Obscura

Switchgrass

Switchgrass (Panicum virgatum) is a warm season grass and is one of the dominant species of the central North American tallgrass prairie. Switchgrass can be found in remnant prairies, along roadsides, pastures and as an ornamental plant in gardens. Other common names for this grass include tall panic grass, Wobsqua grass, lowland switchgrass, blackbent, tall prairiegrass, wild redtop and thatchgrass.

posted by Cobb @ 11:32 AM

Carbon Sequestration

CO2 sequestration is the capture, extraction, separation, collection, etc, of carbon dioxide and a means for its storage or use.

See main article on carbon capture and storage for information on large scale permanent sequestration and/or storage of industrially-produced CO2 into deep saline aquifers, which is proposed as a means of mitigating the accumulation of green houses gases in the atmosphere from fossil fuel burning.

Atmospheric levels of CO₂ have risen from preindustrial levels of 280 parts per million (ppm) to present levels of 375 ppm. Evidence suggests this observed rise in atmospheric CO₂ levels is due primarily to expanding use of fossil fuels for energy. Predictions of global energy use in the next century suggest a continued increase in carbon emissions and rising concentrations of CO₂ in the atmosphere unless major changes are made in the way we produce and use energy—in particular, how we manage carbon. One way to manage carbon is to use energy more efficiently to reduce our need for a major energy and carbon source—fossil fuel combustion. Another way is to increase our use of low-carbon and carbon-free fuels and technologies (nuclear power and renewable sources such as solar energy, wind power, and biomass fuels). Both approaches are supported by the U.S. Department of Energy (DOE). The third and newest way to manage carbon is through carbon sequestration.

Carbon sequestration refers to the provision of long-term storage of carbon in the terrestrial biosphere, underground, or the oceans so that the buildup of carbon dioxide (the principal greenhouse gas) concentration in the atmosphere will reduce or slow. In some cases, this is accomplished by maintaining or enhancing natural processes; in other cases, novel techniques are developed to dispose of carbon. DOE's Office of Science is focusing its carbon sequestration efforts on:

• Sequestering Carbon in Underground Geologic Repositories: Geosciences research related to understanding the geophysics and geochemistry of potential reservoirs appropriate for subsurface sequestration of carbon dioxide.
• Enhancing the Natural Terrestrial Cycle: Identifying ways to enhance carbon sequestration of the terrestrial biosphere through CO₂ removal from the atmosphere by vegetation and storage in biomass and soils.
  Current Projects
• Carbon Sequestration in the Oceans: Enhancing the net oceanic uptake from the atmosphere by fertilization of phytoplankton with nutrients, and injecting CO₂ to ocean depths greater than 1000 meters.
• Sequencing Genomes of Micro-organism for Carbon Management: Sequencing the genomes of microbes that produce fuels such as methane and hydrogen or aid in carbon sequestration, to allow an evaluation of their potential use to produce, for example, methane or hydrogen from either fossil fuels or other carbonaceous sources, including biomass or even some waste products.

Understanding how carbon dioxide "sinks" perform so we can enhance the ongoing natural processes, and developing innovative new processes, may add powerful new measures to carbon management options.

View DOE Office of Science poster Carbon Sequestration Research Programs in PDF format.

posted by Cobb @ 11:28 AM

Albedo

Albedo is the ratio of reflected to incident electromagnetic radiation. It is a unitless measure indicative of a surface's or body's diffuse reflectivity. The word is derived from albus, a Latin word for "white".

The albedo is an important concept particularly in climatology and astronomy. In climatology it is sometimes expressed as a percentage. Its value depends on the frequency of radiation considered: unqualified, it usually refers to some appropriate average across the spectrum of visible light. In general, the albedo depends on the direction and directional distribution of incoming radiation. Exceptions are Lambertian surfaces, which scatter radiation equally in all directions, so their albedo does not depend on the incoming distribution. In realistic cases, a bidirectional reflectance distribution function (BRDF) is required to characterise the scattering properties of a surface accurately, although albedos are a very useful first approximation

posted by Cobb @ 11:25 AM

William Warfield

William Caesar Warfield (22 January 1920 - 26 August 2002), concert baritone singer, was born in West Helena, Arkansas. He gave his recital debut in New York's Town Hall on March 19, 1950. He was quickly invited by the Australian Broadcasting Corporation to tour that continent for 35 concerts. In 1952, Warfield performed in Porgy and Bess during a tour of Europe sponsored by the U.S. State Department (he made six separate tours for the US Department of State, more than any other American solo artist.) In this production he played opposite the opera star Leontyne Price, whom he soon married, but the demands of two separate careers left them little time together. They divorced in 1972, but were featured together in a 1963 studio recording of excerpts from Porgy and Bess.

posted by Cobb @ 7:51 PM