William Rison - Academia.edu (original) (raw)

Papers by William Rison

Research paper thumbnail of Correlated lightning mapping array and radar observations of the initial stages of three sequentially triggered Florida lightning discharges

Journal of Geophysical Research: Atmospheres, 2013

Research paper thumbnail of An Examination of Lightning-Strike-Grounding Physics

Research paper thumbnail of Using VHF Lightning Observations to Monitor Explosive Volcanic Activity

Lightning is an integral part of explosive volcanic eruptions and volcanic lightning measurements... more Lightning is an integral part of explosive volcanic eruptions and volcanic lightning measurements are a useful tool for volcano monitoring. VHF measurements of volcanic lightning can be made remotely, at distances of up to 100 km. A strategically placed network of 6 or more VHF ground stations could locate lightning in eruption columns from several regional volcanoes, and a minimum of two stations could be used to monitor a single volcano. Such a network would be particularly useful for detection or confirmation of explosive activity in situations where volcanoes are remotely located, and thus lack visual observations, or are not well instrumented with seismic networks. Furthermore, clouds are fully transparent to VHF signals, making lightning detection possible even when weather obscures visual observations. Recent VHF observations of volcanic lightning at Augustine Volcano (Alaska, USA, 2006), Redoubt Volcano (Alaska, USA, 2009) and Eyjafjallajökull (Iceland, 2010) have shown that...

Research paper thumbnail of Lightning and electrical activity during the eruption of Mt. Augustine

Lightning during several of the eruptions were observed using a technique that we use to observe ... more Lightning during several of the eruptions were observed using a technique that we use to observe thunderstorms. Very high frequency radio emissions (60 MHz) emitted by electrical discharges are located by their times of arrival at several receiving stations. In a typical thunderstorm lightning flash we locate several thousand events giving a 3-D map of the lightning. In mid January we set up two stations about 100 km east of the volcano, near Homer, AK. We received and located the source of thousands of radio emissions from the vicinity of Mt Augustine during the January 28 eruption. With two stations we were able to determine the azimuthal direction to the sources, their power, the time history and relationship to other pulses. On one lightning flash we used an interferometric effect to infer altitude. We observed two distinct forms of electrical activity. The first was many short bursts (less than a milliseconds) that occurred coincident with the explosive eruption. These seemed t...

Research paper thumbnail of The 2010 eruption of Eyjafjallajökull: Lightning and plume charge structure

Journal of Geophysical Research: Atmospheres, 2014

Research paper thumbnail of 3-Dimensional Lightning Observations Using a Time-of-Arrival Lightning Mapping System

SAE Technical Paper Series, 2001

Research paper thumbnail of The Electrical Structure of Two Supercell Storms during STEPS

Monthly Weather Review, 2005

Balloon soundings were made through two supercell storms during the Severe Thunderstorm Electrifi... more Balloon soundings were made through two supercell storms during the Severe Thunderstorm Electrification and Precipitation Study (STEPS) in summer 2000. Instruments measured the vector electric field, temperature, pressure, relative humidity, and balloon location. For the first time, soundings penetrated both the strong updraft and the rainy downdraft region of the same supercell storm. In both storms, the strong updraft had fewer vertically separated charge regions than found near the rainy downdraft, and the updraft’s lowest charge was elevated higher, its bottom being near the 40-dBZ boundary of the weak-echo vault. The simpler, elevated charge structure is consistent with the noninductive graupel–ice mechanism dominating charge generation in updrafts. In the weak-echo vault, the amount of frozen precipitation and the time for particle interactions are too small for significant charging. Inductive charging mechanisms and lightning may contribute to the additional charge regions fo...

Research paper thumbnail of Helium isotopes in geothermal and volcanic gases of the western United States, I. Regional variability and magmatic origin

Journal of Volcanology and Geothermal Research, 1988

Research paper thumbnail of PHETS (Permanent High Explosive Test Site) Lightning Hardening Program: Misty Picture Event

... UNCLASSI FIED SECURITY CLASSIFICATION OF THIS 3AT T ABITO REPORT DOCUMENTATION PAGE Ia. REPOR... more ... UNCLASSI FIED SECURITY CLASSIFICATION OF THIS 3AT T ABITO REPORT DOCUMENTATION PAGE Ia. REPORT SECURITY CLASSIFICATION lb. ... PERSONAL AUTHOR(S) Chapman, GP,; Gardner, RL; Lu, GS; Rison, W.; and Gurbaxani, SH 13a. TYPE OF ...

Research paper thumbnail of Lightning and electrical activity during the 2009 eruptions of Redoubt Volcano

The warning of the impending eruption of Redoubt by the Alaska Volcano Observatory enabled us to ... more The warning of the impending eruption of Redoubt by the Alaska Volcano Observatory enabled us to set up a 4-station VHF Lightning Mapping Array (LMA) along the Kenai coast in time to capture the complete sequence of eruptions. The network was situated along a 60 km long north-south line, 70-80 km east of Redoubt on the opposite side of Cook

Research paper thumbnail of Correlated lightning mapping array and radar observations of the initial stages of three sequentially triggered Florida lightning discharges

Journal of Geophysical Research: Atmospheres, 2013

Research paper thumbnail of An Examination of Lightning-Strike-Grounding Physics

Research paper thumbnail of Using VHF Lightning Observations to Monitor Explosive Volcanic Activity

Lightning is an integral part of explosive volcanic eruptions and volcanic lightning measurements... more Lightning is an integral part of explosive volcanic eruptions and volcanic lightning measurements are a useful tool for volcano monitoring. VHF measurements of volcanic lightning can be made remotely, at distances of up to 100 km. A strategically placed network of 6 or more VHF ground stations could locate lightning in eruption columns from several regional volcanoes, and a minimum of two stations could be used to monitor a single volcano. Such a network would be particularly useful for detection or confirmation of explosive activity in situations where volcanoes are remotely located, and thus lack visual observations, or are not well instrumented with seismic networks. Furthermore, clouds are fully transparent to VHF signals, making lightning detection possible even when weather obscures visual observations. Recent VHF observations of volcanic lightning at Augustine Volcano (Alaska, USA, 2006), Redoubt Volcano (Alaska, USA, 2009) and Eyjafjallajökull (Iceland, 2010) have shown that...

Research paper thumbnail of Lightning and electrical activity during the eruption of Mt. Augustine

Lightning during several of the eruptions were observed using a technique that we use to observe ... more Lightning during several of the eruptions were observed using a technique that we use to observe thunderstorms. Very high frequency radio emissions (60 MHz) emitted by electrical discharges are located by their times of arrival at several receiving stations. In a typical thunderstorm lightning flash we locate several thousand events giving a 3-D map of the lightning. In mid January we set up two stations about 100 km east of the volcano, near Homer, AK. We received and located the source of thousands of radio emissions from the vicinity of Mt Augustine during the January 28 eruption. With two stations we were able to determine the azimuthal direction to the sources, their power, the time history and relationship to other pulses. On one lightning flash we used an interferometric effect to infer altitude. We observed two distinct forms of electrical activity. The first was many short bursts (less than a milliseconds) that occurred coincident with the explosive eruption. These seemed t...

Research paper thumbnail of The 2010 eruption of Eyjafjallajökull: Lightning and plume charge structure

Journal of Geophysical Research: Atmospheres, 2014

Research paper thumbnail of 3-Dimensional Lightning Observations Using a Time-of-Arrival Lightning Mapping System

SAE Technical Paper Series, 2001

Research paper thumbnail of The Electrical Structure of Two Supercell Storms during STEPS

Monthly Weather Review, 2005

Balloon soundings were made through two supercell storms during the Severe Thunderstorm Electrifi... more Balloon soundings were made through two supercell storms during the Severe Thunderstorm Electrification and Precipitation Study (STEPS) in summer 2000. Instruments measured the vector electric field, temperature, pressure, relative humidity, and balloon location. For the first time, soundings penetrated both the strong updraft and the rainy downdraft region of the same supercell storm. In both storms, the strong updraft had fewer vertically separated charge regions than found near the rainy downdraft, and the updraft’s lowest charge was elevated higher, its bottom being near the 40-dBZ boundary of the weak-echo vault. The simpler, elevated charge structure is consistent with the noninductive graupel–ice mechanism dominating charge generation in updrafts. In the weak-echo vault, the amount of frozen precipitation and the time for particle interactions are too small for significant charging. Inductive charging mechanisms and lightning may contribute to the additional charge regions fo...

Research paper thumbnail of Helium isotopes in geothermal and volcanic gases of the western United States, I. Regional variability and magmatic origin

Journal of Volcanology and Geothermal Research, 1988

Research paper thumbnail of PHETS (Permanent High Explosive Test Site) Lightning Hardening Program: Misty Picture Event

... UNCLASSI FIED SECURITY CLASSIFICATION OF THIS 3AT T ABITO REPORT DOCUMENTATION PAGE Ia. REPOR... more ... UNCLASSI FIED SECURITY CLASSIFICATION OF THIS 3AT T ABITO REPORT DOCUMENTATION PAGE Ia. REPORT SECURITY CLASSIFICATION lb. ... PERSONAL AUTHOR(S) Chapman, GP,; Gardner, RL; Lu, GS; Rison, W.; and Gurbaxani, SH 13a. TYPE OF ...

Research paper thumbnail of Lightning and electrical activity during the 2009 eruptions of Redoubt Volcano

The warning of the impending eruption of Redoubt by the Alaska Volcano Observatory enabled us to ... more The warning of the impending eruption of Redoubt by the Alaska Volcano Observatory enabled us to set up a 4-station VHF Lightning Mapping Array (LMA) along the Kenai coast in time to capture the complete sequence of eruptions. The network was situated along a 60 km long north-south line, 70-80 km east of Redoubt on the opposite side of Cook