News Article | October 25, 2016
Two former researchers at the troubled Arecibo Observatory in Puerto Rico have filed a lawsuit claiming that illegal discrimination and retaliation led to their dismissal. James Richardson and Elizabeth Sternke are suing the Universities Space Research Association (USRA), which oversees radio astronomy and planetary science at Arecibo, and the observatory’s deputy director, Joan Schmelz — a prominent advocate for women in astronomy. Richardson and Sternke, a married couple in their mid-50s, allege that Schmelz discriminated against them because of their age and because Richardson is legally blind. Soon after Sternke revealed in November 2015 that she planned to file a complaint with the US Equal Opportunity Commission (EEOC), which investigates workplace bias, USRA announced that her contract job with Arecibo’s education programme would end early. Richardson filed his own EEOC complaint, and in April 2016, USRA terminated his employment as a staff scientist. The EEOC ultimately found evidence of discrimination and that Sternke and Richardson were terminated in retaliation for their complaints, according to documents provided by the researchers' lawyer. In their lawsuit, filed on 4 October in the US District Court in Puerto Rico, Richardson and Sternke are seeking more than US$20 million in back pay and damages. Schmelz says that she cannot comment on the lawsuit, and declined to answer Nature's questions. But USRA, her co-defendant and employer, “firmly denies these allegations and plans to vigorously defend this matter”, it said in a statement to Nature. The legal challenge comes as the 53-year-old observatory battles to survive. Its single-dish radio telescope, one of the world’s biggest, is still in high demand. But the US National Science Foundation (NSF), which provides roughly two-thirds of the observatory’s $12 million funding, is facing a budget crunch. The agency is now conducting an environmental review of major changes to the site, a possible prelude to mothballing or even demolishing the facility. The NSF’s decision on Arecibo’s fate is expected in 2017. Some Arecibo supporters worry that the lawsuit could nudge the observatory closer to the edge. “With all those budget difficulties they’re having now, getting bad press is not going to be good for them,” says Alan Harris of the planetary-science consulting firm MoreData! in La Cañada, California. USRA hired Richardson in 2014 as a scientist with Arecibo’s planetary radar group, which observes potentially dangerous asteroids and other Solar-System bodies. He did not follow the typical academic path: according to Richardson’s website, he worked as a nuclear engineer — including a stint on a US Navy submarine — before being blinded in a chemical accident and re-training as a planetary scientist. In 2014, Sternke, a sociologist who was Richardson’s fiancée at the time, joined him at Arecibo and later began working at the observatory on a short-term contract in 2015. According to EEOC determinations issued in June, Sternke and Richardson’s work initially drew no complaints from management. After Richardson’s boss, the head of planetary radar, announced his resignation in early 2015, Richardson sought the job. Several months later, Schmelz took up her post at Arecibo. From the start, the lawsuit says, Schmelz “ignored and/or chose to avoid all contact” with Richardson, assigned duties to younger colleagues rather than to him, and “marginalized and ostracized” Richardson and Sternke. The EEOC report also says that USRA altered the description of the job Richardson wanted “to make it more suitable for another internal candidate to qualify”. USRA subsequently promoted an Arecibo staffer in his 30s. Sternke submitted her resignation in November, the EEOC says. She later told USRA that she planned to file a complaint with the EEOC, the agency’s report says, and was terminated on 4 December, eight days before her scheduled last day. The lawsuit alleges that in December of 2015, officials from the USRA human-resources department accused Richardson of “angry behavior, bullying, and prejudices”. He was terminated in April 2016 after USRA determined that he failed to meet the terms of its 'Performance Improvement Plan'. (Richardson disagrees with that assessment.) In its report on Richardson’s case, the EEOC said Schmelz “made direct discriminatory age based comments”, writing in her own performance evaluation that she had recruited “a set of effective young leaders”. The EEOC also found that Richardson was “disciplined and terminated from his employment” on the basis of his age and disability, and in retaliation for his association with Sternke and for filing an EEOC charge. In a separate report, the agency found that USRA terminated Sternke’s employment “due to her age (over 50) and in retaliation for complaining about illegal discrimination”. The EEOC suggested that USRA pay Richardson $400,000 in damages, plus back pay, and give Sternke $200,000. But settlement talks with the EEOC failed, and in late July the agency notified Richardson and Sternke that they had 90 days to file suit. Richardson’s former colleagues say that he is not a bully. “I never heard him raise his voice, let alone get angry,” says Phillip Nicholson, an astronomer at Cornell University in Ithaca, New York, where Richardson did research. His postdoctoral supervisor at Cornell, astronomer Joseph Veverka, describes Richardson as courteous and kind, if demanding. “If anyone asked Jim to do something which he did not consider completely scientifically proper, he would strongly object.” Meanwhile, former Arecibo director Robert Kerr says that his USRA colleagues — including Schmelz — displayed “the utmost professionalism”. “Joan was no different from the rest,” he adds. Meg Urry, an astrophysicist at Yale University in New Haven, Connecticut, notes that Schmelz is a tireless advocate for the right of female astronomers to work without harassment. “She's devoted a lot of time to justice,” says Urry, the past president of the American Astronomical Society. In one notable case, Schmelz helped to bring harassment complaints against astronomer Geoff Marcy; after the University of California, Berkeley, found that Marcy violated its policies on harassment, he retired in late 2015. The district court in Puerto Rico has not yet scheduled a hearing on Richardson and Sternke’s lawsuit. In the meantime, Nicholson is struggling to make sense of the situation, given what he knows of the parties on both sides. “Nothing seems to ring true to the character of the people,” he says.
News Article | February 16, 2017
Gif composed of thirteen delay-Doppler images of Comet 45P/HMP after 2 hours of observation. Credit: Universities Space Research Association Though not visible to the naked eye or even with binoculars, the green-tailed Comet 45P/Honda-Mrkos-Pajdusakova (HMP) did not escape the gaze of the world-renowned Arecibo Observatory. Scientists from the University of Arizona's Lunar and Planetary Laboratory (LPL) and the Universities Space Research Association (USRA) at Arecibo Observatory have been studying the comet with radar to better understand its solid nucleus and the dusty coma that surrounds it. "Comets are remnants of the planet forming process and are part of a group of objects made of water ice and rocky material that formed beyond Neptune," noted Dr. Ellen Howell, Scientist at LPL and the leader of the observing campaign at Arecibo. "Studying these objects gives us an idea of how the outer reaches of our Solar System formed and evolved over time." Studying the comet with radar not only very precisely determines its orbit, allowing scientists to better predict its location in the future, but also gives a glimpse of the typically unseen part, the comet's nucleus, which is usually hidden behind the cloud of gas and dust that makes up the its coma and tail. "The Arecibo Observatory planetary radar system can pierce through the comet's coma and allows us to study the surface properties, size, shape, rotation, and geology of the comet nucleus," said Dr. Patrick Taylor, USRA Scientist and Group Lead for Planetary Radar at Arecibo. "We gain roughly the same amount of knowledge from a radar observation as a spacecraft flyby of the same object, but at considerably less cost." In fact, the new radar observations have revealed Comet 45P/HMP to be somewhat larger than previously estimated. The radar images suggest a size of about 1.3 km (0.8 mi) and that it rotates about once every 7.6 hours. "We see complex structures and bright regions on the comet and have been able to investigate the coma with radar," indicated Cassandra Lejoly, graduate student at the University of Arizona. This comet is only the seventh imaged using radar because comets rarely come close enough to the Earth to get such detailed radar images. In fact, though 45P/HMP has an orbital period of about 5.3 years, it rarely passes close to Earth, as it is doing now. Comet 45P is one of a group of comets called Jupiter family comets (JFCs), whose orbits are controlled by Jupiter's gravity and typically orbit the sun about every 6 years. Comet 45P/HMP, which is passing by Earth at a speed of about 23 km/s (relative to Earth) and a close approach of about 32 Earth-Moon distances, will be observed widely at different wavelengths to characterize the gas and dust emanating from the nucleus that forms the coma. As comets orbit the sun, the ices sublime from solids to gases and escape the nucleus. The nucleus gradually shrinks and will disappear completely within in less than a million years. Radar observations at Arecibo of Comet 45P/HMP began on February 9, 2017 and will continue through February 17, 2017. Explore further: Comet's trip past Earth offers first in a trio of opportunities
News Article | February 16, 2017
Researchers have completed the first flights of a NASA-led field campaign that is targeting one of the biggest gaps in scientists' understanding of Earth's water resources: snow. NASA uses the vantage point of space to study all aspects of Earth as an interconnected system. But there remain significant obstacles to measuring accurately how much water is stored across the planet's snow-covered regions. The amount of water in snow plays a major role in water availability for drinking water, agriculture and hydropower. Enter SnowEx, a NASA-led multi-year research campaign to improve remote-sensing measurements of how much snow is on the ground at any given time and how much water is contained in that snow. SnowEx is sponsored by the Terrestrial Hydrology Program at NASA Headquarters in Washington, D.C., and managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. The first year of the ground and air campaign takes place in February in western Colorado. "This is the most comprehensive campaign we have ever done on snow," said Edward Kim, a remote sensing scientist at NASA Goddard and the SnowEx project scientist. "An army of nearly 100 scientists from universities and agencies across the U.S., Europe and Canada are participating. Our goal is to find and refine the best snow-measuring techniques and how they could work together." Scientists know that they will need multiple sensors to measure the water content in snow. "No one instrument is perfect," said Charles Gatebe from NASA Goddard, SnowEx deputy project scientist and senior scientist with Universities Space Research Association. "One of our biggest problems is detecting snow through trees. We will work closely with our ground team to try new techniques to see if we can figure out how to do that accurately." More than one-sixth of the world's population relies on seasonal snow for water. In the western U.S., nearly three-quarters of the annual streamflow that provides the water supply arrives as spring and summer melt from the mountain snow packs. Right now, predictions of streamflow can vary widely due to limited ground measurement sites. This is one of the reasons scientists and resource managers are interested in a comprehensive view from space of what they call snow-water equivalent -- the amount of liquid water contained in snow cover. Scientists use snow-water equivalent to estimate the amount of water that will melt into mountain streams, rivers and reservoirs. Snow also effects and is affected by the climate. Scientists have detected changes in snow quantity and snowmelt timing that track with other changes prompted by Earth's warming climate. While satellites are not able to measure snow-water equivalent accurately over all snowy landscapes, satellites have monitored the extent of seasonal snow-covered areas for decades. Since 1967, Northern Hemisphere spring snow cover has declined by about 1 million square miles. Loss of snow cover results in Earth absorbing more sunlight, accelerating the planet's warming. In the air, on the ground The instruments and techniques developed in campaigns such as SnowEx could one day result in a snow-observing space mission. "We will also figure out a better way to optimize the use of existing satellites to make measurements," said Jared Entin, program manager of the Terrestrial Hydrology Program at NASA Headquarters. Five aircraft with a total of 10 different sensors are part of the SnowEx campaign. From an operations base at Peterson Air Force Base, Colorado Springs, SnowEx will deploy a P-3 Orion aircraft operated by the Scientific Development Squadron ONE (VXS-1), stationed at the Naval Air Station Patuxent River, Maryland. High-altitude NASA jets will fly from NASA's Johnson Space Center in Houston, and NASA's Armstrong Flight Research Center in Palmdale, California. A King Air and a Twin Otter will fly out of Grand Junction, Colorado. The planes will carry one passive and four active microwave sensors that are good at measuring snow-water equivalent in dry snow, but are less optimal for measuring snow in forests or light snow cover; a thermal infrared camera and a remote thermometer (KT-15) for measuring surface temperature; laser instrument that it good at measuring snow depth and snow water equivalent through trees; an imaging spectrometer which measures snow albedo -- the amount of sunlight reflected and absorbed by snow, which controls the speed of snowmelt and the timing of its runoff. The King Air carries the Airborne Snow Observatory from NASA's Jet Propulsion Laboratory in Pasadena, California. ASO is the first remote sensing system to ever measure snow depth, snow water equivalent and snow albedo across entire mountain basins, and has uniquely quantified snow water equivalent over mountainous regions since 2013. The field portion of the campaign is based in Grand Mesa and Senator Beck Basin. Scientists will use measurement and sampling procedures that will allow the team to validate the remotely-sensed measurements acquired by the multiple sensors on the various aircraft. Traditional and high-tech equipment is being used for the ground campaign, including snow pits and remote sensing instruments hoisted 40 feet in the air on boom trucks. "The big challenge to the ground campaign is collecting high-quality field measurements while keeping everyone safe and healthy in these harsh environments," said Kelly Elder, research hydrologist with the U.S. Forest Service's Rocky Mountain Research Station, Fort Collins, Colorado, who is leading the overall ground campaign. Scientists will be working above 10,000 feet in potentially windy and freezing conditions up to 10 hours a day. They need snow goggles or sunglasses to protect their eyes. Hypothermia is a very real threat, so researchers wear special clothing designed to wick away sweat and keep them dry. The teams use snowshoes, skis and snowmobiles to access the ground measurement locations on Grand Mesa and Senator Beck Basin. The Senator Beck Research Basin study area is near the headwaters of the Rio Grande River Basin. "Its research areas are the first major mountain systems downwind of the desert Southwest and Colorado Plateau, making it an ideal place to study the effects of dust on snowmelt," said Hans-Peter Marshall, of Boise State University, who is leading ground operations in Senator Beck Research Basin. "Grand Mesa was chosen for its flatness and range of forest conditions," said Chris Hiemstra, a research physicist with the U.S. Army Corps of Engineers, and the lead for the Grand Mesa ground operations. The variety of terrain and environments make the ground sites good models for developing global measurements of snow. Ground equipment was installed in September 2016, before snow started to fall. A ground site near a campground will host specialized equipment too large to move around. This Local Scale Observation Site effort is led by Ludovic Brucker from NASA Goddard. Teams of 50 researchers are making ground measurements, rotating in and out of the field every week over a three-week period. Data acquired from the SnowEx campaign will be stored at the National Snow and Ice Data Center in Boulder, Colorado, and will be available to anyone at no cost, as is the case with all NASA data. After the field work, SnowEx scientists will analyze data and recommend to NASA how to proceed in the next few years. "This campaign will generate the best ideas from the global community of snow experts," Kim said. Senator Beck Basin is managed by the Center for Snow and Avalanche Studies CSAS, a non-profit organization that hosts research studies on snowpack at the basin.
News Article | February 22, 2017
Needless to say, the definition they adopted resulted in fair degree of controversy from the astronomical community. For this reason, a team of planetary scientists – which includes famed "Pluto defender" Alan Stern – have come together to propose a new meaning for the term "planet". Based on their geophysical definition, the term would apply to over 100 bodies in the solar system, including the moon itself. The current IAU definition (known as Resolution 5A) states that a planet is defined based on the following criteria: "(1) A "planet" is a celestial body that (a) is in orbit around the sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. (2) A "dwarf planet" is a celestial body that (a) is in orbit around the sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. (3) All other objects , except satellites, orbiting the sun shall be referred to collectively as "small solar-system bodies" Because of these qualifiers, Pluto was no longer considered a planet, and became known alternately as a "dwarf planet", Plutiod, Plutino, Trans-Neptunian Object (TNO), or Kuiper Belt Object (KBO). In addition, bodies like Ceres, and newly discovered TNOs like Eris, Haumea, Makemake and the like, were also designated as "dwarf planets". Naturally, this definition did not sit right with some, not the least of which are planetary geologists. Led by Kirby Runyon – a final year PhD student from the Department of Earth and Planetary Sciences at Johns Hopkins University – this team includes scientists from the Southwest Research Institute (SwRI) in Boulder, Colorado; the National Optical Astronomy Observatory in Tuscon, Arizona; the Lowell Observatory in Flagstaff, Arizona; and the Department of Physics and Astronomy at George Mason University. Their study – titled "A Geophysical Planet Definition", which was recently made available on the Universities Space Research Association (USRA) website – addresses what the team sees as a need for a new definition that takes into account a planet's geophysical properties. In other words, they believe a planet should be so-designated based on its intrinsic properties, rather than its orbital or extrinsic properties. From this more basic set of parameters, Runyon and his colleagues have suggested the following definition: "A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters." As Runyon told Universe Today in a phone interview, this definition is an attempt to establish something that is useful for all those involved in the study of planetary science, which has always included geologists: "The IAU definition is useful to planetary astronomers concerned with the orbital properties of bodies in the solar system, and may capture the essence of what a 'planet' is to them. The definition is not useful to planetary geologists. I study landscapes and how landscapes evolve. It also kind of irked me that the IAU took upon itself to define something that geologists use too. "The way our brain has evolved, we make sense of the universe by classifying things. Nature exists in a continuum, not in discrete boxes. Nevertheless, we as humans need to classify things in order to bring order out of chaos. Having a definition of the word planet that expresses what we think a planet ought to be, is concordant with this desire to bring order out of chaos and understand the universe." The new definition also attempts to tackle many of the more sticky aspects of the definition adopted by the IAU. For example, it addresses the issue of whether or not a body orbits the sun – which does apply to those found orbiting other stars (i.e. exoplanets). In addition, in accordance with this definition, rogue planets that have been ejected from their solar systems are technically not planets as well. And then there's the troublesome issue of "neighborhood clearance". As has been emphasized by many who reject the IAU's definition, planets like Earth do not satisfy this qualification since new small bodies are constantly injected into planet-crossing orbits – i..e near-Earth objects (NEOs). On top of that, this proposed definition seeks to resolve what is arguably one of the most regrettable aspects of the IAU's 2006 resolution. "The largest motivation for me personally is: every time I talk about this to the general public, the very next thing people talk about is 'Pluto is not a planet anymore'," said Runyon. "People's interest in a body seems tied to whether or not it has the name 'planet' labelled on it. I want to set straight in the mind of the public what a planet is. The IAU definition doesn't jive with my intuition and I find it doesn't jive with other people's intuition." The study was prepared for the upcoming 48th Lunar and Planetary Science Conference. This annual conference – which will be taking place this year from March 20th-24th at the Universities Space Research Association in Houston, Texas – will involve specialists from all over the worlds coming together to share the latest research findings in planetary science. Here, Runyon and his colleagues hope to present it as part of the Education and Public Engagement Event. It is his hope that through an oversized poster, which is a common education tool at Lunar and Planetary Science Conference, they can show how this new definition will facilitate the study of the solar system's many bodies in a way that is more intuitive and inclusive. "We have chosen to post this in a section of the conference dedicated to education," he said. "Specifically, I want to influence elementary school teachers, grades K-6, on the definitions that they can teach their students. This is not the first time someone has proposed a definition other than the one proposed by the IAU. But few people have talked about education. They talk among their peers and little progress is made. I wanted to post this in a section to reach teachers." Naturally, there are those who would raise concerns about how this definition could lead to too many planets. If intrinsic property of hydrostatic equilibrium is the only real qualifier, then large bodies like Ganymede, Europa, and the moon would also be considered planets. Given that this definition would result in a solar system with 110 "planets", one has to wonder if perhaps it is too inclusive. However, Runyon is not concerned by these numbers. "Fifty states is a lot to memorize, 88 constellations is a lot to memorize," he said. "How many stars are in the sky? Why do we need a memorable number? How does that play into the definition? If you understand the periodic table to be organized based on the number of protons, you don't need to memorize all the atomic elements. There's no logic to the IAU definition when they throw around the argument that there are too many planets in the solar system." Since its publication, Runyon has also been asked many times if he intends to submit this proposal to the IAU for official sanction. To this, Runyon has replied simply: "No. Because the assumption there is that the IAU has a corner on the market on what a definition is. We in the planetary science field don't need the IAU definition. The definition of words is based partly on how they are used. If [the geophysical definition] is the definition that people use and what teachers teach, it will become the de facto definition, regardless of how the IAU votes in Prague." Regardless of where people fall on the IAU's definition of planet (or the one proposed by Runyon and his colleagues) it is clear that the debate is far from over. Prior to 2006, there was no working definition of the term planet; and new astronomical bodies are being discovered all the time that put our notions of what constitutes a planet to the test. In the end, it is the process of discovery which drives classification schemes, and not the other way around. Explore further: UCLA professor proposes simpler way to define what makes a planet
News Article | February 24, 2017
Obstacles to determine how much water is locked up in the world's mountain snow have yet to be conquered. No single instrument, even the space-based, had ever come close to hurdle it. Against this backdrop, NASA's SnowEx has joined the fray with a goal — to find the best snow-measuring techniques. "This is the most comprehensive campaign we have ever done on snow," declared Edward Kim, a remote sensing scientist at NASA Goddard and the SnowEx project scientist. Seventy percent of the world's surface is covered by water of which only 2.5 percent of this is fresh water. Of the available fresh water, more than two-thirds are locked in glaciers. In addition, about 20 percent of the Earth's land surface is covered by snow land, which also has water locked in it. This has far-reaching consequences on a society where more than a billion people depend largely on snow for their fresh water, Kim said. The water locked in the world's mountain snow has other consequences for people, such as devastating floods, drought, and instability when its supply is scarce. It is said some 663 million people worldwide have no access to drinking water. Snow packs that melt, for instance, provided a major supply to the annual streamflow in the western United States when spring and summer arrive. Yet there is no information available, at present, how much water will pour out from melting snow owing to inadequate ground measurement sites. This situation has led to the birth of SnowEx. Scientists and resource managers wanted to have a comprehensive view from space the amount of water contained in the snow-covered land that will eventually melt into streams, rivers, and reservoirs. The snow-covered mountains of Colorado were combed by aircraft with sensors as researchers have completed the first flights of the SnowEx campaign this month. The NASA-led experiment uses five aircraft with 10 sensors with a goal to find the right combination to develop instruments and techniques which could be used in a snow-observing space mission in the future. "We will also figure out a better way to optimize the use of existing satellites to make measurements," Jared Entin of the Terrestrial Hydrology Program at NASA said. Multiple sensors are needed to address the difficulty in measuring water content in snow including those under the canopies. "We will work closely with our ground team to try new techniques to see if we can figure out how to do that accurately," said Charles Gatebe from NASA Goddard, SnowEx deputy project scientist and senior scientist with Universities Space Research Association. The Terrestrial Hydrology Program at NASA Headquarters in Washington, D.C. sponsored SnowEx while NASA's Goddard Space Flight Center in Greenbelt, Maryland managed the multi-year campaign. Storage of data generated from the campaign will be at the National Snow and Ice Data Center in Boulder, Colorado and will be accessible to all. The campaign is expected to "generate the best ideas from the global community of snow experts," Kim said. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Plante I.,Universities Space Research Association
Radiation and Environmental Biophysics | Year: 2011
The importance of the radiolysis of water in irradiation of biological systems has motivated considerable theoretical and experimental work in the radiation chemistry of water and aqueous solutions. In particular, Monte-Carlo simulations of radiation track structure and non-homogeneous chemistry have greatly contributed to the understanding of experimental results in radiation chemistry of heavy ions. Actually, most simulations of the non-homogeneous chemistry are done using the Independent Reaction Time (IRT) method, a very fast technique. The main limitation of the IRT method is that the positions of the radiolytic species are not calculated as a function of time, which is needed to simulate the irradiation of more complex systems. Step-by-step (SBS) methods, which are able to provide such information, have been used only sparsely because these are time consuming in terms of calculation. Recent improvements in computer performance now allow the regular use of the SBS method in radiation chemistry. In the present paper, the first of a series of two, the SBS method is reviewed in detail. To these ends, simulation of diffusion of particles and chemical reactions in aqueous solutions is reviewed, and implementation of the program is discussed. Simulation of model systems is then performed to validate the adequacy of stepwise diffusion and reaction schemes. In the second paper, radiochemical yields of simulated radiation tracks calculated by the SBS program in different conditions of LET, pH, and temperature are compared with results from the IRT program and experimental data. © 2011 Springer-Verlag.
Cecil D.J.,University of Alabama in Huntsville |
Blankenship C.B.,Universities Space Research Association
Journal of Climate | Year: 2012
An 8-yr climatology of storms producing large hail is estimated from satellite measurements using Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E). This allows a unique, consistent comparison between regions that cannot be consistently compared using ground-based records because of varying data collection standards. Severe hailstorms are indicated most often in a broad region of northern Argentina and southern Paraguay and a smaller region in Bangladesh and eastern India. Numerous hailstorms are also estimated in the central and southeastern United States, northern Pakistan and northwestern India, central and western Africa, and southeastern Africa (and adjacent waters). Fewer hailstorms are estimated for other regions over land and scattered across subtropical oceans. Very few are estimated in the deep tropics other than in Africa. Most continental regions show seasonality with hailstorms peaking in late spring or summer. The South Asian monsoon alters the hailstorm climatology around the Indian subcontinent. About 75% of the hailstorms on the eastern side (around Bangladesh) occur from April through June, generally before monsoon onset. Activity shifts northwest to northern India in late June and July. An arc along the foothills in northern Pakistan becomes particularly active from mid-June through mid-August. The AMSR-E measurements are limited to early afternoon and late night. Tropical Rainfall Measuring Mission (TRMM) measurements are used to investigate diurnal variability in the tropics and subtropics. All of the prominent regions have hailstorm peaks in late afternoon and early evening. The United States and central Africa have the fewest overnight and early morning storms, while subtropical South America and Bangladesh have the most. © 2012 American Meteorological Society.
Agency: NSF | Branch: Continuing grant | Program: | Phase: PHYSICAL & DYNAMIC METEOROLOGY | Award Amount: 124.86K | Year: 2013
With this award, the investigators will examine physical processes occurring in growing and evolving convective clouds as they begin to produce lightning. The study will utilize: Satellite-based cloud observations and retrieved cloud properties, including time-series (5-15-min) of Geostationary Operational Environmental Satellite (GOES) and Meteosat Second Generation (MSG) visible and infrared (IR) measurements; S-band dual-polarimetric National Weather Service Surveillance 1988 Doppler (WSR-88D) radar observations across the United States; Ground-based VHF Lightning Mapping Array (LMA) observations (e.g., over Northern Alabama, Central Oklahoma); Observations collected during the Cloud processes of the main precipitation systems in Brazil: A contribution to cloud resolving modeling and to the Global Precipitation Measurement(CHUVA) campaign; Retrieved aerosol observations from satellites such as MODerate resolution Imaging Spectroradiometer (MODIS), and ground, such as from the AErosol RObotic NETwork (AERONET).
The award seeks to address a fundamental question in lightning prediction: How does the combination of multi-scale processes influence total lightning production? The corollary to this is: How do we obtain a longer lead time (>10-15 min) in lightning forecasting?
The specific goals are: (1) To improve understanding of the physical processes and precursory signals of lightning evolution within the 0-1 h timeframe through the collection and interpretation of high-temporal and spatial resolution space- and ground-based remote sensing observations of hydrometeor and aerosol type, amount and distribution; (2) To seek improvement in lightning amount nowcasting skill for longer lead-time (~30-45 min) and higher accuracy using combined data from geostationary satellite observations, radar and models; (3) To significantly bolster graduate- and undergraduate-level university education directly through transition of scientific discoveries to students, and indirectly via curriculum enhancements.
The Broader Impacts will be improving understanding of lightning processes that are inherently difficult to observe, more skillful 0-1 hour quantitative lightning nowcasts, and exploitation of WSR-88D dual-polarimetric data. Improved lightning nowcasts will benefit the general public, and especially the aviation industry that suffer substantial costs due to lightning-disrupted ground operations. Relatively few studies have developed physical relationships related to lightning nowcasting using combined datasets with a focus on satellite data. Use of WSR-88D radar in conjunction with satellite is timely in light of new observations from the GOES-R Advanced Baseline Imager and Geostationary Lightning Mapper expected in 2016, and from the Meteosat Third Generation Lightning Imager in ~2019. In addition, collaboration with other university scientists and graduate students will further extend this research to the larger academic and educational community.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 219.79K | Year: 2011
The collaborative research lead by Dr. Andersson (Universities Space Research Association), Dr. Jones (University of Minnesota), and Dr. Lazarian (University of Wisconsin, Madison) advances our ability to trace magnetic fields in the interstellar medium and molecular clouds through new multi-wavelength observations and theoretical modeling. It leads to a better understanding of the foregrounds to the cosmic microwave background (CMB) polarization through targeted observations of interstellar grain alignment and modeling based on the leading theoretical paradigm. The combined new quantitative effort addresses interstellar grain alignment mechanisms. A quantitative theory based on radiative alignment torques provides specific, testable predictions of the grain alignment as functions of the environment and grain characteristics. Observations, employing optical and near-infrared (NIR) polarimetry, directly probe the theoretical predictions of the variations of grain alignment efficiencies from the molecular cloud surfaces to the depths where (sub-)mm wave polarized emission is observed. Extensive modeling of the grain alignment, simulating the polarization arising from aligned grains, supports interpretations of the observations. A quantitative understanding of the alignment mechanism is important to understand the structure and strength of the magnetic field (through the geometry of the polarization vectors and the Chandrasekhar-Fermi method, respectively). The impact on related research ranges from models of star formation (through a reliable magnetic field tracing) to the physics of Early Universe (through a reliable separation of polarized dust foreground from the CMB polarized radiation) as well as a better understandinging micro-physics of interstellar dust grains. This project trains young researchers and graduate students in the acquisition, analysis and interpretation of the optical and NIR observations, and on computational models necessary for the study of astrophysical magnetic fields and the nature of interstellar polarization.
Universities Space Research Association | Date: 2012-08-29
A process for producing isotopes by continuously flowing a liquid stream, carrying capsules of target nuclei (NP-237) in solution, through a nuclear reactor (a TRIGA style nuclear reactor). Upon removal from the core of the nuclear reactor and after allowing for the decay of Np-238 to Pu-238, the capsules are emptied and the mixture of elements and isotopes are chemically separated using solvent extraction or ion exchange. Isotopes that are capable of further processing into Pu-238 are recycled to the core for further processing