Improving the accuracy in radiative transfer codes used within general circulation models (GCMs) is an important climate research priority in the U.S. Department of Energy. Our understanding of the gaseous absorption in the mid-infrared (i.e., from 316 m), which underlies these radiation codes, has undergone many important improvements due to the well-characterized radiation measurements [...]

Absorption and emission of radiation by atmospheric gases are important drivers of Earths climate. Due to the inherent physical properties of water vapor molecules and their abundance in the atmosphere, radiative processes due to water vapor play an especially prominent role. Absorption/emission by water vapor molecules occurs at discrete spectral locations, called absorption lines, and [...]

Making its debut at the European Geosciences Union (EGU) General Assembly, the ARM Climate Research Facility "crossed the pond" to attend Europe's leading forum for Earth and space sciences during the week of April 22-27, 2012, in Vienna, Austria. Participating in the meeting for the first time, ARM Facility staff visited with a steady stream [...]

In April, the 8th grade class from Watershed School in Fairbanks, Alaska, made the long trek to the North Slope for a week-long field trip filled with science, history, and cultural studies. Their field trip included a visit to the ARM site in Barrow, where NSA Site Manager Mark Ivey, along with Facilities Manager and [...]

On March 31, the ARM Mobile Facility stationed at Nainital, India, completed its 9-month deployment for the Ganges Valley Aerosol Experiment. Highlights from the data set include measurements of the subtropical jetstream over the Ganges Valley region; cloud cover and cloud heights for the monsoon period; and water vapor profiles through the various seasons. In addition, measurements from Doppler and Micropulse lidars indicate that aerosol distribution could be much more localized than previously assumed, and also confined to thin layers of a few hundred meters in the lower atmosphere.

On April 30, at about 10:30 p.m, a tornado touched down in Medford, Oklahoma, northwest of the Central Facility at ARMs Southern Great Plains site. As the storm track moved southeast, ARM's new network of scanning precipitation radars captured the storm signatures in extreme detail. Unfortunately, SGP site staff experienced even more detail, as the path of destruction included their personal property.

The Intergovernmental Panel on Climate Change (IPCC) listed the indirect effects of aerosols on climate change as one of the largest uncertainties in current climate models. Evaluating distinct components such as the first indirect effect can help identify where problems occur and where model representations are more robust, and can thus lead to a narrowing [...]

Today at the European Geosciences Union General Assembly in Vienna, the EGU media and communications office hosted a debate called Open Science and the Future of Publishing. Not being well versed in the issue, I figured this was an excellent opportunity to get up to speed. Perhaps I wasnt the only one, as [...]

Aerosol optical depth (AOD) is a measure of the 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 [...]

The Merged Sounding evaluation product has moved into the ARM Data Archive as a value-added product (VAP). This Merged Sounding VAP, initially designed by Dr. Gerald Mace, was modified by software developer David Troyan under the scientific direction of Michael Jensen to better serve the ARM community. Data are available for the following sites: Southern [...]

The Aerosol Best Estimate (ABE) value-added product (VAP) provides best-estimate time series of total column aerosol optical depth (AOD) and the associated column Angstrom exponent, as well as time/height profiles of aerosol extinction, single-scattering albedo, asymmetry parameter, and Angstrom exponents above the Central Facility at the ARM Southern Great Plains (SGP) site. As inputs, ABE uses [...]

On March 31, the <a href="http://campaign.arm.gov/amie/">ARM Madden-Julian Oscillation (MJO) Investigation Experiment, or AMIE</a>, came to an end, signaling the return of the second ARM Mobile Facility (AMF2) to the United States and a return to routine operations at the ARM site on <a href="http://www.arm.gov/sites/twp/C1">Manus Island</a> in Papua New Guinea. Researchers have already begun analyzing the AMIE data set.

VIENNA The U.S. Department of Energys Atmospheric Radiation Measurement (ARM) Climate Research Facility is attending the European Geophysical Union (EGU) General Assembly 2012 in Vienna, Austria. In its first time attending the assembly, the Facility will share information about ARMs climate observation sites around the world, including instrumentation, measurements, and how researchers can use these capabilities and data, at no cost, for their own research, in addition to scientific presentations that include ARM data.

Ozone precursor emissions influence regional and global climate and air quality through changes in tropospheric ozone and oxidants, which also influence methane (CH4) and sulfate aerosols.

Large-scale observation network in Korea opens door to new collaborations Dr. Kyungjeen Park, Korea Meteorological Administration, faces a tremendous responsibility: develop a microscale observing capability to support a major urban atmospheric measurement and modeling project. The project is to take place in the metropolitan area of Seoul Citya megacity of close to 20 million [...]

Editor's note: Dave Turner is a scientist at NOAA's National Severe Storms Laboratory in Norman, Oklahoma. He was heavily involved in the development of several ARM instruments&mdash;notably the AERI and Raman lidar&mdash;and is a longtime user of ARM data. In early March, he brought two professors and six graduate students from the University [...]

After 15 years with the management team for ARMs Tropical Western Pacific site office, Larry Jones is saying goodbye to his co-workers at Los Alamos National Laboratory and colleagues throughout the ARM Facility. He said that ARMs overall purpose toward improving climate science made him proud of the work he did every day, and he [...]

Information about all things ARM is readily available through ARMs comprehensive website. In addition to this online resource, high-quality print products are developed throughout the year to help communicate with new collaborators, stakeholders, and public audiences. The latest edition of the ARM Climate Research Facility Annual Report was published in December 2011. The [...]

The third annual Atmospheric System Research (ASR) Science Team Meeting, held March 12-16 in Arlington, Virginia, brought together members of ASR and the ARM Climate Research Facility. ASR and ARM collaborate through the use of ARM facilities for targeted field campaigns and data gathered at ARM sites for climate model improvement. The [...]

Tropical clouds and precipitation are a key component of the Earth's climate system and therefore critical to simulate faithfully in climate models. However, even the most detailed cloud-resolving models (CRMs) have difficulty representing the complex array of processes and scales that occur in tropical storms, including wind patterns, cloud particles, rain, and ice, in [...]

Observations of long-lived mixed-phase Arctic boundary-layer clouds on 7 May 1998 during the FIRE-ACE/SHEBA campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication) at cloud-top temperatures of -20C, well above the homogeneous freezing temperature (where cloud droplets freeze spontaneously), [...]

Each ARM site launches four balloon-borne sounding systems, or weather balloons, each day. The measurements they provide&mdash;temperature, pressure, humidity, and wind speed&mdash;are the backbone of many atmospheric-related research efforts. At the ARM Southern Great Plains site, operations personnel have conducted these launch duties for nearly 20 years. In mid-January, SGP staff shared their extensive [...]

Accurate retrievals of liquid water path (LWP) from passive microwave radiometers rely on the use of radiative transfer models to describe the absorption of radiation by various atmospheric components. When clouds are present, atmospheric absorption is affected by the dielectric properties of liquid water. The purpose of the study is to compare measurements of microwave [...]

Sandia National Laboratories is seeking a facility manager and project lead for an ARM facility on the North Slope of Alaska. ARM installations at Barrow and Atqasuk, Alaska, have been collecting and archiving atmospheric data for more than ten years. A new extended-deployment mobile facility is being developed for Oliktok Point, Alaska, with routine [...]

Editor's note: As part of the preparations for the upcoming Marine ARM GPCI Investigations of Clouds (MAGIC) field campaign, principal investigator Ernie Lewis, AMF2 site manager Brad Orr, and co-investigator Mike Reynolds participated in an "evaluation cruise" to simulate some of the conditions and activities that will take place during the campaign. Hawaii was wonderful. We [...]

Climate models indicate that the reduction of surface albedo caused by black carbon contamination of snow contributes to global warming and near-worldwide melting of ice. However, model predictions of BC-caused snow albedo reduction over a range of BC levels and snow grain sizes have not been verified by measurements. The main reason is that the [...]

The Arctic is warming twice as fast as the rest of the Earth, and scientists now have more data to understand why. From Fairbanks to Barrow, Alaska, a team of researchers, including scientists from Pacific Northwest National Laboratory, found strong seasonal differences in the number of ice-forming particles in Arctic clouds. The results provide a [...]

Using ten years of data gathered at three unique measurement sites, scientists at Pacific Northwest National Laboratory and Lawrence Livermore National Laboratory found that global climate models are not representing just how much clouds mask the suns warming energy. And for the first time, scientists used data on the spatial coverage, height, and transparency of [...]

The Pacific Northwest National Laboratory (PNNL) is currently seeking applicants for multiple postdocs in the areas of cloud parameterization, boundary-layer parameterization, and numerics of scale-aware physics parameterizations for climate models. Focus will be on development of parameterizations that function well on multi-resolution grids. Funding for these positions is being provided by the U.S. Department of Energy's [...]

As an important component of Earths climate system, sea ice has a particularly strong influence on the Arctic sea surface temperature, evaporation, and reflectivity, or albedo. The critical relationship among sea ice, evaporation, and precipitation is linked to a number of climate change effects. At the American Geophysical Union meeting in December 2011, scientists from [...]

Like testing the wind direction before taking flight, researchers led by scientists at Pacific Northwest National Laboratory assessed the meteorological conditions during a large observational study of carbon-containing atmospheric particles in central California. Researchers documented the weather conditions during the study and gauged how these affected the sampled areas on a daily basis. This study [...]

The climate system is substantially dependent on cloud radiative forcing and atmospheric heating rates. To keep climate simulations computationally manageable, it is necessary to use parameterized cloud-radiation schemes, and therefore, by design, all parameterizations produce systematic errors to some degree. Minimizing these errors is critically important to accurately quantifying the result of changing components in [...]

Increases in anthropogenic emissions of ozone precursors are believed to make a substantial contribution to the rising levels of surface ozone (O3) observed at many long-term measurement stations over past decades. As a strong oxidant detrimental to human health and damaging to plant growth and crop yields, surface O3 contributes to poor air quality and [...]

The solution of the radiative transfer equation depends on its boundary conditions (solar illumination and surface reflectance) and on three independent variablesoptical depth, phase function, and single scattering albedo. This study assumes that the functional dependence of the solution of the radiative transfer equation on optical depth and phase function does not change with [...]

To understand the ongoing buildup of CO2 in the atmosphere, we need to better quantify fossil fuel emissions and how much CO2 is taken up by terrestrial and oceanic systems. One indicator of these sources and sinks is the 13C carbon isotope ratio of atmospheric CO2 (13C-CO2). For example, inverse and forward models have [...]

Anthropogenic change of Earths climate is one of the biggest challenges facing humankind in the 21st century. The last several decades have featured increasing awareness of the growing levels of atmospheric carbon dioxide and other greenhouse gases and their impact on climate. At the same time, other anthropogenic impacts on the climate system have been [...]