Tag Archives: precipitation

Study Provides New Insights on Drought Predictions in East Africa

By Guest PostFebruary 4, 2013Environment20th century, aridity, atmospheric convection, charcoal, climate, climate model simulations, climate variability, columbia university, drought conditions, drought predictions, earth observatory, east africa, east african climate, eastern africa, el niño, famine, future predictions, geologic past, geologist, geopolitical significance, global warming, gulf of aden, historical fluctuations, historical patterns, horn of africa, humanitarian crisis, indian ocean, jason smerdon, jessica tierney, lake sediment cores, lamont-doherty, little brother, little ice age, long term shifts, medieval times, moisture balance, oceanographic institution, pacific, pacific ocean, paleoclimate record, paleorecord, pollen, precipitation, projections, rainfall, region, run off events, study, surface temperatures, temperature, warm sea surface, water isotopes, western indian ocean, whoi, woods hole

Research May Also Help Determine Effects of Global Warming in the Region

With more than 40 million people living under exceptional drought conditions in East Africa, the ability to make accurate predictions of drought has never been more important. In the aftermath of widespread famine and a humanitarian crisis caused by the 2010-2011 drought in the Horn of Africa—possibly the worst drought in 60 years— researchers are striving to determine whether drying trends will continue.

While it is clear that El Niño can affect precipitation in this region of East Africa, very little is known about the drivers of long-term shifts in rainfall. However, new research described in the journal Nature helps explain the mechanisms at work behind historical patterns of aridity in Eastern Africa over many decades, and the findings may help improve future predictions of drought and food security in the region. (more…)

2001-02 Drought Helped to Shift Rocky Mountain Pine Beetle Outbreak into Epidemic

By Guest PostNovember 5, 2012Environment19th century, alpine research, Arctic, beetles, boulder, british columbia, climate, colorado, continental divide, drought, dynamics, epidemic, episode, evan pugh, forest, front range, lodgepole pine, mountain, native insect, new mexico, North America, northern, pine beetle, ponderosa pine, precipitation, rocky mountains, tania schoennagel, teresa chapman, thomas veblen, university, warmer climate, western slope, wyoming

A new University of Colorado Boulder study shows for the first time that episodes of reduced precipitation in the southern Rocky Mountains, especially during the 2001-02 drought, greatly accelerated development of the mountain pine beetle epidemic.

The study, the first ever to chart the evolution of the current pine beetle epidemic in the southern Rocky Mountains, compared patterns of beetle outbreak in the two primary host species, the ponderosa pine and lodgepole pine, said CU-Boulder doctoral student Teresa Chapman. The current mountain pine beetle outbreak in the southern Rockies — which range from southern Wyoming through Colorado and into northern New Mexico –is estimated to have impacted nearly 3,000 square miles of forests, said Chapman, lead study author. (more…)

UA Climate Scientists Put Predictions to the Test

By Guest PostSeptember 18, 2012Environmentaerosol, arizona, atmosphere, climate, climate change, climate model, climate scientist, climate variability, cloud, criteria, deforestation, earth system, emission, fossil fuel, global temperature, greenhouse gas, hindcast, ipcc, koichi sakaguchi, michael brunke, model, ocean current, particle, precipitation, prediction, solar activity, spatial resolution, surface, surface moisture, university, urbanization, volcanic eruption, weather forecaster, xubin zeng

A new study has found that climate-prediction models are good at predicting long-term climate patterns on a global scale but lose their edge when applied to time frames shorter than three decades and on sub-continental scales.

Climate-prediction models show skills in forecasting climate trends over time spans of greater than 30 years and at the geographical scale of continents, but they deteriorate when applied to shorter time frames and smaller geographical regions, a new study has found.

Published in the Journal of Geophysical Research-Atmospheres, the study is one of the first to systematically address a longstanding, fundamental question asked not only by climate scientists and weather forecasters, but the public as well: How good are Earth system models at predicting the surface air temperature trend at different geographical and time scales? (more…)

CU-led Mountain Forest Study Shows Vulnerability to Climate Change

By Guest PostSeptember 16, 2012Environmentalpine, anne kelly, Arctic, atmosphere, boulder, carbon dioxide, change, climate change, colorado, data, dry, energy, ernesto trujillo, flux towers, forest greenness, ground measurement, high resolution, michael golden, mid elevation, moisture change, mountain ecosystem, mountain range, noah molotch, precipitation, radiometer, rising temperature, roger bales, satellite image, sensitivity, sierra nevada, snowmelt, tipping point, united states, university, water vapor, western, wet, year

A new University of Colorado Boulder-led study that ties forest “greenness” in the western United States to fluctuating year-to-year snowpack indicates mid-elevation mountain ecosystems are most sensitive to rising temperatures and changes in precipitation and snowmelt.

Led by CU-Boulder researcher Ernesto Trujillo and Assistant Professor Noah Molotch, the study team used the data — including satellite images and ground measurements — to identify the threshold where mid-level forests sustained primarily by moisture change to higher-elevation forests sustained primarily by sunlight and temperature. Being able to identify this “tipping point” is important because it is in the mid-level forests — at altitudes from roughly 6,500 to 8,000 feet — where many people live and play in the West and which are associated with increasing wildfires, beetle outbreaks and increased tree mortality, said Molotch. (more…)

Droughts are Pushing Trees to the Limit

By Guest PostSeptember 8, 2012Environmentaerial surveys, atmospheric sponge, borderland, carbon dioxide, catastrophic disruption, climate change, deficit, drought, ecological disturbance, elevation, embolism, forest service, four corners, greenhouse experiment, growing season, high plains, index, jeremy weiss, jonathan overpeck, julio betancourt, leaf water, Mexico, moisture, mountainous terrain, photosynthesis, plant growth, precipitation, regional warming, southwest, stomates, temperatures rise, university of arizona, US, vapor pressure, vicious circle, weather data, wildfires

Droughts in the Southwest made more severe by warming temperatures are putting plants in stressful growing conditions, a new study has found, identifying an increasingly water-thirsty atmosphere as a key force that sucks moisture from plants, leading to potentially higher stress – especially in mid and low elevations.

As temperatures rise and droughts become more severe in the Southwest, trees are increasingly up against extremely stressful growing conditions, especially in low to middle elevations, University of Arizona researchers report in a study soon to be published in the Journal of Geophysical Research Biogeosciences.

Lead author Jeremy Weiss, a senior research specialist in the UA department of geosciences, said: “We know the climate in the Southwest is getting warmer, but we wanted to investigate how the higher temperatures might interact with the highly variable precipitation typical of the region.” (more…)

Study Finds Ancient Warming Greened Antarctica

By Guest PostJune 20, 2012Environment, Sciencealgae, ancient warming, andrill campaign, antarctic coast, antarctic ice sheet, atmospheric water vapor, aura spacecraft, carbon dioxide, climate system, fossil, frozen continent, greened antarctica, hydrogen isotope ratio, ian raine, jung eun lee, louisiana state university, margins of antarctica, marine organisms, microscopic pores, middle miocene epoch, miocene epoch, model, modern humans, NASA, past climate, plant leaf, plant life, pollen, precipitation, ross ice shelf, sarah j feakins, sediment core, sophie warny, southern mcmurdo sound, vegetation, vegetation on antarctica, wax remnants

PASADENA, Calif. — A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation — including stunted trees — along the edges of the frozen continent.

The team of scientists involved in the study, published online June 17 in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and Louisiana State University in Baton Rouge.

By examining plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, the research team found summer temperatures along the Antarctic coast 15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today, with temperatures reaching as high as 45 degrees Fahrenheit (7 degrees Celsius). Precipitation levels also were found to be several times higher than today. (more…)

Acid Rain

By Guest PostMay 4, 2012Environmentacid rain, acidic, acidity, air, basic, canopy, cape henlopen, carbonic acid, clean air act, concentration, copper, delaware rain, ecosystem, joseph scudlark, lake sediments, lead, lewes, marine studies, mercury, monitoring, nitric, organism, ph, pollutant, precipitation, rainwater, state park, sulfuric, thomas church, trace metal, zinc

UD’s long-term monitoring shows 60 percent reduction in acidity of Delaware rain

Several decades ago, precipitation in Delaware was among the most acidic in the country. Pollutants in the air reacted with rainwater to sprinkle sulfuric, nitric and carbonic acids onto the ground below, affecting crops and ecosystems statewide.

The scientific consensus is that pollution controls enacted through the Clean Air Act Amendments in the 1990s and other measures have helped decrease the acidity of rain by approximately 60 percent to less harmful levels, as reflected in data gathered nationwide and by UD researchers in Lewes, Del., as part of a longstanding study. (more…)

MU Expert Predicts Hot, Dry Summer for Midwest

By Guest PostMarch 4, 2012EnvironmentAl Gore, climate pattern, drought, eastern pacific ocean, global climate change, heat dome, la niña, la nina scenario, midwest, missouri area, nobel peace prize, precipitation, purdue, rainfall, southwest united states, summer, temperature, texas to iowa, thunderstorms, tony lupo, university of missouri, weather

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…)