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

Building a Better Weather Forecast? SMAP May Help

SMAP's soil moisture measurements will help with forecasts of precipitation and temperature. Image credit: UCAR

If you were trying to forecast tomorrow's weather, you would probably look up at the sky rather than down at the ground. But if you live in the U.S. Midwest or someplace with a similar climate, one key to a better weather forecast may lie beneath your feet.

Precipitation and temperature are part of every weather forecast. Precipitation comes from clouds, clouds are formed of airborne water vapor, and vapor comes from evaporating soil moisture -- so soil moisture governs precipitation. Evaporating soil moisture also makes air cooler, so it affects temperature. In certain kinds of climate, scientists believe, soil moisture is so influential that better observations of it might improve weather forecasts. These climates are transitional: not too humid and not too dry. For example, the agriculturally productive states of the U.S. Midwest fall into that category.

"Better soil moisture observations lead to better land-atmosphere interaction in weather forecasting models and ultimately to a better prediction of temperature and precipitation," said Michael Ek, leader of the Land Hydrology Team at the Environmental Monitoring Center of the National Oceanic and Atmospheric Administration (NOAA). "Weather models need good initial observations of the land surface, or you're starting from the wrong place."

Better soil moisture observations are just what the Soil Moisture Active Passive (SMAP) mission will provide. Scheduled for launch on Jan. 29, SMAP will collect the most accurate and highest-resolution soil moisture measurements ever made from a satellite SMAP will cover the entire globe in two to three days. Ek is a member of one of five groups in SMAP's Early Adopter program that have been working for several years on the question of how best to incorporate the new data into national weather forecasting models.

Forecasts will not improve, however, the moment SMAP starts collecting data. U.S. Department of Agriculture research scientist Wade Crow, a member of SMAP's science team, explained that, since closely spaced global soil moisture measurements have never existed before, the mathematical models used in weather forecasting are not configured to include them directly. Getting the best use out of the new observations has been a subject of active research for several years and will require some significant changes in how soil moisture data are assimilated into the models.

Data assimilation is necessary because weather forecasting models all drift a bit, like cars. If you're driving on a perfectly straight road, you still need to keep a hand on the steering wheel or you'll run off the edge sooner or later. Data assimilation in a model serves the same purpose as the slight movements of your hands that keep your car on course.

Drift is not a fatal flaw for a weather forecasting model any more than it is for a car. It is simply a sign that the Earth system is too vast and complicated to model perfectly with the resources available today. To steer forecasts toward greater realism, models ingest, or assimilate, real-world data and use them in sophisticated mathematical techniques. Each time updated observations become available, they are assimilated to improve the starting point for the next forecast.

Closely spaced and highly accurate global measurements are an important part of the process. For soil moisture, however, current observations are not on a fine enough scale to meet the needs of weather forecasting models directly. "Modelers compensate for the lack of direct observations of soil moisture by using more indirect measures, such as estimating it from observations of temperature and precipitation," Crow explained. "As a consequence, modeled soil moisture tends to diverge from reality. SMAP will be directly observing the state that they want, so they won't have to back it out from proxy measurements."

JPL scientist Eni Njoku is working with researchers at another forecasting center, the European Centre for Medium-Range Weather Forecasts (ECMWF) in Reading, England. Njoku said, "SMAP will provide benefits of higher soil moisture accuracy and spatial resolution than have previously been available from satellites. This could lead potentially to improved regional and global weather forecasts by ECMWF." Environment Canada, the branch of the Canadian government responsible for weather forecasting in that nation, is also working on assimilating SMAP data into its models.

"The numerical weather prediction centers are adapting to the new availability of soil moisture information and thinking of ways they can exploit it," Crow summarized. "It will be really exciting to see what they find."

SMAP is managed for NASA's Science Mission Directorate in Washington by the agency's Jet Propulsion Laboratory in Pasadena, California, with instrument hardware and science contributions made by NASA's Goddard Space Flight Center in Greenbelt, Maryland. JPL is responsible for project management, system engineering, radar instrumentation, mission operations and the ground data system. Goddard is responsible for the radiometer instrument. Both centers collaborate on science data processing and delivery to the Alaska Satellite Facility, in Fairbanks, and the National Snow and Ice Data Center, at the University of Colorado in Boulder, for public distribution and archiving. NASA's Launch Services Program at the agency's Kennedy Space Center in Florida is responsible for launch management. JPL is managed for NASA by the California Institute of Technology in Pasadena.

Source: Nasa

The NASA and NOAA's Nighttime and Daytime Views of the Blizzard of 2015

On January 27, 2015 at 17:35 UTC (12:35 p.m. EST) NOAA's Geostationary Operational Environmental or GOES- East satellite captured an image of the nor'easter over New England. Credit: NASA/NOAA GOES Project

NASA and NOAA have provided night-time and daytime views of the Blizzard of 2015 from the Suomi NPP and the GOES-East satellites.

A combination of the day-night band and high resolution infrared imagery from the NASA-NOAA's Suomi NPP satellite showed the historic blizzard near peak intensity as it moves over the New York through Boston Metropolitan areas at 06:45Z (1:45 a.m. EST) on January 27, 2015. The nighttime lights of the region were blurred by the high cloud tops associated with the most intense parts of the storm. 

The center of the low pressure center was about 85 miles southeast of Nantucket, Massachusetts at 9:00 a.m. EST and had an estimated pressure of 975 millibars. The center of the storm was moving in a north-northeasterly direction.

At 10 a.m. EST, the National Weather Service noted "the powerful nor'easter that brought moderate to heavy snowfall and blizzard conditions to the Northeast on Monday will continue to affect the region on Tuesday, with heavy snow and blizzard conditions expected from eastern Long Island to Maine as the system slowly moves to the northeast. Snow and strong winds will being tapering off from south to north Tuesday night into Wednesday morning."

Later on January 27, 2015 at 17:35 UTC (12:35 p.m. EST) NOAA's Geostationary Operational Environmental or GOES-East satellite captured an image of the nor'easter over New England. The image was created by the NASA/NOAA GOES Project and showed the clouds associated with the nor'easter blanketing New England.  An occluded front extended north and eastward out of the low pressure area's center out into the Atlantic Ocean.

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

Predicting the predator threatening a squirrel by analyzing its sounds and tail movements

Thaddeus McRae poses in the Gifford Arboretum with his remote-controlled cat, after being interviewed by WSVN. Credit: University of Miami College of Arts and Sciences

Everyone has watched squirrels playfully climbing trees, gracefully leaping from branch to branch, and scurrying across parks. Thaddeus McRae, Ph.D '12, adjunct assistant research professor of biology in the University of Miami College of Arts Sciences, has taken these observations to a scientific level.

McRae studied squirrel colonies on the Coral Gables campus to see how their sounds and tail movements differ in response to different kinds of threats. He is looking to discover why squirrels interact using both vocalizations and gestures.

"These multimodal signals, which simultaneously send information via two or more sensory modalities to communicate, are ubiquitous," McRae said, adding that people and other mammals, birds, insects and spiders -- and even some plants -- communicate in this manner.

The different sounds, expressions and gestures might "reinforce each other, or maybe they contain different information, or maybe they reach different audiences," he said.

To conduct his research -- the basis of his Ph.D. dissertation -- McRae designed a unique tool: a remote-controlled cat, which he used to chase squirrels while recording their reactions to ground-based predators. Gliders painted to resemble hawks showed the squirrels' responses to threats from the air.

McRae has become somewhat of a local celebrity scientist, with recent and upcoming stories about his study appearing on the Miami New Times "Riptide" blog, and WSVN. He sees three reasons for this media attention.

Squirrels "are often most abundant in the same places people are most abundant," McRae said, adding that they're "cute and fuzzy with a bushy tail, which for some people goes a long way toward earning goodwill."

He also conducted his research in a "very public setting, outdoors on UM's campus in the middle of the city." McRae believes that this helps to breakdown the "mysterious aura" of science, "putting scientific curiosity out there where passersby can see it and become curious themselves."

Finally, he admits that "there's something a little bit humorous" about his research process and his unusual tools.

"To me, this squirrel study isn't cool because I used remote control cats, although enjoying whatever tools you use is nice, it's cool because we learned something about squirrels that we didn't know before," McRae said.

Over two years of observation McRae, working closely with Professor of Biology Steven Green, found that he could quite accurately predict what type of predator was threatening a squirrel by analyzing its sounds and tail movements.

He measured the response of three distinct squirrel sounds: the "kuk" (a short bark), the "quaa" (a longer squeal) and the "moan" (a whistling sound).

He also looked for specific patterns for tail motions in combination with these noises. The "twitch" involves a controlled movement in an arc shape, while the "flag" can take the shape of an arc, figure eight, circle or squiggle.

McRae theorizes that the squirrels use the vocal and tail alarm calls for two purposes -- to let predators know that they have been spotted, and to warn other squirrels of danger in the area. To this end, he is now conducting follow-up research to determine how squirrels react to distress signals from their peers.

For both his current study and his dissertation research, McRae has worked extensively with undergraduate research assistants.

"I try to give them a taste of various steps in the process, from thinking about the organisms and asking questions, to collecting data, to the sometimes tedious task of converting those data into analyzable form, to drawing conclusions. I share with them the joy of discovery," he said.

"Even a small, fast research project can show us something we never knew before. It may not shake the earth, but it's another tiny piece of understanding. ... For a young student to be one of the first handful of people on Earth to share even a small discovery is, frankly, freaking awesome."

Source: University of Miami

On a safari through the genome: Genes offer new insights into the distribution of giraffes

Three young, male Angola giraffes. Credit: © Julian Fennessy, GCF

The Giraffe (Giraffa camelopardalis), a symbol of the African savanna and a fixed item on every safari's agenda, is a fascinating animal. However, contrary to many of the continent's other wild animals, these long-necked giants are still rather poorly studied. Based on their markings, distribution and genome, nine subspecies are recognized -- including the two subspecies Angola Giraffe (Giraffa c. angolensis) and South African Giraffe (Giraffa c. giraffa).

South African Giraffes occur farther north than previously assumed

Like most other giraffes, these subspecies are now mainly found in nature reserves. Until recently, scientists assumed a clear demarcation of their ranges: Angola Giraffes occur in Namibia and northern Botswana, while South African Giraffes reside in southern Botswana and South Africa. "However, according to our studies, the distribution areas prove to be much more complex. South African Giraffes also occur in northeastern Namibia and northern Botswana, and Angola Giraffes can be found in northwestern Namibia and southern Botswana, as well," explains the study's author, Friederike Bock from the Biodiversity and Climate Research Center (BiK-F). A look at the new distribution map reveals the presence of a population of Angola Giraffes in the Central Kalahari Game Reserve, the world's second-largest national park, quasi nestled between two populations of the South African Giraffe, with both subspecies living side by side.

Subspecies were the result of early geographic separation

According to the research team, the fact that two genetically distinct subspecies could develop within the same region may be explained by the local geographic conditions that prevailed approximately 500,000 to two million years ago. Back then, the mountain range along the East African Rift Valley was sinking, creating vast wetlands and lakes, such as the paleo lake Makgadikgadi. According to Professor Dr. Axel Janke from the BiK-F, "these large bodies of water may have separated the populations for long periods of time. Moreover, female giraffes likely do not migrate across long distances, thereby contributing to a clear separation of the maternal lines." Today, there no longer exist any barriers that prevent the possible mingling of both subspecies; an investigation of these processes is however subject to further genetic analyses.

Angola and South African Giraffes can be uniquely identified by their maternal gene profile

For the study, the researchers created a profile of the subspecies' mitochondrial DNA, using tissue samples from about 160 giraffes from various populations across the entire African continent. On the basis of this genetic material, inherited from the maternal side, the often similarly marked subspecies can be uniquely identified genetically and the relationships between various populations can be clearly demonstrated. "Our focus was on giraffes in southern Africa, in particular in Botswana and South Africa. There, we sampled populations that had not been genetically analyzed before," says Bock.

New insights enable improved protection measures for the giraffe

According to estimates by the World Conservation Organization IUCN, the world's giraffe population is about 100,000 individuals -- showing a decreasing trend. In Botswana alone, the population has dwindled by more than half in recent years. In order to achieve effective protection measures that will preserve the majority of the giraffe's subspecies, it is indispensable to gain knowledge that allows their reliable identification as well as detailed information regarding their distribution. The surprising results concerning the distribution of the two subspecies in Namibia and Botswana emphasize the importance of additional taxonomic research on all giraffe subspecies.

Source: Senckenberg Research Institute and Natural History Museum

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

Long-running Jason-1 ocean satellite takes final bow

Artist's concept of the joint NASA/CNES Jason-1 ocean altimetry satellite. During its 11-1/2-year life, Jason-1 helped create a 20-plus-year climate record of global ocean surface topography, providing new insights into ocean circulation, tracking our rising seas and enabling more

The curtain has come down on a superstar of the satellite oceanography world that played the "Great Blue Way" of the world's ocean for 11-1/2 years. The successful joint NASA and Centre National d'Etudes Spatiales (CNES) Jason-1 ocean altimetry satellite was decommissioned this week following the loss of its last remaining transmitter.

Launched Dec. 7, 2001, and designed to last three to five years, Jason-1 helped create a revolutionary 20-plus-year climate data record of global ocean surface topography that began in 1992 with the launch of the NASA/CNES Topex/Poseidon satellite. For more than 53,500 orbits of our planet, Jason-1 precisely mapped sea level, wind speed and wave height for more than 95 percent of Earth's ice-free ocean every 10 days. The mission provided new insights into ocean circulation, tracked our rising seas and enabled more accurate weather, ocean and climate forecasts.

"Jason-1 has been a resounding scientific, technical and international success," said John Grunsfeld, associate administrator of NASA's Science Mission Directorate in Washington. 

"The mission met all of its requirements, performed an extended mission and demonstrated how a long-term climate data record should be established from successively launched satellites. Since launch, it has charted nearly 1.6 inches (4 centimeters) of rise in global sea levels, a critical measure of climate change and a direct result of global warming. The Jason satellite series provides the most accurate measure of this impact, which is felt all over the globe."

During parts of its mission, Jason-1 flew in carefully coordinated orbits with both its predecessor Topex/Poseidon and its successor, the Ocean Surface Topography Mission/Jason-2, launched in 2008. These coordinated orbit periods, which lasted about three years each, cross-calibrated the satellites, making possible a 20-plus-year unbroken climate record of sea level change. These coordination periods also doubled data coverage.

Combined with data from the European Space Agency's Envisat mission, which also measured sea level from space, these data allow scientists to study smaller-scale ocean circulation phenomena, such as coastal tides, ocean eddies, currents and fronts. These small-scale features are thought to be responsible for transporting and mixing heat and other properties, such as nutrients and dissolved carbon dioxide, within the ocean.

"Jason-1 was an exemplary and multi-faceted altimeter mission and contributed so much to so many scientific disciplines," said Jean-Yves Le Gall, CNES president in Paris. "Not only did Jason-1 extend the precise climate record established by Topex/Poseidon, it made invaluable observations for mesoscale ocean studies on its second, interleaved orbit. Even from its 'graveyard' orbit, Jason-1 continued to make unprecedented new observations of the Earth's gravity field, with precise measurements right till the end."

The in-orbit Jason-2 mission, operated by the meteorological agencies of the United States and Europe (the National Oceanic and Atmospheric Administration and EUMETSAT, respectively) in collaboration with NASA and CNES, is in good health and continues to collect science and operational data. This same U.S./European team is preparing to launch the next satellite in the series, Jason-3, in March 2015.

Contact was lost with the Jason-1 satellite on June 21 when it was out of visibility of ground stations. At the time of the last contact, Jason-1 and its instruments were healthy, with no indications of any alarms or anomalies. Subsequent attempts to re-establish spacecraft communications from U.S. and French ground stations were unsuccessful. Extensive engineering operations undertaken to recover downlink communications also were unsuccessful.

After consultation with the spacecraft and transmitter manufacturers, it was determined a non-recoverable failure with the last remaining transmitter on Jason-1 was the cause of the loss of contact. The spacecraft's other transmitter experienced a permanent failure in September 2005. There now is no remaining capability to retrieve data from the Jason-1 spacecraft.

On July 1, mission controllers commanded Jason-1 into a safe hold state that reinitialized the satellite. After making several more unsuccessful attempts to locate a signal, mission managers at CNES and NASA decided to proceed with decommissioning Jason-1. The satellite was then commanded to turn off its magnetometer and reaction wheels. Without these attitude control systems, Jason-1 and its solar panels will slowly drift away from pointing at the sun and its batteries will discharge, leaving it totally inert within the next 90 days. The spacecraft will not reenter Earth's atmosphere for at least 1,000 years.

"Like its predecessor Topex/Poseidon, Jason-1 provided one of the most comprehensive pictures of changes in the tropical Pacific Ocean, including the comings and goings of El Nino and La Nina events," said Lee-Lueng Fu, Jason-1 project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "These Pacific Ocean climate cycles are responsible for major shifts in sea level, ocean temperatures and rainfall every two to five years and can sometimes be so large that worldwide weather patterns are affected. Jason-1 data have been instrumental in monitoring and predicting these ever-changing cycles."

In the spring of 2012, based on concern over the limited redundancy of Jason-1's aging control systems, NASA and CNES moved the satellite into its planned final "graveyard" orbit, depleted its extra fuel and reconfigured the mission to make observations that will improve our knowledge of Earth's gravity field over the ocean, in addition to delivering its oceanographic data products.

The first full 406-day marine gravity mission was completed on June 17. The resulting data have already led to the discovery of numerous small seamounts, which are underwater mountains that rise above the deep-sea floor. The data also have significantly increased the resolution of Earth's gravity field over the ocean, while increasing our knowledge of ocean bathymetry, which is the underwater depth of the ocean floor.

JPL manages the U.S. portion of the Jason-1 mission for NASA's Science Mission Directorate. CNES manages the French portion of the mission.

Source: NASA/Jet Propulsion Laboratory

Tornado strength, frequency, linked to climate change

Tornado (stock image). New research by a Florida State University geography professor shows that climate change may be playing a key role in the strength and frequency of tornadoes hitting the United States. Credit: © fotola70 / Fotolia

New research by a Florida State University geography professor shows that climate change may be playing a key role in the strength and frequency of tornadoes hitting the United States.

Published Wednesday in the journal Climate Dynamics, Professor James Elsner writes that though tornadoes are forming fewer days per year, they are forming at a greater density and strength than ever before. So, for example, instead of one or two forming on a given day in an area, there might be three or four occurring.

"We may be less threatened by tornadoes on a day-to-day basis, but when they do come, they come like there's no tomorrow," Elsner said.

Elsner, an expert in climate and weather trends, said in the past, many researchers dismissed the impact of climate change on tornadoes because there was no distinct pattern in the number of tornado days per year. In 1971, there were 187 tornado days, but in 2013 there were only 79 days with tornadoes.

But a deeper dive into the data showed more severity in the types of storms and that more were happening on a given day than in previous years.

"I think it's important for forecasters and the public to know this," Elsner said. "It's a matter of making sure the public is aware that if there is a higher risk of a storm, there may actually be multiple storms in a day."

The United States experiences more tornadoes than any other country, and despite advances in technology and warning systems, they still remain a hazard to residents in storm-prone areas. The 2011 tornado season, for example, had nearly 1,700 storms and killed more than 550 people.

So far, in 2014, there have been 189 storms with a death toll of 43, according to the NOAA/National Weather Service Storm Prediction Center.

One bright spot of news in the research, Elsner added, was that the geographic areas impacted most regularly by tornadoes do not appear to be growing.

Elsner was joined on the paper by independent researcher Thomas H. Jagger, formerly a research associate at Florida State University, and meteorologist Svetoslava Elsner.

Source: Florida State University

Engineers to simulate, model tornado winds, their effects on buildings

Partha Sarkar designed and built the Iowa State University Tornado Simulator a decade ago. A recent grant will support new simulator studies of tornado winds and their impacts on homes and buildings. Credit: Bob Elbert

The Iowa State University Tornado Simulator kicked up a thick and slowly spinning funnel cloud over a model of a small town, overwhelming the miniature streets, buildings and homes.

Partha Sarkar turned from the laboratory vortex and announced, "That's an EF3."

Most tornadoes (about 90 percent of them) are EF3 or less in intensity. And so Sarkar advocates that homes and buildings within tornado alley across the middle of the U.S. be designed to withstand EF3 tornadoes and their top wind speeds of 165 mph.

Sarkar, an Iowa State professor of aerospace engineering, knows something about the biggest tornadoes. He walked the debris fields of Parkersburg in 2008 and Joplin, Missouri, in 2010, and has seen what the 200-plus mph winds of EF5 storms can do to cities, buildings and people.

To study the interaction of tornadoes with human-made structures, he designed and built a tornado simulator that can create and move a tornado-like vortex back and forth over a test bed. He, his coworkers and Iowa State students have worked with the simulator for a decade, studying the loads and pressures caused by laboratory storms passing over models of homes and buildings.

But, Sarkar said, there's still a lot engineers don't understand about tornado winds:

How, for example, do nearby structures and terrain affect those winds? How do building codes, building ages, structure shapes, roof types and even construction quality influence tornado damage? How do internal pressures inside buildings influence tornado damage? And, how are the wind loads distributed and shared by a building's components, such as roof sheathing, roof trusses, walls, studs and nails?

To find these answers, the National Science Foundation has awarded a pair of three-year, $250,000 collaborative research grants to Sarkar and to Texas Tech University researchers Daan Liang, an associate professor of construction engineering and engineering technology, and Xinzhong Chen, an associate professor of civil and environmental engineering.

As part of this new project, "We will try to quantify the uncertainties in estimating tornado winds and the corresponding structural damage," Sarkar said.

To do that, Sarkar said his research group will use the latest advances in tornado simulation, data acquisition and computer modeling to answer engineering questions about tornado winds and their effects on buildings.

One result of this research could be refinements to the Enhanced Fujita (EF) Scale that considers storm damage to measure the strength of tornadoes. Another result could be new provisions in building codes and construction practices for tornado-resistant buildings.

"The overarching goal of this research is to enhance society's resiliency to tornadoes through innovative design and construction of building components and systems in tornado-prone regions," the Iowa State and Texas Tech researchers wrote in a project summary.

At Iowa State, Sarkar said the grant will support experiments and data collection with the tornado simulator. One experiment, for example, will study actual buildings damaged in tornadoes by creating computer and physical models of the buildings and their structural failures. The computer models will be refined and verified by running lab tornadoes over the physical models. The computational models -- called finite element models -- will help researchers understand and predict the damage caused by tornado winds.

Data from the experiments and models will also be shared with the Texas Tech construction engineers who will study building performance in tornado winds.

"In the long run," the researchers wrote in their summary, "the research is expected to contribute to methods and strategies that can be implemented for preventing tornado hazards from becoming disasters."

Source: Iowa State University

Intensity of hurricanes: New study helps improve predictions of storm intensity

Rough sea with big waves (stock image). "The air-water interface -- whether it had significant waves or significant spray -- is a big factor in storm intensity," said Alex Soloviev, Ph.D., a professor at Nova Southeastern University's Oceanographic Center. "Hurricanes gain heat energy through the interface and they lose mechanical energy at the interface." Credit: © mimadeo / Fotolia

They are something we take very seriously in Florida -- hurricanes. The names roll off the tongue like a list of villains -- Andrew, Charlie, Frances and Wilma.

In the past 25 years or so, experts have gradually been improving prediction of the course a storm may take. This is thanks to tremendous advancements in computer and satellite technology. While we still have the "cone of uncertainty" we've become familiar with watching television weather reports, today's models are more accurate than they used to be.

The one area, however, where there is still much more to be researched and learned is in predicting just how intense a storm may be. While hurricane hunter aircraft can help determine wind speed, velocity, water temperature and other data, the fact is we often don't know why or how a storm gets stronger or weaker. There has been virtually no progress in hurricane intensity forecasting during the last quarter century.

But, thanks to new research being conducted, all that's about to change.

"The air-water interface -- whether it had significant waves or significant spray -- is a big factor in storm intensity," said Alex Soloviev, Ph.D., a professor at Nova Southeastern University's Oceanographic Center. "Hurricanes gain heat energy through the interface and they lose mechanical energy at the interface."

Soloviev is also an Adjunct Professor at the University of Miami Rosenstiel School of Marine and Atmospheric Science (UM RSMAS) and a Fellow at the Cooperative Institute for Marine and Atmospheric Studies (CIMAS.) He and his fellow researchers used a computational fluid dynamics model to simulate microstructure of the air-sea interface under hurricane force winds. In order to verify these computer-generated results, the group conducted experiments at the UM's Rosenstiel School Air-Sea Interaction Salt Water Tank (ASIST) where they simulated wind speed and ocean surface conditions found during hurricanes.

The study "The Air-Sea Interface and Surface Stress Under Tropical Cyclones" was published in the June 16, 2014 issue of the journal Nature Scientific Reports. Soloviev was the lead author of this study, which was conducted by a multi-institutional team including Roger Lukas (University of Hawaii), Mark Donelan and Brian Haus (UM RSMAS), and Isaac Ginis (University of Rhode Island.)

The researchers were surprised at what they found. Under hurricane force wind, the air-water interface was producing projectiles fragmenting into sub millimeter scale water droplets. This process is known from some engineering applications, including rocket science, as the Kelvin-Helmholtz (KH) instability. This new study then looked at how changes in microphysics of the air-sea interface can make a storm grow or weaken in intensity. With wind speed exceeding a Category 1 threshold, the ocean surface unexpectedly became more "slippery."

When the wind exceeded Category 3 hurricane force, the "slippery" effect started gradually disappearing and was completely gone at Category 5. The conclusion was that some hurricanes might rapidly intensify to Category 3 and then stay in a "comfortable" zone around Category 3 status. This finding is consistent with the global best-track tropical cyclone statistics on maximum intensity for 1982-2009. So far, these early results showed that physical conditions where the air and the ocean interact must be a vital part of any successful hurricane forecasting model and would help explain, and predict, how a storm might intensify as it moves through across the water based on the physical stress at the ocean's surface.

This work has been supported by the NOPP project "Advanced coupled atmosphere-wave-ocean modeling for improving tropical cyclone prediction models" (PIs: Isaac Ginis, URI and Shuyi Chen, UM) and by the Gulf of Mexico Research Initiative (GoMRI) Consortium for Advanced Research on the Transport of Hydrocarbons in the Environment -- CARTHE (PI: Tamay Özgökmen, UM). GoMRI is a 10-year, $500 million independent research program established by an agreement between BP and the Gulf of Mexico Alliance.

The plan is for the team to continue their research and experiments at UM's Alfred C. 

Glassell, Jr. SUSTAIN facility, which has recently been designed by one of the Nature article co-authors, Brian Haus (UM). It's the unique lab facility where they can recreate the conditions found in a Category 5 storm.

"We've got more work to do, but this is a great first step," Soloviev said. "But remember, no matter how good we get in predicting a storm's intensity, people in the path need to prepare accordingly regardless of what Category it is -- that's most important."

Source: Nova Southeastern University

Re-thinking Southern California earthquake scenarios in Coachella Valley, San Andreas Fault

New 3D numerical modeling that captures more geometric complexity of an active fault segment in southern California than any other suggests that the overall earthquake hazard for towns on the west side of the Coachella Valley such as Palm Springs may be slightly lower than previously believed. Credit: Courtesy Google Earth and UMass Amherst

New three-dimensional (3D) numerical modeling that captures far more geometric complexity of an active fault segment in southern California than any other, suggests that the overall earthquake hazard for towns on the west side of the Coachella Valley such as Palm Springs and Palm Desert may be slightly lower than previously believed.

New simulations of deformation on three alternative fault configurations for the Coachella Valley segment of the San Andreas Fault conducted by geoscientists Michele Cooke and Laura Fattaruso of the University of Massachusetts Amherst, with Rebecca Dorsey of the University of Oregon, appear in the December issue of Geosphere.

The Coachella Valley segment is the southernmost section of the San Andreas Fault in California. It has a high likelihood for a large rupture in the near future, since it has a recurrence interval of about 180 years but has not ruptured in over 300 years, the authors point out.

The researchers acknowledge that their new modeling offers "a pretty controversial interpretation" of the data. Many geoscientists do not accept a dipping active fault geometry to the San Andreas Fault in the Coachella Valley, they say. Some argue that the data do not confirm the dipping structure. "Our contribution to this debate is that we add an uplift pattern to the data that support a dipping active fault and it rejects the other models," say Cooke and colleagues.

Their new model yields an estimated 10 percent increase in shaking overall for the Coachella segment. But for the towns to the west of the fault where most people live, it yields decreased shaking due to the dipping geometry. It yields a doubling of shaking in mostly unpopulated areas east of the fault. "This isn't a direct outcome of our work but an implication," they add.

Cooke says, "Others have used a dipping San Andreas in their models but they didn't include the degree of complexity that we did. By including the secondary faults within the Mecca Hills we more accurately capture the uplift pattern of the region."

Fattaruso adds, "Others were comparing to different data sets, such as geodesy, and since we were comparing to uplift it is important that we have this complexity." In this case, geodesy is the science of measuring and representing the Earth and its crustal motion, taking into account the competition of geological processes in 3D over time.

Most other models of deformation, stress, rupture and ground shaking have assumed that the southern San Andreas Fault is vertical, say Cooke and colleagues. However, seismic, imaging, aerial magnetometric surveys and GPS-based strain observations suggest that the fault dips 60 to 70 degrees toward the northeast, a hypothesis they set out to investigate.

Specifically, they explored three alternative geometric models of the fault's Coachella Valley segment with added complexity such as including smaller faults in the nearby Indio and Mecca Hills. "We use localized uplift patterns in the Mecca Hills to assess the most plausible geometry for the San Andreas Fault in the Coachella Valley and better understand the interplay of fault geometry and deformation," they write.

Cooke and colleagues say the fault structures in their favored model agree with distributions of local seismicity, and are consistent with geodetic observations of recent strain. "Crustal deformation models that neglect the northeast dip of the San Andreas Fault in the Coachella Valley will not replicate the ground shaking in the region and therefore inaccurately estimate seismic hazard," they note.

This work was supported by the National Science Foundation.

Source:  University of Massachusetts at Amherst

Yellowstone's thermal springs: Their colors unveiled

This is a photograph of Morning Glory Pool from Aug. 23, 2012.
Credit: Joseph Shaw, Montana State University

Researchers at Montana State University and Brandenburg University of Applied Sciences in Germany have created a simple mathematical model based on optical measurements that explains the stunning colors of Yellowstone National Park's hot springs and can visually recreate how they appeared years ago, before decades of tourists contaminated the pools with make-a-wish coins and other detritus.

The model, and stunning pictures of the springs, appear today in the journal Applied Optics, which is published by The Optical Society (OSA).

If Yellowstone National Park is a geothermal wonderland, Grand Prismatic Spring and its neighbors are the ebullient envoys, steaming in front of the camera and gracing the Internet with their ethereal beauty. While the basic physical phenomena that render these colorful delights have long been scientifically understood -- they arise because of a complicated interplay of underwater vents and lawns of bacteria -- no mathematical model existed that showed empirically how the physical and chemical variables of a pool relate to their optical factors and coalesce in the unique, stunning fashion that they do.

"What we were able to show is that you really don't have to get terribly complex -- you can explain some very beautiful things with relatively simple models," said Joseph Shaw, a professor at Montana State University and director of the university's Optical Technology Center. Shaw, along with his Ph.D. student Paul Nugent and German colleague Michael Vollmer, co-authored the new paper.

Using a relatively simple one-dimensional model for light propagation, the group was able to reproduce the brilliant colors and optical characteristics of Yellowstone National Park's hot springs by accounting for each pool's spectral reflection due to microbial mats, their optical absorption and scattering of water and the incident solar and diffuse skylight conditions present when measurements were taken.

"When we started the study, it was clear we were just doing it for fun," Vollmer said. But they quickly discovered there was very little in the scientific literature on the subject. That's when things got interesting.

Montana State University, in Bozeman, Mont., is a short drive away from Yellowstone National Park. In the summer of 2012, Vollmer, on sabbatical from the Brandenburg University of Applied Sciences, travelled with Shaw and Nugent to the park. Using handheld spectrometers, digital SLR cameras for visible images and long wave infrared thermal imaging cameras for non-contact measurement of the water temperatures, the group took measurements at a number of pools in Yellowstone, including Morning Glory Pool, Sapphire Pool and Grand Prismatic Spring. Using these data, along with previously available information about the physical dimensions of the pools, they were able to create a simple model whose renderings of the pools were strikingly similar to actual photographs.

In the case of Morning Glory Pool, they were even able to simulate what the pool once looked like between the 1880s and 1940s, when its temperatures were significantly higher. 

During this time, its waters appeared a uniform deep blue. An accumulation of coins, trash and rocks over the intervening decades has partially obscured the underwater vent, lowering the pool's overall temperature and shifting its appearance to a terrace of orange-yellow-green. This change from blue was demonstrated to result from the change in composition of the microbial mats, as a result of the lower water temperature.

A general relationship between shallow water temperature (hence microbial mat composition) and observed colors was confirmed in this study. However, color patterns observed in deeper segments of the pool are caused more by absorption and scattering of light in the water. These characteristics -- mats having greater effect on color in shallow water, and absorption and scattering winning out in the deeper areas -- are consistent across all the measured pools.

"Our paper describes a very simple, one-dimensional model, that gives the first clue if you really want to do more," Vollmer said.

"We didn't start this project as experts on thermal pools," Shaw said. "We started this project as experts on optical phenomena and imaging, and so we had a lot to learn."

"There are people at my university who are world experts in the biological side of what's going on in the pools," Shaw said. "They're looking for ways to monitor changes in the biology -- when the biology changes, that causes color changes -- so we're actually looking at possibilities of collaborating in the future."

Future work for Nugent, Vollmer and Shaw includes delving further into infrared imaging at Yellowstone National Park.

Source:  American Institute of Physics (AIP)

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

Even in restored forests, extreme weather strongly influences wildfire's impacts

Fire Sweeps Up, South Flank, Rim Fire. Credit: Mike McMillan - USFS

The 2013 Rim Fire, the largest wildland fire ever recorded in the Sierra Nevada region, is still fresh in the minds of Californians, as is the urgent need to bring forests back to a more resilient condition. Land managers are using fire as a tool to mimic past fire conditions, restore fire-dependent forests, and reduce fuels in an effort to lessen the potential for large, high-intensity fires, like the Rim Fire. A study led by the U.S. Forest Service's Pacific Southwest Research Station (PSW) and recently published in the journal Forest Ecology and Management examined how the Rim Fire burned through forests with restored fire regimes in Yosemite National Park to determine whether they were as resistant to high-severity fire as many scientists and land managers expected.

Since the late 1960s, land managers in Yosemite National Park have used prescribed fire and let lower intensity wildland fires burn in an attempt to bring back historical fire regimes after decades of fire suppression. For this study, researchers seized a unique opportunity to study data on forest structure and fuels collected in 2009 and 2010 in Yosemite's old-growth, mixed-conifer forests that had previously burned at low to moderate severity. Using post-Rim Fire data and imagery, researchers found that areas burned on days the Rim Fire was dominated by a large pyro-convective plume -- a powerful column of smoke, gases, ash, and other debris -- burned at moderate to high severity regardless of the number of prior fires, topography, or forest conditions.

"The specific conditions leading to large plume formation are unknown, but what is clear from many observations is that these plumes are associated with extreme burning conditions," says Jamie Lydersen, PSW biological science technician and the study's lead author. "Plumes often form when atmospheric conditions are unstable, and result in erratic fire behavior driven by its own local effect on surface wind and temperatures that override the influence of more generalized climate factors measured at nearby weather stations."

When the extreme conditions caused by these plumes subsided during the Rim Fire, other factors influenced burn severity. "There was a strong influence of elapsed time since the last burn, where forests that experienced fire within the last 14 years burned mainly at low severity in the Rim Fire. Lower elevation areas and those with greater shrub cover tended to burn at higher severity," says Lydersen.

When driven by extreme weather, which often coincides with wildfires that escape initial containment efforts, fires can severely burn large swaths of forest regardless of ownership and fire history. These fires may only be controlled if more forests across the landscape have been managed for fuel reduction to allow early stage suppression before weather- and fuels-driven fire intensity makes containment impossible. Coordination of fire management activities by land management agencies across jurisdictions could favor burning under more moderate weather conditions when wildfires start and reduce the occurrences of harmful, high-intensity fires.

Source: USDA Forest Service - Pacific Southwest Research Station

Early warning signals of abrupt climate change

Drought (stock image). Credit: © carloscastilla / Fotolia

A new study by researchers at the University of Exeter has found early warning signals of a reorganisation of the Atlantic ocean's circulation which could have a profound impact on the global climate system.

The research, published today in the journal Nature Communications, used a simulation from a highly complex model to analyse the Atlantic Meridional Overturning Circulation (AMOC), an important component of the Earth's climate system.

It showed that early warning signals are present up to 250 years before it collapses, suggesting that scientists could monitor the real world overturning circulation for the same signals.

The AMOC is like a conveyor belt in the ocean, driven by the salinity and temperature of the water. The system transports heat energy from the tropics and Southern Hemisphere to the North Atlantic, where it is transferred to the atmosphere.

Experiments suggest that if the AMOC is 'switched off' by extra freshwater entering the North Atlantic, surface air temperature in the North Atlantic region would cool by around 1-3°C, with enhanced cooling of up to 8°C in the worst affected regions.

The collapse would also encourage drought in the Sahel -- the area just south of the Sahara desert -- and dynamic changes in sea level of up to 80cm along the coasts of Europe and North America.

"We found that natural fluctuations in the circulation were getting longer-lived as the collapse was approached, a phenomenon known as critical slowing down," said lead author Chris Boulton.

"We don't know how close we are to a collapse of the circulation, but a real world early warning could help us prevent it, or at least prepare for the consequences" adds co-author Professor Tim Lenton.

The study is the most realistic simulation of the climate system in which this type of early warning signal has been tested.

"The best early warning signals in the model world are in places where major efforts are going into monitoring the circulation in the real world -- so these efforts could have unexpected added value' adds Professor Lenton.

Source: University of Exeter