Friday, September 23, 2011

Solar Activity Subsiding - Auroras Ablaze

Solar activity is subsiding after last week's flurry of strong flares from sunspot 1283. The sunspot remains capable of M-class eruptions, but Earth would be unaffected by further blasts as the sunspot rotates over the sun's western limb.

A coronal mass ejection (CME) struck Earth's magnetic field on Sept. 9, sparking more than 18 hours of bright auroras around the Arctic Circle. In the United States, Northern Lights were spotted as far south as Michigan, Washington, Wisconsin, Vermont, Montana, Maine, Minnesota and North and South Dakota. A similar display could be in the offing on Sept. 12-13 when another CME from sunspot 1283 is expected to sail past Earth.

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Monday, September 19, 2011

NASA Global Hawks Prepare for 2012 Hurricane Study

A group of environmental scientists has set up an office in an aircraft hangar at NASA's Dryden Flight Research Center at Edwards, Calif., in preparation for a multi-year airborne science investigation of hurricane formation and intensification.

As they work on their computers, the scientists are also monitoring the installation and testing of specialized weather-monitoring instruments on one of NASA's Global Hawk remotely operated unmanned aircraft. This hands-on approach to research is part of a critical buildup to a hurricane study sponsored by NASA's Earth Venture Program that begins collecting data next summer.

NASA's Hurricane and Severe Storm Sentinel, or HS3, investigation is a multi-year study of the processes that underlie hurricane formation and intensity change in the Atlantic Ocean.

"The high-altitude and long-duration capabilities of NASA's Global Hawks allow HS3 to sample storms virtually anywhere in the Atlantic and for durations up to three times that of conventional aircraft," said principal investigator Scott Braun of NASA’s Goddard Space Flight Center in Greenbelt, Md. "Being able to stay over a storm for 15 or more hours allows us to observe storms in ways that were simply not possible before."

HS3 conducted two checkout flights of one of NASA's Global Hawks, one of 24 hours duration Sept. 8 - 9 over the Pacific Ocean and the second of about 19.5 hours on Sept. 13 – 14 over the Gulf of Mexico. Data were gathered by three scientific instruments that will be used during the mission.

The payload included NOAA's Airborne Vertical Atmospheric Profiling System (the NOAA dropsonde) in the tail of the Global Hawk. Dropsondes are small devices designed to be dropped from an aircraft to collect atmospheric data as they fall to the ground or the ocean surface. This system was designed by the National Center for Atmospheric Research in Boulder, Colo.

In addition, the University of Wisconsin-Madison's Scanning High-Resolution Interferometer Sounder, or S-HIS, was mounted in the Global Hawk’s belly. The sensor measures emitted thermal radiation to obtain temperature and water vapor profiles of the atmosphere.

The third instrument was the High Altitude MMIC Sounding Radiometer, or HAMSR, developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif. HAMSR provides measurements that can be used to infer the 3-D distribution of temperature, water vapor and cloud-liquid water in the atmosphere, even in the presence of clouds. Like S-HIS and the dropsondes, it provides information on the vertical profile of temperature and humidity.

The goal of the Pacific flight was to compare the temperature and humidity profiles from the S-HIS and HAMSR remote sensors with in situ measurements provided by the dropsondes. Given the uncertainty associated with measuring these quantities from a distance using infrared and microwave technologies, data from the two instruments will be compared to the accurate and much higher resolution data from the dropsondes.

During the 19.5-hour flight to the Gulf of Mexico, the Global Hawk rendezvoused with a NOAA Gulfstream IV. Both aircraft were equipped with dropsonde systems and this flight provided comparison data between them.

These checkout flights were flown to prepare for the deployment of two Global Hawks to NASA's Wallops Flight Facility in Wallops Island, Va., during the summer of 2012. NASA first used the Global Hawk for hurricane research in 2010 during the Genesis and Rapid Intensification Processes, or GRIP, experiment, but those flights operated from Dryden because the Global Hawk mobile operations facility had not yet been built. This meant that the aircraft had to traverse the southern United States to reach the Atlantic Ocean.

"For HS3, we will operate from Wallops because it gives us direct access to the Atlantic and increases our time near or over storms by up to 10 hours," added Braun.

The Global Hawk will carry sensors to collect data that address the controversial role of the Saharan Air Layer in tropical storm formation and intensification as well as the role of deep thunderstorms in the core region of tropical storms. The aircraft will deploy for about one month each summer in 2012, 2013 and 2014.

NASA’s Earth Science Project Office, located at Ames Research Center on Moffett Field, Calif., manages the Hurricane and Severe Storm Sentinel (HS3) project. The office is responsible for the project’s safety, technical integrity, performance and mission success.

The HS3 study is one of NASA's Earth Venture missions, part of NASA's Earth System Science Pathfinder program funded by the Earth Science Division of the agency's Science Mission Directorate in Washington. The small, targeted science investigations complement NASA's larger research missions. In 2007, the National Research Council recommended that NASA undertake these types of regularly solicited, quick-turnaround projects.

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Monday, September 12, 2011

NASA Satellite Rainmap Shows Extent of Tropical Storm Lee's Heavy Rainfall

NASA has a rain gauge flying in space called TRMM, and data from that satellite has been used to create a map of the massive rainfall generated by landfalling Tropical Storm Lee.

After forming in the north central Gulf of Mexico, Tropical Storm Lee came ashore over south central Louisiana on the morning of Sunday September 4th, 2011. Over the next two and a half days, the slow-moving storm worked its way across central Louisiana and central Mississippi and into northern Alabama, dumping heavy rains along the way. Tropical Storm Lee joined a frontal system to soak the eastern U.S.

The primary mission of the Tropical Rainfall Measuring Mission or TRMM satellite is to measure rainfall over the global Tropics using a combination of passive microwave and active radar sensors. TRMM is a joint mission between NASA and the Japanese space agency JAXA. For expanded coverage, TRMM can be used to calibrate rainfall estimates from other satellites. Rainfall estimates from the TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA) at the NASA Goddard Space Flight Center in Greenbelt, Md. are shown here for the period August 31 to September 8, 2011 for the eastern half of the U.S.

TMPA shows heavy rains extending inland from the northern Gulf of Mexico across eastern Louisiana, Mississippi, northwestern Alabama, and into central Tennessee. Rainfall totals in this region generally exceed 100 mm (~4 inches) with some parts of Mississippi and Louisiana receiving upwards of 250 mm (~10 inches) Chattanooga, Tennessee broke their all time 24-hour rainfall total with 9.69 inches.

After coming ashore, Tropical Storm Lee began to merge with a slowing-moving frontal system advancing eastward out of the Mississippi valley. This frontal system was associated with a quasi-stationary upper-level low pressure center located over the Ohio valley. As a result, tropical moisture was drawn up the eastern seaboard, bringing heavy rains from the mid-Atlantic up into the northern Appalachians.

TMPA rainfall totals of 125 mm (~5 inches, shown in bright green) to as much as 200 to 250 mm (~8 to 10 inches, shown in orange and red) extend from south central Pennsylvania up into central New York, where the Susquehanna River reached record flood levels in downtown Binghamton. Elsewhere across the mid-Atlantic, where pockets of rain exceed anywhere from 100 to 150 mm (~4 to 6 inches), numerous roads and streets were closed due to widespread localized flooding.

On Sept. 9, 2011 at 5 a.m. EDT, heavy rains associated with Lee's remnants are slowly coming to an end across the Mid-Atlantic. The large-scale extra-tropical low pressure area that absorbed Lee's moisture and energy was centered over Indiana and will continue weakening. Meanwhile, The National Weather Service's Hydrometeorological Prediction Center (HPC) expects "tropical moisture to continue streaming up from the Atlantic Ocean leading to the potential for another round of heavy rains across the region."

For updated rain totals from Tropical Storm Lee, visit the HPC's webpage:

While much of the nation east of the Mississippi received too much rain, there was no relief for Texas and parts of the Central Plains, which remain locked in a drought. TRMM satellite data is also helpful in determining areas of drought.

At NASA Goddard, TMPA rainfall anomalies were created for the one-month period from August 7 to September 7, 2011 that showed a stark contrast between the drought-stricken, well-below normal areas (nearly all of Texas and most of Kansas) and those with well-above normal rain along and east of the Mississippi due to the passage of Lee. The anomalies were constructed by computing the average rainfall rate over the period and then subtracting the 10-year average rate for the same period.

Those drought-stricken areas are hoping that Tropical Storm Nate, currently in the southwestern Gulf of Mexico will bring them some wet relief.

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A NASA-led team of scientists took to the Chesapeake Bay this summer to study a diverse yet close-to-home ecosystem in a field campaign that will help the agency determine how to study ocean health and air quality in coastal regions from space.

Two weeks of research cruises throughout the Chesapeake during a steamy July provided scientists with a detailed wealth of data on what might be called the fundamentals of the ecosystem. How do nutrient levels, pollutants, organic matter, water temperature and dissolved oxygen change throughout the day? What is the makeup of particulate matter in the air, and how does poor air from nearby urban and industrial regions move around above the water and ultimately influence the bay? And how does the air, water and land – or in this case, wetland – affect one another?

Antonio Mannino, an oceanographer at Goddard Space Flight Center, Greenbelt, Md., and Maria Tzortziou, an oceanographer and physicist at the University of Maryland and Goddard Space Flight Center, led the campaign as chief scientists. Both are working toward what would be a first for NASA and a significant milestone for their field: a geostationary satellite designed to make detailed measurements of ocean color and air quality along the coasts. Current and former NASA satellite instruments have measured ocean color – in essence, a measure of the amount of sediment, dissolved organics and phytoplankton in the water – from polar orbits. These have provided significant and long-term global data on the composition, productivity and health of the oceans. But NASA has never had a geostationary satellite – meaning it would occupy the same spot hundreds of miles above Earth, rather than orbiting around the planet – for ocean color. This would provide constant coverage of dynamic ecosystems, providing important information of the sort Mannino,Tzortziou and more than 20 other scientists from nine US academic and research institutes were gathering directly in the field this summer – how do air and ocean qualities change throughout a day, not just over long periods of time? And how can we measure this from space?


The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission was outlined by the National Research Council in its 2007 Earth science decadal survey as one of the most important goals for Earth science research from space. While it is years from being scheduled for launch, scientists such as Mannino and Tzortziou continue to lay the groundwork for a successful mission.

Like with any mission, Mannino said, "We can't build our dream instrument because of the cost. We're trying to understand what can we study given certain specs."

To that end, ten full days on the Chesapeake gave scientists plenty to start with. The Chesapeake was chosen because the campaign could tie in to a series of flights over the Baltimore -Washington region during the month of July as part of NASA's DISCOVER-AQ mission . But the diversity of the bay's different nooks and regions was an added benefit. Leaving from Annapolis, Md., every morning, a group of about 20 researchers made transects in all directions, released a drifter to take measurements wherever the currents led, anchored in one location throughout the day, and took a trip on a Zodiac inflatable power boat to sample shallow water near the marshes of the Blackwater Wildlife Refuge. One key question Tzortziou has been investigating is the influence of marshes and wetlands on nearby water quality and carbon cycling."The idea was to go as close as possible to wetlands, which act as sources of dissolved organic and inorganic carbon, and look at the tidal exchanges of carbon and nutrients at the land-ocean interface where rapid processes occur," Tzortziou said. "How far into the main stem of the Bay can you detect the signal of the marsh? And how can we use satellite observations to capture and understand wetland influences on estuarine biology and biogeochemistry?"

Scientists are studying nutrients, dissolved and particulate carbon, organic nitrogen, phytoplankton, chlorophyll pigment, primary production, and dissolved oxygen concentrations. They are also studying optics in the water, necessary to link biological and chemical measurements to satellite ocean color data, and levels of compounds deposited in the water by air pollution. The bay's notorious water quality struggles, particularly during the height of summer, revealed themselves one day as the ship came upon a fish kill of dozens of striped bass, one of the Chesapeake's signature species. "Unusually high nutrient pollution levels have resulted in a particularly large dead-zone in the Bay this year," said Tzortziou.

"We wanted to see how the biology, biogeochemistry, and optics were changing over time," Mannino said of the suite of measurements. "Typically with satellites, we're comparing pixels over a week or month. With GEO-CAPE, we expect to quantify changes such as phytoplankton growth more directly instead of inferring this from models and limited satellite data".

From the research ship (NOAA SRVx; NOAA Marine Sanctuaries Program) and from three research airplanes that performed flights over the ship and spiraled downward close to the water surface, the scientists measured trace gases and particulates in the air to get a measure of the impact of nearby major cities, traffic arteries and industry. These measurements will help toward GEO-CAPE's goal to measure both coastal air quality and marine ecosystem processes.

Next steps

Like with any field campaign, the part in the field is only the beginning. Mannino and Tzortziou said the campaign team has only just begun to process and analyze its data. In addition to scientists from Goddard and the University of Maryland, researchers from NOAA, University of New Hampshire, University of South Florida, Old Dominion University, East Carolina University, Johns Hopkins University, and the Smithsonian Environmental Research Center participated in the Chesapeake field campaign. High school, undergraduate and graduate students were involved in the campaign, gaining "hands on" experience at the field.

The Chesapeake turned out to be an ideal location, because it was both accessible and diverse. The northern bay, near Baltimore and Annapolis, provided a sediment-heavy region due to freshwater flow from the Susquehanna River. More polluted waters (and air) near Baltimore provided an opportunity to contrast the shallows near the more pristine Blackwater refuge. And waters farther south in the bay gave scientists a look at some of the clearer regions of the estuary. Future field campaigns will likely fill in knowledge gaps and answer questions toward making GEO-CAPE a reality, Mannino said.

"Ultimately, we're looking for the best satellite instruments possible for observing coastal ecosystems – instruments that will be able to make high quality ocean color observations within regions with high levels of sediment, colored dissolved organic matter, and phytoplankton," he said. "High resolution space-based observations from such instruments will help us understand ecosystem processes in highly dynamic coastal regions" added Tzortziou. "Having observations from such a diverse array of environments will help us plan future expeditions."

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Thursday, September 8, 2011

Tributes to Terrorism Victims are on Mars

In September 2001, Honeybee Robotics employees in lower Manhattan were building a pair of tools for grinding weathered rinds off rocks on Mars, so that scientific instruments on NASA's Mars Exploration Rovers Spirit and Opportunity could inspect the rocks' interiors.

That month's attack on the twin towers of the World Trade Center, less than a mile away, shook the lives of the employees and millions of others.

Work on the rock abrasion tools needed to meet a tight schedule to allow thorough testing before launch dates governed by the motions of the planets. The people building the tools could not spend much time helping at shelters or in other ways to cope with the life-changing tragedy of Sept. 11. However, they did find a special way to pay tribute to the thousands of victims who perished in the attack.

An aluminum cuff serving as a cable shield on each of the rock abrasion tools on Mars was made from aluminum recovered from the destroyed World Trade Center towers. The metal bears the image of an American flag and fills a renewed purpose as part of solar system exploration.

Honeybee Robotics collaborated with the New York mayor's office; a metal-working shop in Round Rock, Texas; NASA's Jet Propulsion Laboratory in Pasadena, Calif.; and the rover missions' science leader, Steve Squyres, at Cornell University, Ithaca, N.Y.

"It's gratifying knowing that a piece of the World Trade Center is up there on Mars. That shield on Mars, to me, contrasts the destructive nature of the attackers with the ingenuity and hopeful attitude of Americans," said Stephen Gorevan, Honeybee founder and chairman, and a member of the Mars rover science team.

On the morning of Sept. 11, 2001, Gorevan was six blocks from the World Trade Center, riding his bicycle to work, when he heard an airliner hit the first tower. "Mostly, what comes back to me even today is the sound of the engines before the first plane struck the tower. Just before crashing into the tower, I could hear the engines being revved up as if those behind the controls wanted to ensure the maximum destruction. I stopped and stared for a few minutes and realized I felt totally helpless, and I left the scene and went to my office nearby, where my colleagues told me a second plane had struck. We watched the rest of the sad events of that day from the roof of our facility."

At Honeybee's building on Elizabeth Street, as in the rest of the area, normal activities were put on hold for days, and the smell from the collapse of the towers persisted for weeks.

Steve Kondos, who was at the time a JPL engineer working closely with the Honeybee team, came up with the suggestion for including something on the rovers as an interplanetary memorial. JPL was building the rovers and managing the project.

To carry out the idea, an early hurdle was acquiring an appropriate piece of material from the World Trade Center site. Through Gorevan's contacts, a parcel was delivered to Honeybee Robotics from the mayor's office on Dec. 1, 2001, with a twisted plate of aluminum inside and a note: "Here is debris from Tower 1 and Tower 2."

Tom Myrick, an engineer at Honeybee, saw the possibility of machining the aluminum into the cable shields for the rock abrasion tools. He hand-delivered the material to the machine shop in Texas that was working on other components of the tools. When the shields were back in New York, he affixed an image of the American flag on each.

The Mars Exploration Rover Spirit was launched from Cape Canaveral Air Force Station, Fla., on June 10, 2003. Opportunity's launch followed on July 7. Both rovers landed the following January and completed their three-month prime missions in April 2004. Nobody on the rover team or at Honeybee spoke publicly about the source of the aluminum on the cable shields until later that year.

"It was meant to be a quiet tribute," Gorevan told a New York Times reporter writing a November 2004 story about Manhattan's participation in the rover missions. "Enough time has passed. We want the families to know."

Since landing on the Red Planet, both rovers have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit ended communications in March 2010. Opportunity is still active, and researchers plan to use its rock abrasion tool on selected targets around a large crater that the rover reached last month.

One day, both rovers will be silent. In the cold, dry environments where they have worked on Mars, the onboard memorials to victims of the Sept. 11 attack could remain in good condition for millions of years.

The Jet Propulsion Laboratory in Pasadena, Calif., a division of the California Institute of Technology, manages the Mars Exploration Rovers for NASA.

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Aquarius Makes First Ocean Salt Measurements

NASA's Aquarius instrument has successfully completed its commissioning phase and is now "tasting" the saltiness of Earth's ocean surface, making measurements from its perch in near-polar orbit.

"This marks the end of the long odyssey to design, build and launch this mission, and the start of a new journey of scientific exploration," said Aquarius Principal Investigator Gary Lagerloef of Earth & Space Research, Seattle. "Scientists from around the world are ready and waiting to study this important new satellite measurement for ocean and climate research."

The Aquarius/SAC-D (Satélite de Aplicaciones Científicas) observatory, a collaboration between NASA and Argentina's space agency, Comisión Nacional de Actividades Espaciales (CONAE), launched from California's Vandenberg Air Force Base on June 10 aboard a United Launch Alliance Delta II rocket and was placed in its proper initial orbit. Ground controllers at the SAC-D Mission Operations Center in Teófilo Tabanera Space Center in Cordoba, Argentina, then began a complete in-orbit checkout of all SAC-D spacecraft systems.

With all observatory systems confirmed to be healthy, SAC-D spacecraft commissioning activities were completed on July 24. The spacecraft's propulsion system then underwent a series of tests, and preliminary orbit adjustments were performed in preparation for turning on the observatory's eight science instruments.

Aquarius will make NASA's first space observations of the salinity, or concentration of salt, at the ocean surface, a key variable in satellite studies of Earth. Variations in salinity influence the ocean's deep circulation, outline the path freshwater takes around our planet and help drive Earth's climate.

On Aug. 14, the Aquarius Instrument Flight Operations Team, together with the SAC-D Mission Flight Operations Team, began powering up the Aquarius instrument, and successfully completed deployment of the Aquarius antenna on Aug. 17. The team then began sequentially powering on the instrument's subsystems. On Aug. 20, the Aquarius radiometer, which collects the brightness temperature data from which salinity measurements are derived, was powered on for the first time in space and transmitted its first science data back to Earth, which were analyzed and found to be as expected. On Aug. 21, the team began powering on Aquarius' radar scatterometer, which corrects for the effects of ocean roughness on the radiometer readings. Commissioning of Aquarius was completed and regular data collection began on Aug. 24.

The Aquarius science team will spend the coming months analyzing and calibrating the measurements and releasing preliminary data.

With the Aquarius instrument commissioning now complete, the SAC-D Instruments Flight Operations Teams, together with the SAC-D Mission Flight Operations Team in Argentina, are now engaged in commissioning the other seven SAC-D instruments. Once all the observatory instruments are commissioned, a maneuver will be conducted to place Aquarius/SAC-D in its final orbit, 408 miles (657 kilometers) above Earth.

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Saturday, September 3, 2011

Hubble Movies Provide Unprecedented View of Supersonic Jets From Young Stars

New movies created from years of still images collected by NASA's Hubble Space Telescope provide new details about the stellar birthing process, showing energetic jets of glowing gas ejected from young stars in unprecedented detail.

The jets are a byproduct of gas accretion around newly forming stars and shoot off at supersonic speeds of about 100 miles per second in opposite directions through space.

These phenomena are providing clues about the final stages of a star's birth, offering a peek at how our Sun came into existence 4.5 billion years ago.

Hubble's unique sharpness allows astronomers to see changes in the jets over just a few years' time. Most astronomical processes change over timescales that are much longer than a human lifetime.

A team of scientists led by astronomer Patrick Hartigan of Rice University in Houston, Texas, collected enough high-resolution Hubble images over a 14-year period to stitch together time-lapse movies of the jets ejected from three young stars.

Never-before-seen details in the jets' structure include knots of gas brightening and dimming over time and collisions between fast-moving and slow-moving material, creating glowing arrowhead features. The twin jets are not ejected in a steady stream, like water flowing from a garden hose. Instead, they are launched sporadically in clumps. The beaded-jet structure might be like a "ticker tape," recording how material episodically fell onto the star.

"For the first time we can actually observe how these jets interact with their surroundings by watching these time-lapse movies," said Hartigan. "Those interactions tell us how young stars influence the environments out of which they form. With movies like these, we can now compare observations of the jets with those produced by computer simulations and laboratory experiments to see what aspects of the interactions we understand and what parts we don't understand."

Jets are an active, short-lived phase of star formation, lasting only about 100,000 years. Astronomers don't know precisely what role jets play in the star-formation process or exactly how the star unleashes them. The jets appear to work in concert with magnetic fields. This helps bleed excess angular momentum from infalling material that is swirling rapidly. Once the material slows down it feeds the growing protostar, allowing it to fully condense into a mature star.

Hartigan and his colleagues used the Wide Field Planetary Camera 2 to study the jets, called Herbig-Haro (HH) objects, named in honor of George Herbig and Guillermo Haro, who studied the outflows in the 1950s. Hubble followed HH 1, HH 2, HH 34, HH 46, and HH 47 over three epochs, 1994, 1998, and 2008.

The team used computer software that wove together the observations to generate movies showing continuous motion.

"Taken together, our results paint a picture of jets as remarkably diverse objects that undergo highly structured interactions both within the material in the outflow and between the jet and the surrounding gas," Hartigan explained. "This contrasts with the bulk of the existing simulations, many of which depict jets as smooth systems."

Hartigan's team's results appeared in the July 20, 2011 issue of The Astrophysical Journal.

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