A lightning fire occurrence model for Ontario

2005 ◽  
Vol 35 (6) ◽  
pp. 1389-1401 ◽  
Author(s):  
B M Wotton ◽  
David L Martell
Keyword(s):  
Forest Floor ◽  
Weather Conditions ◽  
Fire Spread ◽  
Positive Influence ◽  
Lightning Strike ◽  
Organic Layer ◽  
Fire Occurrence ◽  
Lightning Strikes ◽  
Cloud To Ground Lightning ◽  
Lightning Fire

Lightning strike, fire weather, and fire occurrence data were used to model (i) the probability that a lightning strike causes a sustainable ignition on the forest floor and (ii) the probability of an ignition being detected and reported to the fire management agency for each ecoregion in the province of Ontario. An index that tracks duff moisture content in very sheltered areas of a forest stand (near the tree boles) was the most significant predictor in each ignition model. The presence of positive cloud-to-ground lightning strikes was also found to have a significant and positive influence on the probability of ignition in most areas of the province with the exception of the far northwest. Weather conditions following a lightning storm influence the probability that a lightning strike causes a sustainable ignition. Models of the probability of detecting a fire ignited by lightning were also created for each of the ecoregions across Ontario. The form of these models varied somewhat among ecoregions, but contained an indicator of receptive surface fire spread conditions and an indicator of the dryness of the heavier fuels (the organic layer) in the forest floor.

Synoptic climatology of lightning-caused forest fires in subalpine and boreal forests

1996 ◽  
Vol 26 (10) ◽  
pp. 1859-1874 ◽  
Author(s):  
C.H. Nash ◽  
E.A. Johnson
Keyword(s):  
High Pressure ◽  
Forest Fires ◽  
Boreal Forests ◽  
Dry Weight ◽  
Weather Conditions ◽  
Synoptic Climatology ◽  
Fuel Moisture ◽  
Fire Occurrence ◽  
Lightning Strikes ◽  
Lightning Fire

The coupling of synoptic scale weather conditions with local scale weather and fuel conditions was examined for 2551 fires and 1 537 624 lightning strikes for the May through August fire seasons in 1988, 1989, 1992, and 1993 in Alberta and Saskatchewan. The probability of lightning fire occurrence (number of fires/number of strikes) is near zero until the Fine Fuel Moisture Code reaches 87 (moisture content of 14% dry weight), after which the probability increases rapidly. Duff Moisture and Drought Codes show less clear increases. In all cases, the probability of fire occurrence was low (the number of strikes greatly exceeded the number of forest fires), suggesting that lightning fire ignition coupled with early spread to detection was an uncommon event. This low probability of fire occurrence even at low fuel moisture may be a result of the arrangement and continuity of fuels in the boreal and subalpine forests. The literature suggests a higher probability of lightning-ignited fires in qualitatively different fuels, e.g., grasslands. The higher probability of fire at lower fuel moistures occurred primarily when high pressure dominated (positive 50-kPa anomaly) for at least 3 days and less than 1.5 mm precipitation occurred. The highest number of lightning strikes and largest number of fires also occurred when high pressure dominated. The high lightning numbers during high pressure systems were logistically related to increasing atmospheric instability (K-index).

Lightning and lightning fire, central cordillera, Canada

2002 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Jack Wierzchowski ◽  
Mark Heathcott ◽  
Michael D. Flannigan
Keyword(s):  
British Columbia ◽  
Forest Fires ◽  
Fire Occurrence ◽  
Fire Weather Index ◽  
Lightning Strikes ◽  
Severity Rating ◽  
Continental Divide ◽  
Significant Difference ◽  
Lightning Discharges ◽  
Lightning Fire

This study examines the influences of fuel, weather and topography on lightning-caused forest fires in portions of southern British Columbia and Alberta, Canada. The results show a significant difference in lightning and lightning-caused fires east and west of the Continental Divide. In British Columbia, on average there was one fire for every 50 lightning discharges whereas in Alberta there was one fire for every 1400 lightning discharges. Elevation, the distribution of lightning strikes, the Daily Severity Rating (a component of the Canadian Forest Fire Weather Index System) and vegetation composition were identified as primary agents controlling lightning fire occurrence. However, the multivariate analysis does suggest that there are other factors influencing fire occurrence other than the biophysical factors we tested. The implications of the lightning and lightning-ignited fires for land managers are discussed.

scholarly journals Tactical Decision-Making Support Information for Aircraft Lightning Avoidance: Feasibility Study in Area of Winter Lightning

2019 ◽  
Vol 100 (8) ◽  
pp. 1443-1452
Author(s):  
Eiichi Yoshikawa ◽  
Tomoo Ushio
Keyword(s):  
Feasibility Study ◽  
Weather Conditions ◽  
Lightning Strike ◽  
Lightning Strikes ◽  
Other Information ◽  
Triggered Lightning ◽  
Tactical Decision ◽  
Japan Aerospace Exploration Agency ◽  
Support Information ◽  
Aviation Weather

AbstractDid you know that aircraft can cause lightning? Researchers began investigating aircraft-triggered lightning after several cases were observed of aircraft receiving lightning strikes from lightning-inactive clouds. The phenomenon of aircraft-triggered lightning was subsequently confirmed by a UHF radar, and today, it is known that most aircraft lightning strikes are aircraft triggered. However, aviation weather support for aircraft lightning avoidance has not been well developed. This is probably because aircraft lightning strikes have been somewhat avoided by using other information such as thunderstorm nowcasting, and have hardly ever caused serious accidents. In fact, today’s aircraft are designed, manufactured, and certified so as not to be seriously affected by lightning. In actual aircraft operations, however, lightning strikes can still cause minor damage to an aircraft’s body and instruments and result in time and expense being incurred by airlines to check for and repair any damage. Moreover, such checks and repairs can sometimes lead to the delay or cancellation of following services. Aircraft lightning strike is therefore recognized as an important issue in aviation weather. The Japan Aerospace Exploration Agency and Tokyo Metropolitan University carried out a feasibility study on providing tactical support information for aircraft lightning avoidance. In this study, weather and flight data were collected from actual cases of aircraft lightning strikes, and their analysis yielded information on trends regarding the relationship between aircraft lightning strikes and weather conditions. A prototype tactical support system was then developed based on the analyzed trends, and its evaluation showed that it could be used to avoid potentially 60%–80% of current aircraft lightning strikes.

scholarly journals Effect of indirect lightning strike to 66kV transmission line in Java-Bali system

2018 ◽  
Vol 197 ◽  
pp. 11001
Author(s):  
Aristo Adi Kusuma ◽  
Putu Agus Aditya Pramana ◽  
Brian Bramantyo S.D.A. Harsono ◽  
Buyung Sofiarto Munir
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Lightning Strike ◽  
Actual Condition ◽  
Peak Current ◽  
Lightning Strikes ◽  
Detection Systems ◽  
Current Magnitude ◽  
Lightning Detection ◽  
Insulator Flashover

Based on Java-Bali grid disturbance data, the 66kV transmission lines that is close to or intersect with 150kV or 500kV transmission line is often experienced earth fault due to insulator flashover. The insulator flashover can be caused by indirect lightning strike since lightning strikes tend to strike higher structure. Therefore, this paper will determine the effect of indirect lightning strike on 150kV or 500kV transmission line to 66kV transmission line by modeling and simulation using application of transient analysis. Variation of lightning peak current magnitude and gap between 66kV transmission line and transmission line with higher voltage is performed during simulation. The range of peak current magnitude follows the data from lightning detection systems, while the value of gap follows the data from actual condition. It is found that higher current peak and closer gap will cause higher transient overvoltage on insulator of 66kV transmission line thus insulator flashover may occur more frequent. Addition of earth wire on 66kV transmission line and gap between each transmission by organizing the sag of conductor can be performed to minimize the insulator flashover.

scholarly journals Earth-termination system for onshore wind Turbines.

2020 ◽  
Vol 11 (7-2020) ◽  
pp. 66-72
Author(s):  
Liubov A. Belova ◽  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Lightning Strike ◽  
Lightning Protection ◽  
Protection Measures ◽  
Lightning Strikes ◽  
Grounding System ◽  
Initial Stage ◽  
Wind Turbine Towers ◽  
Surge Protection

The earth-termination system for towers of ground-based wind turbines in addition to protective and functional grounding provides lightning protection grounding, which is especially important since the wind turbine is susceptible to lightning strikes. If insufficient protective measures are taken, the risk of damage to a wind turbine due to a lightning strike increases. Therefore, a well-thought-out built-in grounding system for wind turbine towers is needed, which would function as necessary and guarantee long-term mechanical strength and corrosion resistance. The configuration of grounding systems for wind turbines is discussed in IEC 61400-24, which deals with the topic of lightning protection for wind turbines, including detailed information on the choice of lightning protection measures and surge protection. It is advisable to create a lightning protection concept at the initial stage of planning a wind turbine in order to avoid later costly repairs and retrofitting.

scholarly journals Evaluation of Lightning Protection Efficacy on Nigerian Installations High Voltage Installations Using Screen and Cone of Protection Methods

2019 ◽  
Vol 4 (7) ◽  
pp. 1-10
Author(s):  
M. O. Oyeleye
Keyword(s):  
High Voltage ◽  
Computer Aided Design ◽  
Travelling Waves ◽  
Screening Method ◽  
Lightning Strike ◽  
Physical Measurement ◽  
Lightning Strikes ◽  
Spatial Design ◽  
Protective System ◽  
Design Values

This study evaluated lightning protective system efficacy on 11kV-132kV substation-power line installation in Ikorodu, Lagos State, Nigeria with reference to cloud to ground(C-G) lightning strike (LS) events. It focus on interception of lightning strikes and its protection with reference to direct lightning strike (DLS) and indirect lightning strike (IDLS). Data were collected from Ikorodu 132/33 kV Transmission Substation and its four major injection stations.  This work was carried out using physical measurement of raw data obtained from the high voltage substation. Installations were scaled down and modelled dimensionally using AutoCAD software in order to measure spatial parameters in order to measure the screening of the existing substations and connected lines, as well as the existing cone angles of protection. Probability of lightning efficiency of lightning protective level (LPL) are used for screening evaluation while spike and sky wire angle of protection are used for cone of protection evaluation. Physical measurement of six substations (33/11 kV and 132/33 kV substations) in the studied area were also carried out to evaluate the effectiveness of the installed lightning arresters with respect to the protected devices using applicable standard. The results under the prevailing lightning protective system, LPS, (screening method), revealed that the existing 33/11 kV and 132/33 kV substations are not adequately protected against lightning strike; 132/33 kV substation is more vulnerable to lightning strike than 33/11kV substation and that the incoming 132kV power lines to the substation are adequately protected. The evaluation of the installed distances of all lightning arresters are within standard range and would adequately protect substation transformers against travelling waves (Indirect Stroke) events. The installed lightning arresters (LAs) would adequately protect substation transformers against travelling waves (Indirect Stroke) events. The adequate protection should be reinforced with proposed design scheme in further study in order to mitigate the disastrous effects of lightning strike. Any proposed design of protective system for electric power installations in Nigeria should be simulated using computer aided design software for scaled validation of dimensional and spatial design values in order to mitigate reported failures and uncertainties in identifying causes of observed failures in the system.

scholarly journals First ground-based observations of sprites over southern Africa

2018 ◽  
Vol 114 (9/10) ◽  
Author(s):  
Stanislaus Nnadih ◽  
Mike Kosch ◽  
Peter Martinez ◽  
Jozsef Bor
Keyword(s):  
South Africa ◽  
Southern Africa ◽  
Dielectric Breakdown ◽  
Electrical Discharges ◽  
Lightning Strikes ◽  
The World ◽  
Lightning Discharges ◽  
Northern Cape ◽  
Cloud To Ground Lightning ◽  
Peak Value

Sprites are the optical signatures of electrical discharges in the mesosphere triggered by large lightning strikes associated with thunderstorms. Since their discovery in the late 1980s, sprites have been observed extensively around the world, although very few observations of sprites from Africa have been documented in the literature. In this paper, we report the first ground-based recorded observations of sprites from South Africa. In 2 out of the 22 nights of observations (11 January and 2 February 2016), about 100 sprite elements were recorded from Sutherland in the Northern Cape, comprising different morphologies (carrot (55%), carrot/column (11%), unclassified (21%), column (13%)). The sprites were triggered by positive cloud-to-ground lightning strikes, which had an average peak value of ~74 kA and were observed at distances from ~400 km to 800 km. The estimated charge moment change of the lightning discharges associated with these events was in agreement with the threshold for dielectric breakdown of the mesosphere and correlates well with the observed sprite brightness.

scholarly journals Changes in Lightning Fire Incidence in the Tasmanian Wilderness World Heritage Area, 1980–2016

Fire ◽  
2018 ◽  
Vol 1 (3) ◽  
pp. 38 ◽  
Author(s):  
Jenny Styger ◽  
Jon Marsden-Smedley ◽  
Jamie Kirkpatrick
Keyword(s):  
Cultural Values ◽  
Fire Regimes ◽  
World Heritage ◽  
Fuel Load ◽  
Lightning Strike ◽  
Lightning Strikes ◽  
World Heritage Area ◽  
Soil Dryness ◽  
Heritage Area ◽  
Fire Incidence

The Tasmanian Wilderness World Heritage Area (TWWHA) has globally significant natural and cultural values, some of which are dependent on the absence of fire or the presence of particular fire regimes. Planned burning is currently used to reduce the risk of loss of world heritage values from unplanned fires, but large and damaging fires still occur, with lightning as the primary ignition source. Lightning-caused fire was rare in the TWWHA before 2000. There has since been an increase in both the number of fires following lightning storms and the area burnt by these fires. In the absence of a direct measurement of lightning strike incidence, we tested whether changes in rainfall, soil dryness and fuel load were responsible for these changes in fire incidence and extent. There were no relationships between these variables and the incidence of fires associated with lightning, but the variability in the Soil Dryness Index and the mean of 25% of driest values did predict both the number and area of fires. Thus, it appears that an increase in the proportion of lightning strikes that occur in dry conditions has increased ignition efficiency. These changes have important implications for the management of the TWWHA’s values, as higher projected fuel loads and drier climates could result in a further increase in the number of fires associated with lightning.

scholarly journals Thinning and Burning Effects on Long-Term Litter Accumulation and Function in Young Ponderosa Pine Forests

2020 ◽  
Vol 66 (6) ◽  
pp. 761-769
Author(s):  
Matt Busse ◽  
Ross Gerrard
Keyword(s):  
Ponderosa Pine ◽  
Forest Floor ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
Pine Forests ◽  
Organic Layer ◽  
Litter Accumulation ◽  
Ponderosa Pine Forests ◽  
Essential Components

Abstract We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control (560–615 trees ha−1) treatments, indicating balanced litterfall and decay rates across these stand densities. Each burn consumed 50–70 percent of the forest floor, yet unlike thinning, postfire accumulation rates were fairly rapid, with forest-floor depth matching preburn levels within 15–20 years. Few differences in forest-floor function (litter decay, carbon storage, physical barrier restricting plant emergence, erosion protection) resulted from thinning or burning after 25 years. An exception was the loss of approximately 300 kg N ha−1 because of repeated burning, or approximately 13 percent of the total site N. This study documents long-term forest-floor development and suggests that common silvicultural practices pose few risks to organic layer functions in these forests. Study Implications: Mechanical thinning and prescribed fire are among the most widespread management practices used to restore forests in the western US to healthy, firewise conditions. We evaluated their effects on the long-term development of litter and duff layers, which serve dual roles as essential components of soil health and as fuel for potential wildfire. Our study showed that thinning and burning provided effective fuel reduction and resulted in no adverse effects to soil quality in dry ponderosa pine forests of central Oregon. Repeated burning reduced the site carbon and nitrogen pools approximately 9–13 percent, which is small compared to C located in tree biomass and N in mineral soil. Litter accumulation after burning was rapid, and we recommend burning on at least a 15–20-year cycle to limit its build-up.

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