An assessment of vegetation fire in Africa (1981–1991): Burned areas, burned biomass, and atmospheric emissions

Barbosa, Paulo; Stroppiana, Daniela; Grégoire, Jean‐Marie; Pereira, José M. C.

doi:10.1029/1999gb900042

Cited by 276 publications

(229 citation statements)

References 38 publications

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“…4b. The BrC contribution (associated with high å abs ) is more important at the end of the dry season and is lower during August, when the aerosol particles likely arrive from Zambian woodland savanna fires (Barbosa et al, 1999), which burn more efficiently and emit aerosol particles with lower ω 0 , 0.84 ± 0.015 at 670 nm in average (Dubovik et al, 2002). Additionally, on average, high σ ap 637 events (see increasing circle size in Fig.…”

Section: Variability Of Optical Properties During the Dry Seasonmentioning

confidence: 93%

“…4a, show a decreasing dominance of ESE winds from August to November, whereas from October to November there is an increasing influence of ENE winds, indicating the south-to-north air mass trajectory shift that occurs during the transition from the dry to the wet season. It is important to note that southerly and easterly winds are most likely to bring BB aerosol to the ATTO site during the dry season, given that very active open fire areas during this period are located in the southern Amazon and the Cerrado region (Andreae et al, 2012;Guyon et al, 2005) and, more remotely, in southern Africa (Andreae et al, 1994;Barbosa et al, 1999;Das et al, 2017). Aerosol optical depth at 550 nm is used in this study as a parameter to study the seasonal pattern of BB emission transport from both areas.…”

Section: Variability Of Optical Properties During the Dry Seasonmentioning

confidence: 99%

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Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Saturno¹,

Holanda²,

Pöhlker³

et al. 2017

Preprint

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Abstract. The Amazon rain forest is considered a very sensitive ecosystem that could be significantly affected by a changing climate. It is still one of the few places on Earth where the atmosphere in the continent approaches near-pristine conditions for some periods of the year. The Amazon Tall Tower Observatory (ATTO) has been built in central Amazonia to monitor the atmospheric and forest ecosystem conditions. The atmospheric conditions at the ATTO site oscillate between biogenic and biomass burning (BB) dominated states. By using a comprehensive ground-based aerosol measurement setup, we studied the physical and chemical properties of aerosol particles at the ATTO site. This parameterization of å abs as a function of the BC to OA mass ratio was investigated and was found applicable to tropical forest emissions but further investigation is required, especially by segregating fuel types. Additionally, important enhancements of the BC mass absorption cross-section (α abs ) were found over the measurement period. This enhancement could be linked to heavy coating of the BC aerosol particles. In the future, the BC mixing state should be systematically investigated by using different instrumental approaches.

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Section: Variability Of Optical Properties During the Dry Seasonmentioning

confidence: 93%

Section: Variability Of Optical Properties During the Dry Seasonmentioning

confidence: 99%

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Saturno¹,

Holanda²,

Pöhlker³

et al. 2017

Preprint

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“…Due to the temporal gaps in the National Land Cover Database (Homer et al, 2004), an averaged normalized difference vegetation index (NDVI) was collected for pre-fire burn areas to quantitatively summarize vegetation conditions, similar to previous studies (Barbosa et al, 1999;Kinoshita and Hogue, 2011;Lee and Chow, 2015). NDVI is defined as…”

Section: Vegetation Datamentioning

confidence: 99%

Characterization and evaluation of controls on post-fire streamflow response across western US watersheds

Saxe

Hogue

Hay

2018

Hydrol. Earth Syst. Sci.

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Abstract. This research investigates the impact of wildfires on watershed flow regimes, specifically focusing on evaluation of fire events within specified hydroclimatic regions in the western United States, and evaluating the impact of climate and geophysical variables on response. Eighty-two watersheds were identified with at least 10 years of continuous pre-fire daily streamflow records and 5 years of continuous post-fire daily flow records. Percent change in annual runoff ratio, low flows, high flows, peak flows, number of zero flow days, baseflow index, and Richards-Baker flashiness index were calculated for each watershed using pre-and post-fire periods. Independent variables were identified for each watershed and fire event, including topographic, vegetation, climate, burn severity, percent area burned, and soils data.Results show that low flows, high flows, and peak flows increase in the first 2 years following a wildfire and decrease over time. Relative response was used to scale response variables with the respective percent area of watershed burned in order to compare regional differences in watershed response. To account for variability in precipitation events, runoff ratio was used to compare runoff directly to PRISM precipitation estimates. To account for regional differences in climate patterns, watersheds were divided into nine regions, or clusters, through k-means clustering using climate data, and regression models were produced for watersheds grouped by total area burned. Watersheds in Cluster 9 (eastern California, western Nevada, Oregon) demonstrate a small negative response to observed flow regimes after fire. Cluster 8 watersheds (coastal California) display the greatest flow responses, typically within the first year following wildfire. Most other watersheds show a positive mean relative response. In addition, simple regression models show low correlation between percent watershed burned and streamflow response, implying that other watershed factors strongly influence response.Spearman correlation identified NDVI, aridity index, percent of a watershed's precipitation that falls as rain, and slope as being positively correlated with post-fire streamflow response. This metric also suggested a negative correlation between response and the soil erodibility factor, watershed area, and percent low burn severity. Regression models identified only moderate burn severity and watershed area as being consistently positively/negatively correlated, respectively, with response. The random forest model identified only slope and percent area burned as significant watershed parameters controlling response.Results will help inform post-fire runoff management decisions by helping to identify expected changes to flow regimes, as well as facilitate parameterization for model application in burned watersheds.

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“…Fire activity is seasonal, generally lasting 3-4 months according to the dry season length (Duncan et al, 2003;Cooke et al, 1996). In southern Africa, the fire season extends from April to October and shows a peak in June-July; in northern Africa, the fire season extends from November to April, and shows a maximum in December-January (Cahoon et al, 1992;Barbosa et al, 1999;Chédin et al, 2008). In South America, the fire seasonality is weaker than in Africa and shows a peak in August for southern South America and in January for northern South America (Hoelzemann et al, 2004).…”

Section: Geographic Distributionmentioning

confidence: 99%

First year of upper tropospheric integrated content of CO<sub>2</sub> from IASI hyperspectral infrared observations

Crévoisier

Chédin²,

Matsueda³

et al. 2009

Atmos. Chem. Phys.

168

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Abstract. Simultaneous observations from the Infrared Atmospheric Sounding Interferometer (IASI) and from the Advanced Microwave Sounding Unit (AMSU), launched together onboard the European MetOp platform in October 2006, are used to retrieve an upper tropospheric content of carbon dioxide (CO 2 ) covering the range 11-15 km (100-300 hPa), in clear-sky conditions, in the tropics, over sea, for the first year of operation of MetOp (January 2008-December 2008. With its very high spectral resolution, IASI provides fourteen channels in the 15 µm band highly sensitive to CO 2 with reduced sensitivities to other atmospheric variables. IASI observations, sensitive to both CO 2 and temperature, are used in conjunction with AMSU observations, only sensitive to temperature, to decorrelate both signals through a non-linear inference scheme based on neural networks. A key point of this approach is that no use is made of prior information in terms of CO 2 seasonality, trend, or geographical patterns. The precision of the retrieval is estimated to be about 2.0 ppmv (∼0.5%) for a 5 • ×5 • spatial resolution on a monthly time scale. Features of the retrieved CO 2 space-time distribution include: (1) a strong seasonal cycle of 4 ppmv in the northern tropics with a maximum in June-July and a minimum in September-October. This cycle is characterized by a backward two-months lag as compared to the surface, by a backward one-month lag as compared to measurements performed at 11 km, and by a forward one-month lag as compared to observations performed at the tropopause (16 km). This is likely due to the time-lagCorrespondence to: C. Crevoisier (cyril.crevoisier@lmd.polytechnique.fr) of CO 2 cycle while transported from the surface to the upper troposphere; (2) a more complex seasonal cycle in the southern tropics, in agreement with in-situ measurements; (3) a latitudinal variation of CO 2 shifting from a South-to-North increase of 3.5 ppmv in boreal spring to a South-to-North decrease of 1.5 ppmv in the fall, in excellent agreement with tropospheric aircraft measurements; (4) signatures of CO 2 emissions transported to the upper troposphere. In addition to bringing an improved view of CO 2 distribution, these results from IASI should provide an additional means to observe and understand atmospheric transport pathways of CO 2 from the surface to the upper troposphere.

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An assessment of vegetation fire in Africa (1981–1991): Burned areas, burned biomass, and atmospheric emissions

Cited by 276 publications

References 38 publications

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Characterization and evaluation of controls on post-fire streamflow response across western US watersheds

First year of upper tropospheric integrated content of CO<sub>2</sub> from IASI hyperspectral infrared observations

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An assessment of vegetation fire in Africa (1981–1991): Burned areas, burned biomass, and atmospheric emissions

Cited by 276 publications

References 38 publications

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Characterization and evaluation of controls on post-fire streamflow response across western US watersheds

First year of upper tropospheric integrated content of CO&lt;sub&gt;2&lt;/sub&gt; from IASI hyperspectral infrared observations

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Product

Resources

About

First year of upper tropospheric integrated content of CO<sub>2</sub> from IASI hyperspectral infrared observations