Satellite Animation Shows February Return of the Pineapple Express

An animation of satellite imagery from NOAA's GOES-West satellite from Feb. 1 to Feb. 4, 2015 captured the movement of a stream of clouds associated with moisture called "The Pineapple Express." Image Credit: NASA/NOAA GOES Project, Dennis Chesters

The "Pineapple Express" has set up again and is bringing wet weather to the U.S. Pacific Northwest. An animation of satellite imagery from NOAA's GOES-West satellite from Feb. 1 to Feb. 4, 2015 captured the movement of a stream of clouds associated with moisture that is expected to bring rain and snow to the region over the next several days.

The ‘‘Pineapple Express’’ occurs when warm air and lots of moisture are transported from the Central Pacific, near Hawaii, to the Eastern Pacific Ocean.

A wide-field movie by NOAA's GOES-West satellite shows the Pineapple Express' stream of clouds and moisture moving into the Pacific Northwest. The video was created by NASA/NOAA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

“Good news for Northern California and the Pacific Northwest," said Bill Patzert, climatologist for NASA's Jet Propulsion Laboratory in Pasadena, California. "Beginning Wednesday, a series of storms pumped up by a moisture-laden ‘Pineapple Express’ system surging out of the warm tropical Pacific will deliver some small relief to rain and snow starved California. Though not a drought buster, we Californians are hoping this might be a preview of coming attractions for February and March. We are in the fourth quarter of our winter rain season and need a ‘hail mary’ to beat this drought down,” Patzert said.

On Feb.4 NOAA's National Weather Service Weather Prediction Center (NPC) in College Park, Maryland issued a short range forecast discussion about the Pineapple Express. NPC noted: A weather system that's tapping into abundant moisture in the Pacific will bring moderate to heavy rainfall to the Pacific Northwest beginning Wednesday. The rain will spread into northern California on Thursday and is expected to continue through the weekend. Some areas could see in excess of 10 inches of rain through early Saturday.

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The Pineapple Express is expected to affect areas from northwest California into coastal Oregon and Washington State. NPC noted that the "Express" is expected to produce mostly light to moderate rainfall totals for the coastal Pacific Northwest on Feb. 4, with much heavier totals expected the following two days.

GOES satellites provide the kind of continuous monitoring necessary for intensive data analysis. Geostationary describes an orbit in which a satellite is always in the same position with respect to the rotating Earth. This allows GOES to hover continuously over one position on Earth's surface, appearing stationary. As a result, GOES provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms and hurricanes.

Source: Nasa

Climate change accelerates maturing of grape in wine production

                             Johann Martínez-Lüscher , Nafarroako Unibertsitatea

The increase in temperatures and of CO2 levels – the consequences of climate change – accelerates the maturing of grapes in wine production, affecting colour and possibly aromas”. This was the conclusion of the PhD thesis defended by Johann Martínez-Lüscher, undertaken jointly by the University of Navarra and the University of Bordeaux.

The biologist explained that if the forecasts by the Intergovernmental Panel on Climate Change of a level of 700ppm of carbon dioxide and a temperature increase of 4ºC are proved correct, “the accumulation of sugars could be so rapid that the rest of these processes that depend on this will not be capable of keeping up. This will mean that, on comparing grapes with the same concentration of sugars or degree of alcohol, the crops under climate change conditions will have poorer colouration and this will be noticed in the wine”.

In fact, “it is increasingly more frequent to find wines with a higher alcoholic degree due to the over maturing of the grape”. Nonetheless, in the framework of climate change, the consequences can vary. “For example, the changes in levels of ultraviolet radiation or the decrease in rainfall may have antagonistic effects to those caused by an increase in temperature or CO2 levels. Thus, there are many unknowns about what the future holds”, he added.

Wine in a new scenario

In this way wine production will have to find solutions in order to confront environmental challenges. “The use of slower maturing ‘clones’ (sub-varieties) could be one of the possible strategies. It would also be very tempting to substitute the varieties planted in each location by others better adapted to warmer climates, but this would to a great extent mean giving up the typical characteristics of each variety of our wines – something unthinkable to date”.

Nevertheless, as this expert pointed out, climate change can provide new opportunities: for example, the production of a type of wine in cooler climes where it was not possible before. “This is the case of the incipient wine industry in the United Kingdom where I intend to continue working”, stated the researcher.

Mr. Martínez-Lüscher’s research has been financed by the University of Navarra, the Navarre-Aquitane Cross-Border Cooperation Programme, the Spanish Ministry of Science and Innovation, and the 7th European Union Framework Programme.

Source: Elhuyar Fundazioa

Heat waves becoming more prominent in urban areas, research reveals

Prolonged periods of extreme heat increased significantly between 1973 and 2012 in almost half of the urban areas the researchers analyzed. Credit: Ucla

The frequency of heat waves has increased dramatically over the past 40 years, and the trend appears to be growing faster in urban areas than in less-populated areas around the world, a new study suggests.

“Our findings suggest that urban areas are experiencing a kind of double whammy — a combination of general climatic warming combined with the heat island effect, wherein human activities and the built environment trap heat, preventing cities from cooling down as fast as rural areas,” said Dennis Lettenmaier, a co-author of the study and a UCLA geography professor. “Everything’s warming up, but the effect is amplified in urban areas.”

Lettenmaier and his co-authors studied 217 urban areas across the globe and found that prolonged periods of extreme heat increased significantly in 48 percent of them between 1973 and 2012.

The results, which were published today in the journal Environmental Research Letters, show that about only 2 percent of those urban areas experienced a significant decline in heat waves. And the change was more dramatic at night: Almost two-thirds of the urban areas showed significant increases in the frequency of extremely hot nights.

“The fact that the trend was so much stronger at night underscores the role of the heat island effect in urban areas,” Lettenmaier said. “You have heat being stored in buildings and in asphalt, concrete and other building materials, and they don’t cool down as quickly as they would outside of the urban area. This effect was likely exacerbated by decreasing wind in most of the urban areas.”

The study is one of the first to focus solely on the extent of extreme weather in urban areas globally and to examine disparities between densely populated and less-densely populated areas.

Lettenmaier collaborated with researchers at the Indian Institute of Technology Gandhinagar, Northeastern University and the University of Washington. The team obtained daily observations for rain, air temperature and wind speed from the National Oceanic and Atmospheric Administration. The researchers identified about 650 urban areas with populations greater than 250,000 and then refined the list to the 217 locales based on the areas’ proximity to weather stations with complete weather records and NOAA data — most were located at airports close to urban areas. Although the researchers would have liked to have more data for urban areas in Africa, Lettenmaier said the report provides as close as possible to a representative sample of changing weather conditions in the world’s cities. 

For each of the locales in the study, the researchers identified extremes for temperature, precipitation and wind, calculated heat and cold waves, and pinpointed individual extremely hot days and nights.

The study defined heat waves as periods in which the daily maximum temperature was hotter than 99 percent of days for the four-decade period and in which those temperatures were sustained for a consecutive period of six or more days. (The median length of heat waves was eight days.) It found that the average number of heat waves per year increased by over 50 percent during the period.

Of the five years with the largest number of heat waves, four were the most recent years for which data was available: 2009, 2010, 2011 and 2012. Urban areas in South America experienced the greatest increase in frequency of heat waves, followed in order by those in Africa, Europe, India and North America.

Researchers also found other striking examples of climate change within urban settings. Sixty percent experienced a significant decline in extreme windy days, 17 percent experienced a significant increase in daily precipitation extremes, and 10 percent experienced a significant increase in maximum annual precipitation.

“Urban areas make up a relatively small part of the global land area, but over half the world’s populations now live in them, so the trend is troublesome,” said lead author Vimal Mishra, an assistant professor of civil engineering at IIT Gandhinagar. “The combination of higher temperatures and lower wind in particular is not a good combination for human health and well-being. This should concern everyone.”

The increase in precipitation could damage cities’ infrastructure, which could also mean large economic losses, Mishra said.

Using a separate data set of 142 pairs of urban and non-urban areas, the researchers found that the frequency of heat waves grew 56 percent more quickly in urban settings than in surrounding areas that were less populated. Urban areas experienced 60 percent fewer extremely windy days than non-urban areas.

“In urban areas, buildings are disrupting the air flow, which affects not only the immediate area of buildings, but apparently the larger regional wind fields,” Lettenmaier said. “The reduction in wind may well be exacerbating the heat island effect.” 

Source: UCLA

Why do zebras have stripes?

A mother zebra with a foal in Tanzania’s Tarangire National Park. Credit: Brenda Larison/UCLA

One of nature’s fascinating questions is how zebras got their stripes.

A team of life scientists led by UCLA’s Brenda Larison has found at least part of the answer: The amount and intensity of striping can be best predicted by the temperature of the environment in which zebras live.

In the January cover story of the Royal Society’s online journal, Open Science, the researchers make the case that the association between striping and temperature likely points to multiple benefits — including controlling zebras’ body temperature and protecting them from diseases carried by biting flies.

“While past studies have typically focused their search for single mechanisms, we illustrate in this study how the cause of this extraordinary phenomenon is actually likely much more complex than previously appreciated, with temperature playing an important role,” said Thomas B. Smith, professor of ecology and evolutionary biology in the UCLA College and senior author of the research.

Larison, a researcher in UCLA’s department of ecology and evolutionary biology and the study’s lead author, and her colleagues examined the plains zebra, which is the most common of three zebra species and has a wide variety of stripe patterns. On zebras in warmer climes, the stripes are bold and cover the entire body. On others — particularly those in regions with colder winters such as South Africa and Namibia — the stripes are fewer in number and are lighter and narrower. In some cases, the legs or other body parts have virtually no striping.

Zebras evolved from horses more than 2 million years ago, biologists have found. Scientists have previously hypothesized that zebras’ stripes evolved for one, or a combination of, four main reasons: confusing predators, protecting against disease-carrying insects, controlling body temperature and social cohesion. And while numerous previous studies of the phenomenon focused on a single hypothesis, the Larison-led study was the first to fully test a large set of hypotheses against one another.

Analyzing zebras at 16 locations in Africa and considering more two dozen environmental factors, the researchers found that temperature was the strongest predictor of zebras’ striping. The finding provides the first evidence that controlling body temperature, or thermoregulation, is the main reason for the stripes and the patterns they form.
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Separate research by Daniel Rubenstein, a Princeton University professor of ecology and evolutionary biology and a co-author of the Open Science paper, and Princeton undergraduate Damaris Iriondo strongly suggests that boldly striped zebras have external body temperatures about five degrees Fahrenheit cooler than other animals of the same size — like antelopes — that do not have stripes but live in the same areas. The Rubenstein study is not yet published, but it is cited in the Open Science paper.

Larison has studied many zebras during her field work throughout Africa — including in Kenya, South Africa, Tanzania, Uganda and Zimbabwe. Using the fact that their stripes are unique like fingerprints, she is able to distinguish one zebra from another.

In addition to Rubenstein, arguably the world’s leading expert on zebras, the study’s co-authors were Alec Chan-Golston and Elizabeth Li, former UCLA undergraduates in mathematics; Ryan Harrigan, an assistant adjunct professor in UCLA’s Center for Tropical Research; and Henri Thomassen, a former UCLA postdoctoral scholar and current research associate at the Institute for Evolution and Ecology at Germany’s University of Tübingen.

The research was supported by the National Geographic Society Committee for Research and Exploration.

Larison and her research team have also collected zebra tissue samples and have used cutting-edge technology to sequence zebra DNA to try to identify which genes code for striping. The team is continuing to study the benefits stripes provide.

Source: UCLA

NASA Study Finds Earth’s Ocean Abyss Has Not Warmed

While the upper part of the world’s oceans continue to absorb heat from global warming, ocean depths have not warmed measurably in the last decade. This image shows heat radiating from the Pacific Ocean as imaged by the NASA’s Clouds and the Earth's Radiant Energy System instrument on the Terra satellite. (Blue regions indicate thick cloud cover.) Image Credit: NASA

The cold waters of Earth’s deep ocean have not warmed measurably since 2005, according to a new NASA study, leaving unsolved the mystery of why global warming appears to have slowed in recent years.

Scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, analyzed satellite and direct ocean temperature data from 2005 to 2013 and found the ocean abyss below 1.24 miles (1,995 meters) has not warmed measurably. Study coauthor Josh Willis of JPL said these findings do not throw suspicion on climate change itself.

"The sea level is still rising," Willis noted. "We're just trying to understand the nitty-gritty details."

In the 21st century, greenhouse gases have continued to accumulate in the atmosphere, just as they did in the 20th century, but global average surface air temperatures have stopped rising in tandem with the gases. The temperature of the top half of the world's oceans -- above the 1.24-mile mark -- is still climbing, but not fast enough to account for the stalled air temperatures.

Many processes on land, air and sea have been invoked to explain what is happening to the "missing" heat. One of the most prominent ideas is that the bottom half of the ocean is taking up the slack, but supporting evidence is slim. This latest study is the first to test the idea using satellite observations, as well as direct temperature measurements of the upper ocean. Scientists have been taking the temperature of the top half of the ocean directly since 2005, using a network of 3,000 floating temperature probes called the Argo array.

"The deep parts of the ocean are harder to measure," said JPL's William Llovel, lead author of the study published Sunday in the journal Nature Climate Change. "The combination of satellite and direct temperature data gives us a glimpse of how much sea level rise is due to deep warming. The answer is -- not much."

Deep sea creatures, like these anemones at a hydrothermal vent, are not yet feeling the heat from global climate change. Although the top half of the ocean continues to warm, the bottom half has not increased measurably in temperature in the last decade. Image Credit: NERC

The study took advantage of the fact that water expands as it gets warmer. The sea level is rising because of this expansion and the water added by glacier and ice sheet melt.
To arrive at their conclusion, the JPL scientists did a straightforward subtraction calculation, using data for 2005-2013 from the Argo buoys, NASA's Jason-1 and Jason-2 satellites, and the agency’s Gravity Recovery and Climate Experiment (GRACE) satellites. 
From the total amount of sea level rise, they subtracted the amount of rise from the expansion in the upper ocean, and the amount of rise that came from added meltwater. The remainder represented the amount of sea level rise caused by warming in the deep ocean.
The remainder was essentially zero. Deep ocean warming contributed virtually nothing to sea level rise during this period.

Coauthor Felix Landerer of JPL noted that during the same period warming in the top half of the ocean continued unabated, an unequivocal sign that our planet is heating up. Some recent studies reporting deep-ocean warming were, in fact, referring to the warming in the upper half of the ocean but below the topmost layer, which ends about 0.4 mile (700 meters) down.

Landerer also is a coauthor of another paper in the same journal issue on 1970-2005 ocean warming in the Southern Hemisphere. Before Argo floats were deployed, temperature measurements in the Southern Ocean were spotty, at best. Using satellite measurements and climate simulations of sea level changes around the world, the new study found the global ocean absorbed far more heat in those 35 years than previously thought -- a whopping 24 to 58 percent more than early estimates.

Both papers result from the work of the newly formed NASA Sea Level Change Team, an interdisciplinary group tasked with using NASA satellite data to improve the accuracy and scale of current and future estimates of sea level change. The Southern Hemisphere paper was led by three scientists at Lawrence Livermore National Laboratory in Livermore, California.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

Source: Nasa

Study Yields Surprising Insights into Global Effects of Wood Fuel Burning

Courtesy of Adrian Ghilardi

The harvesting of wood to meet the heating and cooking demands for billions of people worldwide has less of an impact on global forest loss and carbon dioxide (CO2) emissions than previously believed, according to a new Yale-led study.

Writing in the journal Nature Climate Change, a team of researchers, including Prof. Robert Bailis of the Yale School of Forestry & Environmental Studies (F&ES), concludes that only about 27 to 34 percent of wood fuel harvested worldwide would be considered “unsustainable.” According to the assessment, “sustainability” is based on whether or not annual harvesting exceeds incremental re-growth.

The other authors are Rudi Drigo, an independent forestry specialist with international experience; and Adrian Ghilardi and Omar Masera of the National Autonomous University of Mexico.

According to the authors, the findings point to the need for more nuanced, local-specific policies that address forest loss, climate change, and public health. They also suggest that existing carbon offset methodologies used to reduce carbon emissions likely overstate the CO2 emission reductions that can be achieved through the promotion of more efficient cookstove technologies.

The study identifies a set of “hotspots” where the majority of wood extraction exceeds sustainable yields. These hotspot regions — located mainly in South Asia and East Africa — support about 275 million people who are reliant on wood fuel.

“If forests and woodlands would have been cut down anyway, then the projects designed to reduce wood fuel demand are not actually going to reduce deforestation.”— Robert Bailis

However, in other regions, the authors say, much of the wood used for this traditional heating and cooking is actually the byproduct of deforestation driven by other factors, such as demand for agricultural land, which would have occurred anyway.

“If forests and woodlands would have been cut down anyway, then the projects designed to reduce wood fuel demand are not actually going to reduce deforestation,” said Bailis, an associate professor at F&ES and lead author of the study. “Sure, you’re reducing wood use, but the underlying pressures driving deforestation are still out there.”

The results stand in contrast to a long-held assumption that the harvesting of wood fuels — which accounts for more than half of the wood harvested worldwide — is a major driver of deforestation and climate change.
  
Using a model originally developed by Drigo and Masera, and already applied in more than 20 countries, the researchers produce a spatially explicit snapshot of wood fuel supply and demand in 90 countries across the world’s tropical regions, where burning wood is a critical source of energy for cooking and heating.

“One of the problems with traditional bio-energy is that the situation is very locally specific, so you can’t come up with a general response for all places,” said Masera. “One of the real strengths of this paper is that it demonstrates a methodology that allows you to identify priority regions for intervention”

The study identified a set of “hotspot” regions in South Asia and Eastern Africa where the majority of wood extraction exceeds sustainable yields.

In addition to the global analysis, the researchers are using the same model to evaluate the sustainability of wood fuel resources in three case studies: Honduras, Kenya, and the Indian state of Karnataka.

“Even within a given country the situation varies a great deal,” said Drigo. “Some areas are over-exploited while others are under-exploited or totally untouched. A better understanding of the relationship between supply and demand requires this type of spatial approach to clarify what the impacts of different policies will be.”

Emissions from wood fuels account for about 1.9 to 2.3 percent of global emissions, the study says. The deployment of 100 million improved cookstoves could reduce this by 11 to 17 percent, said Bailis, who also studies the factors that influence the adoption of cleaner cookstoves in developing nations.

These reductions would be worth more than $1 billion per year in avoided greenhouse gas emissions if black carbon were integrated into carbon markets, he said.

“We need to be able to understand where these different components of non-renewability are coming from in order to get a better sense of the positive impacts of putting stoves into peoples' homes or promoting transitions to cooking with gas or electricity,” he said.

The research was funded by the Global Alliance for Clean Cookstoves, an initiative supported by the UN Foundation.

Source: Yale University

Small volcanic eruptions could be slowing global warming

The Sarychev Peak Volcano, on Matua Island, erupted on June 12, 2009. New research shows that eruptions of this size may contribute more to the recent lull in global temperature increases than previously thought. Credit: NASA

Small volcanic eruptions might eject more of an atmosphere-cooling gas into Earth's upper atmosphere than previously thought, potentially contributing to the recent slowdown in global warming, according to a new study.

Scientists have long known that volcanoes can cool the atmosphere, mainly by means of sulfur dioxide gas that eruptions expel. Droplets of sulfuric acid that form when the gas combines with oxygen in the upper atmosphere can remain for many months, reflecting sunlight away from Earth and lowering temperatures. However, previous research had suggested that relatively minor eruptions -- those in the lower half of a scale used to rate volcano "explosivity" -- do not contribute much to this cooling phenomenon.

Now, new ground-, air- and satellite measurements show that small volcanic eruptions that occurred between 2000 and 2013 have deflected almost double the amount of solar radiation previously estimated. By knocking incoming solar energy back out into space, sulfuric acid particles from these recent eruptions could be responsible for decreasing global temperatures by 0.05 to 0.12 degrees Celsius (0.09 to 0.22 degrees Fahrenheit) since 2000, according to the new study accepted to Geophysical Research Letters, a journal of the American Geophysical Union.

These new data could help to explain why increases in global temperatures have slowed over the past 15 years, a period dubbed the 'global warming hiatus,' according to the study's authors.

The warmest year on record is 1998. After that, the steep climb in global temperatures observed over the 20th century appeared to level off. Scientists previously suggested that weak solar activity or heat uptake by the oceans could be responsible for this lull in temperature increases, but only recently have they thought minor volcanic eruptions might be a factor.

Climate projections typically don't include the effect of volcanic eruptions, as these events are nearly impossible to predict, according to Alan Robock, a climatologist at Rutgers University in New Brunswick, N.J., who was not involved in the study. Only large eruptions on the scale of the cataclysmic 1991 Mount Pinatubo eruption in the Philippines, which ejected an estimated 20 million metric tons (44 billion pounds) of sulfur, were thought to impact global climate. But according to David Ridley, an atmospheric scientist at the Massachusetts Institute of Technology in Cambridge and lead author of the new study, classic climate models weren't adding up.

"The prediction of global temperature from the [latest] models indicated continuing strong warming post-2000, when in reality the rate of warming has slowed," said Ridley. That meant to him that a piece of the puzzle was missing, and he found it at the intersection of two atmospheric layers, the stratosphere and the troposphere- the lowest layer of the atmosphere, where all weather takes place. Those layers meet between 10 and 15 kilometers (six to nine miles) above the Earth.

Traditionally, scientists have used satellites to measure sulfuric acid droplets and other fine, suspended particles, or aerosols, that erupting volcanoes spew into the stratosphere. But ordinary water-vapor clouds in the troposphere can foil data collection below 15 km, Ridley said. "The satellite data does a great job of monitoring the particles above 15 km, which is fine in the tropics. However, towards the poles we are missing more and more of the particles residing in the lower stratosphere that can reach down to 10 km."

To get around this, the new study combined observations from ground-, air- and space-based instruments to better observe aerosols in the lower portion of the stratosphere.
Four lidar systems measured laser light bouncing off aerosols to estimate the particles' stratospheric concentrations, while a balloon-borne particle counter and satellite datasets provided cross-checks on the lidar measurements. A global network of ground-based sun-photometers, called AERONET, also detected aerosols by measuring the intensity of sunlight reaching the instruments. Together, these observing systems provided a more complete picture of the total amount of aerosols in the stratosphere, according to the study authors.

Including these new observations in a simple climate model, the researchers found that volcanic eruptions reduced the incoming solar power by -0.19 ± 0.09 watts of sunlight per square meter of the Earth's surface during the 'global warming hiatus', enough to lower global surface temperatures by 0.05 to 0.12 degrees Celsius (0.09 to 0.22 degrees Fahrenheit). By contrast, other studies have shown that the 1991 Mount Pinatubo eruption warded off about three to five watts per square meter at its peak, but tapered off to background levels in the years following the eruption. The shading from Pinatubo corresponded to a global temperature drop of 0.5 degrees Celsius (0.9 degrees Fahrenheit).

Robock said the new research provides evidence that there may be more aerosols in the atmosphere than previously thought. "This is part of the story about what has been driving climate change for the past 15 years," he said. "It's the best analysis we've had of the effects of a lot of small volcanic eruptions on climate."

Ridley said he hopes the new data will make their way into climate models and help explain some of the inconsistencies that climate scientists have noted between the models and what is being observed.

Robock cautioned, however, that the ground-based AERONET instruments that the researchers used were developed to measure aerosols in the troposphere, not the stratosphere. To build the best climate models, he said, a more robust monitoring system for stratospheric aerosols will need to be developed.

Source; American Geophysical Union

Atlantic warming turbocharges Pacific trade winds

Tropical beach (stock image). Rapid warming of the Atlantic Ocean, likely caused by global warming, has turbocharged Pacific Equatorial trade winds, according to new research. Credit: © michaelfitz / Fotolia

New research has found rapid warming of the Atlantic Ocean, likely caused by global warming, has turbocharged Pacific Equatorial trade winds. Currently the winds are at a level never before seen on observed records, which extend back to the 1860s.

The increase in these winds has caused eastern tropical Pacific cooling, amplified the Californian drought, accelerated sea level rise three times faster than the global average in the Western Pacific and has slowed the rise of global average surface temperatures since 2001.

It may even be responsible for making El Nino events less common over the past decade due to its cooling impact on ocean surface temperatures in the eastern Pacific.

"We were surprised to find the main cause of the Pacific climate trends of the past 20 years had its origin in the Atlantic Ocean," said co-lead author Dr Shayne McGregor from the ARC Centre of Excellence for Climate System Science (ARCCSS) at the University of New South Wales.

"It highlights how changes in the climate in one part of the world can have extensive impacts around the globe."

The record-breaking increase in Pacific Equatorial trade winds over the past 20 years had, until now, baffled researchers.

Originally, this trade wind intensification was considered to be a response to Pacific decadal variability. However, the strength of the winds was much more powerful than expected due to the changes in Pacific sea surface temperature.

Another riddle was that previous research indicated that under global warming scenarios Pacific Equatorial Trade winds would slow down over the coming century.

The solution was found in the rapid warming of the Atlantic Ocean basin, which has created unexpected pressure differences between the Atlantic and Pacific. This has produced wind anomalies that have given Pacific Equatorial trade winds an additional big push.

"The rapid warming of the Atlantic Ocean created high pressure zones in the upper atmosphere over that basin and low pressure zones close to the surface of the ocean," said Prof Axel Timmermann co-lead and corresponding author from the University of Hawaii.

"The rising air parcels, over the Atlantic eventually sink over the eastern tropical Pacific, thus creating higher surface pressure there. The enormous pressure see-saw with high pressure in the Pacific and low pressure in the Atlantic gave the Pacific trade winds an extra kick, amplifying their strength. It's like giving a playground roundabout an extra push as it spins past."

Many climate models appear to have underestimated the magnitude of the coupling between the two ocean basins, which may explain why they struggled to produce the recent increase in Pacific Equatorial trade wind trends.

While active, the stronger Equatorial trade winds have caused far greater overturning of ocean water in the West Pacific, pushing more atmospheric heat into the ocean, as shown by co-author and ARCCSS Chief Investigator Prof Matthew England earlier this year. This increased overturning appears to explain much of the recent slowdown in the rise of global average surface temperatures.

Importantly, the researchers don't expect the current pressure difference between the two ocean basins to last. When it does end, they expect to see some rapid changes, including a sudden acceleration of global average surface temperatures.

"It will be difficult to predict when the Pacific cooling trend and its contribution to the global hiatus in surface temperatures will come to an end," Prof England said.

"However, a large El Niño event is one candidate that has the potential to drive the system back to a more synchronized Atlantic/Pacific warming situation."

Source: University of New South Wales

NASA HS3 instrument views two dimensions of clouds

The second Cloud Physics Lidar built to fly on NASA's unmanned Global Hawk aircraft. In this summer's Hurricane and Severe Storm Sentinel or HS3 mission, the CPL is studying the changing profile of the atmosphere in detail to learn more about how hurricanes form and strengthen. Credit: NASA

Looking out the window of a commercial plane during takeoff is like taking the nickel tour of the profile of the atmosphere. As the plane ascends, what may start as a gloomy day on the ground, can turn into rain streaking across the window as you pass through the white-gray cloud, and then sunny skies above once the plane reaches cruising altitude.

NASA's Cloud Physics Lidar (CPL) instrument, flying aboard an unmanned Global Hawk aircraft in this summer's Hurricane and Severe Storm Sentinel, or HS3, mission, is studying the changing profile of the atmosphere in detail to learn more about how hurricanes form and strengthen.

"CPL profiles the atmosphere to get a two-dimensional picture of cloud and aerosols, from the top down," said Matt McGill of NASA's Goddard Space Flight Center in Greenbelt, Maryland, who led the instrument team that designed and built the CPL. Its data, presented as if it were a curtain hanging from the sky, shows what's in the atmosphere's different layers.

From about 60,000 feet on the Global Hawk, twice the altitude of a commercial plane, 94 percent of the atmosphere lies below the instrument. The lidar works by sending rapid pulses of light that, like a radar beam, bounce and scatter off any particles they encounter, such as cloud droplets or dust particles. Some of the scattered light returns to the instrument where it records how long it took for the photons to leave and return -- giving the altitude of the particles.

CPL sends out 5,000 pulses of light per second in three different wavelengths, allowing the science team to discriminate between different types of particles, McGill said. "Is it a cloud made of water? Is it a cloud made of ice or mixed [water and ice]? And we can say something about what type of airborne particle we are seeing. Is it dust or smoke or pollution?"
For the scientists studying hurricanes, those distinctions are important. One of the major areas of study is how Saharan dust off of Africa travels across the Atlantic and affects hurricane formation and intensification. CPL data have been used to verify model projections of Saharan dust in the tropics. The CPL data showed dust layers had a vertical distribution different than models predicted. Instead dust layers occupied narrower altitude ranges. The finding led to an improvement in the dust models, which then feed into hurricane models.

Situated in the nose of the Global Hawk flying over the storm environment, CPL also has a role in on-the-fly mission planning. While in flight, the CPL sends its data back to the team on the ground. "The mission scientists involved in the flight planning can sit there and watch the data with us in real time and say, 'Oh, we're not getting what we want.' Then they can go work with the flight planners and pilots to reroute the aircraft into different areas," said McGill. "They love that."

The airborne science community takes full advantage of the quick look capability, as well as the 24-hour turn around for the final data products. CPL is one of the most flown instruments in NASA's Earth science fleet. "It's a workhorse for the field campaigns," said McGill.

The original CPL was built in 1999 and took its first flight on the ER-2 high altitude research aircraft in 2000. Over the years CPL has been used as a satellite simulator for ground validation efforts, a cloud spotter for other instruments needing a clear view of the ground, as well as the main data collector for scientists studying atmospheric composition and Earth's energy budget where thin clouds and aerosols are major players. The lidar was also part of the proof of concept flights for the A-Train, a series of satellites flying in the same orbit making near-simultaneous measurements of the Earth system using many different instruments. That proof of concept airborne campaign showed scientists the power of combining multiple Earth observing data sets.

In 2007, when talk began of using Global Hawks for Earth science, CPL was among the first sensors considered; its size is perfect for the instrument compartment. Worries about the untested Global Hawk led to a second nearly identical instrument being built for use on the unmanned aircraft. It flew on NASA's maiden Global Hawk Pacific campaign in 2009. Since then, the Global Hawk CPL has flown in two multi-year campaigns, alternating between the Airborne Tropical Tropopause Experiment (ATTREX) and HS3.

Compact and fully autonomous, the CPL lidar design pioneered photon-counting technology that has led to the development of two instruments that will fly in space, the Cloud-Aerosol Transport System (CATS), which launches to the International Space Station this December, and the Advanced Topographic Laser Altimeter System (ATLAS), which will fly on the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) scheduled to launch in 2017.

The solid design of the instrument has borne up surprisingly well over the years, said McGill, who uses CPL as a learning tool for interns and young scientists getting their hands dirty in the field. Together, the twin CPL instruments have flown 26 missions. HS3 will mark the 27th overall and the seventh for the Global Hawk CPL.

"It's still going strong," McGill said.

The HS3 mission is funded by NASA Headquarters and overseen by NASA's Earth System Science Pathfinder Program at NASA's Langley Research Center in Hampton, Virginia, and is one of five large field campaigns operating under the Earth Venture program. The HS3 mission also involves collaborations with partners including the National Centers for Environmental Prediction, Naval Postgraduate School, Naval Research Laboratory, NOAA's Hurricane Research Division and Earth System Research Laboratory, Northrop Grumman Space Technology, National Center for Atmospheric Research, State University of New York at Albany, University of Maryland -- Baltimore County, University of Wisconsin and University of Utah. The HS3 mission is managed by the Earth Science Project Office at NASA's Ames Research Center in Moffett Field, California. The aircraft are maintained and based at NASA's Armstrong Flight Research Center in Edwards, California.

Source: NASA

Lightning expected to increase by 50 percent with global warming

Today's climate models predict a 50 percent increase in lightning strikes across the United States during this century as a result of warming temperatures associated with climate change. Credit: © Sondem / Fotolia

Today's climate models predict a 50 percent increase in lightning strikes across the United States during this century as a result of warming temperatures associated with climate change.

Reporting in the Nov. 14 issue of the journal Science, University of California, Berkeley, climate scientist David Romps and his colleagues look at predictions of precipitation and cloud buoyancy in 11 different climate models and conclude that their combined effect will generate more frequent electrical discharges to the ground.

"With warming, thunderstorms become more explosive," said Romps, an assistant professor of earth and planetary science and a faculty scientist at Lawrence Berkeley National Laboratory. "This has to do with water vapor, which is the fuel for explosive deep convection in the atmosphere. Warming causes there to be more water vapor in the atmosphere, and if you have more fuel lying around, when you get ignition, it can go big time."

More lightning strikes mean more human injuries; estimates of people struck each year range from the hundreds to nearly a thousand, with scores of deaths. But another significant impact of increased lightning strikes would be more wildfires, since half of all fires -- and often the hardest to fight -- are ignited by lightning, Romps said. More lightning also would likely generate more nitrogen oxides in the atmosphere, which exert a strong control on atmospheric chemistry.

While some studies have shown changes in lightning associated with seasonal or year-to-year variations in temperature, there have been no reliable analyses to indicate what the future may hold. Romps and graduate student Jacob Seeley hypothesized that two atmospheric properties -- precipitation and cloud buoyancy -- together might be a predictor of lightning, and looked at observations during 2011 to see if there was a correlation.

"Lightning is caused by charge separation within clouds, and to maximize charge separation, you have to loft more water vapor and heavy ice particles into the atmosphere," he said. "We already know that the faster the updrafts, the more lightning, and the more precipitation, the more lightning."

Precipitation -- the total amount of water hitting the ground in the form of rain, snow, hail or other forms -- is basically a measure of how convective the atmosphere is, he said, and convection generates lightning. The ascent speeds of those convective clouds are determined by a factor called CAPE -- convective available potential energy -- which is measured by balloon-borne instruments, called radiosondes, released around the U.S. twice a day.

"CAPE is a measure of how potentially explosive the atmosphere is, that is, how buoyant a parcel of air would be if you got it convecting, if you got it to punch through overlying air into the free troposphere," Romps said. "We hypothesized that the product of precipitation and CAPE would predict lightning."

Using U.S. Weather Service data on precipitation, radiosonde measurements of CAPE and lightning- strike counts from the National Lightning Detection Network at the University of Albany, State University of New York (UAlbany), they concluded that 77 percent of the variations in lightning strikes could be predicted from knowing just these two parameters.

'Blown away'

"We were blown away by how incredibly well that worked to predict lightning strikes," he said.

They then looked at 11 different climate models that predict precipitation and CAPE through this century and are archived in the most recent Coupled Model Intercomparison Project (CMIP5). CMIP was established as a resource for climate modelers, providing a standard protocol for studying the output of coupled atmosphere-ocean general circulation models so that these models can be compared and validated.

"With CMIP5, we now have for the first time the CAPE and precipitation data to calculate these time series," Romps said.

On average, the models predicted an 11 percent increase in CAPE in the U.S. per degree Celsius rise in global average temperature by the end of the 21st century. Because the models predict little average precipitation increase nationwide over this period, the product of CAPE and precipitation gives about a 12 percent rise in cloud-to-ground lightning strikes per degree in the contiguous U.S., or a roughly 50 percent increase by 2100 if Earth sees the expected 4-degree Celsius increase (7 degrees Fahrenheit) in temperature. This assumes carbon dioxide emissions keep rising consistent with business as usual.

Exactly why CAPE increases as the climate warms is still an area of active research, Romps said, though it is clear that it has to do with the fundamental physics of water. Warm air typically contains more water vapor than cold air; in fact, the amount of water vapor that air can "hold" increases exponentially with temperature. Since water vapor is the fuel for thunderstorms, lightning rates can depend very sensitively on temperature.

In the future, Romps plans to look at the distribution of lightning-strike increases around the U.S. and also explore what lightning data can tell climatologists about atmospheric convection.

Romps' co-authors are Jacob Seeley, also of the Department of Earth and Planetary Science at UC Berkeley, and David Vollaro and John Molinari of the Department of Atmospheric and Environmental Sciences at UAlbany.

The work was supported by the U.S. Department of Energy's Office of Advanced Scientific Computing Research and Office of Biological and Environmental Research, and the National Science Foundation.

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Source: University of California - Berkeley

Permafrost soil: Possible source of abrupt rise in greenhouse gases at end of last ice age

Pleistocene Ice Complex cliff: 35 meters high Pleistocene Ice Complex cliff at Sobo Sise Island (Lena Delta), Siberian Arctic. Credit: Alfred-Wegener-Institut / Thomas Opel

Scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have identified a possible source of carbon dioxide (CO2) and other greenhouse gases that were abruptly released to the atmosphere in large quantities around 14,600 years ago. According to this new interpretation, the CO2 -- released during the onset of the Bølling/Allerød warm period -- presumably had their origin in thawing Arctic permafrost soil and amplified the initial warming through positive feedback. The study now appears online in the journal Nature Communications.

One of the most abrupt rises in the carbon dioxide concentration in the atmosphere at the end of the last ice age took place about 14,600 years ago. Ice core data show that the CO2 concentration at that time increased by more than 10 ppm (parts per million, unit of measure for the composition of gases) within 200 years. This CO2 increase, i.e. approx. 0.05 ppm per year, was significantly less than the current rise in atmospheric CO2 of 2-3 ppm in the last decade caused by fossil fuels. These data describe an abrupt change in the global carbon cycle during the transition from the last ice age to the present-day warm interglacial and allow conclusions to be drawn about similar processes that could play a role in the future.

To determine the origin of the greenhouse gas, a team around by the geoscientists and climate researchers Dr. Peter Köhler and Dr. Gregor Knorr from the Alfred Wegener Institute has carried out computer simulations focusing on the new interpretation of these CO2 data. These calculations were motivated by new radiocarbon data (14C) that provide information on the age of the CO2 released to the atmosphere. The age of the carbon then allows conclusions to be drawn about the carbon source.

"The virtual lack of radiocarbon in the CO2 that was released into the atmosphere shows us that the carbon must have been very old," says Köhler. The carbon therefore cannot be originated from the deep ocean, Köhler adds: "The carbon stored in the deep ocean has been subject to exchange with the atmosphere over a period of millennia. In the atmosphere 14C has its only source. It is produced through the impact of galactic cosmic rays on molecules in the atmosphere." However, radiocarbon is unstable and decays with a half-life of around 5,700 years. The atmospheric data of CO2 and 14C can only be explained if a carbon source is assumed that contains virtually no 14C any more -- thus the greenhouse gases must have had another source than the deep ocean.

Permafrost soil contains, to some extent, very old organic material, which is released in the form of the greenhouse gases CO2 and methane when the soil thaws. Permafrost soil thus might be a possible source of old carbon. The thawing of Arctic permafrost soil might have been caused by a sudden resumption of large-scale Atlantic heat transport in the ocean that initiated the Bølling/Allerød warm period in the high northern hemisphere.

The scientists were able to estimate the amount of the carbon dioxide released to the atmosphere by applying a computer model that simulates the global carbon cycle. The simulation results indicate that the input of more than half a gigaton of carbon per year (1 gigaton = 1 petagram) over a period of two centuries is necessary to explain the observed data. This corresponds to a total amount of more than 100 gigatons of carbon. Present-day anthropogenic CO2 emissions due to fossil fuels, at approx. ten gigatons of carbon a year, are greater than the release rates of this natural process by a factor of at least ten.

According to the study, the proposed thawing of large areas of permafrost, followed by the rise in greenhouse gases, occurred at the same time as the warming in the northern hemisphere at the beginning of the Bølling warm period. The released greenhouse gases may amplify the initial warming through feedback effects.

A similar effect is also predicted for the future in the current IPCC report. Warming in Siberia, for instance, is already leading to thawing of permafrost soil: outgassing of CO2 and methane takes place. The same processes observed today -- and are expected to an even greater extent in the coming decades -- presumably occurred in a similar manner 14,600 years ago. "However, the state of the climate on Earth today has already been changed by anthropogenically emitted greenhouse gases. Future CO2 release due to the proposed thawing of permafrost will be substantially less than the input due to fossil fuels. However, these emissions from permafrost soil are additional greenhouse gas sources that further amplify the anthropogenically induced effect," says Köhler.

Source:  Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

Birds Sensed severe storms and fled before tornado outbreak

This golden-winged warbler spends the breeding season in the Cumberland Mountains of Tennessee. Credit: Henry Streby and Gunnar Kramer

Golden-winged warblers apparently knew in advance that a storm that would spawn 84 confirmed tornadoes and kill at least 35 people last spring was coming, according to a report in the Cell Press journal Current Biology on December 18. The birds left the scene well before devastating supercell storms blew in.

The discovery was made quite by accident while researchers were testing whether the warblers, which weigh "less than two nickels," could carry geolocators on their backs. It turns out they can, and much more. With a big storm brewing, the birds took off from their breeding ground in the Cumberland Mountains of eastern Tennessee, where they had only just arrived, for an unplanned migratory event. All told, the warblers travelled 1,500 kilometers in 5 days to avoid the historic tornado-producing storms.

"The most curious finding is that the birds left long before the storm arrived," says Henry Streby of the University of California, Berkeley. "At the same time that meteorologists on The Weather Channel were telling us this storm was headed in our direction, the birds were apparently already packing their bags and evacuating the area."

The birds fled from their breeding territories more than 24 hours before the arrival of the storm, Streby and his colleagues report. The researchers suspect that the birds did it by listening to infrasound associated with the severe weather, at a level well below the range of human hearing.

"Meteorologists and physicists have known for decades that tornadic storms make very strong infrasound that can travel thousands of kilometers from the storm," Streby explains. While the birds might pick up on some other cue, he adds, the infrasound from severe storms travels at exactly the same frequency the birds are most sensitive to hearing.

The findings show that birds that follow annual migratory routes can also take off on unplanned trips at other times of the year when conditions require it. That's probably good news for birds, as climate change is expected to produce storms that are both stronger and more frequent. But there surely must be a downside as well, the researchers say.

"Our observation suggests [that] birds aren't just going to sit there and take it with regards to climate change, and maybe they will fare better than some have predicted," Streby says. "On the other hand, this behavior presumably costs the birds some serious energy and time they should be spending on reproducing." The birds' energy-draining journey is just one more pressure human activities are putting on migratory songbirds.

In the coming year, Streby's team will deploy hundreds of geolocators on the golden-winged warblers and related species across their entire breeding range to find out where they spend the winter and how they get there and back.

"I can't say I'm hoping for another severe tornado outbreak," Streby says, "but I am eager to see what unpredictable things happen this time."

Source: Cell Press

'Tipping points' for sea level rise related flooding determined

Annapolis, Maryland, pictured here in 2012, is one of three major East Coast urban areas already being faced with nuisance flooding in excess of 30 days per year. Credit: With permission from Amy McGovern

By 2050, a majority of U.S. coastal areas are likely to be threatened by 30 or more days of flooding each year due to dramatically accelerating impacts from sea level rise, according to a new NOAA study, published today in the American Geophysical Union's online peer-reviewed journal Earth's Future.

The findings appear in the paper "From the Extreme to the Mean: Acceleration and Tipping Points for Coastal Inundation due to Sea Level Rise," and follows the earlier study, Sea Level Rise and Nuisance Flood Frequency Changes around the United States, by the report's co-author, William Sweet, Ph.D., oceanographer at NOAA's Center for Operational Oceanographic Products and Services (CO-OPS). The new analysis was presented at a news conference today at the annual AGU fall meeting in San Francisco.

NOAA scientists Sweet and Joseph Park established a frequency-based benchmark for what they call "tipping points," when so-called nuisance flooding, defined by NOAA's National Weather Service as between one to two feet above local high tide, occurs more than 30 or more times a year.

Based on that standard, the NOAA team found that these tipping points will be met or exceeded by 2050 at most of the U.S. coastal areas studied, regardless of sea level rise likely to occur this century. In their study, Sweet and Park used a 1½ to 4 foot set of recent projections for global sea level rise by year 2100 similar to the rise projections of the Intergovernmental Panel for Climate Change, but also accounting for local factors such as the settlement of land, known as subsidence.

These regional tipping points will be surpassed in the coming decades in areas with more frequent storms, the report said. These tipping points will be also be exceeded in areas where local sea levels rise more than the global projection of one and half to four feet. This also includes coastal areas like Louisiana where subsidence, which is not a result of by climate change, is causing land to sink below sea level.

NOAA tide gauges show the annual rate of daily floods reaching these levels has drastically increased -- often accelerating -- and are now five to ten times more likely today than they were 50 years ago.

"Coastal communities are beginning to experience sunny-day nuisance or urban flooding, much more so than in decades past," said Sweet. "This is due to sea level rise. Unfortunately, once impacts are noticed, they will become commonplace rather quickly. We find that in 30 to 40 years, even modest projections of global sea level rise -- 1½ feet by the year 2100 -- will increase instances of daily high tide flooding to a point requiring an active, and potentially costly response, and by the end of this century, our projections show that there will be near-daily nuisance flooding in most of the locations that we reviewed."

"Communities across the country become increasingly vulnerable to water inundation and flooding, effective risk management is going to become more heavily reliant on environmental data and analysis," said Holly Bamford, Ph.D., NOAA acting assistant secretary for conservation and management. "Businesses, coastal managers, federal, state, and local governments, and non-governmental organizations can use research such as this as another tool as they develop plans to reduce vulnerabilities, adapt to change, and ensure they're resilient against future events."

"The importance of this research is that it draws attention to the largely neglected part of the frequency of these events. This frequency distribution includes a hazard level referred to as 'nuisance': occasionally costly to clean up, but never catastrophic or perhaps newsworthy," said Earth's Future editor Michael Ellis in accepting the paper for the online journal.

Ellis also observed that "the authors use observational data to drive home the important point that nuisance floods (from inundating seas) will cross a tipping point over the next several decades and significantly earlier than the 2100 date that is generally regarded as a target date for damaging levels of sea-level. The paper also raises the interesting question of what frequency of 'nuisance' corresponds to a perception of 'this is no longer a nuisance but a serious hazard due to its rapidly growing and cumulative impacts'."

The scientists base the projections on NOAA tidal stations where there is a 50-year or greater continuous record. The study does not include the Miami area, as the NOAA tide stations in the area were destroyed by Hurricane Andrew in 1992 and a continuous 50-year data set for the area does not exist.

Based on that criteria, the NOAA team is projecting that Boston; New York City; Philadelphia; Baltimore; Washington, D.C.; Norfolk, Virginia; and Wilmington, North Carolina; all along the Mid-Atlantic coast, will soon make, or are already being forced to make, decisions on how to mitigate these nuisance floods earlier than planned. In the Gulf, NOAA forecasts earlier than anticipated floods for Galveston Bay and Port Isabel, Texas. Along the Pacific coast the earlier impacts will be most visible in the San Diego/La Jolla and San Francisco Bay areas.

Mitigation decisions could range from retreating further inland to coastal fortification or to a combination of "green" infrastructure using both natural resources such as dunes and wetland, along with "gray" human-made infrastructure such as sea walls and redesigned storm water systems.

Source: National Oceanic and Atmospheric Administration