Earle Williams - Academia.edu (original) (raw)

Papers by Earle Williams

Research paper thumbnail of POSTER Bou Karam et al

Research paper thumbnail of The start of lightning: Evidence of bidirectional lightning initiation

Scientific Reports, 2015

Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms... more Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leaders. We report here a serendipitous recording of bidirectional lightning initiation in virgin air under the cloud base at ~11,000 images per second, and the differences in characteristics of opposite polarity leader sections during the earliest stages of the discharge. This case reveals natural lightning initiation, propagation and a return stroke as in negative cloud-to-ground flashes, upon connection to another lightning channel - without any masking by cloud.

Research paper thumbnail of The physical origin of the land–ocean contrast in lightning activity

Research paper thumbnail of High-speed video and electromagnetic analysis of two natural bipolar cloud-to-ground lightning flashes

Journal of Geophysical Research-Atmospheres, 2014

Research paper thumbnail of A dusty gust front of synoptic scale initiated and maintained by moist convection over the Sahara desert

In this study we document the evolution, the synoptic trigger and the characteristics of an inten... more In this study we document the evolution, the synoptic trigger and the characteristics of an intense dust event which occurred over the Sahara desert on August 3-5, 2006. The motivation for this study is to highlight the large scale dust production over the Sahara associated with gust fronts of squall lines. The dust emission during this event was initiated by a large-scale cold pool emanated from a squall line that developed over Niger and Mali on August 3. We examine the development of this squall line and its subsequent dust lifting using high temporal resolution false color dust product images from the Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI). Observations from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are used to characterize the vertical structure of the dust plume as it spreads over the Sahara and near the Atlantic coast line. The European Centre for Medium-Range Weather Forecasting African Monsoon ...

Research paper thumbnail of Observation of deep convection initiation from shallow convection environment

In the afternoon of 10 July 2006, deep convective cells initiated right in the field of view of t... more In the afternoon of 10 July 2006, deep convective cells initiated right in the field of view of the Massachusetts Institute Technology (MIT) C-band Doppler radar. This radar, with its 3D exploration at 10 min temporal resolution and 250 m radial resolution, allows us to track the deep convective cells and also provides clear air observations of the boundary layer structure prior to deep convection initiation. Several other observational platforms were operating then which allow us to thoroughly analyse this case: Vertically pointing aerosol lidar, W-band radar and ceilometer from the ARM Mobile Facility, along with radiosoundings and surface measurements enable us to describe the environment, from before their initiation to after the propagation of of one propagating cell that generated a circular gust front very nicely caught by the MIT radar. The systems considered here differ from the mesoscale convective systems which are often associated with African Easterly Waves, increasing ...

Research paper thumbnail of Introduction to the AMMA Special Issue on ‘Advances in understanding atmospheric processes over West Africa through the AMMA field campaign’

Quarterly Journal of the Royal Meteorological Society, 2010

Research paper thumbnail of Comment on “Current budget of the atmospheric electric global circuit” by H. W. Kasemir

Journal of Geophysical Research, 1996

ABSTRACT

Research paper thumbnail of Reply to the comment on “The physical origin of the land–ocean contrast in lightning activity”

Comptes Rendus Physique, 2004

Research paper thumbnail of Global lightning acquisition system installed

Eos, Transactions American Geophysical Union, 2000

Research paper thumbnail of Signatures of the day-night asymmetry of the Earth-ionosphere cavity in high time resolution Schumann resonance records

Radio Science, 2007

... Mariusz Neska. ... Citation: S??tori, G., M. Neska, E. Williams, and J. Szendr??i (2007), Sig... more ... Mariusz Neska. ... Citation: S??tori, G., M. Neska, E. Williams, and J. Szendr??i (2007), Signatures of the day-night asymmetry of the Earth-ionosphere cavity in high time resolution Schumann resonance records, Radio Sci., 42, RS2S10, doi:10.1029/2006RS003483. Cited By. ...

Research paper thumbnail of A calibrated Franklin chimes

Journal of Geophysical Research, 1994

Research paper thumbnail of Microphysical growth state of ice particles and large-scale electrical structure of clouds

Journal of Geophysical Research, 1994

Research paper thumbnail of Islands as miniature continents: Another look at the land-ocean lightning contrast

Journal of Geophysical Research, 2004

Research paper thumbnail of World-wide lightning location using VLF propagation in the Earth-ionosphere waveguide

IEEE Antennas and Propagation Magazine, 2000

Research paper thumbnail of Geochemical and isotopic characterization of the Bodélé Depression dust source and implications for transatlantic dust transport to the Amazon Basin

Earth and Planetary Science Letters, 2013

Research paper thumbnail of The behavior of total lightning activity in severe Florida thunderstorms

Atmospheric Research, 1999

Research paper thumbnail of Signature of the seasonal migration of global lightning in the variation of Schumann resonance peak frequencies - Theory versus experiment

Geophysical Research Abstracts Vol. 12, EGU2010-12071, 2010 EGU General Assembly 2010 © Author(s)... more Geophysical Research Abstracts Vol. 12, EGU2010-12071, 2010 EGU General Assembly 2010 © Author(s) 2010 ... Signature of the seasonal migration of global lightning in the variation of ... Schumann resonance peak frequencies - Theory versus experiment

Research paper thumbnail of CHASER: An Innovative Satellite Mission Concept to Measure the Effects of Aerosols on Clouds and Climate

Bulletin of the American Meteorological Society, 2013

Research paper thumbnail of POSTER Bou Karam et al

Research paper thumbnail of The start of lightning: Evidence of bidirectional lightning initiation

Scientific Reports, 2015

Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms... more Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leaders. We report here a serendipitous recording of bidirectional lightning initiation in virgin air under the cloud base at ~11,000 images per second, and the differences in characteristics of opposite polarity leader sections during the earliest stages of the discharge. This case reveals natural lightning initiation, propagation and a return stroke as in negative cloud-to-ground flashes, upon connection to another lightning channel - without any masking by cloud.

Research paper thumbnail of The physical origin of the land–ocean contrast in lightning activity

Research paper thumbnail of High-speed video and electromagnetic analysis of two natural bipolar cloud-to-ground lightning flashes

Journal of Geophysical Research-Atmospheres, 2014

Research paper thumbnail of A dusty gust front of synoptic scale initiated and maintained by moist convection over the Sahara desert

In this study we document the evolution, the synoptic trigger and the characteristics of an inten... more In this study we document the evolution, the synoptic trigger and the characteristics of an intense dust event which occurred over the Sahara desert on August 3-5, 2006. The motivation for this study is to highlight the large scale dust production over the Sahara associated with gust fronts of squall lines. The dust emission during this event was initiated by a large-scale cold pool emanated from a squall line that developed over Niger and Mali on August 3. We examine the development of this squall line and its subsequent dust lifting using high temporal resolution false color dust product images from the Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI). Observations from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are used to characterize the vertical structure of the dust plume as it spreads over the Sahara and near the Atlantic coast line. The European Centre for Medium-Range Weather Forecasting African Monsoon ...

Research paper thumbnail of Observation of deep convection initiation from shallow convection environment

In the afternoon of 10 July 2006, deep convective cells initiated right in the field of view of t... more In the afternoon of 10 July 2006, deep convective cells initiated right in the field of view of the Massachusetts Institute Technology (MIT) C-band Doppler radar. This radar, with its 3D exploration at 10 min temporal resolution and 250 m radial resolution, allows us to track the deep convective cells and also provides clear air observations of the boundary layer structure prior to deep convection initiation. Several other observational platforms were operating then which allow us to thoroughly analyse this case: Vertically pointing aerosol lidar, W-band radar and ceilometer from the ARM Mobile Facility, along with radiosoundings and surface measurements enable us to describe the environment, from before their initiation to after the propagation of of one propagating cell that generated a circular gust front very nicely caught by the MIT radar. The systems considered here differ from the mesoscale convective systems which are often associated with African Easterly Waves, increasing ...

Research paper thumbnail of Introduction to the AMMA Special Issue on ‘Advances in understanding atmospheric processes over West Africa through the AMMA field campaign’

Quarterly Journal of the Royal Meteorological Society, 2010

Research paper thumbnail of Comment on “Current budget of the atmospheric electric global circuit” by H. W. Kasemir

Journal of Geophysical Research, 1996

ABSTRACT

Research paper thumbnail of Reply to the comment on “The physical origin of the land–ocean contrast in lightning activity”

Comptes Rendus Physique, 2004

Research paper thumbnail of Global lightning acquisition system installed

Eos, Transactions American Geophysical Union, 2000

Research paper thumbnail of Signatures of the day-night asymmetry of the Earth-ionosphere cavity in high time resolution Schumann resonance records

Radio Science, 2007

... Mariusz Neska. ... Citation: S??tori, G., M. Neska, E. Williams, and J. Szendr??i (2007), Sig... more ... Mariusz Neska. ... Citation: S??tori, G., M. Neska, E. Williams, and J. Szendr??i (2007), Signatures of the day-night asymmetry of the Earth-ionosphere cavity in high time resolution Schumann resonance records, Radio Sci., 42, RS2S10, doi:10.1029/2006RS003483. Cited By. ...

Research paper thumbnail of A calibrated Franklin chimes

Journal of Geophysical Research, 1994

Research paper thumbnail of Microphysical growth state of ice particles and large-scale electrical structure of clouds

Journal of Geophysical Research, 1994

Research paper thumbnail of Islands as miniature continents: Another look at the land-ocean lightning contrast

Journal of Geophysical Research, 2004

Research paper thumbnail of World-wide lightning location using VLF propagation in the Earth-ionosphere waveguide

IEEE Antennas and Propagation Magazine, 2000

Research paper thumbnail of Geochemical and isotopic characterization of the Bodélé Depression dust source and implications for transatlantic dust transport to the Amazon Basin

Earth and Planetary Science Letters, 2013

Research paper thumbnail of The behavior of total lightning activity in severe Florida thunderstorms

Atmospheric Research, 1999

Research paper thumbnail of Signature of the seasonal migration of global lightning in the variation of Schumann resonance peak frequencies - Theory versus experiment

Geophysical Research Abstracts Vol. 12, EGU2010-12071, 2010 EGU General Assembly 2010 © Author(s)... more Geophysical Research Abstracts Vol. 12, EGU2010-12071, 2010 EGU General Assembly 2010 © Author(s) 2010 ... Signature of the seasonal migration of global lightning in the variation of ... Schumann resonance peak frequencies - Theory versus experiment

Research paper thumbnail of CHASER: An Innovative Satellite Mission Concept to Measure the Effects of Aerosols on Clouds and Climate

Bulletin of the American Meteorological Society, 2013