Impact of the summer 2004 Alaska fires on top of the atmosphere clear-sky radiation fluxes

[1] In this study we estimate the radiative impact of wildfires in Alaska during the record wildfire season of 2004 by integrating model simulations and satellite observations of the top of the atmosphere (TOA) radiative fluxes and aerosol optical depth. We compare results for the summer of 2004 to results for the summer of 2000 when fire activity in the boreal zone was low. Both observations and model show a decrease in TOA clear-sky fluxes over the Alaska fire region during summer 2004 of -7 ± 6 W m -2 and -10 ± 4 W m -2 , respectively. About two thirds of the change occurs in the longwave, and one third in the shortwave, spectral range. On the bases of detailed model analysis we estimate that the changes in the longwave flux are predominantly explained by a higher surface temperature in summer 2004 compared to 2000. The change in the shortwave flux is largely caused by scattering of solar radiation on organic carbon aerosols emitted from the 2004 fires. This cooling is somewhat mitigated by the warming effect due to absorbing black carbon aerosols emitted from the fires and to a lesser extent by ozone and other greenhouse gases produced and released from the fires. Sensitivity studies with varying aerosol emission scenarios indicate that the ratio of black to organic carbon aerosol emissions of the boreal fires used in this study needs to be increased considerably to match both observations of aerosol optical depth and TOA radiation fluxes, or the biomass burning aerosols must be considerably more absorbing than parameterized in the model. While this study cannot resolve the cause of this discrepancy, it presents a powerful methodology to constrain aerosol emissions. This methodology will benefit from future improvements in measurements and modeling techniques.

[1]  R. Betts,et al.  Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2 , 2007 .

[2]  D. Jacob,et al.  Inventory of boreal fire emissions for North America in 2004 : Importance of peat burning and pyroconvective injection , 2007 .

[3]  David J. Diner,et al.  Aerosol source plume physical characteristics from space-based multiangle imaging , 2007 .

[4]  Louisa Emmons,et al.  Ozone production from the 2004 North American boreal fires , 2006 .

[5]  J. Randerson,et al.  The Impact of Boreal Forest Fire on Climate Warming , 2006, Science.

[6]  J. Randerson,et al.  Interannual variability in global biomass burning emissions from 1997 to 2004 , 2006 .

[7]  F. Achard,et al.  Ecology: Human role in Russian wild fires , 2006, Nature.

[8]  J. Hansen,et al.  Efficacy of climate forcings , 2005 .

[9]  Paul Ginoux,et al.  Response of a coupled chemistry‐climate model to changes in aerosol emissions: Global impact on the hydrological cycle and the tropospheric burdens of OH, ozone, and NOx , 2005 .

[10]  J. Hansen,et al.  Aerosol organic carbon to black carbon ratios: Analysis of published data and implications for climate forcing , 2005 .

[11]  J. Lamarque,et al.  Quantifying CO emissions from the 2004 Alaskan wildfires using MOPITT CO data , 2005 .

[12]  Michael Schulz,et al.  Estimates of global multicomponent aerosol optical depth and direct radiative perturbation in the Laboratoire de Météorologie Dynamique general circulation model , 2005 .

[13]  Kathleen A. Crean,et al.  Multiangle imaging spectroradiometer (MISR) global aerosol optical depth validation based on 2 years of coincident Aerosol Robotic Network (AERONET) observations : Global aerosol system , 2005 .

[14]  David R. Doelling,et al.  Angular Distribution Models for Top-of-Atmosphere Radiative Flux Estimation from the Clouds and the Earth’s Radiant Energy System Instrument on the Terra Satellite. Part II: Validation , 2005 .

[15]  E. Vermote,et al.  The MODIS Aerosol Algorithm, Products, and Validation , 2005 .

[16]  Paul Ginoux,et al.  Assessment of the global impact of aerosols on tropospheric oxidants , 2005 .

[17]  J. Lamarque,et al.  Monthly CO surface sources inventory based on the 2000–2001 MOPITT satellite data , 2004 .

[18]  T. Eck,et al.  A review of biomass burning emissions part III: intensive optical properties of biomass burning particles , 2004 .

[19]  Veerabhadran Ramanathan,et al.  Saharan Dust Aerosol Radiative Forcing Measured from Space , 2004 .

[20]  J. Lamarque,et al.  Observations of carbon monoxide and aerosols from the Terra satellite: Northern Hemisphere variability , 2004 .

[21]  Mark R. Schoeberl,et al.  Transport of smoke from Canadian forest fires to the surface near Washington, D.C.: Injection height, entrainment, and optical properties , 2004 .

[22]  William D. Collins,et al.  Effect of clouds on photolysis and oxidants in the troposphere , 2003 .

[23]  C. Timmreck,et al.  Monthly Averages of Aerosol Properties: A Global Comparison Among Models, Satellite Data, and AERONET Ground Data , 2003 .

[24]  Yoram J. Kaufman,et al.  An Enhanced Contextual Fire Detection Algorithm for MODIS , 2003 .

[25]  Mian Chin,et al.  Indonesian wildfires of 1997: Impact on tropospheric chemistry , 2003 .

[26]  J. Haywood,et al.  Solar radiative forcing by biomass burning aerosol particles during SAFARI 2000: A case study based on measured aerosol and cloud properties , 2003 .

[27]  Richard G. Derwent,et al.  Radiative forcing in the 21st century due to ozone changes in the troposphere and the lower stratosphere , 2003 .

[28]  Makiko Sato,et al.  Global atmospheric black carbon inferred from AERONET , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[29]  M. Flannigan,et al.  Fire Regimes and Climatic Change in Canadian Forests , 2003 .

[30]  W. Collins,et al.  Simulation of aerosol distributions and radiative forcing for INDOEX: Regional climate impacts , 2002 .

[31]  Larry W. Thomason,et al.  Climate forcings in Goddard Institute for Space Studies SI2000 simulations , 2002 .

[32]  O. Boucher,et al.  A satellite view of aerosols in the climate system , 2002, Nature.

[33]  V. Ramaswamy,et al.  A general circulation model study of the global carbonaceous aerosol distribution , 2002 .

[34]  J. Conny,et al.  Black carbon and organic carbon in aerosol particles from crown fires in the Canadian boreal forest , 2002 .

[35]  B. Holben,et al.  Validation of MODIS aerosol optical depth retrieval over land , 2002 .

[36]  Teruyuki Nakajima,et al.  Tropospheric aerosol optical thickness from the GOCART model and comparisons with satellite and sun photometer measurements , 2002 .

[37]  C. Land,et al.  A Comparison of Model- and Satellite-Derived Aerosol Optical Depth and Reflectivity , 2002 .

[38]  V. Ramanathan,et al.  Aerosols, Climate, and the Hydrological Cycle , 2001, Science.

[39]  M. Andreae,et al.  Emission of trace gases and aerosols from biomass burning , 2001 .

[40]  Guy P. Brasseur,et al.  Effects of aerosols on tropospheric oxidants: A global model study , 2001 .

[41]  R. A. Cox,et al.  Atmospheric chemistry of small organic peroxy radicals , 2001 .

[42]  J. Lamarque,et al.  A global simulation of tropospheric ozone and related tracers: Description and evaluation of MOZART, version 2 , 2001 .

[43]  M. Jacobson,et al.  Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols , 2022 .

[44]  Joyce Chou,et al.  Estimation of Shortwave Direct Radiative Forcing of Biomass-Burning Aerosols Using New Angular Models , 2000 .

[45]  K. Shine.  Radiative Forcing of Climate Change , 2000 .

[46]  Joyce Chou,et al.  Shortwave direct radiative forcing of biomass burning aerosols estimated using VIRS and CERES data , 2000 .

[47]  B. Huebert,et al.  Uncertainties in data on organic aerosols , 2000 .

[48]  D. Tanré,et al.  Remote Sensing of Tropospheric Aerosols from Space: Past, Present, and Future. , 1999 .

[49]  C. Liousse,et al.  Construction of a 1° × 1° fossil fuel emission data set for carbonaceous aerosol and implementation and radiative impact in the ECHAM4 model , 1999 .

[50]  B. Benner,et al.  Isotopic and molecular fractionation in combustion; three routes to molecular marker validation, including direct molecular 'dating' (GC/AMS) , 1999 .

[51]  D. Blake,et al.  Emission factors of hydrocarbons, halocarbons, trace gases and particles from biomass burning in Brazil , 1998 .

[52]  J. Reid,et al.  Physical and optical properties of young smoke from individual biomass fires in Brazil , 1998 .

[53]  C. C. Chuang,et al.  Climate forcing by carbonaceous and sulfate aerosols , 1998 .

[54]  Patrick Minnis,et al.  Temporal Interpolation Methods for the Clouds and the Earth’s Radiant Energy System (CERES) Experiment , 1998 .

[55]  P. Koepke,et al.  Optical Properties of Aerosols and Clouds: The Software Package OPAC , 1998 .

[56]  N. Mahowald,et al.  Transport of 222radon to the remote troposphere using the Model of Atmospheric Transport and Chemistry and assimilated winds from ECMWF and the National Center for Environmental Prediction/NCAR , 1997 .

[57]  Philip J. Rasch,et al.  Representations of transport, convection, and the hydrologic cycle in chemical transport models : Implications for the modeling of short-lived and soluble species , 1997 .

[58]  J. Penner,et al.  Modeling the spectral optical properties of ammonium sulfate and biomass burning aerosols , 1997 .

[59]  J. Penner,et al.  A global three‐dimensional model study of carbonaceous aerosols , 1996 .

[60]  B. Barkstrom,et al.  Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment , 1996 .

[61]  Bryan A. Baum,et al.  Clouds and the Earth's Radiant Energy System (CERES) , 1995 .

[62]  John F. B. Mitchell,et al.  On Surface Temperature, Greenhouse Gases, and Aerosols: Models and Observations , 1995 .

[63]  J. Houghton.  Climate change 1994 : radiative forcing of climate change and an evaluation of the IPCC IS92 emission scenarios , 1995 .

[64]  Bruce A. Wielicki,et al.  Top-of-Atmosphere Radiative Fluxes: Validation of ERBE Scanner Inversion Algorithm Using Nimbus-7 ERB Data , 1992 .

[65]  Christine A. O'Neill,et al.  Effects of Aerosol from Biomass Burning on the Global Radiation Budget , 1992, Science.

[66]  W. R. Cofer,et al.  Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem. Revision , 1990 .

[67]  J. Levine.  Global biomass burning - Atmospheric, climatic, and biospheric implications , 1990 .

[68]  E. M. Patterson,et al.  Absorption characteristics of forest fire particulate matter , 1984 .