Mesquite trees and woody shrubs are better adapted than grasslands to a Southwestern climate predicted to shift toward higher temperatures and greater variability in rainfall, UA ecologists have discovered.
As the desert Southwest becomes hotter and drier, semi-arid grasslands are slowly being replaced by a landscape dominated by mesquite trees, such as Prosopis velutina, and other woody shrubs, a team of University of Arizona researchers has found.
In a “leaf-to-landscape” approach, the team combined physiological experiments on individual plants and measurements across entire ecosystems to quantify how well grasslands, compared to mesquite trees and woody shrubs, cope with heat and water stress across seasonal precipitation periods. (more…)
COLUMBIA, Mo. – For nearly a year, the Midwest and southwest United States have experienced drought and warmer than normal conditions. A University of Missouri expert is predicting no relief, as he expects drought and hot conditions to continue this summer.
“I expect one of two scenarios to play out; the first is a continued La Nina climate pattern to affect our weather this summer,” said Tony Lupo, professor and chair of the Department of Atmospheric Science in the School of Natural Resources. “This will lead to a drought and above average heat throughout the Midwest from Texas to Iowa, where farmers with parched fields can least afford dry conditions. However, it is also possible that a new El Nino pattern could develop this fall. While I don’t see this happening, it would bring more favorable temperatures and precipitation patterns to the Midwest.” (more…)
ANN ARBOR, Mich.— For the first time, the chemical “fingerprints” of the element mercury have been used by University of Michigan researchers to directly link environmental pollution to a specific coal-burning power plant.
The primary source of mercury pollution in the atmosphere is coal combustion. The U-M mercury-fingerprinting technique – which has been under development for a decade – provides a tool that will enable researchers to identify specific sources of mercury pollution and determine how much of it is being deposited locally. (more…)
When NASA’s salt-seeking Aquarius instrument ascends to the heavens this June, the moon above its launch site at California’s Vandenberg Air Force Base won’t be in the seventh house, and Jupiter’s latest alignment with Mars will be weeks in the past, in contrast to the lyrics of the song from the popular Broadway musical “Hair.” Yet for the science team eagerly awaiting Aquarius’ ocean surface salinity data, the dawning of NASA’s “Age of Aquarius” promises revelations on how salinity is linked to Earth’s water cycle, ocean circulation and climate.
Salinity – the concentration of salt – on the ocean surface is a key missing puzzle piece in satellite studies of Earth that will improve our understanding of how the ocean and atmosphere are coupled and work in tandem to affect our climate. While satellites already measure sea surface temperature and winds, rainfall, water vapor, sea level, and ocean color, measurements of ocean surface salinity have, until quite recently, been limited to sparse data collected from ships, buoys and a small number of airborne science campaigns. (more…)
WASHINGTON —The extreme rain events that have caused flooding across northern Australia may become an increasingly familiar occurrence, new research suggests. The study uses the growth patterns in near-shore corals to determine which summers brought more rain than others, creating a centuries-long rainfall record for northern Australia.
“This reconstruction provides a new insight into rainfall in northeast Queensland,” says Janice Lough, climate scientist of the Australian Institute of Marine Science (AIMS) in Townsville, Queensland, who authored the study. “These coral samples, which date from 1639 to 1981, suggest that the summer of 1973–1974 was the wettest in 300 years. This summer is now being compared with that record-setting one.” (more…)
WASHINGTON — Five days before intense monsoonal deluges unleashed vast floods across Pakistan last July, computer models at a European weather-forecasting center were giving clear indications that the downpours were imminent. Now, a new scientific study that retrospectively examines the raw data from these computer models, has confirmed that, if the information had been processed, forecasters could have predicted extremely accurate rainfall totals 8-10 days beforehand.
The study also finds that the floods themselves could have been predicted if this data, which originated from the European Centre for Medium-Range Weather Forecasting (ECMWF), had been processed and fed into a hydrological model, which takes terrain into account. (more…)
Average observed tropical (black) and estimated SST (blue) rose together in the last 30 years. Image credit: University of Hawaii at Mānoa
Scientists have long known that atmospheric convection in the form of hurricanes and tropical ocean thunderstorms tends to occur when sea surface temperature rises above a threshold. So how do rising ocean temperatures with global warming affect this threshold? If the threshold does not rise, it could mean more frequent hurricanes.
A new study by researchers at the International Pacific Research Center (IPRC) of the University of Hawaii at Mānoa shows this threshold sea surface temperature for convection is rising under global warming at the same rate as that of the tropical oceans. Their paper appears in the Advance Online Publications of Nature Geoscience. (more…)
Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air.
Some suspect that extended “volcanic winters” from gigantic eruptions helped kill off dinosaurs and Neanderthals.
In the summer following Indonesia’s 1815 Tambora eruption, frost wrecked crops as far away as New England, and the 1991 blowout of the Philippines’ Mount Pinatubo lowered average global temperatures by 0.7 degrees F — enough to mask the effects of greenhouse gases for a year or so. (more…)
