Operational Numerical Weather Prediction (NWP) models now routinely use explicit deep convection, so that all simulated surface precipitation (stratiform and convective) originates from the microphysical parameterization. Previous work has shown that simulations of frontal stratiform precipitation events are sensitive to the representation of snow in the cloud microphysics parameterization, while convective precipitation events are [...]

As high-resolution climate models have increasingly moved towards an explicit representation of convection, the research spotlight shifts towards the parameterization of cloud microphysics in deep convection. Over the past decade or so, these parameterizations have rapidly gained complexity. With this increase in complexity also comes an increased computational burden, so it is important to understand [...]

Progress in the representation of Mesoscale Convective Systems (MCS) within cloud-resolving models can only be achieved if the physical reasons for discrepancies between different models are truly understood.

On Wednesday, May 15, the U.S. Department of Energys Office of Science posted a Funding Opportunity Announcement (FOA) accepting applications for Office of Biological and Environmental Research (BER) grants for research in support of the Atmospheric Radiation Measurement (ARM) Green Ocean Amazon (GOAmazon) field campaign taking place from 2014-2015 in the state of Amazonas, Brazil. [...]

In chilly, early April, more than 11,000 scientists from 95 countries gathered at the European Geosciences Union General Assembly in Vienna, Austria. The weeklong meeting saw 4,684 oral, 8,207 poster, and 452 PICO (presenting interactive content) presentations. Joining the fray for the second time, representatives from the ARM Facility presented information about ARM in several [...]

To quote Ben Franklin, "If a man empties his purse into his head, no man can take it away from him. An investment in knowledge always pays the best interest." ARM Climate Research Facility staff who attended the fourth annual Atmospheric System Research (ASR) Science Team Meeting in April received a healthy dose of interest [...]

Tropical cloudiness has its own timeline. Thats what researchers at Pacific Northwest National Laboratory found when they compared development of turbulent clouds to the timing of the atmospheric perturbation that rolls over the region every 60 to 90 days. Contrary to past assumptions, rather than a smooth transition, they found two peaks in cloudiness and [...]

Their fluffy appearance is deceiving. Fair-weather clouds have a darker side, according to scientists at Pacific Northwest National Laboratory. Fair-weather cumulus clouds contain an increasing amount of droplets formed around pollution particles. The new simulations, using data collected over Oklahoma, show how pollution from Oklahoma City increased the number of cloud droplets and reduced their [...]

It's easy to visualize particles and gases from vehicle exhaust or burning trash wafting into the atmosphere. It's harder to envision similar gases and minute particles emitted from trees and plants in the forest. What these two have in common is carbon. According to a multi-institutional team of scientists led by Pacific Northwest National Laboratory, [...]

After more than a decade of site measurements, the U.S. Department of Energy (DOE) has amassed extensive atmospheric data collections from two tropical western Pacific sites. A team of scientists led by researchers at Pacific Northwest National Laboratory showed how these data are used extensively in atmospheric and climate research by scientists around the world. [...]

Contrasts often provide unique perspectives, and scientists seize any such opportunitywhen it arises. In a new research paper, published in the Journal of Atmospheric Sciences, scientists compared weather and climate observations from two field campaigns that took place around the same time, but in environments that could not offer any greater contrast. They found that the [...]

Measurements acquired over long periods, decades at a stretch, matter quite a bit when it comes to making sense of the Earths climate system, not to mention improving the performance of global climate models. A new paper published earlier this year once again demonstrates why this is so. Based on seven years (20032010) of measurements of [...]

Heavy rains, scorching sun, and 100% humidity? No problem for ARM Mobile Facility operations personnel from Los Alamos National Laboratory. In March, they installed an initial suite of instruments outside Manaus, Brazil, as field work ramps up for the GOAMAZON field campaign in 2014.

School break means vacation, and around Cape Cod, that often means a trip to the seashore. On April 17, families looking for fun and educational outdoor activities spent several hours at Cape Cod National Seashore's Highlands Center for Junior Ranger Day. They were drawn to an event announcement in the park activities newsletter that [...]

This week, the U.S. Department of Energy begins its National Science Bowl competition, a nationwide academic competition that tests students' knowledge in all areas of science. Created 22 years ago in 1991, the DOE National Science Bowl strives to encourage students to excel in mathematics and science and to pursue careers in these fields and [...]

Interview with scientists spearheading a research campaign: 120 flight hours through burning biomasses in the Pacific Northwest and Memphis this summer. From "flash" to "smoldering" to"aging"I'm not talking about men or women. It is firesspecifically those from burning organic matter, also called 'burning biomasses.' Fires are sparked by a large number of causes, both natural and [...]

A new cooperative agreement between the U.S. Department of Energy and the Indian Institute of Science formalizes efforts between the two countries to study aerosols and cloud processes and the Indian Monsoon. The official Memorandum of Understanding, signed in March and effective for 10 years, establishes a framework for collaboration between DOE and the Indian atmospheric research community through the ARM Climate Research Facility and related science and education activities and exchanges.

On April 2, staff at the ARM Southern Great Plains site got the chance to show around a very distinguished guestDr. Anjuli Bamzai from the National Science Foundation. Bamzai leads the Climate and Large-Scale Dynamics program at NSF. She was visiting the area with her family and contacted the site to make arrangements for [...]

From April 7-12 at the European Geophysical Union's General Assembly, visitors to the ARM Facility exhibit (#4) can learn about ARM capabilities and data collections for climate research, as well as field campaigns in the United States and around the world. Speakers will also present research advances through ARM in the scientific program.

Posted by Atreyee Bhattacharya It is spring and time for some fresh air! ARM News is happy to announce a new blog, Air Time. While we are working out the many details, here is a sneak peek of things to come. At Air Time, you will find weekly updates on new research in climate and atmospheric sciences [...]

Winter snowfall in the Boston area is not uncommon, and in February they got it in spadesjust in time for the second phase of research flights for the Two-Column Aerosol Project at Cape Cod, Massachusetts. Despite a few snow days the ARM Aerial Facility (AAF) team completed a very full and successful schedule of research [...]

Research published today in the journal <em><a href="http://www.nature.com/">Nature</a></em> shows that low-level clouds in Greenland that contain just the right amount of water are thick enough to block heat from escaping to space, but thin enough to allow sunlight to reach the surface. This cloud cocktail leads to enhanced warming near the surface. Measurements from ARM instruments at Summit Station are helping researchers study important climate processes in the Arctic.

What does it mean for the carbon cycle? The deep drought in the United States that fueled wildfires and damaged crops in 2012 has now continued well into 2013. However, long before the droughts and fires wreaked havoc, a team of scientists from the U.S. Department of Energys (DOE) Lawrence Berkeley National Laboratory (LBNL) and [...]

Many studies use fine-scale models of the atmosphere to develop and test sub-grid scale parameterizations of convection in general circulation models (GCMs, also known as climate models). In fact, many experiments, including those run by the ARM Climate Research Facility, supplement observing capabilities with balloon-borne sounding arrays with forcing fine-scale models in mind. Due to [...]

A new study investigates the impact of aerosols on regional climate in southeast China On January 12 of this year news of extreme levels of air pollution in Beijing shocked the world. For decades, poor air quality has been a major health and environmental concernnot just for China, but for the rest of the world as [...]

Clouds reflect incoming energy from the sun but trap outgoing energy from the Earth. How much energy clouds retain versus reflect, however, determines their emissivity their ability to act as a source of energy themselves. Emissivity of clouds depends on more than just the total amount of clouds in the sky. The height at which [...]

Scientists use ground-based observations to understand the relationship between aerosol abundance in the atmosphere and its effects on cloud properties. Striking the right balancecritical as it may beis often difficult. Aerosols, or dust-sized particles in the atmosphere emitted from both natural and anthropogenic sources, pose one such challenge. Aerosols act as surfaces for atmospheric water vapor to [...]

Raman Lidar data obtained at the Darwin site have been reprocessed with an improved cloud mask, attenuation flag, and extended height range to 20 kilometers. Data are now available at 2-minute and 10-minute resolution for the Raman Lidar Profiles - Depolarization Ratio (RLPROFDEP) value-added product (VAP), which includes the following primary variables: cloud mask depolarization ratio extinction coefficient backscatter [...]

Aerosol optical depth (AOD) measurements have been provided for the Above-Cloud Radiation Budget field campaign at Pico Observatory, Azores, held in conjunction with the 2010 deployment of the ARM Mobile Facility (AMF) in Graciosa Island, Azores. AOD measures the total aerosol burden in the atmosphere. The spectral dependence of AOD, typically described by [...]

A new large-scale forcing data set is now available for the Variational Analysis (VARANAL) value-added product (VAP) using data from the Small Particles in Cirrus (SPARTICUS) field campaign. The constrained variational objective analysis approach described in Zhang and Lin (1997) and Zhang et al. (2001) was used to derive the large-scale single-column/cloud-resolving model forcing and evaluation [...]

The Vertical Air Motion during Large-Scale Stratiform Rain (VERVELSR) value-added product (VAP) uses the unique properties of a 95-GHz radar Doppler velocity spectra to produce vertical profiles of air motion during low-to-moderate (1&ndash;20 mm/hr) rainfall events. It is designed to run at ARM sites that include a W-band ARM cloud radar (WACR) radar with [...]

Cloud droplet number concentration is an important factor in understanding aerosol-cloud interactions. As aerosol concentration increases, it is expected that droplet number concentration, Nd, will increase and droplet size decrease for a given liquid water path, which will greatly affect cloud albedo as smaller droplets reflect more shortwave radiation. However, the magnitude and variability of [...]

Now showing on a computer near you is a completely new and dynamic tool for accessing and ordering ARM data!

Moisture trapped in soil provides water necessary for vegetation and crops, but how much of that moisture makes its way into the atmosphere and influences regional meteorology? The poor understanding of the role of soil moisture in regional and global climate is primarily because monitoring soil moisture, particularly on a large scale, continues to be [...]

Deep convective systems (DCSs) consist of intense convective cores (CC), large stratiform rain (SR) regions, and extensive nonprecipitating anvil clouds (AC). This research aims at improving the fundamental understanding of the processes responsible for the evolution of these components associated with midlatitude continental DCSs. Many aspects of deep convection are poorly represented in current global [...]

High atop the Greenland Ice Sheet, cloudy skies portend warmer temperatures and higher winds. These clouds alter the surface energy budget, diminish the strong near-surface atmospheric stability, and precipitate ice crystal to the surface. Together these processes comprise the focus of the Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit [...]

Researchers, including DOE scientists working at Pacific Northwest National Laboratory, used two field campaigns to understand the distribution and mixing state of carbonaceous aerosols in California. Research for the Nexus of Air Quality and Climate Change (CalNex) campaign sampled aerosols over southern California to understand the role of particle composition on air quality and climate [...]

Stratiform mixed-phase clouds have been shown to commonly occur and impact the surface energy budget at high latitudes (e.g., de Boer et al. 2009, Shupe et al. 2006), and cloud-induced changes to the surface energy budget have been hypothesized to contribute in modulation of sea-ice extent (Kay et al. 2008). An area of research [...]

Reanalysis data have been widely used in various climate-related studies; for example, they serve as surrogate observations where there are either no observations or only sparse observations, or as boundary conditions for regional climate modeling. Evaluation of cloud properties in reanalysis also directly sheds light on the deficiencies of relevant parameterizations in climate models [...]

Different turbulent entrainment-mixing processes (e.g., homogeneous and inhomogeneous) in clouds give rise to distinct cloud properties, and thus accurate representation of these processes is critical for improving in large scale-models; however, scientists still lack such a parameterization that spans the spectrum of entrainment-mixing processes. Department of Energy scientists at Brookhaven National Laboratory and collaborators tried [...]

Despite their widely recognized importance, aerosol indirect effects are still full of uncertainty, even controversy for some aspects. One reason for the uncertainty/controversy is that aerosol effects are often intertwined with changes in cloud dynamics such as vertical velocity, and separation of aerosol indirect effects from dynamical effects poses a confounding challenge, especially in observations. [...]

The rate at which cloud engulfs dry air (entrainment rate) has proven to be one of the strongest controls on the climate sensitivity of climate models; it is also one of the least understood problems in convection parameterization. Studies on the dependence of entrainment rate on dry air sources and on the probability density [...]

French scientists suggest heating of the Earths 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 [...]

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 [...]