing of Climate by Carbon Dioxide
Jul 21, 2016 [ Research Highlights ]       
We explored the state-of-the-science of how rising atmospheric CO2 concentrations warm the climate system through radiative forcing caused by spectroscopic absorption features. We found that uncertainties in the absorption line parameters and understanding of the shape of CO2 lines, both of which are important for CO2 radiative forcing, are much smaller than the actual forcing.

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Field Testing the Next-Generation of Radiosondes
Jul 21, 2016 [ Research Highlights ]       
During 3-8 June 2014, an intercomparison study of Vaisala radiosondes RS92 (the current ARM instrumentation) and RS41 (next generation) was undertaken at the ARM SGP site. The results indicate that the sounding measurements generally agree well within manufactured-defined uncertainties with notable exceptions when exiting liquid cloud layers where evaporative cooling impacts are mitigated for the [...]

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Trace Gas Removal by Deep Convective Storms
Jul 20, 2016 [ Research Highlights ]       
Deep convective storms have a large impact on the climate by sending atmospheric trace gases high into the atmosphere where they participate in particle formation and ozone formation that affect the amount of sunlight, or radiative energy, that passes through the atmosphere to Earth’s surface. Understanding how storms, or convective systems, transport trace-gas concentrations to [...]

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Observing the Amazon: the Role of Time and Place in Cloud Measurements
Jul 20, 2016 [ Research Highlights ]       
Research led by Department of Energy scientists at Pacific Northwest National Laboratory laid the groundwork for future explorations of the Green Ocean Amazon, GOAmazon, 2014/15 field campaign data sets by documenting the variability in space and time of deep convection around the field campaign surface sites distributed upwind and downwind of Manaus, Brazil. Understanding the [...]

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Capturing Biogenic Volatile Organic Compounds in a Coupled-Model System Compared to Observation
Jul 20, 2016 [ Research Highlights ]       
Current climate models still have large uncertainties in estimating biogenic (naturally emitted) trace gases, which can significantly affect atmospheric chemistry and secondary aerosol formation that ultimately influence the capacity of aerosol particles to affect Earth’s energy balance (aerosol radiative forcing) and air quality. These uncertainties result from many factors, including uncertainties in land-surface processes (exchanges [...]

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Hiding in Plain Sight: a Less-Explored Secret of Secondary Organic Aerosols
Jul 19, 2016 [ Research Highlights ]       
More than 50% of the fine atmospheric aerosol particle mass is often comprised of organic aerosols, most of which are secondary organic aerosols (SOA), formed by atmospheric oxidation of organic gases. Recent measurements suggest that a major fraction of SOA has volatility that is orders of magnitude lower than previously assumed. It is important to [...]

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Getting Cloud Ice from Pollution
Jul 19, 2016 [ Research Highlights ]       
Atmospheric soot (black carbon) particles absorb solar energy to warm the atmosphere—yet high in the atmosphere they may instigate cloud ice formation. But when these particles mix with other aerosols and compounds in the atmosphere, their ice-forming (ice-nucleating) ability suffers, thus altering the properties of pure ice clouds (cirrus), vital for their impact to moderate [...]

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Three Dimensions Are Better Than Two, When It Comes to Representing Aerosols
Jul 19, 2016 [ Research Highlights ]       
A research team led by scientists at Pacific Northwest National Laboratory developed a novel three-dimensional particle representation for aerosol modeling. This new add-on solves for particle size, the amount of black carbon in the particle, and the ability of the particle to draw moisture, or hygroscopicity. All three attributes are needed to accurately estimate how [...]

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ARM Instruments Reel in Decades of Data
Jul 18, 2016 [ Feature Stories and Releases ]       
Looking back on climate gear both rugged and precise This is the second article about a recently published monograph on the first 25 years of the ARM ClimateResearch Facility. During its more than two data-rich decades, the Atmospheric Radiation Measurement (ARM) Climate Research Facility has provided science with many enduring gifts, including an organizational template for climate research across the [...]

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Reconfiguring ARM: Arctic Eyes in the Sky
Jul 18, 2016 [ Feature Stories and Releases ]       
The Inaugural Campaigns for ARM Research using Unmanned Systems—or ICARUS—is underway at Oliktok Point, Alaska. In response to researcher input, ICARUS was developed as the Atmospheric Radiation Measurement (ARM) Climate Research Facility's first initiative to begin routine operations using unmanned aerial systems (UAS) and tethered balloon systems (TBS) to collect spatial information about the rapidly changing arctic environment.

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In India, a Science Journal Celebrates Insights from a Ganges Valley Climate Study
Jul 18, 2016 [ Feature Stories and Releases ]       
ARM instrumentation played a big role in the first joint U.S.-Indian experiment of its kind The Ganges River begins in a narrow valley in the Himalayas and flows eastward through a vast valley of farms, cities, power plants, and factories before exiting mightily into the Bay of Bengal. The 2,500-kilometer waterway, fed by Himalayan runoff and [...]

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Next Round of Deadlines for Small Campaigns Coming Up
Jul 18, 2016 [ Facility News ]       
The next deadline to propose for smaller field campaigns will be August 22. Small campaigns do not require a full deployment of ARM Facility equipment, like an ARM mobile or aerial facility. They require just an instrument or two, or are in conjunction with a larger facility operation. Costing less than $25,000, these campaigns give [...]

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ARM Azores Observations Help Identify Deficiencies in Climate Model Simulations of Low Clouds
Jul 16, 2016 [ Research Highlights ]       
The correctness of low-cloud representation in climate models is crucial to climate change projections and needs to be comprehensively evaluated.

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Pollution from a Megacity in the Amazon: the Case of Manaus, Brazil
Jul 12, 2016 [ Research Highlights ]       
This special journal issue outlines the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment. The field campaign research sought to quantify how aerosol and cloud life cycles in a clean background in the tropics are influenced by pollutant outflow from a large tropical city. The team used ground-based research sites and aircraft measurement [...]

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Two-Column Aerosol Project: Impact of Elevated Particle Layers on Particle Optical Depth
Jul 11, 2016 [ Research Highlights ]       
A group of DOE-funded scientists on an ARM field campaign discovered elevated levels of aerosols even on Cape Cod's cloud-free days—and these aerosols have a large impact on the amount of sunlight reaching the surface. The year-long study included measurements to examine the chemical composition of the particles, the way they reflect or scatter light, [...]

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Fall Speeds of Cirrus Crystals Faster Than Expected
Jul 11, 2016 [ Research Highlights ]       
The fall speeds of high cirrus cloud crystals depend upon crystal mass, for which no direct measurements exist. Based on new measurements of crystal images, calculated mass yields fall speeds as a function of maximum particle dimension that are, surprisingly, roughly twice as large as derived in the most commonly used past studies.

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Sub-micrometre Particulate Matter Is Primarily in Liquid Form over Amazon Rain Forest
Jul 07, 2016 [ Research Highlights ]       
A team of scientists, including U.S. Department of Energy-funded researchers, found that particles with diameters smaller than 1 μm are primarily in liquid form over the tropical rainforest of central Amazonia, where the relative humidity is greater than 80% more than 70% to 80% of the time during the dry and wet seasons. These findings are [...]

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Call for Abstracts for AGU Fall Meeting and AMS Annual Meeting
Jun 29, 2016 [ AGU, Events ]       
Sessions for this year’s Fall Meeting of the American Geophysical Union and Annual Meeting of the American Meteorological Society are being announced. If you will be leading a session, please let us know. Sessions shared with us will be added to this web page and shared in two emails to be sent July 20 and [...]

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Smoke is in the Air
Jun 27, 2016 [ ARM Mobile Facility 1, Blog, LASIC ]       
We have the first evidence of smoke being present in the Ascension Island boundary layer from the LASIC [Layered Atlantic Smoke Interactions with Clouds] measurements from June 13 to 15. This indicates the surface-based measurements are picking up the signal of smoke present in the free troposphere and confirms the island is a good place [...]

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Prepping an Aerosol Observing System for Delivery
Jun 24, 2016 [ Blog, Field Notes, SGP ]       
This afternoon, June 21, Brookhaven National Laboratory (BNL) took delivery of the enclosure for the new Southern Great Plains (SGP) aerosol observing system (AOS). This photo shows the SeaTainer sitting in its temporary home at BNL. Over the coming months, BNL will install instruments, the inlet mast, electronics, plumbing, signal wiring and other infrastructure components. [...]

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Caring for CARES: A California Air Study Keeps Spinning a Web of Research
Jun 20, 2016 [ Feature Stories and Releases ]       
During June of 2010, a lot of people cared about the Carbonaceous Aerosols and Radiative Effects Study (CARES), a 26-day investigation of the composition, evolution, and fate of aerosols in an air transport region where both natural and urban emissions mix.

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BAMS Article Reports on a Data-Rich ARM/NASA Storm Clouds Campaign
Jun 20, 2016 [ Feature Stories and Releases ]       
Midlatitude Continental Convective Clouds Experiment to be published in upcoming edition Convective clouds distribute water, heat, and momentum throughout the lowest layer of the Earth’s atmosphere, where weather happens. They get their name from the convective motion prompted when the surface of the Earth heats up, causing air to become buoyant and rise into the atmosphere. With [...]

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Small ARM Campaigns Do Big Science, and You Could Too
Jun 20, 2016 [ Facility News ]       
Next round of deadlines for small campaigns coming up; five recently approved campaigns span from Ascension Island to Mount Bachelor Not every science campaign requires a full deployment of ARM Climate Research Facility equipment; important work can be done with just an instrument or two, or in conjunction with a larger operation. These projects fall under [...]

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Urban Emissions Significantly Enhance SOA Production at a Rural Site in the NE US
Jun 12, 2016 [ Research Highlights ]       
During our study, we observed that aerosol concentration and composition at a rural site in the Northeastern U.S. were influenced strongly by upwind urban emissions. A possible reason is that anthropogenic pollutants advected from urban areas interacted with biogenic emissions in the rural region and led to a substantial enhancement of secondary organic aerosol production.

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Chamber Studies Uncover New Pathways for Atmospheric Aerosol Growth
May 31, 2016 [ Research Highlights ]       
The first few hours following the formation of a new atmospheric aerosol particle are a competition between the growth of the particle due to the condensation of low volatility “sticky” gases and the loss of the particle by collisions with other aerosol particles. New observations from the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at CERN [...]

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Spiraling Through a Storm
May 26, 2016 [ Research Highlights ]       
A multi-sensor effort that blends observations from UND Citation aircraft spirals and ground-based ARM scanning precipitation and cloud radars to investigate the signatures associated with riming and aggregation processes.

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On the Impacts of Different Definitions of Maximum Dimension for Nonspherical Cloud Particles
May 25, 2016 [ Research Highlights ]       
Knowledge of ice crystal particle size distributions (PSDs) is critical for development of microphysical parameterization schemes for numerical models and remote-sensing retrieval algorithms. Two-dimensional in situ images captured by cloud-imaging probes on aircraft are widely used to derive PSDs in term of maximum particle dimension (Dmax). However, inconsistencies in the definition of Dmax used in [...]

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Isoprene Photochemistry over the Amazon Rainforest
May 24, 2016 [ Research Highlights ]       
Isoprene is a biogenic volatile organic compound that, when oxidized by sunlight, heavily influences atmospheric chemistry over forested areas. Using field measurements from the ground and the air, this paper tracked the fate of isoprene over the central Amazon for eight weeks during the wet season. The main research site, 70 kilometers downwind of the [...]

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Regime Dependence of Cloud Water Variability Observed at the ARM Sites
May 11, 2016 [ Research Highlights ]       
Observations from ARM sites across the world have improved our understanding of how the amount of water in clouds varies at small scales. Based on these observations, a new way of describing how cloud water varies with cloud regime has been developed for use in global weather and climate models.

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Microphysical Piggybacking: Understanding the Coupling Between Cloud Dynamics and Microphysics
May 08, 2016 [ Research Highlights ]       
A novel modeling approach was developed to clearly document the impact of cloud microphysics (i.e., the model representation of growth and fallout of cloud and precipitation particles) on cloud simulations. A traditional approach is to perform parallel simulations with different microphysics schemes or scheme parameters. In such parallel simulations, clearly separating physical impacts from merely [...]

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