EGU2020-16359, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-16359
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Importance of Vegetation Build Up for Burnt Area Seasonality

Alexander Kuhn-Regnier1, Apostolos Voulgarakis1,2, Sandy Harrison3, and Colin Prentice4
Alexander Kuhn-Regnier et al.
  • 1Imperial College London, Physics, London, United Kingdom of Great Britain and Northern Ireland (ahk114@ic.ac.uk)
  • 2School of Environmental Engineering, Technical University of Crete, Chania, Greece (a.voulgarakis@enveng.tuc.gr)
  • 3University of Reading, Geography and Environmental Science, Reading, United Kingdom of Great Britain and Northern Ireland (s.p.harrison@reading.ac.uk)
  • 4Imperial College London, Life Sciences, London, United Kingdom of Great Britain and Northern Ireland (c.prentice@imperial.ac.uk)

Vegetation build up is a major controlling factor for wildfires globally. The exact nature of the dependency of wildfire activity on past vegetation productivity is still under debate, however. Given the potential future rise in conditions conducive to extremely damaging fires in many regions of the world, controlling factors like this need to be investigated urgently to better understand and manage especially extreme wildfire events.
To improve our understanding of wildfires and the advice given to policy makers, a comprehensive understanding of all contributing factors is required. Changes to land management can be controversial and thus concrete evidence is required to assess and modify longstanding management practices and regulations if needed.
We therefore used global satellite datasets extending from 2005 to 2011 to assess the relationship between burnt area and various biophysical variables. Vegetation proxy data included vegetation optical depth and the fraction of absorbed photosynthetically activate radiation. Different regions and time periods were analysed separately to isolate regional and temporal effects respectively. The relationship between pre-season vegetation productivity and burnt area was modelled as a regionally and temporally varying weighted sum of past monthly productivity proxies.
As expected, significant differences in fire regimes were found across biomes, signified for example by significant shifts in the seasonality of burnt area. Understanding these shifts in the seasonality of both burnt area and the accompanying temporal dependence on past vegetation growth is key to reproducing observed wildfire regimes in fire models. As these relationships were found to vary both temporally and regionally, judicious inclusion of biophysical variables in fire models coupled with algorithms able to capture these relationships is necessary. 
However, remotely sensed observations were of different quality in different areas due to inhomogeneous cloud cover patterns, making assessments for much-affected regions like South America and South East Asia especially difficult. Likewise, the found correlation between decreasing cloud cover and increasing burnt area biased our results. Due also to the short time span of the data available in this investigation, these factors warrant further investigation to more fully quantify the temporal and regional relationships at work.

How to cite: Kuhn-Regnier, A., Voulgarakis, A., Harrison, S., and Prentice, C.: The Importance of Vegetation Build Up for Burnt Area Seasonality, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-16359, https://doi.org/10.5194/egusphere-egu2020-16359, 2020

Comments on the presentation

AC: Author Comment | CC: Community Comment | Report abuse

Presentation version 4 – uploaded on 14 May 2020 , no comments
Fixed typo.
Presentation version 3 – uploaded on 06 May 2020 , no comments
Added interaction figures and map of affected regions.
Presentation version 2 – uploaded on 06 May 2020 , no comments
Presentation version 1 – uploaded on 06 May 2020 , no comments