Radiative forcing of fire-induced albedo change
Wildland fire is a primary dirver for vegetation dynamics, carbon cycling, and surface energy exchange, by altering vegetation structure, albedo, surface temperature, and evapotranspiration, in many ecosystems. The integrated net effects at a landscape scale depends on fire regime, including the area and severity, local climate (e.g., snow season), and the processes that influence post-fire vegetation succession.
We used historical fire perimeter data and time series of satellite observations to examine how burn severity affected vegetation recovery and albedo change dring early succession in boreal North America, and quantify how the radiative forcing varied as a function of snow season length and post-fire vegetation recovery along a boreal ecoclimatic transect. Our studies found that fires reduce surface net radiation considerably for many boreal ecosystems, and also highlighted the importance of considering vegetation-mediated impacts of fire disturbance in managing these forests for climate change mitigation.
Jin, Y., J. T. Randerson, M. L. Goulden, and S. J. Goetz (2012), Post-fire changes in net shortwave radiation along a latitudinal gradient in boreal North America, Geophysical Research Letters, 39, L13403, doi:10.1029/2012GL051790.
Jin, Y., J. T. Randerson, S. J. Goetz, P. S. A. Beck, M. M. Loranty, and M. L. Goulden (2012), The influence of burn severity on post-fire vegetation recovery and albedo change during early succession in North American boreal forests, Journal of Geophysical Research-Biogeosciences, 117, G01036, doi:10.1029/2011JG001886.
Loranty, M. M., L. T. Berner, S. J. Goetz, Y. Jin, and J. T. Randerson (2013), Vegetation controls on northern high latitude snow-albedo feedback, Global Change Biology, 20(2), 594-606, doi: 10.1111/gcb.12391.
Beck, P. S. A., S. J. Goetz, M.C. Mack, H.D. Alexander, Y. Jin, J. T. Randerson, and M. M. Loranty (2011), The impacts and implications of an intensifying fire regime on Alaskan boreal forest composition and albedo, Global Change Biology, 17, 2853–2866. doi: 10.1111/j.1365-2486.2011.02412.x
Lyons, E.A., Y. Jin, and J.T. Randerson (2008), Changes in surface albedo after fire in boreal forest ecosystems of interior Alaska assessed using MODIS satellite observations, Journal of Geophysical Research-Biogeosciences, vol. 113, G02012, doi:10.1029/2007JG000606.
Jin, Y., and D.P. Roy (2005), Fire-induced albedo change and its radiative forcing at the surface in northern Australia, Geophysical Research Letters, 32(13), L13401, doi:10.1029/2005GL022822.
Interactions between wildfire, climate, and vegetation
Climate, fuel load, fuel connectivity, human ignition, and the occurrence of extreme weather are considered the primary drivers of fire regime in Southern California, but the relative importance of these factors is still being debated. We systematically partitioned fires into two distinct types, those coincident with and without Santa Ana events, and developed separate fire-meteorology models to represent the seasonal and interannual variations for Santa Ana and non-Santa Ana fires. Our analysis shows that these two types of fire exhibit distinct spatial patterns and the dominant controls vary with fire types, opening the possibility of further targeting management strategy based on local fire regime.
Faivre, N., Y. Jin, M. L. Goulden, and J. T. Randerson (2014), Modeling the spatial pattern of wildfire ignitions in Southern Californian Mediterranean ecosystems, International Journal of Wildland Fire. [PDF]
Socio-economic impacts of California's wildfire
Santa Ana and non-Santa Ana fires contributed almost equally to burned area, yet SA fires were responsible for 80% of cumulative economic losses during 1990-2009 ($3.1 Billion). The westward expansion towards the urbanized coastal zone, higher fire spread rate, and greater intensity of SA fires were probably the main drivers of the disproportionate economic impact of this fire type. Non-SA fires were comparatively more sensitive to age-dependent fuels; these fires often occurred in higher elevation forests, lasted for extended periods, and accounted for 70% of total suppression costs. An improved distinction of fire type has implications for management and future projections.
Future fire projections