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| Titel |
LSA SAF Meteosat FRP products – Part 2: Evaluation and demonstration for use in the Copernicus Atmosphere Monitoring Service (CAMS) |
| VerfasserIn |
G. Roberts, M. J. Wooster, W. Xu, P. H. Freeborn, J.-J. Morcrette, L. Jones, A. Benedetti, H. Jiangping, D. Fisher, J. W. Kaiser |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 22 ; Nr. 15, no. 22 (2015-11-30), S.13241-13267 |
| Datensatznummer |
250120194
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| Publikation (Nr.) |
 copernicus.org/acp-15-13241-2015.pdf |
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| Zusammenfassung |
| Characterising the dynamics of landscape-scale wildfires at very high
temporal resolutions is best achieved using observations from Earth
Observation (EO) sensors mounted onboard geostationary satellites. As a
result, a number of operational active fire products have been developed
from the data of such sensors. An example of which are the Fire Radiative
Power (FRP) products, the FRP-PIXEL and FRP-GRID products, generated by the
Land Surface Analysis Satellite Applications Facility (LSA SAF) from imagery
collected by the Spinning Enhanced Visible and Infrared Imager (SEVIRI)
onboard the Meteosat Second Generation (MSG) series of geostationary EO
satellites. The processing chain developed to deliver these FRP products
detects SEVIRI pixels containing actively burning fires and characterises
their FRP output across four geographic regions covering Europe, part of
South America and Northern and Southern Africa. The FRP-PIXEL product
contains the highest spatial and temporal resolution FRP data set, whilst the
FRP-GRID product contains a spatio-temporal summary that includes bias
adjustments for cloud cover and the non-detection of low FRP fire pixels.
Here we evaluate these two products against active fire data collected by
the Moderate Resolution Imaging Spectroradiometer (MODIS) and compare the
results to those for three alternative active fire products derived from
SEVIRI imagery. The FRP-PIXEL product is shown to detect a substantially
greater number of active fire pixels than do alternative SEVIRI-based
products, and comparison to MODIS on a per-fire basis indicates a strong
agreement and low bias in terms of FRP values. However, low FRP fire pixels
remain undetected by SEVIRI, with errors of active fire pixel detection
commission and omission compared to MODIS ranging between 9–13 % and 65–77 % respectively in Africa. Higher errors of omission result in greater
underestimation of regional FRP totals relative to those derived from
simultaneously collected MODIS data, ranging from 35 % over the Northern
Africa region to 89 % over the European region. High errors of active fire
omission and FRP underestimation are found over Europe and South America
and result from SEVIRI's larger pixel area over these regions. An advantage
of using FRP for characterising wildfire emissions is the ability to do so
very frequently and in near-real time (NRT). To illustrate the potential of
this approach, wildfire fuel consumption rates derived from the SEVIRI
FRP-PIXEL product are used to characterise smoke emissions of the 2007
"mega-fire" event focused on Peloponnese (Greece) and used within the European
Centre for Medium-Range Weather Forecasting (ECMWF) Integrated Forecasting
System (IFS) as a demonstration of what can be achieved when using
geostationary active fire data within the Copernicus Atmosphere Monitoring
Service (CAMS). Qualitative comparison of the modelled smoke plumes with
MODIS optical imagery illustrates that the model captures the temporal and
spatial dynamics of the plume very well, and that high temporal resolution
emissions estimates such as those available from a geostationary orbit are
important for capturing the sub-daily variability in smoke plume parameters
such as aerosol optical depth (AOD), which are increasingly less well
resolved using daily or coarser temporal resolution emissions data sets.
Quantitative comparison of modelled AOD with coincident MODIS and AERONET (Aerosol Robotic Network)
AOD indicates that the former is overestimated by ~ 20–30 %, but captures the observed AOD dynamics with a high degree of
fidelity. The case study highlights the potential of using geostationary FRP
data to drive fire emissions estimates for use within atmospheric transport
models such as those implemented in the Monitoring Atmospheric Composition
and Climate (MACC) series of projects for the CAMS. |
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