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Improving High-Resolution Model Forecasts Of Downslope Winds In The Las Vegas Valley, Andre K. Pattantyus, Sen Chiao, Stanley Czyzyk
Improving High-Resolution Model Forecasts Of Downslope Winds In The Las Vegas Valley, Andre K. Pattantyus, Sen Chiao, Stanley Czyzyk
Ocean Engineering and Marine Sciences Faculty Publications
Numerical simulations for severe downslope winds as well as trapped lee waves in Nevada’s Las Vegas Valley were performed in this study. The goal of this study was to improve model forecasts of downslope wind- event intensities. This was measured by assessing different planetary boundary layer (PBL) schemes in the mountain–valley region. The Weather Research and Forecasting Model was adopted for this research. The numerical experiments were constructed using two nested domains, with 4- and 1-km grid resolution. The working hypothesis was that the occurrence of low-level wind shear and surface gustiness in the Las Vegas Valley was guided by …
A Terrestrial Gamma Ray Flash Observed From An Aircraft, D. M. Smith, Michael E. Splitt, Steven M. Lazarus
A Terrestrial Gamma Ray Flash Observed From An Aircraft, D. M. Smith, Michael E. Splitt, Steven M. Lazarus
Aerospace, Physics, and Space Science Faculty Publications
On 21 August 2009, the Airborne Detector for Energetic Lightning Emissions (ADELE), an array of six gamma-ray detectors, detected a brief burst of gamma rays while flying aboard a Gulfstream V jet near two active thunderstorm cells. The duration and spectral characteristics of the event are consistent with the terrestrial gamma ray flashes (TGFs) seen by instruments in low Earth orbit. A long-duration, complex +IC flash was taking place in the nearer cell at the same time, at a distance of ∼10 km from the plane. The sferics that are probably associated with this flash extended over 54 ms and …
The Lightning-Tgf Relationship On Microsecond Ttimescales, Steven A. Cummer, Gaopeng Lu, Michael S. Briggs, Valerie Connaughton, Shaolin Xiong, Gerald Jerry Fishman, Joseph R. Dwyer
The Lightning-Tgf Relationship On Microsecond Ttimescales, Steven A. Cummer, Gaopeng Lu, Michael S. Briggs, Valerie Connaughton, Shaolin Xiong, Gerald Jerry Fishman, Joseph R. Dwyer
Aerospace, Physics, and Space Science Faculty Publications
We analyze the count rates of two terrestrial gamma-ray flashes (TGFs) detected by the Fermi Gamma-ray Burst Monitor (GBM) with the broadband magnetic fields (1 to 300 kHz) produced by the simultaneous lightning processes. The microsecond-scale absolute time accuracy for these data, combined with independent geolocations of the source lightning, enable this analysis with higher accuracy than previously possible. In both events, fast discharge-like processes occur within several tens of microseconds of the gamma-ray generation, although not with a consistent relationship. The magnetic field data also show a slower signal component produced by a source current that in both events …
Novel Optical Remote Sensing Technology For Prediction Of Harmful Algal Blooms, Elizabeth Tobin
Novel Optical Remote Sensing Technology For Prediction Of Harmful Algal Blooms, Elizabeth Tobin
Link Foundation Ocean Engineering and Instrumentation Fellowship Reports
Harmful Algal Blooms (HABs) are outbreaks of planktonic algae that threaten public health, degrade aquatic ecosystems and cause major economic losses. Most HABs are detected only after they reach an advanced stage, when they have already caused significant ecological and economic damage. However, many HAB-forming species have two distinct life stages, a dormant benthic stage and a vegetative pelagic stage.The primary objective of this project was to construct and test a prototype of an autonomous optical sensor for the detection and characterization of HAB-forming algae as they emerge from the sediments.
High-Speed X-Ray Images Of Triggered Lightning Dart Leaders, Joseph R. Dwyer, M. M. Schaal, Hamid K. Rassoul, Martin A. Uman, Douglas M. Jordan, Dustin Hill
High-Speed X-Ray Images Of Triggered Lightning Dart Leaders, Joseph R. Dwyer, M. M. Schaal, Hamid K. Rassoul, Martin A. Uman, Douglas M. Jordan, Dustin Hill
Aerospace, Physics, and Space Science Faculty Publications
We present the first high-time resolution two-dimensional images of X-ray emissions from lightning. The images were recorded at a rate of 10 million per second using a new pinhole-type camera, located 44 m from rocket-and-wire- triggered lightning. We report observations of two dart leaders, one in each of two lightning flashes triggered during the summer of 2010 in north-central Florida. In both events, as the dart leader approached the ground, the X-ray source was also seen to descend along the previous lightning channel. For the second event, the X-ray source exhibited a downward speed of 4.5 × 10 7 m/s, …