scholarly journals Mega fire emissions in Siberia: potential supply of bioavailable iron from forests to the ocean

2011 ◽  
Vol 8 (6) ◽  
pp. 1679-1697 ◽  
Author(s):  
A. Ito
Keyword(s):  
Spatial Distribution ◽  
Forest Fires ◽  
Transport Model ◽  
Burned Area ◽  
Emission Rates ◽  
Chemistry Transport Model ◽  
Fire Emissions ◽  
Soluble Iron ◽  
Atmospheric Processing ◽  
Dust Sources

Abstract. Significant amounts of carbon and nutrients are released to the atmosphere due to large fires in forests. Characterization of the spatial distribution and temporal variation of the intense fire emissions is crucial for assessing the atmospheric loadings of trace gases and aerosols. This paper discusses issues of the representation of forest fires in the estimation of emissions and the application to an atmospheric chemistry transport model (CTM). The potential contribution of forest fires to the deposition of bioavailable iron (Fe) into the ocean is highlighted, with a focus on mega fires in eastern Siberia. Satellite products of burned area, active fire, and land cover are used to estimate biomass burning emissions in conjunction with a biogeochemical model. Satellite-derived plume height from MISR is used for the injection height of boreal forest fire emissions. This methodology is applied to quantify fire emission rates in each three-dimensional grid location in the high latitude Northern Hemisphere (>30° N latitude) over a 5-yr period from 2001 to 2005. There is large interannual variation in forest burned area during 2001–2005 (13–49 × 103 km2 yr−1) which results in a corresponding variation in the annual emissions of carbon monoxide (CO) (14–81 Tg CO y−1). Satellite observations of CO column from MOPITT are used to evaluate the model performance in simulating the spatial distribution and temporal variation of the fire emissions. The model results for CO enhancements due to eastern Siberian fires are in good agreement with MOPITT observations. These validation results suggest that the model using emission rates estimated in this work is able to describe the interannual changes in CO due to intense forest fires. Bioavailable iron is derived from atmospheric processing of relatively insoluble iron from desert sources by anthropogenic pollutants (mainly sulfuric acid formed from oxidation of SO2) and from direct emissions of soluble iron from combustion sources. Emission scenarios for IPCC AR5 report (Intergovernmental Panel on Climate Change; Fifth Assessment Report) suggest that anthropogenic SO2 emissions are suppressed in the future to improve air quality. In future warmer and drier climate, severe fire years such as 2003 may become more frequent in boreal regions. The fire emission rates estimated in this study are applied to the aerosol chemistry transport model to examine the relative importance of biomass burning sources of soluble iron compared to those from dust sources. The model reveals that extreme fire events contribute to a significant deposition of soluble iron (20–40 %) to downwind regions over the western North Pacific Ocean, compared to the dust sources with no atmospheric processing by acidic species. These results suggest that the supply of nutrients from large forest fires plays a role as a negative biosphere-climate feedback with regards to the ocean fertilization.

scholarly journals Mega fire emissions in Siberia: potential supply of soluble iron from forests to the ocean

2011 ◽  
Vol 8 (1) ◽  
pp. 1483-1527
Author(s):  
A. Ito
Keyword(s):  
Spatial Distribution ◽  
Biomass Burning ◽  
Forest Fires ◽  
Transport Model ◽  
Burned Area ◽  
Emission Rates ◽  
Chemistry Transport Model ◽  
Fire Emissions ◽  
Soluble Iron ◽  
Dust Sources

Abstract. Significant amounts of carbon and nutrients are released to the atmosphere due to large fires in forests. Characterization of the spatial distribution and temporal variation of the intense fire emissions is crucial for assessing the atmospheric loadings of aerosols and trace gases. This paper discusses issues of the representation of forest fires in the estimation of emissions and the application to an atmospheric chemistry transport model (CTM). The potential contribution of forest fires to the deposition of soluble iron (Fe) into the ocean is highlighted, with a focus on mega fires in eastern Siberia. Satellite products of burned area, active fire, and land cover are used to estimate biomass burning emissions in conjunction with a biogeochemical model. Satellite-derived plume height from MISR is used for the injection height of boreal forest fire emissions. This methodology is applied to quantify fire emission rates in each three-dimensional grid location in the high latitude Northern Hemisphere (> 30° N latitude) over a 5-year period from 2001 to 2005. There is large interannual variation in forest burned area during 2001–2005 (13–51 × 103 km2 yr−1) which results in a corresponding variation in the annual emissions of carbon monoxide (CO) (12–78 Tg CO yr−1). Satellite observations of CO from MOPITT are used to evaluate the model performance in simulating the spatial distribution and temporal variation of the fire emissions. During the major Siberian fire seasons in the summer of 2002 and in the spring of 2003, the model results for CO enhancements due to intense fires are in good agreement with MOPITT observations. These fire emission rates are applied to the aerosol chemistry transport model to examine the relative importance of biomass burning sources of soluble iron compared to those from dust sources. Compared to the dust sources without the atmospheric processing by acidic species, extreme fire events contribute to a significant deposition of soluble iron (10–60%) to downwind regions over the western North Pacific Ocean. It may imply that the supply of nutrients from large forest fires plays a role as a negative biosphere-climate feedback with regards to the ocean fertilization.

scholarly journals Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data

2004 ◽  
Vol 4 (7) ◽  
pp. 1857-1868 ◽  
Author(s):  
N. Spichtinger ◽  
R. Damoah ◽  
S. Eckhardt ◽  
C. Forster ◽  
P. James ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Fire ◽  
Transport Model ◽  
Hot Spot ◽  
Measurement Data ◽  
Atmospheric Composition ◽  
Burned Area ◽  
Strong Impact ◽  
Tracer Transport ◽  
Fire Emissions

Abstract. Forest fire emissions have a strong impact on the concentrations of trace gases and aerosols in the atmosphere. In order to quantify the influence of boreal forest fire emissions on the atmospheric composition, the fire seasons of 1997 and 1998 are compared in this paper. Fire activity in 1998 was very strong, especially over Canada and Eastern Siberia, whereas it was much weaker in 1997. According to burned area estimates the burning in 1998 was more than six times as intense as in 1997. Based on hot spot locations derived from ATSR (Along Track Scanning Radiometer) data and official burned area data, fire emissions were estimated and their transport was simulated with a Lagrangian tracer transport model. Siberian and Canadian forest fire tracers were distinguished to investigate the transport of both separately. The fire emissions were transported even over intercontinental distances. Due to the El Niño induced meteorological situation, transport from Siberia to Canada was enhanced in 1998. Siberian fire emissions were transported towards Canada and contributed concentrations more than twice as high as those due to Canada's own CO emissions by fires. In 1998 both tracers arrive at higher latitudes over Europe, which is due to a higher North Atlantic Oscillation (NAO) index in 1998. The simulated emission plumes are compared to CMDL (Climate Monitoring and Diagnostics Laboratory) CO2 and CO data, Total Ozone Mapping Spectrometer (TOMS) aerosol index (AI) data and Global Ozone Monitoring Experiment (GOME) tropospheric NO2 and HCHO columns. All the data show clearly enhanced signals during the burning season of 1998 compared to 1997. The results of the model simulation are in good agreement with ground-based as well as satellite-based measurements.

scholarly journals The sensitivity of CO and aerosol transport to the temporal and vertical distribution of North American boreal fire emissions

2009 ◽  
Vol 9 (3) ◽  
pp. 11951-12006 ◽  
Author(s):  
Y. Chen ◽  
Q. Li ◽  
J. T. Randerson ◽  
E. A. Lyons ◽  
R. A. Kahn ◽  
...  
Keyword(s):  
North America ◽  
Biomass Burning ◽  
Forest Fires ◽  
Transport Model ◽  
Source Region ◽  
Fire Season ◽  
Height Distribution ◽  
Chemical Transport Model ◽  
Fire Emissions ◽  
Fire Source

Abstract. Forest fires in Alaska and West Canada represent important sources of aerosols and trace gases in North America. Among the largest uncertainties when modeling forest fire effects are the timing and injection height of biomass burning emissions. Here we simulate CO and aerosols over North America during the 2004 fire season, using the GEOS-Chem chemical transport model. We apply different temporal distributions and injection height profiles to the biomass burning emissions, and compare model results with satellite-, aircraft-, and ground-based measurements. We find that averaged over the fire season, the use of finer temporal resolved biomass burning emissions usually decreases CO and aerosol concentrations near the fire source region, and often enhances long-range transport. Among the individual temporal constraints, switching from monthly to 8-day time intervals for emissions has the largest effect on CO and aerosol distributions, and shows better agreement with measured day-to-day variability. Injection height substantially modifies the surface concentrations and vertical profiles of pollutants near the source region. In comparison with CO, the simulation of black carbon aerosol is more sensitive to the temporal and injection height distribution of emissions. The use of MISR-derived injection height improves agreement with surface aerosol measurements near the fire source. Our results indicate that the discrepancies between model simulations and MOPITT CO measurements near the Hudson Bay can not be attributed solely to the representation of injection height within the model. Frequent occurrence of strong convection in North America during summer tends to limit the influence of injection height distribution of fire emissions in Alaska and West Canada on CO and aerosol distributions over eastern North America.

scholarly journals Constraining CO<sub>2</sub> emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia

2014 ◽  
Vol 14 (2) ◽  
pp. 3099-3168 ◽  
Author(s):  
I. B. Konovalov ◽  
E. V. Berezin ◽  
P. Ciais ◽  
G. Broquet ◽  
M. Beekmann ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Biomass Burning ◽  
Transport Model ◽  
Regional Scale ◽  
Satellite Observations ◽  
Emission Model ◽  
Chemistry Transport Model ◽  
Conversion Factors ◽  
Fire Emissions ◽  
Global Emission

Abstract. A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2 emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the Fire Radiative Power (FRP) derived from the MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated by using the IASI carbon monoxide (CO) retrievals and the MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry transport model. The constrained CO emissions are validated through comparison of the respective simulations with the independent data of ground based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with the earlier published estimates obtained from local measurements of experimental fires), the total CO2 emissions from wildfires in Siberia in 2012 are estimated to be in the range from 262 to 477 Tg C, with the optimal (maximum likelihood) value of 354 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2 emissions in Siberia are robust with respect to the modelling options (the different estimates vary within less than 10% of their magnitude). The obtained CO2 emission estimates for several years are compared with the independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2 emissions in the period from 2007 to 2011 in Siberia are by factors of 2.3 and 1.7 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis.

scholarly journals Evolution of aerosol optical thickness over Europe during the August 2003 heat wave as seen from CHIMERE model simulations and POLDER data

2006 ◽  
Vol 6 (7) ◽  
pp. 1853-1864 ◽  
Author(s):  
A. Hodzic ◽  
R. Vautard ◽  
H. Chepfer ◽  
P. Goloub ◽  
L. Menut ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Forest Fires ◽  
Atmospheric Aerosol ◽  
Large Scale ◽  
Transport Model ◽  
Anthropogenic Sources ◽  
Chemistry Transport Model ◽  
Model Simulations ◽  
High Particle ◽  
Sun Photometer

Abstract. This study describes the atmospheric aerosol load encountered during the large-scale pollution episode that occurred in August 2003, by means of the aerosol optical thicknesses (AOTs) measured at 865 nm by the Polarization and Directionality of the Earth's Reflectances (POLDER) sensor and the simulation by the CHIMERE chemistry-transport model. During this period many processes (stagnation, photochemistry, forest fires) led to unusually high particle concentrations and optical thicknesses. The observed/simulated AOT comparison helps understanding the ability of the model to reproduce most of the gross AOT features observed in satellite data, with a general agreement within a factor 2 and correlations in the 0.4–0.6 range. However some important aerosol features are missed when using regular anthropogenic sources. Additional simulations including emissions and high-altitude transport of smoke from wildfires that occurred in Portugal indicate that these processes could dominate the AOT signal in some areas. Our results also highlight the difficulties of comparing simulated and POLDER-derived AOTs due to large uncertainties in both cases. Observed AOT values are significantly lower than the simulated ones (30–50%). Their comparison with the ground-based Sun photometer Aerosol Robotic Network (AERONET) measurements suggests, for the European sites considered here, an underestimation of POLDER-derived aerosol levels with a factor between 1 and 2. AERONET AOTs compare better with simulations (no particular bias) than POLDER AOTs.

scholarly journals The empirical relationship between satellite-derived tropospheric NO<sub>2</sub> and fire radiative power and possible implications for fire emission rates of NO<sub>x</sub>

2014 ◽  
Vol 14 (5) ◽  
pp. 2447-2466 ◽  
Author(s):  
S. F. Schreier ◽  
A. Richter ◽  
J. W. Kaiser ◽  
J. P. Burrows
Keyword(s):  
Empirical Relationship ◽  
Fire Intensity ◽  
Burned Area ◽  
Emission Rates ◽  
Monthly Means ◽  
Fire Emissions ◽  
Vegetation Fires ◽  
Radiative Power ◽  
The Tropics ◽  
Fire Radiative Power

Abstract. Nitrogen oxides (NOx) play key roles in atmospheric chemistry, air pollution, and climate. While the largest fraction of these reactive gases is released by anthropogenic emission sources, a significant amount can be attributed to vegetation fires. In this study, NO2 from GOME-2 on board EUMETSAT's MetOp-A and OMI on board NASA's Aura as well as fire radiative power (FRP) from the measurements of MODIS on board NASA's Terra and Aqua satellites are used to derive fire emission rates (FERs) of NOx for different types of vegetation using a simple statistical approach. Monthly means of tropospheric NO2 vertical columns (TVC NO2) have been analyzed for their temporal correlation with the monthly means of FRP for five consecutive years from 2007 to 2011 on a horizontal 1° × 1° grid. The strongest correlation is found to be largely confined to tropical and subtropical regions, which account for more than 80% of yearly burned area, on average, globally. In these regions, the seasonal variation of fire intensity, expressed by the FRP data, is similar to the pattern of TVC NO2. As chemical models typically require values for the amount of NOx being released as a function of time, we have converted the retrieved TVC NO2 into production rates of NOx from fire (Pf) by assuming a constant lifetime of NOx. The comparison between Pf and NOx emissions from the Global Fire Emissions Database (GFEDv3.1) over 5 characteristic biomass burning regions in the tropics and subtropics shows good agreement. By separating the monthly means of Pf and FRP according to land cover type, FERs of NOx could be derived for different biomes. The estimated FERs for the dominating types of vegetation burned are lowest for open shrublands and savannas (0.28–1.03 g NOx s−1 MW−1) and highest for croplands and woody savannas (0.82–1.56 g NOx s−1 MW−1). This analysis demonstrates that the strong empirical relationship between TVC NO2 and FRP and the following simplified assumptions are a useful tool for the characterization of NOx emission rates from vegetation fires in the tropics and subtropics. Possible factors affecting the magnitude of the obtained values are discussed.

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 Interaction of anthropogenic and natural emission sources during a wild-land fire event – influence on ozone formation

2012 ◽  
Vol 12 (1) ◽  
pp. 3467-3507
Author(s):  
E. Bossioli ◽  
M. Tombrou ◽  
A. Karali ◽  
A. Dandou ◽  
D. Paronis ◽  
...  
Keyword(s):  
Eastern Europe ◽  
Transport Model ◽  
Biogenic Emissions ◽  
Fire Event ◽  
Chemistry Transport Model ◽  
Fire Emissions ◽  
Natural Emission ◽  
Lower Ratio ◽  
The Impact ◽  
Surface O3

Abstract. The objective of this study is to investigate the contribution of biomass burning in the formation of tropospheric O3. Furthermore, the impact of biogenic emissions under fire and no fire conditions is examined. This is achieved by applying the CAMx chemistry transport model for a wild-land fire event over Western Russia (24 April–10 May 2006). The model results are compared with O3 and isoprene observations from 117 and 9 stations of the EMEP network, respectively. Model computations show that the fire episode altered the O3 sensitivity in the area. In particular, the fire emissions increased surface O3 over Northern and Eastern Europe by up to 80% (40–45 ppb). In case of adopting a high fire NOx/CO emission ratio (0.06), the area (Eastern Europe and Western Russia) is characterized by VOC-sensitive O3 production and the impact of biogenic emissions is proven significant, contributing up to 8 ppb. Under a lower ratio (0.025), total surface O3 is almost doubled due to higher O3 production at the fire spots and lower fires' NO emissions. In this case as well as in the absence of fires, the impact of biogenic emissions is almost negligible. Injection height of the fire emissions accounted for O3 differences of the order of 10%, both at surface and over the planetary boundary layer (PBL).

scholarly journals Constraining CO<sub>2</sub> emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia

2014 ◽  
Vol 14 (19) ◽  
pp. 10383-10410 ◽  
Author(s):  
I. B. Konovalov ◽  
E. V. Berezin ◽  
P. Ciais ◽  
G. Broquet ◽  
M. Beekmann ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Biomass Burning ◽  
Transport Model ◽  
Regional Scale ◽  
Satellite Observations ◽  
Emission Model ◽  
Chemistry Transport Model ◽  
Conversion Factors ◽  
Fire Emissions ◽  
Global Emission

Abstract. A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2 emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the fire radiative power (FRP) derived from MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated using the Infrared Atmospheric Sounding Interferometer (IASI) carbon monoxide (CO) retrievals and MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry-transport model. The constrained CO emissions are validated through comparison of the respective simulations with independent data of ground-based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with earlier published estimates obtained from local measurements of experimental fires), the total CO2 emissions from wildfires in Siberia in 2012 are estimated to be in the range from 280 to 550 Tg C, with the optimal (maximum likelihood) value of 392 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2 emissions in Siberia are robust with respect to the modeling options (the different estimates vary within less than 15% of their magnitude). The CO2 emission estimates obtained for several years are compared with independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2 emissions in the period from 2007 to 2011 in Siberia are by factors of 2.5 and 1.8 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis.

scholarly journals The sensitivity of CO and aerosol transport to the temporal and vertical distribution of North American boreal fire emissions

2009 ◽  
Vol 9 (17) ◽  
pp. 6559-6580 ◽  
Author(s):  
Y. Chen ◽  
Q. Li ◽  
J. T. Randerson ◽  
E. A. Lyons ◽  
R. A. Kahn ◽  
...  
Keyword(s):  
North America ◽  
Biomass Burning ◽  
Forest Fires ◽  
Transport Model ◽  
Source Region ◽  
Fire Season ◽  
Western Canada ◽  
Height Distribution ◽  
Fire Emissions ◽  
Fire Source

Abstract. Forest fires in Alaska and western Canada represent important sources of aerosols and trace gases in North America. Among the largest uncertainties when modeling forest fire effects are the timing and injection height of biomass burning emissions. Here we simulate CO and aerosols over North America during the 2004 fire season, using the GEOS-Chem chemical transport model. We apply different temporal distributions and injection height profiles to the biomass burning emissions, and compare model results with satellite-, aircraft-, and ground-based measurements. We find that averaged over the fire season, the use of finer temporal resolved biomass burning emissions usually decreases CO and aerosol concentrations near the fire source region, and often enhances long-range transport. Among the individual temporal constraints, switching from monthly to 8-day time intervals for emissions has the largest effect on CO and aerosol distributions, and shows better agreement with measured day-to-day variability. Injection height substantially modifies the surface concentrations and vertical profiles of pollutants near the source region. Compared with CO, the simulation of black carbon aerosol is more sensitive to the temporal and injection height distribution of emissions. The use of MISR-derived injection heights improves agreement with surface aerosol measurements near the fire source. Our results indicate that the discrepancies between model simulations and MOPITT CO measurements near the Hudson Bay can not be attributed solely to the representation of injection height within the model. Frequent occurrence of strong convection in North America during summer tends to limit the influence of injection height parameterizations of fire emissions in Alaska and western Canada with respect to CO and aerosol distributions over eastern North America.

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