Changes on albedo after a large forest fire in Mediterranean ecosystems

Fires are one of the main causes of environmental alteration in Mediterranean forest ecosystems. Albedo varies and evolves seasonally based on solar illumination. It is greatly influenced by changes on vegetation: vegetation growth, cutting/planting forests or forest fires. This work analyzes albedo variations due to a large forest fire that occurred on 19- 21 September 2012 in northwestern Spain. From this area, albedo post-fire images (immediately and 1-year after fire) were generated from Landsat 7 Enhanced Thematic Mapper (ETM+) data. Specifically we considered total shortwave albedo, total-, direct-, and diffuse-visible, and near-infrared albedo. Nine to twelve weeks after fire, 111 field plots were measured (27 unburned plots, 84 burned plots). The relationship between albedo values and thematic class (burned/unburned) was evaluated by one-way analysis of variance. Our results demonstrate that albedo changes were related to burned/unburned variable with statistical significance, indicating the importance of forestry areas as regulators of land surface energy fluxes and revealing the potential of post-fire albedo for assessing burned areas. Future research, however, is needed to evaluate the persistence of albedo changes.

[1]  Jindi Wang,et al.  Estimation of surface albedo and directional reflectance from Moderate Resolution Imaging Spectroradiometer (MODIS) observations , 2012 .

[2]  B. Quayle,et al.  A Project for Monitoring Trends in Burn Severity , 2007 .

[3]  J. Randerson,et al.  Recovery of Aboveground Plant Biomass and Productivity After Fire in Mesic and Dry Black Spruce Forests of Interior Alaska , 2008, Ecosystems.

[4]  J. Randerson,et al.  The influence of burn severity on postfire vegetation recovery and albedo change during early succession in North American boreal forests , 2011 .

[5]  S. Stehman,et al.  Validation of the 2008 MODIS-MCD45 global burned area product using stratified random sampling , 2014 .

[6]  F. S. Chapin,et al.  Fire effects on surface‐atmosphere energy exchange in Alaskan black spruce ecosystems: Implications for feedbacks to regional climate , 2002 .

[7]  M. Roman,et al.  Surface albedo darkening from wildfires in northern sub-Saharan Africa , 2012 .

[8]  Alan G. Barr,et al.  The effect of post-fire stand age on the boreal forest energy balance , 2006 .

[9]  Philippe Michaut,et al.  Forest Fires in Europe, Middle East and North Africa 2013 , 2014 .

[10]  D. Roberts,et al.  Spectral and Structural Measures of Northwest Forest Vegetation at Leaf to Landscape Scales , 2004, Ecosystems.

[11]  L. Hutley,et al.  Fire impacts on surface heat, moisture and carbon fluxes from a tropical savanna in northern Australia , 2003 .

[12]  Ruben Van De Kerchove,et al.  Assessment of post-fire changes in land surface temperature and surface albedo, and their relation with fire–burn severity using multitemporal MODIS imagery , 2012 .

[13]  D. Roberts,et al.  Multiple Endmember Spectral Mixture Analysis (MESMA) to map burn severity levels from Landsat images in Mediterranean countries , 2013 .

[14]  Jay D. Miller,et al.  Quantifying burn severity in a heterogeneous landscape with a relative version of the delta Normalized Burn Ratio (dNBR) , 2007 .

[15]  J. Randerson,et al.  Changes in surface albedo after fire in boreal forest ecosystems of interior Alaska assessed using MODIS satellite observations , 2008 .

[16]  S. Liang.  Narrowband to broadband conversions of land surface albedo I Algorithms , 2001 .

[17]  Michael L. Goulden,et al.  Age‐dependent variation in the biophysical properties of boreal forests , 2008 .

[18]  Crystal B. Schaaf,et al.  Radiative forcing of natural forest disturbances , 2012 .

[19]  D. Roy,et al.  MODIS–Landsat fusion for large area 30m burned area mapping , 2015 .

[20]  P. Teillet,et al.  On the Slope-Aspect Correction of Multispectral Scanner Data , 1982 .

[21]  P. Gessler,et al.  Evaluation of novel thermally enhanced spectral indices for mapping fire perimeters and comparisons with fire atlas data , 2005 .

[22]  Elena Marcos,et al.  Post-fire natural regeneration of a Pinus pinaster forest in NW Spain , 2008, Plant Ecology.

[23]  Chad J. Shuey,et al.  Narrowband to broadband conversions of land surface albedo: II , 2003 .

[24]  C. Quintano,et al.  Linear fractional-based filter as a pre-classifier to map burned areas in Mediterranean countries , 2015 .

[25]  P. Chavez.  Image-Based Atmospheric Corrections - Revisited and Improved , 1996 .