scholarly journals Perturbation of the European free troposphere aerosol by North American forest fire plumes during the ICARTT-ITOP experiment in summer 2004

2007 ◽  
Vol 7 (19) ◽  
pp. 5105-5127 ◽  
Author(s):  
A. Petzold ◽  
B. Weinzierl ◽  
H. Huntrieser ◽  
A. Stohl ◽  
E. Real ◽  
...  
Keyword(s):  
Central Europe ◽  
Forest Fire ◽  
Forest Fires ◽  
General Circulation ◽  
Atmospheric Transport ◽  
Dispersion Model ◽  
Circulation Model ◽  
Distribution Width ◽  
Fire Plumes ◽  
Research Aircraft

Abstract. During the ICARTT-ITOP Experiment in summer 2004 plumes from large wildfires in North America were transported to Central Europe at 3–8 km altitude above sea level (a.s.l.). These plumes were studied with the DLR (Deutsches Zentrum fuer Luft- und Raumfahrt) research aircraft Falcon which was equipped with an extensive set of in situ aerosol and trace gas instruments. Analyses by the Lagrangian dispersion model FLEXPART provided source regions, transport times and horizontal extent of the fire plumes. Results from the general circulation model ECHAM/MADE and data from previous aerosol studies over Central Europe provided reference vertical profiles of black carbon (BC) mass concentrations for year 2000 conditions with forest fire activities below the long-term average. Smoke plume observations yielded a BC mass fraction of total aerosol mass with respect to PM 2.5 of 2–8%. The ratio of BC mass to excess CO was 3–7.5 mg BC (g CO)−1. Even after up to 10 days of atmospheric transport, both characteristic properties were of the same order as for fresh emissions. This suggests an efficient lifting of BC from forest fires to higher altitudes with only minor scavenging removal of particulate matter. Maximum aerosol absorption coefficient values were 7–8 Mm−1 which is about two orders of magnitude above the average European free tropospheric background value. Forest fire aerosol size distributions were characterised by a strong internally mixed accumulation mode centred at modal diameters of 0.25–0.30 µm with an average distribution width of 1.30. Nucleation and small Aitken mode particles were almost completely depleted.

scholarly journals Perturbation of the European free troposphere aerosol by North American forest fire plumes during the ICARTT-ITOP Experiment in summer 2004

2007 ◽  
Vol 7 (2) ◽  
pp. 4925-4979 ◽  
Author(s):  
A. Petzold ◽  
B. Weinzierl ◽  
H. Huntrieser ◽  
A. Stohl ◽  
E. Real ◽  
...  
Keyword(s):  
Central Europe ◽  
Forest Fire ◽  
Forest Fires ◽  
General Circulation ◽  
Atmospheric Transport ◽  
Dispersion Model ◽  
Circulation Model ◽  
Distribution Width ◽  
Fire Plumes ◽  
Research Aircraft

Abstract. During the ICARTT-ITOP Experiment in summer 2004 plumes from large wildfires in North America were transported to Central Europe at 3–8 km altitude above sea level (a.s.l.). These plumes were studied with the DLR (Deutsches Zentrum fuer Luft- und Raumfahrt) research aircraft Falcon which was equipped with an extensive set of in situ aerosol and trace gas instruments. Analyses by the Lagrangian dispersion model FLEXPART provided source regions, transport times and horizontal extent of the fire plumes. Results from the general circulation model ECHAM/MADE and data from previous aerosol studies over Central Europe provided reference vertical profiles of black carbon (BC) mass concentrations for year 2000 conditions with forest fire activities below the long-term average. Smoke plume observations yielded a BC mass fraction of total aerosol mass with respect to PM2.5 of 3–10%. The ratio of BC mass to excess CO was 3–7.5 mg BC (g CO)−1. Even after up to 10 days of atmospheric transport, both characteristic properties were of the same order as for fresh emissions. This suggests an efficient lifting of BC from forest fires to higher altitudes with only minor scavenging removal of particulate matter. Maximum aerosol absorption coefficient values were 7–8×10–6m−1 which is about two orders of magnitude above the average European free tropospheric background value. Forest fire aerosol size distributions were characterised by a strong internally mixed accumulation mode centred at modal diameters of 0.25–0.30 μm with an average distribution width of 1.30. Nucleation and small Aitken mode particles were almost completely depleted. Even after more than one week of atmospheric transport, no steady state of the size distribution was observed.

Future fire in Canada's boreal forest: paleoecology results and general circulation model - regional climate model simulations

2001 ◽  
Vol 31 (5) ◽  
pp. 854-864 ◽  
Author(s):  
Mike Flannigan ◽  
Ian Campbell ◽  
Mike Wotton ◽  
Christopher Carcaillet ◽  
Pierre Richard ◽  
...  
Keyword(s):  
Boreal Forest ◽  
General Circulation Model ◽  
Forest Fire ◽  
Forest Fires ◽  
General Circulation ◽  
Climate Model ◽  
Circulation Model ◽  
Regional Variability ◽  
Fire Weather Index ◽  
Model Simulations

General circulation model simulations suggest the Earth's climate will be 1–3.5°C warmer by AD 2100. This will influence disturbances such as forest fires, which are important to circumpolar boreal forest dynamics and, hence, the global carbon cycle. Many suggest climate warming will cause increased fire activity and area burned. Here, we use the Canadian Forest Fire Weather Index to simulate future forest fire danger, showing the expected increase in most of Canada but with significant regional variability including a decrease in much of eastern Canada. These results are in general agreement with paleoecological data and general circulation model results from the 6000 calendar years BP interval, which was a time of a warmer climate that may be an analogue for a future climate.

Forest fires in Russia: carbon dioxide emissions to the atmosphere

1993 ◽  
Vol 23 (4) ◽  
pp. 700-705 ◽  
Author(s):  
Robert K. Dixon ◽  
Olga N. Krankina
Keyword(s):  
Greenhouse Gases ◽  
General Circulation Model ◽  
Forest Fire ◽  
Forest Fires ◽  
General Circulation ◽  
Vegetation Change ◽  
Circulation Model ◽  
Fire Control ◽  
Fire Emissions ◽  
Biogenic Carbon

Boreal forests of Russia play a prominent role in the global carbon cycle and the flux of greenhouse gases to the atmosphere. Large areas of Russian forest burn annually, and contributions to the net flux of carbon to the atmosphere may be significant. Forest fire emissions were calculated for the years 1971–1991 using fire frequency and distribution data and fuel and carbon density for different forest ecoregions of Russia. Both direct carbon release and indirect post-fire biogenic carbon flux were estimated. From 1971 to 1991 the annual total forest area burned by wildfire ranged from 1.41 × 106 to 10.0 × 106 ha. Approximately 15 000–25 000 forest fires occurred annually during this period. Mean annual direct CO2-C emissions from wildfire was approximately 0.05 Pg over this 21-year period. Total post-fire biogenic CO2-C emissions for 1971–1991 ranged from 2.5 to 5.9 Pg (0.12–0.28 Pg annually). Forest fires and other disturbances are expected to be a primary mechanism driving vegetation change associated with projected global climate change. Future forest fire scenarios in Russia based on general circulation model projections suggest that up to 30–50% of the land surface area, or 334 × 106 to 631 × 106 ha of forest, will be affected. An additional 6.7 × 106 to 12.6 × 106 ha of Russian boreal forest are projected to burn annually if general circulation model based vegetation-change scenarios are achieved within the next 50 years. The direct flux of CO2-C from future forest fires is estimated to total 6.1–10.7 Pg over a 50-year period. Indirect post-fire biogenic release of greenhouse gases in the future is expected to be two to six times greater than direct emissions. Forest management and fire-control activities may help reduce wildfire severity and mitigate the associated pulse of greenhouse gases into the atmosphere.

scholarly journals Production of peroxy nitrates in boreal biomass burning plumes over Canada during the BORTAS campaign

2016 ◽  
Vol 16 (5) ◽  
pp. 3485-3497 ◽  
Author(s):  
Marcella Busilacchio ◽  
Piero Di Carlo ◽  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Cesare Dari Salisburgo ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Fire ◽  
Biomass Burning ◽  
Forest Fires ◽  
Chemical Mechanism ◽  
Fire Emissions ◽  
Fire Plumes ◽  
Peroxy Nitrates ◽  
In Fire ◽  
The Impact

Abstract. The observations collected during the BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign in summer 2011 over Canada are analysed to study the impact of forest fire emissions on the formation of ozone (O3) and total peroxy nitrates ∑PNs, ∑ROONO2). The suite of measurements on board the BAe-146 aircraft, deployed in this campaign, allows us to calculate the production of O3 and of  ∑PNs, a long-lived NOx reservoir whose concentration is supposed to be impacted by biomass burning emissions. In fire plumes, profiles of carbon monoxide (CO), which is a well-established tracer of pyrogenic emission, show concentration enhancements that are in strong correspondence with a significant increase of concentrations of ∑PNs, whereas minimal increase of the concentrations of O3 and NO2 is observed. The ∑PN and O3 productions have been calculated using the rate constants of the first- and second-order reactions of volatile organic compound (VOC) oxidation. The ∑PN and O3 productions have also been quantified by 0-D model simulation based on the Master Chemical Mechanism. Both methods show that in fire plumes the average production of ∑PNs and O3 are greater than in the background plumes, but the increase of ∑PN production is more pronounced than the O3 production. The average ∑PN production in fire plumes is from 7 to 12 times greater than in the background, whereas the average O3 production in fire plumes is from 2 to 5 times greater than in the background. These results suggest that, at least for boreal forest fires and for the measurements recorded during the BORTAS campaign, fire emissions impact both the oxidized NOy and O3,  but (1 ∑PN production is amplified significantly more than O3 production and (2) in the forest fire plumes the ratio between the O3 production and the ∑PN production is lower than the ratio evaluated in the background air masses, thus confirming that the role played by the ∑PNs produced during biomass burning is significant in the O3 budget. The implication of these observations is that fire emissions in some cases, for example boreal forest fires and in the conditions reported here, may influence more long-lived precursors of O3 than short-lived pollutants, which in turn can be transported and eventually diluted in a wide area.

A Synoptic Climatology for Forest-Fires in the NE US and Future Implications From GCM Simulations

1994 ◽  
Vol 4 (4) ◽  
pp. 217 ◽  
Author(s):  
ES Takle ◽  
DJ Bramer ◽  
WE Heilman ◽  
MR Thompson
Keyword(s):  
West Virginia ◽  
Forest Fire ◽  
Surface Pressure ◽  
Forest Fires ◽  
Circulation Model ◽  
Synoptic Climatology ◽  
Global Circulation Model ◽  
Weather Patterns ◽  
Forest Fire Danger ◽  
Drying Conditions

We studied surface-pressure patterns corresponding to reduced precipitation, high evaporation potential, and enhanced forest-fire danger for West Virginia, which experienced extensive forest-fire damage in November 1987. From five years of daily weather maps we identified eight weather patterns that describe distinctive flow situations throughout the year. Map patterns labeled extended-high, back-of-high, and pre-high were the most frequently occurring patterns that accompany forest fires in West Virginia and the nearby four-stare region. Of these, back-of-high accounted for a disproportionately large amount of fire-related damage. Examination of evaporation acid precipitation data showed that these three patterns and high-to-the-south patterns ail led to drying conditions and all other patterns led to moistening conditions. Surface-pressure fields generated by the Canadian Climate Centre global circulation model for simulations of the present (1xCO2) climate and 2xCO2 climate were studied to determine whether forest-fire potential would change under increased atmospheric CO2. The analysis showed a tendency for increased frequency of drying in the NE US, but the results were not statistically significant.

On the Synergistic Climatic Effects of Covarying Major Mountain Range Topographies

2020 ◽  
Author(s):  
Sebastian G. Mutz ◽  
Todd A. Ehlers
Keyword(s):  
General Circulation ◽  
Atmospheric Transport ◽  
Circulation Model ◽  
Careful Consideration ◽  
Mountain Range ◽  
Earth Surface ◽  
Climatic Effects ◽  
Climate Conditions ◽  
Mountain Ranges ◽  
The Impact

<p>The interpretation of Earth surface archives often requires consideration of distant off-site events. One such event is the surface uplift of Earth’s major mountain ranges, which affects climate and the Earth’s surface globally. In this study, the individual and synergistic climatic effects of topographic changes in major mountain ranges are explored with a series of General Circulation Model (GCM) experiments and analyses of atmospheric teleconnections. The GCM experiments are forced with different topographic scenarios for Himalaya-Tibet (TBT) and the Andes (ADS), while environmental boundary conditions are kept constant. The topographic scenarios are constructed by successively lowering modern topography to 0% of its modern height in increments of 25%. This results in a total of 5 topographic scenarios for TBT (tbt100, tbt075, tbt050, tbt025, tbt000) and ADS (ads100, ads075, ads050, ads025, ads000). TBT scenarios are then nested in ADS scenarios, resulting in a total of 25 experiments with unique topographic settings. The climate for each of those 25 scenarios is simulated with the GCM ECHAM5-wiso. We then explore possible synergies and distant impacts of topographic changes by testing the hypothesis that varying ADS has no effect on simulated climate conditions in the TBT region (c_tbt) and vice versa. This can be expressed as the null hypothesis c_tbt(ads100) = c_tbt(ads075) = c_tbt(ads050) = c_tbt(ads025) = c_tbt(ads000) for each of the 5 TBT scenarios, and vice versa. We conduct Kruskal-Wallis tests for a total of 10 treatment sets to address these hypotheses. The results suggest that ADS climate is mostly independent of TBT topography changes, whereas TBT climate is sensitive to ADS topography changes when TBT topography is high, but insensitive when TBT topography is strongly reduced. Analyses of atmospheric pressure fields suggest that TBT height acts as a control on cross-equatorial atmospheric transport and modifies the impact of ADS topography on northern hemisphere climate. These results dictate a more careful consideration of global (off-site) conditions in the interpretation of Earth surface records.</p>

scholarly journals Relations between Northward Ocean and Atmosphere Energy Transports in a Coupled Climate Model

2008 ◽  
Vol 21 (3) ◽  
pp. 561-575 ◽  
Author(s):  
Michael Vellinga ◽  
Peili Wu
Keyword(s):  
Heat Transport ◽  
General Circulation ◽  
Energy Transport ◽  
Climate Model ◽  
Atmospheric Transport ◽  
Circulation Model ◽  
Meridional Overturning Circulation ◽  
Ocean Heat Transport ◽  
Poleward Heat Transport ◽  
Low Latitudes

Abstract The Third Hadley Centre Coupled Ocean–Atmosphere General Circulation Model (HadCM3) is used to analyze the relation between northward energy transports in the ocean and atmosphere at centennial time scales. In a transient water-hosing experiment, where suppressing the Atlantic meridional overturning circulation (MOC) causes a reduction in northward ocean heat transport of up to 0.75 PW (i.e., 75%), the atmosphere compensates by increasing its northward transport of moist static energy. This compensation is very efficient at low latitudes and near complete at the equator throughout the experiment, but is incomplete farther north across the northern midlatitude storm tracks. The change in atmosphere energy transport enables the model to find a new global-mean radiative equilibrium after 240 yr. In a perturbed physics ensemble of HadCM3 it was found that time-averaged meridional energy transports in ocean and atmosphere can act opposingly. Where model formulation causes an unbalanced mean climate state, for example, an excessive top-of-the-atmosphere radiative surplus at low latitudes, the atmosphere increases its poleward energy transport to disperse this excess. MOC and ocean poleward heat transport tend to be reduced in such model versions, and this offsets the increased poleward atmospheric transport of the low-latitude energy surplus. Model versions that are close to net radiative equilibrium also have ocean heat transport and MOC close to observed values.

scholarly journals A case study of pyro-convection using transport model and remote sensing data

2006 ◽  
Vol 6 (1) ◽  
pp. 173-185 ◽  
Author(s):  
R. Damoah ◽  
N. Spichtinger ◽  
R. Servranckx ◽  
M. Fromm ◽  
E. W. Eloranta ◽  
...  
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Transport Model ◽  
Dispersion Model ◽  
Deep Convection ◽  
Particle Dispersion ◽  
Convective Transport ◽  
Yukon Territory ◽  
Pollutant Emissions ◽  
Fire Emissions

Abstract. Summer 2004 saw severe forest fires in Alaska and the Yukon Territory that were mostly triggered by lightning strikes. The area burned (>2.7×106 ha) in the year 2004 was the highest on record to date in Alaska. Pollutant emissions from the fires lead to violation of federal standards for air quality in Fairbanks. This paper studies deep convection events that occurred in the burning regions at the end of June 2004. The convection was likely enhanced by the strong forest fire activity (so-called pyro-convection) and penetrated into the lower stratosphere, up to about 3 km above the tropopause. Emissions from the fires did not only perturb the UT/LS locally, but also regionally. POAM data at the approximate location of Edmonton (53.5° N, 113.5° W) show that the UT/LS aerosol extinction was enhanced by a factor of 4 relative to unperturbed conditions. Simulations with the particle dispersion model FLEXPART with the deep convective transport scheme turned on showed transport of forest fire emissions into the stratosphere, in qualitatively good agreement with the enhancements seen in the POAM data. A corresponding simulation with the deep convection scheme turned off did not result in such deep vertical transport. Lidar measurements at Wisconsin on 30 June also show the presence of substantial aerosol loading in the UT/LS, up to about 13 km. In fact, the FLEXPART results suggest that this aerosol plume originated from the Yukon Territory on 25 June.

scholarly journals A subsiding regional forest fire aerosol layer at Whistler, BC: implications for interpretation of mountaintop chemistry observations

2010 ◽  
Vol 10 (8) ◽  
pp. 20303-20327
Author(s):  
I. G. Mc Kendry ◽  
J. Gallagher ◽  
P. Campuzano Jost ◽  
A. Bertram ◽  
K. Strawbridge ◽  
...  
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Aerosol Layer ◽  
Synoptic Scale ◽  
Fire Plume ◽  
Fire Plumes ◽  
Physico Chemical ◽  
Air Chemistry ◽  
Regional Forest ◽  
Remote Sensing Methods

Abstract. On 30 August 2009, intense forest fires in interior BC, together with synoptic scale meteorological subsidence and easterly winds resulted in transport of a broad forest fire plume across southwestern BC. The physico-chemical and optical characteristics of the plume as observed from Saturna island (AERONET), CORALNet-UBC and the Whistler Mountain air chemistry facility were consistent with forest fire plumes that have been observed elsewhere in continental North America. However, the importance of smoke plume subsidence in relation to the interpretation of mountaintop chemistry observations is highlighted on the basis of deployment both a CL31 ceilometer and a single particle mass spectrometer (SPMS) in a mountainous setting. The SPMS was used to identify the biomass plume based on levoglucosan and potassium markers. Data from the SPMS are also used to show that the biomass plume was correlated with nitrate, but not correlated with sulphate or sodium. This study not only provides baseline measurements of biomass burning plume physico-chemical characteristics in western Canada, but also highlights the importance of lidar remote sensing methods in the interpretation of mountaintop chemistry measurements.

scholarly journals Horizontal and vertical structure of the Eyjafjallajökull ash cloud over the UK: a comparison of airborne lidar observations and simulations

2012 ◽  
Vol 12 (4) ◽  
pp. 9125-9159 ◽  
Author(s):  
A. L. M. Grant ◽  
H. F. Dacre ◽  
D. J. Thomson ◽  
F. Marenco
Keyword(s):  
Vertical Structure ◽  
Atmospheric Transport ◽  
Dispersion Model ◽  
Atmospheric Dispersion ◽  
General Purpose ◽  
Airborne Lidar ◽  
Research Aircraft ◽  
The Uk ◽  
Ash Cloud ◽  
Eruption Plume

Abstract. During April and May 2010 the ash cloud from the eruption of the Icelandic volcano Eyjafjallajökull caused widespread disruption to aviation over northern Europe. Because of the location and impact of the eruption a wealth of observations of the ash cloud were obtained and can be used to assess modelling of the long range transport of ash in the troposphere. The UK's BAe-146-301 Atmospheric Research Aircraft overflew the ash cloud on a number of days during May. The aircraft carries a downward looking lidar which detected the ash layer through the backscatter of the laser light. The ash concentrations are estimated from lidar extinction coefficients and in situ measurements of the ash particle size distributions. In this study these estimates of the ash concentrations are compared with simulations of the ash cloud made with NAME (Numerical Atmospheric-dispersion Modelling Environment), a general purpose atmospheric transport and dispersion model. The ash layers seen by the lidar were thin, with typical depths of 550–750 m. The vertical structure of the ash cloud simulated by NAME was generally consistent with the observed ash layers. The layers in the simulated ash clouds that could be identified with observed ash layers are about twice the depth of the observed layers. The structure of the simulated ash clouds were sensitive to the profile of ash emissions that was assumed. In terms of horizontal and vertical structure the best results were mainly obtained by assuming that the emission occurred at the top of the eruption plume, consistent with the observed structure of eruption plumes. However, when the height of the eruption plume was variable and the eruption was weak, then assuming that the emission of ash was uniform with height gave better guidance on the horizontal and vertical structure of the ash cloud. Comparison between the column masses in the simulated and observed ash layers suggests that about 3% of the total mass erupted by the volcano remained in the ash cloud over the United Kingdom. The problems with the interpretation of this estimate of the distal fine ash fraction are discussed.

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