scholarly journals Asymmetrical Lightning Fire Season Expansion in the Boreal Forest of Northeast China

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1023
Author(s):  
Cong Gao ◽  
Ran An ◽  
Wenqian Wang ◽  
Chunming Shi ◽  
Mingyu Wang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Boreal Forest ◽  
Northeast China ◽  
Early Spring ◽  
Snow Accumulation ◽  
Fire Season ◽  
Fuel Moisture ◽  
Julian Date ◽  
Lightning Fire

All-season warming is assumed to advance snowmelt and delay snow accumulation; additionally, coupled with warming-induced drought stress, all-season warming could extend both the beginning and the end of the fire season. Using fire data updated for 1968–2018, we found an asymmetrical expansion of the lightning fire season in the boreal forest of Northeast China. Lightning fires have not advanced into the early fire season (May–June) but have largely extended into the snowless late fire season (July–September) since the late 1990s (mean end Julian date delayed by 51.1 days for 1998–2018 compared with 1968–1997, p < 0.001). Despite significant warming, the Julian days of snowmelt have changed only slightly, which has prohibited the fire season from advancing into early spring. The expansion of lightning fires into July–September was associated with a warming-induced significant increase in evapotranspiration and a decrease in soil/fuel moisture.

Asymmetrical Lightning-ignited Fire Season Expansion in the Boreal Forest of Northeast China

2020 ◽  
Author(s):  
Chunming Shi ◽  
Gao Cong ◽  
Liu Kezhen ◽  
Wu Xiaoxu ◽  
Wu Guocan ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Northeast China ◽  
Fire Season

EVALUATION OF CLOVERS ON SANDY COASTAL SOIL

1977 ◽  
pp. 130-138 ◽  
Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper
Keyword(s):  
New Zealand ◽  
Drought Stress ◽  
Sandy Soil ◽  
White Clover ◽  
Plant Material ◽  
Red Clover ◽  
Early Spring ◽  
Commercial Cultivars ◽  
Mediterranean Origin ◽  
Winter Annual

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.

scholarly journals Evaluating the Effects of Projected Climate Change on Forest Fuel Moisture Content

2014 ◽  
Vol 37 ◽  
pp. 65-69
Author(s):  
Kellen Nelson ◽  
Daniel Tinker
Keyword(s):  
Climate Change ◽  
Moisture Content ◽  
Stand Structure ◽  
Canopy Cover ◽  
Fire Season ◽  
Climate Change Scenarios ◽  
Fuel Moisture ◽  
Mature Forest ◽  
Forest Fuel ◽  
Fuel Moisture Content

Understanding how live and dead forest fuel moisture content (FMC) varies with seasonal weather and stand structure will improve researchers’ and forest managers’ ability to predict the cumulative effects of weather on fuel drying during the fire season and help identify acute conditions that foster wildfire ignition and high rates of fire spread. No studies have investigated the efficacy of predicting FMC using mechanistic water budget models at daily time scales through the fire season nor have they investigated how FMC may vary across space. This study addresses these gaps by (1) validating a novel mechanistic live FMC model and (2) applying this model with an existing dead FMC model at three forest sites using five climate change scenarios to characterize how FMC changes through time and across space. Sites include post-fire 24-year old forest, mature forest with high canopy cover, and mature forest affected by the mountain pine beetle with moderate canopy cover. Climate scenarios include central tendency, warm/dry, warm/wet, hot/dry, and hot/wet.

Effects of drought stress on growth, physiology and secondary metabolites of Two Adonis species in Northeast China

2020 ◽  
Vol 259 ◽  
pp. 108795 ◽  
Author(s):  
Shanshan Gao ◽  
Yanlin Wang ◽  
Shuai Yu ◽  
Yanqing Huang ◽  
Huanchu Liu ◽  
...  
Keyword(s):  
Drought Stress ◽  
Secondary Metabolites ◽  
Northeast China ◽  
Growth Physiology ◽  
Effects Of Drought

scholarly journals Arctic sea-ice albedo derived from RGPS-based ice-thickness estimates

2001 ◽  
Vol 33 ◽  
pp. 225-229 ◽  
Author(s):  
R.W. Lindsay
Keyword(s):  
Sea Ice ◽  
Empirical Relationship ◽  
Early Spring ◽  
Snow Accumulation ◽  
Arctic Sea Ice ◽  
Ice Thickness ◽  
First Year ◽  
Large Set ◽  
Radar Images ◽  
Arctic Sea

AbstractThe RADARSAT geophysical processor system (RGPS) uses sequential synthetic aperture radar images of Arctic sea ice taken every 3 days to track a large set of Lagrangian points over the winter and spring seasons. The points are the vertices of cells, which are initially square and 10 km on a side, and the changes in the area of these cells due to opening and closing of the ice are used to estimate the fractional area of a set of first-year ice categories. The thickness of each category is estimated by the RGPS from an empirical relationship between ice thickness and the freezing degree-days since the formation of the ice. With a parameterization of the albedo based on the ice thickness, the albedo may be estimated from the first-year ice distribution. We compute the albedo for the first spring processed by the RGPS, the early spring of 1997. The data include most of the Beaufort and Chukchi Seas. We find that the mean albedo is 0.79 with a standard deviation of 0.04, with lower albedo values near the edge of the perennial ice zone. The biggest source of error is likely the assumed rate of snow accumulation on new ice.

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).

The Massive New Year 2020 pyroCb Event in Australia: Observations of Unprecedented Stratospheric Smoke

2020 ◽  
Author(s):  
Michael Fromm ◽  
George Kablick III
Keyword(s):  
Remote Sensing ◽  
Pacific Northwest ◽  
Satellite Remote Sensing ◽  
Remote Sensing Data ◽  
Early Spring ◽  
Fire Season ◽  
Smoke Plume ◽  
South Wales ◽  
Stratospheric Composition ◽  
The Impact

&lt;p&gt;The 2019/2020 fire season in Australia has been unusually energetic since early spring. In the last days of December and early January an unprecedented number of pyrocumulonimbus (pyroCb) storms erupted in New South Wales and Victoria, creating a seemingly unrivaled stratospheric smoke plume as well as devastation on the ground. Preliminary indications from satellite remote sensing are that the clustering of active pyroCbs and smoke injection heights exceeded all previous Australian pyroCb events, and perhaps pyroCb events worldwide. Similar to another extraordinary pyroCb event, the so-called Pacific Northwest Event in 2017, the Australian smoke plume has been observed to rise above its injection altitude by several kilometers. We report on the active blowups and quantify the impact on stratospheric composition using satellite remote sensing. Our analysis also consists of a quantitative comparison of the 2019/20 Australian pyrocb event with other major pyroCb events such as Black Saturday, Victoria, Australia in 2009. At the time of submission of this abstract, this is an unfolding episode; our report will characterize the unusual nature of this pyroCb event as the evolving plume and satellite remote sensing data permit.&lt;/p&gt;

Fire weather index system components for large fires in the Canadian boreal forest

2004 ◽  
Vol 13 (4) ◽  
pp. 391 ◽  
Author(s):  
B. D. Amiro ◽  
K. A. Logan ◽  
B. M. Wotton ◽  
M. D. Flannigan ◽  
J. B. Todd ◽  
...  
Keyword(s):  
Weather Conditions ◽  
Fire Season ◽  
Fire Weather ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
System Parameters ◽  
System Components ◽  
Large Fires ◽  
Canadian Boreal Forest

Canadian Fire Weather Index (FWI) System components and head fire intensities were calculated for fires greater than 2 km2 in size for the boreal and taiga ecozones of Canada from 1959 to 1999. The highest noon-hour values were analysed that occurred during the first 21 days of each of 9333 fires. Depending on ecozone, the means of the FWI System parameters ranged from: fine fuel moisture code (FFMC), 90 to 92 (82 to 96 for individual fires); duff moisture code (DMC), 38 to 78 (10 to 140 for individual fires); drought code (DC), 210 to 372 (50 to 600 for individual fires); and fire weather index, 20 to 33 (5 to 60 for individual fires). Fine fuel moisture code decreased, DMC had a mid-season peak, and DC increased through the fire season. Mean head fire intensities ranged from 10 to 28 MW m−1 in the boreal spruce fuel type, showing that most large fires exhibit crown fire behaviour. Intensities of individual fires can exceed 60 MW m−1. Most FWI System parameters did not show trends over the 41-year period because of large inter-annual variability. A changing climate is expected to create future weather conditions more conducive to fire throughout much of Canada but clear changes have not yet occurred.

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