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Yuyun Fu

Projet de recherche :

Potential relationship between forest fire emission and fire severity

Wildtires have huge impacts on both atmosphere and ecosystem (Bergeron and Gauthiers, 2017) as substantial vegetation being removed and large amounts of aerosol and trace gases being released into the atmosphere (Crutzen et al., 1990; Andreae et al., 2001). As two important tire regime parameters, satellite retrieved tire intensity and tire severity show huge potential applications in assessing the tire impacts on atmosphere and ecosystem.

For tire intensity, it can be directly obtained from satellite products. Previous works (lchoku and Ellison, 2014; Mebust et al., 2011) have applied the tire intensity parameter tire radiative power (FRP) to estimate emission coefficients (mass released per unit energy, g/MJ) of aerosol and nitrogen oxides.

For fire severity, it can be quantitied by the differenced Normalized Burn Ratios (dNBR), which is calculated using the change of reflectance of the NIR (near infrared) and MIR (middle infrared) bands between pre-fire and post-fire im.ages (Key and Benson, 2006). lts validation has been valued by Soverel et al. (2010) and Boucher et al. (2017). What's more, it has been applied to estimate the carbon emission (Rogers et al., 2014) and study the proportion of different burn-severity classes across forest composition and structure types (Meigs et al., 2018).

However, such kinds of studies are few. More investigations are needed to apply the tire intensity and fire severity to fire emission estimation, and to study the fire severity impacts on post-fire surface characteristics especially under the context of climate change.

Therefore, my thesis will be preliminarily entitled as: Using remote sensing to assess effects of tire severity on air quality and post fire ground conditions which will include 3 chapters (papers):

1) Evaluation of atmospheric aerosol and trace gas production according to tire intensity/fires severity, fuel type and forest types;

Fire radiative power and dNBR will be used to estimate the aerosol productions. The microwave index EDVI will be applied to assess the effect of vegetation water content on the fire intensity/fire severity and aerosol emissions .

2) Explore the effect of the fire severity on post fire ground characteristics;

This study will focus on the changes of surface albedo, the post-fire evaporation transpiration(ET) process, and the post-fire leaf area coverage.

3) Analyze the impacts of current and future climate on fire severity and radiative forcing.

This part will focus on the role of precipitation/drought and temperature on the fire severity. Further, the radiative forcing introduced will be studied through the pathways of changing surface albedo and the radiation transfer process in the atmosphere."

Yuyun Fu, Rui Li, Yves Bergeron, Raphaël Chavardes, Jiheng Hu, Yipu Wang, Jiawei Duan, Dong Li, Yuanxi Cheng, Osvaldo Valeria. Assessing forest fire properties in Northeastern Asia and Southern China with satellite microwave Emissivity Difference Vegetation Index (EDVI). 2022. ISPRS Journal of Photogrammetry and Remote Sensing 183:54-65
DOI : 10.1016/j.isprsjprs.2021.10.019    

Rui Li, Yipu Wang, Jiheng Hu, Yu Wang, Qilong Min, Yves Bergeron, Zongting Gao, Jinjun Liu, Yuyun Fu, Osvaldo Valeria. Spatiotemporal Variations of Satellite Microwave Emissivity Difference Vegetation Index in China Under Clear and Cloudy Skies 2020. Ecography 7(5):e2020EA001145
DOI : 10.1029/2020EA001145    

Yuyun Fu, Rui Li, Yves Bergeron, Yunfei Fu, Yu Wang, Zongting Gao, Jian-Guo Huang. Satellite-Observed Impacts of Wildfires on Regional Atmosphere Composition and the Shortwave Radiative Forcing: A Multiple Case Study. 2018. J. Geophys. Res. 123(15): 8326-8343
DOI : 10.1029/2017JD027927     

voir la liste complète

 Yuyun Fu, Osvaldo Valeria, Rui Li, Yves Bergeron. Forest fire emission and fire severity estimation using satellite detection and modeling 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30) 

 Yuyun Fu Estimation des émissions et de la sévérité des feux de forêt à l'aide de la détection par satellites et la modélisation. projet thèse (2019-10-25)