scholarly journals The relationship between the polar jet stream and extreme wildfire events in North America

2021 ◽  
pp. 1-59
Author(s):  
Piyush Jain ◽  
Mike Flannigan
Keyword(s):  
North America ◽  
Management Strategies ◽  
Fire Regimes ◽  
Fire Spread ◽  
Fire Season ◽  
Boreal Summer ◽  
Jet Stream ◽  
Eastern Canada ◽  
Split Flow ◽  
Flow Configurations

AbstractNorthern hemisphere mid-latitudeweather is strongly influenced by the polar jet stream (PJS), which dictates the position of storm tracks; this influence also extends to weather patterns conducive to the ignition and growth of large wildfires. We examined the role of the PJS on extreme wildfire events in North America (NA) between 40° and 70°N latitude, using fire spread events (FSEs) for 2002—2016. Climatologies of the 300-hPa wind components and derived quantities show that the PJS weakens and moves northward in the Boreal summer coincident with the fire season. We use spatio-temporal compositing of 300-hPa winds and 500-hPa geopotential height anomalies to show that FSEs are associated with an upper-level ridge and high centered over events, except eastern Canada where patterns are displaced westward. Ridge patterns persist longer for FSEs in western NA compared with Eastern NA, as well as for May to August compared with April, September and October. These tropospheric patterns also occur concomitantly with surface weather drivers of fire spread including positive daily mean temperature and vapor pressure deficit anomalies and negative precipitation anomalies. Distributions of maximum and minimum latitudinal jet stream peak, ridge and trough positions, relative to FSEs, confirm that events occur predominantly southward of the jet stream core and near a ridge for low split flow configurations but not necessarily for high split flow configurations. These findings have wide-reaching implications for better understanding NA fire regimes and potential fire management strategies (eg. resource pre-positioning and tactical suppression) through improved forecasting of fire weather.

Trend analysis of fire season length and extreme fire weather in North America between 1979 and 2015

2017 ◽  
Vol 26 (12) ◽  
pp. 1009 ◽  
Author(s):  
Piyush Jain ◽  
Xianli Wang ◽  
Mike D. Flannigan
Keyword(s):  
North America ◽  
Statistical Significance ◽  
Kendall Test ◽  
Fire Season ◽  
Fire Weather ◽  
Season Length ◽  
Eastern Canada ◽  
Reanalysis Dataset ◽  
Fire Weather Index ◽  
Extreme Fire

We have constructed a fire weather climatology over North America from 1979 to 2015 using the North American Regional Reanalysis dataset and the Canadian Fire Weather Index (FWI) System. We tested for the presence of trends in potential fire season length, based on a meteorological definition, and extreme fire weather using the non-parametric Theil–Sen slope estimator and Mann–Kendall test. Applying field significance testing (i.e. joint significance of multiple tests) allowed the identification of the locations of significant trends, taking into account spatial correlations. Fire season length was found to be increasing over large areas of North America, especially in eastern Canada and the south-western US, which is consistent with a later fire season end and an earlier fire season start. Both positive and negative trends in potential fire spread days and the 99th percentile of FWI occurred in Canada and the contiguous United States, although the trends of largest magnitude and statistical significance were mostly positive. In contrast, the proportion of trends with significant decreases in these variables were much lower, indicating an overall increase in extreme fire weather. The smaller proportion of significant positive trends found over Canada reflects the truncation of the time series, necessary because assimilation of precipitation observations over Canada ceased in the reanalysis post-2002.

scholarly journals Biology, Ecology, and Management of Eastern Grape Leafhopper (Hemiptera: Cicadellidae), a Key Pest of Vineyards in North America

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kevin R Jarrell ◽  
Eric J Rebek ◽  
Astri C Wayadande ◽  
Kristopher L Giles
Keyword(s):  
United States ◽  
North America ◽  
Management Strategies ◽  
Early Spring ◽  
Native Range ◽  
Historical Account ◽  
Northeastern United States ◽  
Eastern Canada ◽  
Mesophyll Cells ◽  
Grape Leafhopper

Abstract Eastern grape leafhopper, Erythroneura comes (Say), is a key pest of grapes (Vitales: Vitaceae) in the central and northeastern United States and eastern Canada. This native insect uses its piercing-sucking mouthparts to puncture the mesophyll cells of leaves and suck out the contents, thereby reducing the quality and quantity of fruit. Eastern grape leafhopper has been reported as a vineyard pest for nearly 200 yr and is one of several Erythroneura spp. that feed on grapes in North America. Overwintered adults become active in early spring and may feed on grasses, weeds, and other plants before feeding on grapevines. Although eastern grape leafhopper has an extensive host range, it is only known to oviposit on wild and cultivated grapes. This multivoltine species can outbreak periodically, which has generated much research into improved monitoring and integrated pest management strategies employed throughout its native range. In this review, we describe the biology, life history, population dynamics, and phenology of eastern grape leafhopper and provide a historical account of monitoring and management strategies for this important vineyard pest.

scholarly journals The influence of vegetation, fire spread and fire behaviour on biomass burning and trace gas emissions: results from a process-based model

2010 ◽  
Vol 7 (6) ◽  
pp. 1991-2011 ◽  
Author(s):  
K. Thonicke ◽  
A. Spessa ◽  
I. C. Prentice ◽  
S. P. Harrison ◽  
L. Dong ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Spread ◽  
Ecosystem Dynamics ◽  
Fire Season ◽  
Burnt Area ◽  
Dynamic Global Vegetation Model ◽  
Active Fire ◽  
Geographic Patterns

Abstract. A process-based fire regime model (SPITFIRE) has been developed, coupled with ecosystem dynamics in the LPJ Dynamic Global Vegetation Model, and used to explore fire regimes and the current impact of fire on the terrestrial carbon cycle and associated emissions of trace atmospheric constituents. The model estimates an average release of 2.24 Pg C yr−1 as CO2 from biomass burning during the 1980s and 1990s. Comparison with observed active fire counts shows that the model reproduces where fire occurs and can mimic broad geographic patterns in the peak fire season, although the predicted peak is 1–2 months late in some regions. Modelled fire season length is generally overestimated by about one month, but shows a realistic pattern of differences among biomes. Comparisons with remotely sensed burnt-area products indicate that the model reproduces broad geographic patterns of annual fractional burnt area over most regions, including the boreal forest, although interannual variability in the boreal zone is underestimated.

scholarly journals Jet stream dynamics, hydroclimate, and fire in California from 1600 CE to present

2019 ◽  
Vol 116 (12) ◽  
pp. 5393-5398 ◽  
Author(s):  
Eugene R. Wahl ◽  
Eduardo Zorita ◽  
Valerie Trouet ◽  
Alan H. Taylor
Keyword(s):  
Native American ◽  
Forest Fire ◽  
Management Practices ◽  
Climate Model ◽  
Fire Suppression ◽  
Population Decline ◽  
Fire Regimes ◽  
Fire Season ◽  
Jet Stream ◽  
Wet Season

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regional hydroclimate and forest fire during the following warm season. We use climate model simulations and paleoclimate data to reconstruct winter NPJ characteristics back to 1571 CE to identify the influence of NPJ behavior on moisture and forest fire extremes in California before and during the more recent period of fire suppression. Maximum zonal NPJ velocity is lower and northward shifted and has a larger latitudinal spread during presuppression dry and high-fire extremes. Conversely, maximum zonal NPJ is higher and southward shifted, with narrower latitudinal spread during wet and low-fire extremes. These NPJ, precipitation, and fire associations hold across pre–20th-century socioecological fire regimes, including Native American burning, postcontact disruption and native population decline, and intensification of forest use during the later 19th century. Precipitation extremes and NPJ behavior remain linked in the 20th and 21st centuries, but fire extremes become uncoupled due to fire suppression after 1900. Simulated future conditions in California include more wet-season moisture as rain (and less as snow), a longer fire season, and higher temperatures, leading to drier fire-season conditions independent of 21st-century precipitation changes. Assuming continuation of current fire management practices, thermodynamic warming is expected to override the dynamical influence of the NPJ on climate–fire relationships controlling fire extremes in California. Recent widespread fires in California in association with wet extremes may be early evidence of this change.

scholarly journals Understanding the Impact of Different Landscape-Level Fuel Management Strategies on Wildfire Hazard in Central Portugal

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 522
Author(s):  
Akli Benali ◽  
Ana C. L. Sá ◽  
João Pinho ◽  
Paulo M. Fernandes ◽  
José M. C. Pereira
Keyword(s):  
Management Strategies ◽  
Treatment Strategies ◽  
Fire Season ◽  
Burned Area ◽  
Treatment Area ◽  
Fuel Treatment ◽  
The North ◽  
Wildfire Hazard ◽  
Central Portugal ◽  
The Impact

The extreme 2017 fire season in Portugal led to widespread recognition of the need for a paradigm shift in forest and wildfire management. We focused our study on Alvares, a parish in central Portugal located in a fire-prone area, which had 60% of its area burned in 2017. We evaluated how different fuel treatment strategies may reduce wildfire hazard in Alvares through (i) a fuel break network with different extents corresponding to different levels of priority and (ii) random fuel treatments resulting from a potential increase in stand-level management intensity. To assess this, we developed a stochastic wildfire simulation system (FUNC-SIM) that integrates uncertainties in fuel distribution over the landscape. If the landscape remains unchanged, Alvares will have large burn probabilities in the north, northeast and center-east areas of the parish that are very often associated with high fireline intensities. The different fuel treatment scenarios decreased burned area between 12.1–31.2%, resulting from 1–4.6% increases in the annual treatment area and reduced the likelihood of wildfires larger than 5000 ha by 10–40%. On average, simulated burned area decreased 0.22% per each ha treated, and cost-effectiveness decreased with increasing area treated. Overall, both fuel treatment strategies effectively reduced wildfire hazard and should be part of a larger, holistic and integrated plan to reduce the vulnerability of the Alvares parish to wildfires.

Forest management strategies for dealing with fire-related uncertainty when managing two forest seral stages

2011 ◽  
Vol 41 (2) ◽  
pp. 309-320 ◽  
Author(s):  
David W. Savage ◽  
David L. Martell ◽  
B. Mike Wotton
Keyword(s):  
Forest Management ◽  
Simulation Model ◽  
Sustainable Forest Management ◽  
Management Strategies ◽  
Fire Regimes ◽  
Analysis Tool ◽  
Planning Model ◽  
Minimum Area ◽  
Forest Management Planning ◽  
Planning Models

Ecological values are an important aspect of sustainable forest management, but little attention has been paid to maintaining these values when using traditional linear programming (LP) forest management planning models in uncertain planning environments. We embedded an LP planning model that specifies when and how much to harvest in a simulation model of a “managed” flammable forest landscape. The simulation model was used to evaluate two strategies for dealing with fire-related uncertainty when managing mature and old forest areas. The two seral stage areas were constrained in the LP planning model to a minimum of 10% of the total forest area and the strategies were evaluated under four representative fire regimes. We also developed a risk analysis tool that can be used by forest managers that wish to incorporate fire-related uncertainty in their decision-making. We found that use of the LP model would reduce the areas of the mature and old forest to their lower bound and fire would further reduce the seral areas below those levels, particularly when the mean annual burn fraction exceeds 0.45% per annum. Increasing the minimum area required (i.e., the right-hand side of the constraint) would increase the likelihood of satisfying the minimum area requirements.

scholarly journals Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America

Science ◽  
2009 ◽  
Vol 326 (5956) ◽  
pp. 1100-1103 ◽  
Author(s):  
J. L. Gill ◽  
J. W. Williams ◽  
S. T. Jackson ◽  
K. B. Lininger ◽  
G. S. Robinson
Keyword(s):  
North America ◽  
Plant Communities ◽  
Fire Regimes

Conodonts as biostratigraphic tools for redefinition and correlation of the Cambrian–Ordovician Boundary

1988 ◽  
Vol 125 (4) ◽  
pp. 349-362 ◽  
Author(s):  
J. F. Miller
Keyword(s):  
North America ◽  
Boundary Point ◽  
Outer Part ◽  
Head Group ◽  
Eastern Canada ◽  
Green Point ◽  
Hierarchical Arrangement ◽  
Stratotype Section ◽  
Evolutionary Lineages ◽  
Zones And Subzones

AbstractThe Cambrian–Ordovician Boundary is recognized at different horizons on various continents by utilizing several fossil groups. Conodonts are abundant, diverse, and less provincial and facies-controlled than other fossils in this interval; many species are widespread and some are cosmopolitan. Strata representing the Cambrian–Ordovician Boundary interval from Asia, Australia, and North America can be correlated easily when those strata are from cratonal or shelf environments. Strata from slope facies have fewer conodonts, fewer taxa, and taxa may have different ranges compared with cratonal and shelf facies. It may be easier to correlate intercontinentally within cratonal/shelf facies than to correlate intracontinentally from cratonal/shelf facies to slope facies.A new hierarchical arrangement of conodont interval zones and subzones is proposed for western North America. These include the Proconodontus tenuiserratus Zone, the P. posterocostatus Zone (new), the P. muelleri Zone (new), the Eoconodontus Zone (new, with Eoconodontus notchpeakensis and Cambrooistodus minutus Subzones), the Cordylodus proavus Zone (emended, with Hirsutodontus hirsutus, Fryxellodontus inornatus, and Clavohamulus elongatus Subzones), the Cordylodus intermedius Zone (new, with Hirsutodontus simplex and Clavohamulus hintzei Subzones), the Cordylodus lindstromi Zone (new), and Cordylodus angulatus Zone (new).The boundary point for the base of the Ordovician System will be chosen so as to coincide with a correlatable conodont zonal boundary; other fossil groups will support correlation of this boundary point. Three alternative horizons are being considered. The base of the Cordylodus proavus Zone is the most distinctive but is regarded by some as older than is appropriate for the base of the Ordovician. The base of the Cordylodus intermedius Zone is recognizable by faunal changes in several evolutionary lineages at a level that is slightly younger than the presently recognized boundary in Australia, North America, and parts of Asia but slightly older than the base of the Tremadoc Series of Europe. The base of the C. lindstromi Zone can be recognized in most areas by the lowest occurrence of the nominate species, which is of questioned taxonomic validity and uncertain biostratigraphic utility; this horizon is closest to the base of the Tremadoc Series of Europe.Choice of a stratotype section has been narrowed to the Cow Head Group in Newfoundland, eastern Canada; and to the Fengshan and Yehli formations in Jilin Province, northeastern China. The Cow Head Group was deposited on and near the base of the continental slope. Erosion by debrisslide breccias resulted in a significant hiatus near the boundary interval in the Broom Point sections, a condition contrary to guidelines for choice of boundary sections. This may be less of a problem in other sections, such as Green Point. The Dayangcha section in China was deposited on the outer part of a continental shelf and has acritarchs, conodonts, graptolites and trilobites. Additional study of the China section is needed to document fully the ranges of critical conodont taxa.

Spatial and temporal variations of fire regimes in the Canadian Rocky Mountains and Foothills of southern Alberta

2016 ◽  
Vol 25 (11) ◽  
pp. 1117 ◽  
Author(s):  
Marie-Pierre Rogeau ◽  
Mike D. Flannigan ◽  
Brad C. Hawkes ◽  
Marc-André Parisien ◽  
Rick Arthur
Keyword(s):  
Rocky Mountains ◽  
Fire History ◽  
Fire Severity ◽  
Ecological Integrity ◽  
Fire Regimes ◽  
Temporal Variations ◽  
Fire Season ◽  
Canadian Rocky Mountains ◽  
Southern Alberta ◽  
Fire Exclusion

Like many fire-adapted ecosystems, decades of fire exclusion policy in the Rocky Mountains and Foothills natural regions of southern Alberta, Canada are raising concern over the loss of ecological integrity. Departure from historical conditions is evaluated using median fire return intervals (MdFRI) based on fire history data from the Subalpine (SUB), Montane (MT) and Upper Foothills (UF) natural subregions. Fire severity, seasonality and cause are also documented. Pre-1948 MdFRI ranged between 65 and 85 years in SUB, between 26 and 35 years in MT and was 39 years in UF. The fire exclusion era resulted in a critical departure of 197–223% in MT (MdFRI = 84–104 years). The departure in UF was 170% (MdFRI = 104 years), while regions of continuous fuels in SUB were departed by 129% (MdFRI = 149 years). The most rugged region of SUB is within its historical range of variation with a departure of 42% (MdFRI = 121 years). More mixed-severity burning took place in MT and UF. SUB and MT are in a lightning shadow pointing to a predominance of anthropogenic burning. A summer fire season prevails in SUB, but occurs from spring to fall elsewhere. These findings will assist in developing fire and forest management policies and adaptive strategies in the future.

Sign in / Sign up

Export Citation Format

Share Document