The September 2010 PIESA/Aerosol Experiments: Difference between revisions
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[[image: BB_freq-map.th_0.8.jas.png|thumb|Frequency of AOT_BB/AOT ratio exceeding 0.8 for JAS, 2004.]] | [[image: BB_freq-map.th_0.8.jas.png|thumb|Frequency of AOT_BB/AOT ratio exceeding 0.8 for JAS, 2004.]] | ||
[[image: QFED_MISR-minimization.global.th-0.5.2004_2006.png|thumb|GEOS5-QFED AOT and MISR AOT differences minimization.]] | [[image: QFED_MISR-minimization.global.th-0.5.2004_2006.png|thumb|GEOS5-QFED AOT and MISR AOT differences minimization.]] | ||
In order to further improve the GEOS-5 modeling capabilities and accelerate the transition of NASA satellite information into operational application, an improved biomass burning emissions dataset - [http://geos5.org/wiki/index.php?title=Quick_Fire_Emission_Dataset_%28QFED%29 Quick Fire Emission Dataset (QFED)] was developed. QFED addresses some of the weaknesses of the Global Fire Emissions Database used in the base system configuration. Among the major limitations of the GFED emissions are the low spatial resolution ( | In order to further improve the GEOS-5 modeling capabilities and accelerate the transition of NASA satellite information into operational application, an improved biomass burning emissions dataset - [http://geos5.org/wiki/index.php?title=Quick_Fire_Emission_Dataset_%28QFED%29 Quick Fire Emission Dataset (QFED)] was developed. QFED addresses some of the weaknesses of the Global Fire Emissions Database used in the base system configuration. Among the major limitations of the GFED emissions are the low spatial resolution (1×1 degree) and temporal resolution (monthly). | ||
The QFED emissions are based on the ''top-down'' approach that uses the fact that the fire radiative power (FRP) at the top of the atmosphere is proportional to the rate of organic/vegetation mass that is burning. On the other hand, the emission of gasses and particulate matter released during burning is proportional to the consumed mass, hence the emissions rates are proportional to the measured FRP. | The QFED emissions are based on the ''top-down'' approach that uses the fact that the fire radiative power (FRP) at the top of the atmosphere is proportional to the rate of organic/vegetation mass that is burning. On the other hand, the emission of gasses and particulate matter released during burning is proportional to the consumed mass, hence the emissions rates are proportional to the measured FRP. | ||
The FRP needed to calculate the biomass burning emission was derived from the MODIS Thermal Anomalies/Fire products (MOD14, MYD14). The calibration of the QFED emissions was done individually for the MODIS/Terra and MODIS/Aqua data using the emissions factors from Andreae and Merlet [2001]. Our first step was to use global monthly mean GFED emissions to find individual global calibration factors for MODIS/Terra and MODIS/Aqua instruments. Using individual calibration factors has an advantage over using a single common factor for the two instruments, because one can account for the differences in the fire strengths at the local time of the satellite overpass, and ensures redundancy in case one of the satellites fails. The QFED fire emissions were used in the 'R_ddQFED' experiment. The benefits of this calibration is that globally the QFED fire emissions are comparable to the commonly used GFED emissions, however they are available daily at finer horizontal resolution of 0. | The FRP needed to calculate the biomass burning emission was derived from the MODIS Thermal Anomalies/Fire products (MOD14, MYD14). The calibration of the QFED emissions was done individually for the MODIS/Terra and MODIS/Aqua data using the emissions factors from Andreae and Merlet [2001]. Our first step was to use global monthly mean GFED emissions to find individual global calibration factors for MODIS/Terra and MODIS/Aqua instruments. Using individual calibration factors has an advantage over using a single common factor for the two instruments, because one can account for the differences in the fire strengths at the local time of the satellite overpass, and ensures redundancy in case one of the satellites fails. The QFED fire emissions were used in the 'R_ddQFED' experiment. The benefits of this calibration is that globally the QFED fire emissions are comparable to the commonly used GFED emissions, however they are available daily at finer horizontal resolution of 0.25×0.25 degrees. | ||
Our next objective was to produce more realistic fire emission magnitudes. As in-situ measurements of fire emissions are very limited, we relied instead on the fact that biomass burning can have significant contribution to the total aerosol loadings near active fires and downwind. Thus, one can use AOT magnitude and relate it to the fire emission strength. | Our next objective was to produce more realistic fire emission magnitudes. As in-situ measurements of fire emissions are very limited, we relied instead on the fact that biomass burning can have significant contribution to the total aerosol loadings near active fires and downwind. Thus, one can use AOT magnitude and relate it to the fire emission strength. | ||