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The 2012 edition of the ARM Climate Research Facility Annual Report was published in January 2013. The report contains information about new ARM sites, a short overview of the Facility, information about featured field campaigns, key research results, and infrastructure achievements. It also provides a summary of 2012 field campaigns conducted throughout the ARM [...]
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French scientists suggest heating of the Earth’s surface plays a major role in semi-arid regions compared to the tropics.
In the western part of North Africa, just south of the Sahara, year-to-year failure of rainfall over the past several decades led to one of the most severe droughts the last century witnessed. In a new paper [...]
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The Shortwave Array Spectroradiometer-Hemispheric (SASHE) is a ground-based instrument that measures both direct and diffuse shortwave irradiance. SASHE provides hyperspectral measurements from about 350 nm to 1700 nm at a wavelength resolution from 1 to several nanometers.
The SASHE Aerosol Optical Depth (SASHE AOD) VAP processes the files created by the SASHE Langley VAP [...]
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A Langley plot is a regression of log (signal) versus airmass. Under appropriate conditions, the Langley regression yields values that represent the response of an instrument in absence of atmosphere (i.e., at the top of atmosphere), and these values are ultimately useful for instrument calibration. The existing LANGLEY VAP (available through special request from the [...]
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Using high-resolution model simulations, two scientists from Pacific Northwest National Laboratory uncovered the relative importance of unique conditions that lead to tropical rainstorm clouds using a novel mathematical approach. Among four key environmental factors, they found that the presence of moisture and vertical wind velocity events, about one hour before the cloud forms, are the [...]
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Guest post and photos by Chad Baldi, Project Engineer, ProSensing Inc.
Three of us from ProSensing recently made a trip to Manus Island in Papua New Guinea to perform some upgrades to two ARM radars. We made a few interesting discoveries.
In 2011, the ARM zenith cloud radar Ka-band antenna was replaced, and the old antenna [...]
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Temperature is one of the most fundamental atmospheric state variables and is crucial to the understanding of many meteorological processes. The Raman lidars at the ARM Climate Research Facility Southern Great Plains (SGP) and Tropical Western Pacific (TWP) Darwin sites are currently the only ARM active remote sensing instruments capable of profiling temperature through much [...]
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Aerosol optical depth (AOD) measures total aerosol burden in the atmosphere. The spectral dependence of AOD, typically described by the Angstrom exponent, is also an indicator of particle size. Small Angstrom exponent values (near zero) indicate presence of large particles, and vice versa.
The AOD value-added product (VAP) provides both the wavelength-dependent values of AOD and [...]
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Dead grass, extreme heat, little to no rainfall. For two years, starting in the summer of 2005, a severe drought brought the states of Oklahoma and Texas to their knees. The drought cost the state of Texas $4.1 billion in losses and two million acres burned in wildfires.
Finally, in May of 2007, a series [...]
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Researchers at Pacific Northwest National Laboratory designed an update to a frequently used computer model that represents the impact of small, puffy, fair-weather clouds on the amount of sunshine reaching Earth’s surface. The new method includes variations in temperature and humidity near the surface and their role in forming these small clouds. Their method offers [...]
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This paper addresses a fundamental question of the relationship between two single-scattering albedo spectra for water droplets (and ice crystals) at weakly absorbing wavelengths. The single-scattering albedo in atmospheric radiative transfer is the ratio of the scattering coefficient to the total extinction coefficient. It is equal to unity if all extinction is due [...]
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Every day, the incomplete combustion of fossil fuels, biofuels, and biomass forms black carbon particles in the atmosphere. Once deposited in the Arctic, these black carbon particles darken the surface of snow and ice, increasing the amount of the sun’s energy converted to heat rather than reflected back to space. At a larger scale, sunlight [...]
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Scientists have long known that global climate models struggle to accurately simulate tropical storms and the clouds they produce in different kinds of meteorological states. Research has shown that tropical weather patterns can be classified into eight such states, including two monsoon states (active monsoon and break monsoon). Additional research comparing a range of global [...]
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A call for abstracts for the Davos Atmosphere and Cryosphere Assembly 2013 (DACA-13) has been requested by the International Radiation Commission. Hosted by the International Association of Meteorology and Atmospheric Sciences (IAMAS) and the International Association of Cryospheric Sciences (IACS), both Associations of the International Union of Geodesy and Geophysics (IUGG), DACA-13 covers a [...]
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The Department of Energy selected four major field campaigns to take place using ARM facilities from 2013 through 2015. The second ARM Mobile Facility will be placed in boreal forests in Finland before traveling to the California coast. This summer, the ARM Aerial Facility will fly near forest fires and agricultural burns in Washington state and Arkansas, while continuing to support aerosol and carbon flights at the ARM SGP site.
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A record crowd of more than 3,300 scientists from academia, government, and private organizations were corralled in Austin, Texas, for the 93rd AMS Annual Meeting in early January. Though ARM outreach personnel did not participate in the exhibit hall this year, the meeting theme “Taking Predictions to the Next Level: Expanding Beyond Today's Weather, [...]
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Absorption and emission of infrared radiation by water high in the atmosphere helps cool the Earth and fuels the updrafts and downdrafts that can lead to cloud formation. Until recently, technology limitations prevented scientists from collecting data in one of the most important subsections of the infrared scale, the far-infrared. Lacking such data, global climate [...]
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Aerosols—tiny airborne particles from sources like pollution or desert dust—can increase the brightness of clouds, changing how much of the sun’s energy is reflected or radiated back to space compared to how much is trapped in the atmosphere. Some current climate change estimates are based on models that combine or aggregate aerosol and cloud observations [...]
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Scientists refer to clouds containing both ice and supercooled water as “mixed-phase” clouds. In the Arctic, these clouds occur frequently during all seasons and can persist for many days at a time. This persistence is remarkable given the inherent instability of ice-liquid mixtures. How is this possible?
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On local to global scales, newly formed particles contribute significantly to the concentration of atmospheric particles. In general, particles influence climate by affecting the balance of atmospheric radiation, both directly through scattering and absorbing incoming solar radiation and indirectly through impacts on cloud properties and lifetimes. However, the process of particle formation has long puzzled [...]
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The Initial Training for Atmospheric Remote Sensing, a European-funded Marie Curie Initial Training Network, seeks four experienced researchers to fill 2-year postdoctoral positions in Germany, Romania, Italy, and the Netherlands. ITARS aims to improve the understanding of aerosols, clouds, and aerosol‐cloud interaction processes and their role in both climate and weather. For this purpose, [...]
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Previous work by Romps (2010) found large entrainment rates of ~100% per kilometer for deep convection using a new technique for large-eddy simulations (LES) called “Eulerian direct measurement”. These results were confirmed by Dawe and Austin (2011) using a related approach. These techniques, however, are unable to pinpoint the reasons for the high [...]
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For Immediate Release: Wednesday, January 9, 2013
AUSTIN, Texas—Today at the 2013 American Meteorological Society Annual Meeting, the U.S. Department of Energy’s Wanda Ferrell is receiving the prestigious “Cleveland Abbe Award for Distinguished Service to Atmospheric Sciences.” The award recognizes Ferrell "for skillful, dedicated leadership in managing the Atmospheric Radiation Measurement Climate Research Facility, which [...]
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At the 93rd American Meteorological Society Annual Meeting, scientists that use ARM data will share their research results ranging from new classes of clouds and black carbon aerosols to highly complex data sets from scanning radars. The meeting takes place in Austin, Texas, from January 6-10, 2013.
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Researchers at Pacific Northwest National Laboratory, in collaboration with colleagues at NASA Ames Research Center, developed a next-generation assessment of tiny airborne particle-understanding capability, the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research, or 4STAR. Their new model demonstrates the potential for the new airborne instrument to obtain the most important climate-related properties of tiny particles suspended [...]
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Anthropogenic aerosols contribute to the global mean radiative forcing. Uncertainties associated with these aerosol radiative forcings are the largest contributor to the overall uncertainty in anthropogenic radiative forcing of climate. Assessments of how regional emission changes will influence aerosol radiative forcing are required from both a scientific and policy perspective.
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Despite recent advances made in climate modeling, large systematic biases are still present in the models’ simulated mean state of climate. However, fully understanding the cause of these systematic biases is difficult because of the complexity of the climate system. Scientists at Lawrence Livermore National Laboratory (LLNL) have used the U.S. Department of Energy (DOE)-funded [...]
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Department of Energy scientists at Pacific Northwest National Laboratory capitalized on the multiple sensors available at ARM's Tropical Western Pacific Darwin site to understand how and when mid-level clouds form in the tropics. Low and high clouds get most of the attention—because they are easier to detect. The researchers found that the timing and temperature [...]
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