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Papers by Jeremy Thomas

Lightning-Driven Electric and Magnetic Fields Measured in the Stratosphere: Implications for Sprites

... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correl... more ... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correlated sprites.Blue jets are optical discharges that propagate from the top of a thundercloud ... Barrington-Leigh et al., 2001], as shown in Figure 1.3. Unlike sprites and jets which ...

Geophysical Research Letters, 2005

Eos, Transactions American Geophysical Union, 2007

During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were... more During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth.

Journal of Geophysical Research, 2008

Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves requi... more Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

Geophysical Research Letters, 2004

1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL),... more 1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL), is being developed to provide real time global coverage with 10 km location accuracy and at least 50% detection efficiency. This paper provides a ''worst case'' analysis of WWLL location accuracy in Brazil where the VLF lightning receivers that make up the network are very distant (>7000 km). Through comparison to a local lightning detection network, we analyze the detection accuracy in Brazil with respect to time, location, and peak current of lightning strokes. In this study, we find that WWLL detection is highly dependent upon the peak return stroke current, resulting in detection of about 0.3% of the total lightning strokes. However, the detected strokes have a location accuracy of 20.25 ± 13.5 km and a temporal accuracy of 0.06 ± 0.2 ms, providing a good overview of regions of overall global lightning activity in real time.

IEEE Transactions on Geoscience and Remote Sensing, 2004

The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langm... more The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langmuir probe instrument designed for stratospheric electric field measurements. In the Sprite Balloon Campaign 2002-2003, this HV instrument was used to measure electric fields between 100 and 200 V/m associated with lightning discharges, which is nearly an order of magnitude higher than previously reported above 30 km in altitude. This increased range is made possible by the availability of new low-leakage HV operational amplifiers. This is a critical instrument, since a large quasi-dc electric field associated with positive cloud-to-ground lightning is a primary component of most sprite generation mechanisms. The difficulty that exists when making electric field measurements in the high-resistance environment of the stratosphere is presented, and how this difficulty is remedied is described. The HV detector is compared to another electric field instrument, the low-voltage detector, used simultaneously on the Sprite Balloon Campaign to verify the accuracy of the HV probes. Finally, a large field perturbation ( 101 V/m and 79 V/m) measured by the HV detector during Flight 1, correlated with nearby +15-kA and +53-kA cloud-to-ground strokes, is presented.

Lightning-Driven Electric and Magnetic Fields Measured in the Stratosphere: Implications for Sprites

... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correl... more ... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correlated sprites.Blue jets are optical discharges that propagate from the top of a thundercloud ... Barrington-Leigh et al., 2001], as shown in Figure 1.3. Unlike sprites and jets which ...

Geophysical Research Letters, 2005

Eos, Transactions American Geophysical Union, 2007

During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were... more During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth.

Journal of Geophysical Research, 2008

Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves requi... more Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

Geophysical Research Letters, 2004

1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL),... more 1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL), is being developed to provide real time global coverage with 10 km location accuracy and at least 50% detection efficiency. This paper provides a ''worst case'' analysis of WWLL location accuracy in Brazil where the VLF lightning receivers that make up the network are very distant (>7000 km). Through comparison to a local lightning detection network, we analyze the detection accuracy in Brazil with respect to time, location, and peak current of lightning strokes. In this study, we find that WWLL detection is highly dependent upon the peak return stroke current, resulting in detection of about 0.3% of the total lightning strokes. However, the detected strokes have a location accuracy of 20.25 ± 13.5 km and a temporal accuracy of 0.06 ± 0.2 ms, providing a good overview of regions of overall global lightning activity in real time.

IEEE Transactions on Geoscience and Remote Sensing, 2004

The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langm... more The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langmuir probe instrument designed for stratospheric electric field measurements. In the Sprite Balloon Campaign 2002-2003, this HV instrument was used to measure electric fields between 100 and 200 V/m associated with lightning discharges, which is nearly an order of magnitude higher than previously reported above 30 km in altitude. This increased range is made possible by the availability of new low-leakage HV operational amplifiers. This is a critical instrument, since a large quasi-dc electric field associated with positive cloud-to-ground lightning is a primary component of most sprite generation mechanisms. The difficulty that exists when making electric field measurements in the high-resistance environment of the stratosphere is presented, and how this difficulty is remedied is described. The HV detector is compared to another electric field instrument, the low-voltage detector, used simultaneously on the Sprite Balloon Campaign to verify the accuracy of the HV probes. Finally, a large field perturbation ( 101 V/m and 79 V/m) measured by the HV detector during Flight 1, correlated with nearby +15-kA and +53-kA cloud-to-ground strokes, is presented.

Lightning-Driven Electric and Magnetic Fields Measured in the Stratosphere: Implications for Sprites

... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correl... more ... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correlated sprites.Blue jets are optical discharges that propagate from the top of a thundercloud ... Barrington-Leigh et al., 2001], as shown in Figure 1.3. Unlike sprites and jets which ...

Geophysical Research Letters, 2005

Eos, Transactions American Geophysical Union, 2007

During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were... more During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth.

Journal of Geophysical Research, 2008

Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves requi... more Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

Geophysical Research Letters, 2004

1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL),... more 1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL), is being developed to provide real time global coverage with 10 km location accuracy and at least 50% detection efficiency. This paper provides a ''worst case'' analysis of WWLL location accuracy in Brazil where the VLF lightning receivers that make up the network are very distant (>7000 km). Through comparison to a local lightning detection network, we analyze the detection accuracy in Brazil with respect to time, location, and peak current of lightning strokes. In this study, we find that WWLL detection is highly dependent upon the peak return stroke current, resulting in detection of about 0.3% of the total lightning strokes. However, the detected strokes have a location accuracy of 20.25 ± 13.5 km and a temporal accuracy of 0.06 ± 0.2 ms, providing a good overview of regions of overall global lightning activity in real time.

IEEE Transactions on Geoscience and Remote Sensing, 2004

The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langm... more The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langmuir probe instrument designed for stratospheric electric field measurements. In the Sprite Balloon Campaign 2002-2003, this HV instrument was used to measure electric fields between 100 and 200 V/m associated with lightning discharges, which is nearly an order of magnitude higher than previously reported above 30 km in altitude. This increased range is made possible by the availability of new low-leakage HV operational amplifiers. This is a critical instrument, since a large quasi-dc electric field associated with positive cloud-to-ground lightning is a primary component of most sprite generation mechanisms. The difficulty that exists when making electric field measurements in the high-resistance environment of the stratosphere is presented, and how this difficulty is remedied is described. The HV detector is compared to another electric field instrument, the low-voltage detector, used simultaneously on the Sprite Balloon Campaign to verify the accuracy of the HV probes. Finally, a large field perturbation ( 101 V/m and 79 V/m) measured by the HV detector during Flight 1, correlated with nearby +15-kA and +53-kA cloud-to-ground strokes, is presented.

Lightning-Driven Electric and Magnetic Fields Measured in the Stratosphere: Implications for Sprites

... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correl... more ... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correlated sprites.Blue jets are optical discharges that propagate from the top of a thundercloud ... Barrington-Leigh et al., 2001], as shown in Figure 1.3. Unlike sprites and jets which ...

Geophysical Research Letters, 2005

Eos, Transactions American Geophysical Union, 2007

During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were... more During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth.

Journal of Geophysical Research, 2008

Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves requi... more Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

Geophysical Research Letters, 2004

1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL),... more 1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL), is being developed to provide real time global coverage with 10 km location accuracy and at least 50% detection efficiency. This paper provides a ''worst case'' analysis of WWLL location accuracy in Brazil where the VLF lightning receivers that make up the network are very distant (>7000 km). Through comparison to a local lightning detection network, we analyze the detection accuracy in Brazil with respect to time, location, and peak current of lightning strokes. In this study, we find that WWLL detection is highly dependent upon the peak return stroke current, resulting in detection of about 0.3% of the total lightning strokes. However, the detected strokes have a location accuracy of 20.25 ± 13.5 km and a temporal accuracy of 0.06 ± 0.2 ms, providing a good overview of regions of overall global lightning activity in real time.

IEEE Transactions on Geoscience and Remote Sensing, 2004

The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langm... more The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langmuir probe instrument designed for stratospheric electric field measurements. In the Sprite Balloon Campaign 2002-2003, this HV instrument was used to measure electric fields between 100 and 200 V/m associated with lightning discharges, which is nearly an order of magnitude higher than previously reported above 30 km in altitude. This increased range is made possible by the availability of new low-leakage HV operational amplifiers. This is a critical instrument, since a large quasi-dc electric field associated with positive cloud-to-ground lightning is a primary component of most sprite generation mechanisms. The difficulty that exists when making electric field measurements in the high-resistance environment of the stratosphere is presented, and how this difficulty is remedied is described. The HV detector is compared to another electric field instrument, the low-voltage detector, used simultaneously on the Sprite Balloon Campaign to verify the accuracy of the HV probes. Finally, a large field perturbation ( 101 V/m and 79 V/m) measured by the HV detector during Flight 1, correlated with nearby +15-kA and +53-kA cloud-to-ground strokes, is presented.

Lightning-Driven Electric and Magnetic Fields Measured in the Stratosphere: Implications for Sprites

... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correl... more ... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correlated sprites.Blue jets are optical discharges that propagate from the top of a thundercloud ... Barrington-Leigh et al., 2001], as shown in Figure 1.3. Unlike sprites and jets which ...

Geophysical Research Letters, 2005

Eos, Transactions American Geophysical Union, 2007

During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were... more During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth.

Journal of Geophysical Research, 2008

Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves requi... more Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

Geophysical Research Letters, 2004

1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL),... more 1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL), is being developed to provide real time global coverage with 10 km location accuracy and at least 50% detection efficiency. This paper provides a ''worst case'' analysis of WWLL location accuracy in Brazil where the VLF lightning receivers that make up the network are very distant (>7000 km). Through comparison to a local lightning detection network, we analyze the detection accuracy in Brazil with respect to time, location, and peak current of lightning strokes. In this study, we find that WWLL detection is highly dependent upon the peak return stroke current, resulting in detection of about 0.3% of the total lightning strokes. However, the detected strokes have a location accuracy of 20.25 ± 13.5 km and a temporal accuracy of 0.06 ± 0.2 ms, providing a good overview of regions of overall global lightning activity in real time.

IEEE Transactions on Geoscience and Remote Sensing, 2004

The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langm... more The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langmuir probe instrument designed for stratospheric electric field measurements. In the Sprite Balloon Campaign 2002-2003, this HV instrument was used to measure electric fields between 100 and 200 V/m associated with lightning discharges, which is nearly an order of magnitude higher than previously reported above 30 km in altitude. This increased range is made possible by the availability of new low-leakage HV operational amplifiers. This is a critical instrument, since a large quasi-dc electric field associated with positive cloud-to-ground lightning is a primary component of most sprite generation mechanisms. The difficulty that exists when making electric field measurements in the high-resistance environment of the stratosphere is presented, and how this difficulty is remedied is described. The HV detector is compared to another electric field instrument, the low-voltage detector, used simultaneously on the Sprite Balloon Campaign to verify the accuracy of the HV probes. Finally, a large field perturbation ( 101 V/m and 79 V/m) measured by the HV detector during Flight 1, correlated with nearby +15-kA and +53-kA cloud-to-ground strokes, is presented.

Lightning-Driven Electric and Magnetic Fields Measured in the Stratosphere: Implications for Sprites

... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correl... more ... 10 1.2 A Gigantic Jet Over the South China Sea [Su et al., 2003] . . . . 11 ... stroke correlated sprites.Blue jets are optical discharges that propagate from the top of a thundercloud ... Barrington-Leigh et al., 2001], as shown in Figure 1.3. Unlike sprites and jets which ...

Geophysical Research Letters, 2005

Eos, Transactions American Geophysical Union, 2007

During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were... more During the night of 22-23 February 2006, more than 400 middle-atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth.

Journal of Geophysical Research, 2008

Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves requi... more Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

Geophysical Research Letters, 2004

1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL),... more 1] An experimental lightning detection network, the World Wide Lightning Location network (WWLL), is being developed to provide real time global coverage with 10 km location accuracy and at least 50% detection efficiency. This paper provides a ''worst case'' analysis of WWLL location accuracy in Brazil where the VLF lightning receivers that make up the network are very distant (>7000 km). Through comparison to a local lightning detection network, we analyze the detection accuracy in Brazil with respect to time, location, and peak current of lightning strokes. In this study, we find that WWLL detection is highly dependent upon the peak return stroke current, resulting in detection of about 0.3% of the total lightning strokes. However, the detected strokes have a location accuracy of 20.25 ± 13.5 km and a temporal accuracy of 0.06 ± 0.2 ms, providing a good overview of regions of overall global lightning activity in real time.

IEEE Transactions on Geoscience and Remote Sensing, 2004

The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langm... more The high-voltage (HV) electric field detector is a new high-voltage, high-impedance, double Langmuir probe instrument designed for stratospheric electric field measurements. In the Sprite Balloon Campaign 2002-2003, this HV instrument was used to measure electric fields between 100 and 200 V/m associated with lightning discharges, which is nearly an order of magnitude higher than previously reported above 30 km in altitude. This increased range is made possible by the availability of new low-leakage HV operational amplifiers. This is a critical instrument, since a large quasi-dc electric field associated with positive cloud-to-ground lightning is a primary component of most sprite generation mechanisms. The difficulty that exists when making electric field measurements in the high-resistance environment of the stratosphere is presented, and how this difficulty is remedied is described. The HV detector is compared to another electric field instrument, the low-voltage detector, used simultaneously on the Sprite Balloon Campaign to verify the accuracy of the HV probes. Finally, a large field perturbation ( 101 V/m and 79 V/m) measured by the HV detector during Flight 1, correlated with nearby +15-kA and +53-kA cloud-to-ground strokes, is presented.