- Number 378 |
- December 17, 2012
By comparing simulations from 20 different computer models to satellite observations, climate scientists from DOE's Lawrence Livermore National Laboratory and colleagues from 16 other organizations have found that tropospheric and stratospheric temperature changes are clearly related to human activities.
(See the animation at https://www.llnl.gov/news/video/orbit.mov)
The team looked at geographical patterns of atmospheric temperature change over the period of satellite observations. The team's goal of the study was to determine whether previous findings of a "discernible human influence" on tropospheric and stratospheric temperature were sensitive to current uncertainties in climate models and satellite data.
It’s a suspense story with a world-climate conclusion. Using high-resolution model simulations, two scientists from DOE's Pacific Northwest National Laboratory uncovered four unique conditions that turn fair-weather clouds into tropical storm clouds. Among four environmental factors, the presence of moisture and vertical wind velocity events, about one hour before the cloud forms, are the prime culprits. The researchers validated the model results with data gathered by a collection of U.S. Department of Energy instruments.
Weather is born in the turbulent tropics. A continual cycle of heat and moisture is pulled from the tropical ocean and transported around the globe on belts of atmospheric energy. Tropical clouds are at the leading-edge of these forces. Understanding how they form, and replicating their lifecycle in global climate models, remains an elusive goal for those aiming to project climate changes accurately.
The Baryon Oscillation Spectroscopic Survey (BOSS), led by scientists from DOE's Lawrence Berkeley National Laboratory and their colleagues in the third Sloan Digital Sky Survey, recently announced the first major result of a new technique for studying dark energy. Instead of plotting the positions of stars or galaxies, the BOSS “Lyman-alpha” result is based on mapping the density of intergalactic hydrogen gas, using the spectra of over 48,000 quasars with redshifts up to 3.5 – active galaxies whose light originated up to 11.5 billion years in the past. By the time BOSS finishes its five-year survey, its collection of distant quasars will have grown to more than 150,000.
Most of the BOSS effort is devoted to mapping 1.5 million visible galaxies, distributed in netlike tendrils and voids throughout the universe. These regularly spaced peaks in density, called baryon acoustic oscillations (BAO), also map underlying invisible dark matter. BAO originated in primordial density variations, “sound waves,” rippling through the hot soup of matter and radiation that constituted the early universe. The echoes of those acoustic oscillations are detectable today as minute variations in the temperature of the cosmic microwave background radiation.
Low-carbon energy options that increase water consumption could be swapping one problem for another. That's the premise of an analysis reported by researchers at DOE's Idaho National Laboratory. They assessed the water footprint of numerous near-term energy generation options and found some surprising results.
Water is an essential component of many types of energy production. Even wind and solar energy have water footprints because they typically require coal, nuclear or natural gas backup to ensure electricity is available when sun or wind is not. Greenhouse gas emission discussions rarely consider water use, which could be the factor tipping support in favor of one approach or against another.