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| Titel |
Estimating Landscape Fire Particulate Matter (PM) Emissions over Southern Africa using MSG-SEVIRI Fire Radiative Power (FRP) and MODIS Aerosol Optical Thickness Observations |
| VerfasserIn |
Bernardo Mota, Martin J. Wooster |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124550
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| Publikation (Nr.) |
 EGU/EGU2016-4001.pdf |
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| Zusammenfassung |
| The approach to estimating landscape fire fuel consumption based on the remotely sensed fire
radiative power (FRP) thermal energy release rate, as opposed to burned area, is now
relatively widely used in studies of fire emissions, including operationally within the
Copernicus Atmosphere Monitoring Service (CAMS). Nevertheless, there are still limitations
to the approach, including uncertainties associated with using only the few daily overpasses
typically provided by polar orbiting satellite systems, the conversion between FRP and smoke
emissions, and the increased likelihood that the more frequent data from geostationary
systems fails to detect the (probably highly numerous) smaller (i.e. low FRP) component of a
regions fire regime. In this study, we address these limitations to directly estimate fire
emissions of Particular Matter (PM; or smoke aerosols) by presenting an approach combining
the "bottom-up" FRP observations available every 15 minutes across Africa from the
Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) Fire Radiative
Product (FRP) processed at the EUMETSAT LSA SAF, and the "top-down" aerosol
optical thickness (AOT) measures of the fire plumes themselves as measured by the
Moderate-resolution Imaging Spectro-radiometer (MODIS) sensors aboard the
Terra (MOD04_L2) and Aqua (MYD04_L2) satellites. We determine PM emission
coefficients that relate directly to FRP measures by combining these two datasets, and the
use of the almost continuous geostationary FRP observations allows us to do this
without recourse to (uncertain) data on wind speed at the (unknown) height of the
matching plume. We also develop compensation factors to address the detection
limitations of small/low intensity (low FRP) fires, and remove the need to estimate fuel
consumption by going directly from FRP to PM emissions. We derive the smoke PM
emissions coefficients per land cover class by comparing the total fire radiative energy
(FRE) released from individual fires and the MODIS AOD seen in the corresponding
plume. Analysis was performed for plumes extracted from 31 study sites covering
10,000km2each, during 10 consecutive days, for the 2011 southern Africa fire season.
Compensation factors associated with undetected low FRP fires was based on extraction and
application of frequency density function shape parameters, characterized by analyzing
4 years (2009-2013) of MSG-SEVIRI FRP data in 0.5o degree cells. Using the
derived emission coefficients and compensation factors we estimate Total Particulate
Matter (TPM) emissions for 2011 on a daily basis and 0.25o spatial resolution across
southern Africa. Preliminary results show agreement between our derived emission
coefficients and those of past studies following similar methods but with MODIS FRP
data, and our annual TPM estimate is in reasonable agreement with those of other
emission inventories based on burned area approaches. The proposed approach
shows strong potential to be applied to other regions, and also to other geostationary
satellite FRP products. Once the smoke emissions coefficients have been derived
via comparison to the AOD data, the method requires only the FRP data, which is
available at very high temporal frequency from geostationary orbit. Therefore our
approach can provide near real time smoke emissions estimates which are essential for
operational activities such as NRT smoke dispersion modeling and air quality forecasting. |
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