141 research outputs found

    Electrical Anomalies Observed During DC3

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    The primary scientific goals of DC3 involved improving our understanding of the chemical impacts of thunderstorms and their anvils. However, the Colorado domain provided opportunities to study other interesting phenomena, including the potential impacts of smoke ingestion on convection and thunderstorms, electrification processes in smoke plumes and pyrocumulonimbus clouds, and the production of sprites by unconventional thunderstorm

    Rediscovery of red wolf ghost alleles in canid population along the American Gulf Coast

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    Rediscovering species once thought to be extinct or on the edge of extinction is rare. Red wolves have been extinct along the American Gulf Coast since 1980, with their last populations found in coastal Louisiana and Texas. We report the rediscovery of red wolf ghost alleles in a canid population on Galveston Island, Texas. We analyzed over 7000 single nucleotide polymorphisms (SNPs) in 60 canid representatives from all legally recognized North American Canis species and two phenotypically ambiguous canids from Galveston Island. We found notably high Bayesian cluster assignments of the Galveston canids to captive red wolves with extensive sharing of red wolf private alleles. Today, the only known extant wild red wolves persist in a reintroduced population in North Carolina, which is dwindling amongst political and taxonomic controversy. Our rediscovery of red wolf ancestry after almost 40 years introduces both positive opportunities for additional conservation action and difficult policy challenges

    Polarimetric and Multi-Doppler Radar Observations of Electrified and Unelectrified Wildfire Smoke Plumes

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    Pyrocumulus clouds above three Colorado wildfires (Hewlett Gulch, High Park, and Waldo Canyon; all occurred during summer 2012) electrified and produced small intracloud discharges whenever the smoke plumes grew to high altitudes (over 10 km above mean sea level, or MSL). This occurred during periods of rapid wildfire growth, as indicated by the shortwave infrared channel on a geostationary satellite, as well as by incident reports. In the Hewlett Gulch case, the fire growth led to increased updrafts within the plume, as inferred by multiple Doppler radar syntheses, which led to the vertical development and subsequent electrification a life cycle as short as 30 minutes. The lightning, detected by a threedimensional lightning mapping network, was favored in highaltitude regions (~10 km MSL) containing modest reflectivities (25 dBZ and lower), ~0 dB differential reflectivity, and reduced correlation coefficient (~0.60.7). This indicated the likely presence of ice particles (crystals and aggregates, possibly rimed) mixed with ash. Though neither multipleDoppler nor polarimetric observations were available during the electrification of the High Park and Waldo Canyon plumes, their NEXRAD observations showed reflectivity structures consistent with Hewlett Gulch. In addition, polarimetric and multipleDoppler scanning of unelectrified High Park plumes indicated only irregularly shaped ash, and not ice, was present (i.e., reflectivities 5 dB, correlation < 0.4), and there was no broaching of the 10 km altitude. Based on these results, the electrification likely was caused by icebased processes that did not involve significant amounts of graupel. The results demonstrate the scientific value of multipleDoppler and polarimetric radar observations of wildfire smoke plumes including the ability to distinguish between regions of pure hydrometeors, regions of pure ash, and mixtures of both and also suggest a possible new application for lightning data in monitoring wildfires

    On the Electrification of Pyrocumulus Clouds

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    The electrification (or lack thereof) of pyrocumulus clouds is examined for several different wildfires that occurred during 20122013. For example, pyrocumulus clouds above three Colorado wildfires (Hewlett Gulch, High Park, and Waldo Canyon; all occurred during summer 2012) electrified and produced small intracloud discharges whenever the smoke plumes grew to high altitudes (over 10 km above mean sea level, or MSL). This occurred during periods of rapid wildfire growth, as indicated by the shortwave infrared channel on a geostationary satellite, as well as by incident reports. In the Hewlett Gulch case, the fire growth led to increased updrafts within the plume, as inferred by multipleDoppler radar syntheses, which led to the vertical development and subsequent electrification a life cycle as short as 30 minutes. The lightning, detected by a threedimensional lightning mapping network, was favored in highaltitude regions (~10 km MSL) containing modest reflectivities (25 dBZ and lower), ~0 dB differential reflectivity, and reduced correlation coefficient (~0.60.7). This indicated the likely presence of ice particles (crystals and aggregates, possibly rimed) mixed with ash. Though neither multipleDoppler nor polarimetric observations were available during the electrification of the High Park and Waldo Canyon plumes, their NEXRAD observations showed reflectivity structures consistent with Hewlett Gulch. In addition, polarimetric and multipleDoppler scanning of unelectrified High Park plumes indicated only irregularly shaped ash, and not ice, was present (i.e., reflectivities 5 dB, correlation < 0.4), and there was no broaching of the 10 km altitude. Based on these results, the electrification likely was caused by icebased processes that did not involve significant amounts of graupel. Results for pyrocumulus clouds above notable 2013 wildfires that also experienced rapid growth (e.g., Black Forest, Yarnell Hill, West Fork, Tres Lagunas, etc.) will be compared against the 2012 cases, with special emphasis on polarimetric NEXRAD and available lightning measurements, in order to better understand the physical processes responsible for pyrocumulus electrification

    Nurses\u27 Alumnae Association Bulletin - Volume 18 Number 1

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    Alumnae Notes Central Dressing Room Committee Reports Digest of Alumnae Association Meetings Graduation Awards - 1952 Greetings from Miss Childs Greetings from the President Marriages Modern Trends in Orthopaedic Surgery Necrology New Arrivals Physical Advances at Jefferson Hospital - 1953 Staff Activities - 1952-1953 Student Activities The Artificial Heart Lung Machin

    Polarimetric and Multi-Doppler Radar Observations of Sprite-producing Storms

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    Sprites are caused by luminous electrical breakdown of the upper atmosphere, and frequently occur over large mesoscale precipitation systems. Two spriteproducing storms (on 8 and 25 June) were observed in Colorado during the summer of 2012. Unlike most past studies of sprites, these storms were observed by a polarimetric radar the CSUCHILL facility which provided both PPI and RHI scans of the cases. Also available were multipleDoppler syntheses from CSUCHILL, local NEXRAD radars, and the CSUPawnee radar; as well as data from the Colorado Lightning Mapping Array (COLMA), high speed cameras, and other lightningdetection instrumentation. This unique dataset provided an unprecedented look at the detailed kinematic and microphysical structures of the thunderstorms as they produced sprites, including electrical alignment signatures in the immediate location of the charge layers neutralized by spriteparent positive cloudtoground lightning strokes. One of the spriteproducing cases (25 June) featured an anomalous charge structure and may serve as a model for how sprites can be produced over convection rather than the more typical stratiform regions. Also to be presented will be evidence for advection of charge into a common stratiform precipitation region (on 8 June), which was then tapped by lightning originating from multiple different convective cores to produce sprites. Depending on the outcome of the 2013 convective season, polarimetric data from additional storms that produce sprites and other transient luminous events (TLEs) may be presented

    Offshore Radiation Observations for Climate Research at the CERES Ocean Validation Experiment

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    When radiometers on a satellite are pointed towards the planet with the goal of understanding a phenomenon quantitatively, rather than just creating a pleasing image, the task at hand is often problematic. The signal at the detector can be affected by scattering, absorption, and emission; and these can be due to atmospheric constituents (gases, clouds, and aerosols), the earth's surface, and subsurface features. When targeting surface phenomena, the remote sensing algorithm needs to account for the radiation associated with the atmospheric constituents. Likewise, one needs to correct for the radiation leaving the surface, when atmospheric phenomena are of interest. Rigorous validation of such remote sensing products is a real challenge. In visible and near infrared wavelengths, the jumble of effects on atmospheric radiation are best accomplished over dark surfaces with fairly uniform reflective properties (spatial homogeneity) in the satellite instrument's field of view (FOV). The ocean's surface meets this criteria; land surfaces - which are brighter, more spatially inhomogeneous, and more changeable with time - generally do not. NASA's Clouds and the Earth's Radiant Energy System (CERES) project has used this backdrop to establish a radiation monitoring site in Virginia's coastal Atlantic Ocean. The project, called the CERES Ocean Validation Experiment (COVE), is located on a rigid ocean platform allowing the accurate measurement of radiation parameters that require precise leveling and pointing unavailable from ships or buoys. The COVE site is an optimal location for verifying radiative transfer models and remote sensing algorithms used in climate research; because of the platform's small size, there are no island wake effects; and suites of sensors can be simultaneously trained both on the sky and directly on ocean itself. This paper describes the site, the types of measurements made, multiple years of atmospheric and ocean surface radiation observations, and satellite validation results

    Supreme Court Clerks\u27 Recollections of October Term 1951, Including the Steel Seizure Cases

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    A roundtable panel discussion at the Chautauqua Institution. The panel brought together five lawyers who fifty-five years ago served as law clerks to Justices of the Supreme Court of the United States. The panelists discussed the Justices and some of the cases of that Supreme Court Term, including the Steel Seizure Cases,1 which came to the Supreme Court in the spring of 1952. The honored guests and panelists are five lawyers who have led high-achieving, diverse and public-spirited lives: Charles C. Hileman, Abner J. Mikva , James C.N. Paul , Neal Person Rutledge, Marshall L. Small
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