AeroCom - aerosol emission data-sets recommendations for years 2000 and 1750 Frank Dentener, Julian Wilson, Luisa Marelli, Jean-Philippe Putaud (IES, JRC, Italy) Tami Bond (Univ. of Illinois-Champagne, USA) Judith Hoelzemann, Stefan Kinne (MPI Hamburg, Germany) Sylvia Generoso, Christiane Textor, Michael Schulz (LSCE Saclay, France) Sylvia Generoso (EPFL-ENAC, Lausanne, Switzerland) Guido van der Werf (Univ. of Amsterdam, Netherlands) Sunling Gong (ARQM Met Service Toronto, Canada) Paul Ginoux (NOAA-GFDL Princeton, USA) Janusz Cofala (IIASA Laxenburg, Austria) Olivier Boucher (Met Office, Exeter, Great Britain ) Akinori Ito, Joyce Penner (Uni of Michigan Ann Arbor, USA) document change record Issue Date Modified Items / Reason for Change 0.0 10 Sep 2004 0. version by F. Dentener 0.1 10.Oct 2005 1. version by S. Kinne 0.2 24.Oct 2005 2. version by S. Kinne 0.3 29. Oct 2005 3. version by S. Kinne 0.4 15.Nov 2005 4. version by S. Kinne … in preparation for ACP techn. notes 1 Emissions of primary aerosol and precursor gases in the years 2000 and 1750 prescribed data-sets for AeroCom F. Dentener, S. Kinne, T. Bond, O. Boucher, J. Cofala, S. Generoso, P. Ginoux, S. Gong, J.J. Hoelzemann, A. Ito, L. Marelli, J. Penner, J.-P. Putaud, C. Textor, M.Schulz, G. van der Werf and J. Wilson Abstract Inventories for global aerosol emissions have been developed for the year 2000 (present-day conditions) and for the year 1750 (pre-industrial conditions). The choices were based on available data for the year 2000. The overall goal was to keep it simple, with the primary goal to harmonize aerosol emission input for model inter-comparisons. Although large uncertainties are expected with respect to carbonaceous aerosol, these data-sets are considered an initial stepping stone to even better aerosol emission inventories in the future. 1 Introduction Large uncertainties in climate modeling are introduced by aerosol (IPCC, 2001). The Aerosol Inter Comparison project AeroCom (http://nansen.ipsl.jussieu.fr/AEROCOM/) has been initiated in 2003 to understand the nature of these uncertainties by performing a systematic analysis of detailed aerosol module output of more than 15 global models, focusing on comparisons to available data from in-situ sampling and remote sensing. Initial model comparisons under the umbrella of AeroCom Experiment ‘A’ illustrate at times significant model diversity (Kinne et al., 2005; Textor et al. 2005). In these initial submissions for modelers were allowed to use aerosol emissions (an essential model input) of their choice, without a clear connection to any particular. Thus, these model comparisons are of limited value. In order to harmonize aerosol input, two additional AeroCom simulations were requested, that applied common emission data for primary aerosol and for aerosol precursor 2 gases. AeroCom Experiment ‘B’ was established to simulate conditions of the year 2000, if possible with actual met-data (via nudging in GCMs) in an effort to establish stronger ties to available observational data. AeroCom Experiment ‘Pre’ was designed to establish a preindustrial modeling reference, around the year 1750, to extract anthropogenic impacts in conjunction with Experiment ‘B’ (Schulz et al., 2005). For both experiments, ‘B’ and Pre’, global data sets for aerosol emissions were defined. Background and details to these data-sets are introduced in this report. 2 General For the years 2000 and 1750, global aerosol emission fields were developed at a spatial resolution of 1°latitude *1°longitude (in units of kg per grid-box – note that the grid-box area varies with latitude). Temporal resolution ranges from daily to yearly depending on the species. Information was given for injection height and for sizes of particulate emissions. Emissions were categorized by their origin as either natural or anthropogenic. Natural emissions are assumed identical for Experiment ‘B’ (year 2000) and Experiment ‘Pre’ (year 1750). Details of the natural emission data-sets are introduced in Chapter 3. Anthropogenic emissions for years 1750 and 2000 differ. Thus, anthropogenic emission datasets are explained separately, for Experiment ‘B’ in Chapter 4 and for Experiment ‘Pre’ in Chapter 5. Temporal resolution of aerosol data-sets is summarized in Chapter 6, injection heights are explained in Chapter 7, and size recommendations are addressed in Chapter 8. All AeroCom emission data-sets are available (in netcdf data format) via a dedicated file transfer site at the Joint Research Center in Ispra, Italy: ftp://ftp.ei.jrc.it/pub/Aerocom/. To help locate specific data, ftp-site subdirectories and their content are listed in Appendix A. 3 Natural emissions Natural emissions include wind-blown contributions of mineral dust (DU) and sea-salt (SS), sulfur (S) contributions from volcanoes and DiMethyl Sulphide (DMS, mainly oceanic) and (Secondary) Organic Aerosol (SOA) formed from natural Volatile Organic Compound (VOC) emissions. Most of S and all of SOA are formed within the atmosphere from precursor gases. Hereby, SOA is added to the flux of Particulate Organic Matter (POM). An overview of annual global amounts and recommendations for injection height are given in Table 1. 3 Table 1. AeroCom natural emissions temporal aerosol resolution type* amount [Tg /yr] injection altitude size ln size ln rm [m] reff [m] dust daily DU 1678 surface .650 C 2.0 C 2.10 sea-salt daily SS 7925 surface .740 C 2.0 C 2.50 DMS daily S+ 18.2 surface .040 1.8 .095 volcanic, explosive yearly S+ 2.0 (VTop+500m)(VTop+1500m .040 50% .015 50% 1.8 .059 volcanic, continuous yearly S+ 12.6 (.67 *VTop)(1.0 *VTop) .040 50% .015 50% 1.8 .059 monthly POM 19.1 surface SOA * DU-dust, SS-sea-salt, S-sulfur (=0.50*SO2,or 0.33*S04), POM-particulate org matter (=1.40*organic carbon) + C 2.5% of sulfur (S) is emitted as particulate SO4 for the cross-section area dominating coarse mode Table 1 also lists size-recommendations in terms of log-normal size-distribution parameters rm (number mode radius) and (standard deviation), plus the resulting reff (this radiatively eff. radius is defined by the ratio of sums of the third and the second radii moments, r3/ r2). 3.1 Dust Dust (DU) data are based on simulations with the year 2000 near surface winds generated by the NASA Goddard Earth Observing System Data Assimilation System (GEOS DAS). Daily average DU fluxes were provided at 1o(latitude) *1o(longitude) resolution (Ginoux et al., 2001, 2003). The original data were distributed over four size-bins (radii ranges of 0.1-1.0, 1.0-1.8, 1.8-3.0, 3.0-6.0m). In order to accommodate modal size schemes, dust flux data were stratified according to size into two domains (assuming equal number within each original size-bin): accumulation size (radii: 0.05-0.5m) and coarse size (radii > 0.5m). Then for each size domain the flux was distributed over a log-normal function, which is defined by the three parameters of mode-radius rm (radius at the peak concentration), standard deviation (distribution width) and number N. Assuming a DU density of 2.5g/cm3 and prescribing the standard deviation (1.59 for the accumulation size mode and 2.0 for the coarse size mode) the number mode-radius was determined at each grid-point and time-step (as data for number N and mass-flux were provided by the original data). Daily global fields for 4 mode-radius and number (along with prescribed values for density and standard deviation) establish to recommended emission input for dust. As this input is tailored to size-modal schemes an extra (IDL) routine is provided that determines the distribution equivalent emission flux models with (size-) bin schemes. Based on the modal approach 98.6% of the dust flux mass is assigned to the coarse domain (and 1.4% to accumulation size domain). The spatial distributions of dust-emissions on an annual and monthly basis are given in Figure 1. Figure 1. Global fields of annual and monthly dust emission flux (based on year 2000 simulations by Ginoux) The characteristic dust maximum dimension is about 4 m (as a mode radius of 0.63 m in conjunction with a standard deviation of 2 for the coarse mode translates into an effective ‘radius’ of 2.1 m). Dust emissions are prescribed to take place in the lowest model layer. Biases may have been introduced by limitations associated with the GEOS DAS meteorology and simplifying assumption. In particular the coarse (daily) temporal resolution and injections into the lowest layer of the model only are expected to contribute to dust flux underestimates. Inaccuracies are introduced with the modal size representation and uncertainties will be introduced during model implementations (e.g. inconsistencies with respect to boundary layer mixing (e.g. dry convection) and/or adaptations to different model resolutions). 5 3.2 Sea-salt Sea-salt (SS) daily emission data are based on year 2000 ECMWF near surface winds. Mass fluxes are provided over 24 size bins (considering sea-salt radii from 0.005 to 20.48m) at 1.175o(latitude) *1.175o(longitude) horizontal resolution (Gong et al., 2003). Here, flux contributions associated with radii larger 10m are ignored. The data were re-gridded to 1o*1o resolution and redistributed over three size domains (assuming equal number within each original size-bin): Aitken size (radii < 0.05m), accumulation size (radii: 0.05-0.5m) and coarse size (radii > 0.5m). Then for each size domain sea-salt fluxes were distributed over a log-normal function, which is defined by the three parameters of mode-radius rm, standard deviation and number N. Assuming a SS density of 2.2g/cm3 and prescribing the standard deviation (1.59 for Aitken and accumulation size mode and 2.0 for the coarse size mode) the number mode-radius was determined at each grid-point and time-step (as data for number N and mass-flux were provided by the original data). Daily global fields for mode-radius and number (along with prescribed values for density and standard deviation) establish to recommended emission input for sea-salt. These daily SS-fluxes were weighted by the monthly ECMWF sea-ice-free-fractions of the year 2000, to avoid SS-emissions over sea-ice. As this input is tailored to accommodate size-modal schemes, an extra (IDL) routine is provided that determines the distribution equivalent emission flux models with (size-) bin schemes. Distributions of sea-salt emissions are displayed in Figure 2. Figure 2. Global fields of annual and monthly sea-salt emission flux (based on year 2000 simulations by Gong) 6 The radiatively characteristic sea-salt diameter is at 5m (a mode radius of 0.74m in conjunction with a standard deviation of 2 for the coarse mode translates into an effective ‘radius’ of 2.5m). Sea-salt emissions are prescribed to take place in the lowest model layer. Uncertainty issues are similar to those for dust, including the blurring by the modal representation. For example, even though sea-salt fluxes associated with radii larger than 10m were rejected, by fitting with the rather large standard deviation for the coarse lognormal size-distribution radii up to 25m in size will contribute to the sea-salt mass flux. 3.3 DMS Daily DMS emission data are based on six hourly data of simulations with the LMDZ general circulation model LOA (Boucher et al. 2003) at 2.5o(latitude) *3.75o(longitude) resolution. Oceanic DMS emissions are derived by applying a parameterization for air-sea transfer velocities (Nightingale, 2000) to simulated climatology tied to measurement samples (Kettle and Andreae, 2000). Continental DMS emission of biogenic origin (Pham et al, 1995) are generally much lower and in order to exclude unrealistic high contributions over land, oceanic contributions are only allowed over ocean only model grid regions. Finally, daily average data are interpolated onto a 1o*1o grid. Distributions of DMS emissions are given in Figure 3. Figure 3. Global fields of annual and monthly DMS (sulfur) emission (based on model simulations by Boucher) 7 3.4 Volcanic Emissions Yearly volcanic (sulfur) emissions data consider both continuous degassing and explosive volcanos. Volcanic sulfur is emitted to 97.5% as SO2 and to 2.5% as SO4. The AEROCOM dataset is based on the GEIA inventory (http://www.igac.noaa.gov/newsletter/22/sulfur.php; http://www.geiacenter.org/) (Andres and Kasgnoc, 1998). However, since there are a number of ambiguities in the description and use of these data; we provide an interpreted and updated dataset, which is summarized next. Explosive emissions are based observational techniques (including TOMS). They occur at only a few locations which are probably not representative for the regions of active explosive volcanism as shown by more recent data. The total emission (at 2 TgS/year) from explosive volcanos is therefore equally distributed over all active volcanoes that had been active over the last 100 years (Halmer et al., 2002). The emissions are continuously released, because only about 1/3 of degassing occurs during highly explosive phases. Injections are placed between 500 and 1500m above each volcano peak. It should be noted that explosive emissions are not specific for the year 2000, as data were not available. Continuous degassing presents significant larger contributions. The annual continuous emissions recommend by GEIA is for various reasons considered to be an underestimate (Graf et al. 1998, Textor et al. 2004). Thus, continuous sulfur-containing emissions of GEIA are multiplied by a factor of 1.2. The new estimate (at 12.6 TgS/year) is still conservative, since many volcanoes are not monitored, or can not be accurately detected by the satellite sensors presently at use. Volcano locations are taken from GEIA. The emissions occur in the upper third of the volcano altitude to account for degassing at the flanks of the volcanoes. 3.5 Secondary Organic Aerosol Secondary Organic Aerosol (SOA) emissions are provided on monthly basis. They are based on the assumption that 15% of natural terpene emissions form SOA, although actual SOA production is much more complicated. It is assumed that SOA is formed on time scales of a few hours and that SOA precursor emissions condense on pre-existing aerosol. In reality, substantial SOA formation can occur at higher altitudes (Kanakidou et al., 2005). Terpene emissions of 127 Tg/year were taken from GEIA (Guenther et al. 1995). This translates into an annual global average of 19.1 Tg POM/year, which is within bounds of other estimates of 10 to 60 Tg POM/year (Kanakidou et al., 2005). 8 4 Anthropogenic emissions – year 2000 Anthropogenic emissions consider sulfur contributions mainly in terms of sulfate (SO2) and carbonaceous contributions, where a distinction is made between organic carbon in terms of Particulate Organic Matter (POM) and strongly absorbing black (or elementary) carbon (BC). Sources are from large scale (wildland) fires (which are also in part natural), bio fuel burning and fossil fuel burning. For the ladder a distinction is made between sources from road traffic, shipping, off-road, industry and power-plants, to account for differences in injection height and particle size, as indicated in Table 2, which summarizes recommendations of individual anthropogenic contributions for the year 2000. Details of the data-sets for the AeroCom Experiment B (year 2000) are introduced next. Table 2. AeroCom anthropogenic emissions for the year 2000 type data temporal aerosol amount [Tg /yr] source resolution type injection altitude wildland fire GFED monthly BC 3.1 6 layers H .040 1.8 .095 GFED monthly POM 34.7 6 layers H .040 1.8 .095 GFED monthly S+ 2.1 6 layers H .040 1.8 .095 SPEW yearly BC 1.6 surface .040 1.8 .095 SPEW yearly POM 9.1 surface .040 1.8 .095 IIASA yearly S+ 4.8 surface .015 1.8 .036 SPEW yearly BC 3.0 surface .015 1.8 .036 SPEW yearly POM 3.2 surface .015 1.8 .036 Roads IIASA yearly S+ 1.0 surface .015 1.8 .036 Shipping IIASA yearly S+ 3.9 surface .500 2.0 1.66 off-road IIASA yearly S+ 0.8 surface .015 1.8 .036 yearly S + 19.6 100-300m .500 2.0 1.66 S + 24.2 100-300m .500 2.0 1.66 biofuel domestic fossil-fuel Industry power-plant IIASA IIASA yearly size (ln) size rm [m] reff [m] * S-sulfur (=0.50*SO2,or 0.33*S04), POM-particulate org matter (=1.40*organic carbon), BC-black carbon + 2.5% of sulfur (S) is emitted as particulate SO4, H 0-100m, 100-500m, 500-1000m, 1-2km, 2-3km, 3-6km 9 4.1 Large-scale (wildland) fire emissions of BC, POM and SO2 Monthly data for large-scale (wildland) fire emissions of carbon and sulfur are based on the Global Fire Emission Database (GFED) inventory (van der Werf et al., 2003, 2004, Randerson et al. 2005). In this data-set satellite derived burnt area products from ATSR and MODIS are combined with present day vegetation cover (Olsen et al, 1985). The data reproduce seasonal variations in biomass burning activities. Annual totals are in overall agreement to other estimates (e.g. Generoso et al., 2003, Bond et al, 2004). Due to strong year-to-year variations, two data-sets are offered: An estimate tied specifically to the year 2000 and a 6-year (1997-2002) average for climatological simulations. Monthly emissions into the atmosphere are distributed over six ecosystem-dependent altitude regimes between the surface and 6km (see section 7). Emission patterns of POM and BC for the year 2000 from large scale biomass burning (wildland fires) are displayed in Figure 4. Figure 4. Organic matter (POM) and black carbon (BC) wildland fire emissions for year 2000 4.2 Biofuel emissions of BC, POM, and SO2 Yearly average data (no annual cycle) for biofuel organic emissions are based on the Speciated Particulate Emissions Wizard (SPEW) inventory (Bond et al., 2004). Biofuel emissions include the burning of charcoal, dung and crop residues and charcoal making. Emission patterns of POM and BC for the year 1996 are displayed in Figure 5. 10 Figure 5. Organic matter (POM) and black carbon (BC) biofuel emissions for the year 1996. Sulfur (-dioxide) biofuel emissions for the year 2000 are based on energy statistics for the year 2000 (Cofala et al., 2005). Country and regional estimates (see Appendix B) were gridded following EDGAR distribution patterns (Dentener, 2005). Emission Patterns of offroad and domestic sulfur dioxide emissions for the year 2000 are displayed in Figure 6. Figure 6. Sulfur emissions of domestic and off-road (rural) activities for the year 2000. 11 4.3 Fossil-fuel emissions of BC, POM, and SO2 Yearly average data (no annual cycle) for fossil-fuel organic emissions are based on the Speciated Particulate Emissions Wizard (SPEW) inventory (Bond et al., 2004). Emission patterns of fossil-fuel POM and fossil-fuel BC of the year 1996 are displayed in Figure 7. Sulfur-dioxide fossil-fuel emissions are based on energy statistics for the year 2000; using technology controlled emission factors from IIASA/RAINS (Cofala et al., 2005). The country and region estimates (see Appendix 2) were gridded following EDGAR (Olivier et al., 2002) distribution patterns (Dentener, 2005). Figure 7. Organic matter (POM) and black carbon (BC) fossil-fuel emissions for year 1996. Ship traffic for the year 2000 is assumed to have increased by 1.5% per year since 1995 over the EDGAR3.2 values. Patterns of industry and power-plant associated sulfur-dioxide emissions for the year 2000 are displayed in Figure 8. 12 Figure 8. Sulfur dioxide emissions off power-plants and related to industry for the year 2000. 4.4 Other Emissions For other emission data (e.g. for full chemistry simulations), it is recommended to use the EDGAR 3.2, 1995 data-base (Olivier et al., 2002; http://arch.rivm.nl/env/int/coredata/edgar). No specific recommendations are given for oxidant fields. 5 Anthropogenic emissions – year 1750 In pre-industrial times, here represented by the year 1750, anthropogenic emissions were not zero, though only a fraction of those for the year 2000. While fossil-fuel emissions are neglected, reduced contributions from wildland fires (open burning) and biofuel emissions are expected. In the absence of observational data, anthropogenic emission estimates for AeroCom Experiment ‘Pre’ are derived on educate-guess assumptions, which are explained next. An overview of resulting annual global amounts and recommendations for injection height and of log-normal size parameters (number-) mode radius rm and standard deviation (plus the associated radiatively effective radius reff ) is given in Table 3. 13 Table 3. AeroCom anthropogenic emissions for the year 1750 temporal resolution wildland fire biofuel aerosol amount [Tg /yr] type* injection altitude size ln size ln rm [m] std.dev. reff [m] monthly BC 1.02 6 layers H .040 1.8 .095 monthly POM 12.8 6 layers H .040 1.8 .095 monthly S+ 0.7 6 layers H .040 1.8 .095 yearly BC 0.26 surface .040 1.8 .095 yearly POM 2.5 surface .040 1.8 .095 yearly S+ 0.06 surface .040 1.8 0.95 * S-sulfur (=0.50*SO2,or 0.33*S04), POM-particulate org matter (=1.40*organic carbon), BC-black carbon + H 2.5% of sulfur (S) is emitted as particulate SO4, 0-100m, 100-500m, 500-1000m, 1-2km, 2-3km, 3-6km 5.1 Large-scale (wildland) fire emissions of BC, POM and SO2 Pre-industrial wildland fire emissions are based on scaled 5 year averages (1998-2002) of monthly data of the Global Fire Emission Database (GFED) inventory (van der Werf et al., 2003, 2004; Randerson et al. 2005). Central to a rescaling is the “year1750-to-year2000” population ratio from HYDE data-set (www.rivm.nl/hyde, see also Table C3 in Appendix C). Actual scaling corrections are then performed according to present day land cover (Olsen et al, 1985). Wet forest emissions scale by population whereas emissions over all other landsurfaces (e.g. grassland, shrub/bush, agricultural activity) scale only to 60% by population (as it is assumed that 40% burns anyhow). Forest emissions in high latitudes of the northern hemisphere (Europe, N.America, Russia) are doubled over current estimates, to account for less fire suppression in the past (Brenkert et al., 1997). 5.2 Biofuel emissions of BC, POM, and SO2 Pre-industrial biofuel estimates are derived separately for carbonaceous aerosol and sulfur emissions. The BC and POM contributions are scaled back to the year 1750 based on statistics for population and crop production in developing countries and in developed countries based on wood consumption, where the switch from electricity or natural gas as predominant cooking fuel back to wood is considered (Ito and Penner, 2005). For sulfate-dioxide a CO biofuel inventory for the year 1890 (van Aardenne et al., 2001) is multiplied by 0.00346, 14 based on the ratio of emission factor estimates (Andreae an Merlet, 2001) for SO2 and CO (0.27g and 78g per kg of burned dry biomass, respectively). A “year1750-to-year1890” population ratio from the HYDE data-set (see Appendix C) establishes the emissions for the year 1750. Emissions at high latitudes in the northern hemisphere (Europe, N.America and Russia) are doubled to account for a higher per person use (Brenkert et al., 1997). 6 Temporal resolution The temporal resolution of the individual datasets is given in Tables 1 to 3. For simplification anthropogenic emissions (with the exception of large scale wildland fires) are constant and inter-annual variations are only prescribed for natural aerosol anthropogenic emissions. However, even the daily resolution for dust, sea-salt and DMS (given the dependence on surface winds) constitutes an approximation. 7 Injection height Recommended injection heights of the individual emission datasets are given in Tables 1 to 3. Most emissions are defined to occur evenly distributed in the lowest model-layer (‘surface’). Fossil fuel emissions from industry and power-plants should be injected between 100 and 300m above the surface, because these emissions are usually released at the top of chimneys. Large-scale wildland fire emissions are provided for six altitude regimes: 0-100m, 100-500m, 500-1km, 1-2km, 2-3km, 3-6km. Emissions are expected to be distributed evenly within each layer. The maximum emission height for wildland fire emissions is given in Figure 9. 15 Figure 9. Maximum emission height (in meter) for (large-scale) wild-fire aerosol The most complex altitude assignment is for volcanic emission. It is based on (a provided list for) volcanic location and volcano top altitude (VTOP). For each volcano, explosive contributions should be evenly placed between 500 and 1500m above VTOP and continuous degassing should occur in the upper 1/3 altitude of each volcano. 8 Size choices for primary emissions Recommended aerosol sizes for particles of the individual emission datasets are given in Tables 1 to 3. Size recommendations are given in terms of log-normal distributions parameters, where the mode radius (rm) describes the peak concentration and the standard deviation () describes the distribution width. From both log-normal values a (radiatively) characteristic size has been determined (reff, as the ratio between the sums of the third and the second moment of the radius: r3/ r2. For wildland fire (open burning) and biofuel aerosol the recommended characteristic size of reff ~0.1m is based on an analysis of numerous field-measurements (see Appendix C). For fossil-fuel two different sizes a given. A large size of reff ~1.6m is recommended for powerplant and industrial emissions (representing fly-ash, and components formed on it). A 16 relatively small size of reff ~.04m, which is recommended for other fossil fuel emissions (e.g. traffic) is based on kerbside measurements in several EU-cities (Putaud et al. 2004, van Dingenen et al., 2004). For particles from volcanic emissions, half of the mass is assigned each to the small fossil-fuel size (reff ~0.1m) and to the biofuel size (reff ~.04m). For dust and sea-salt, size recommendations are more complex, because they are defined by two and three size-modes, respectively, with variations on a daily basis. However, since the mass flux is dominated by contributions of the coarse size domain, the average characteristic size of the coarse mode seems relevant with reff ~2.1m for dust and at reff ~2.5m for sea-salt. 9 Discussion and Conclusion The above emissions, recommended for AeroCom, represent the state-of-the-art for global aerosol emissions inventories in the year 2003. In some cases several alternative datasets were available, such as three large-scale burning wildland fire inventories (van der Werf et al., 2003; Generoso et al. 2003; Hoelzemann et al. 2004; see Appendix D). This often necessitates choices. The overall goal was to keep it simple, with the primary goal to harmonize aerosol emission input for model inter-comparison exercises (e.g. AeroCom Experiment ‘B’). 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Global Biogeochemical Cycles, 15(4) , 909-928, 2001. van der Werf, G.R., J.T. Randerson, G.J. Collatz, and L. Giglio, Carbon emissions from fires in tropical and subtropical ecosystems, Global Change Biology, 9 (4), 547-562, 2003. van der Werf, G.R., J.T. Randerson, G.J. Collatz, L. Giglio, P.S. Kasibhatla, A.F. Arellano, S.C. Olsen, and E.S. Kasischke, Continental-scale partitioning of fire emissions during the 1997 to 2001 El Nino/La Nina period, Science, 303 (5654), 73-76, 2004. van Dingenen R., F.Raes, J.Putaud et al., A European aerosol phenomenology 1: physical charcateristics of particulate matter at kerbside, urban, rural and background sites in Europe, Atmospheric Environment, 38, 2561-2577, 2004. 21 Appendix A Names and location of data-files on IES, JRC ftp-web site All AeroCom emission data-sets are available (in netcdf data format) via a dedicated file transfer site at the Joint Research Center in Ispra, Italy: ftp://ftp.ei.jrc.it/pub/Aerocom/. To help locate specific data ftp-site subdirectories and their content is outlined below: dust data ‘dust200001.nc’ (Jan 2000), …, ‘dust200012.nc’ (Dec 2000) /seasalt_ncf salt data ‘salt200001.nc’ (Jan 2000), … , ‘salt200012.nc’ (Dec 2000) /DMS_ncf ‘dms200001.nc’ (Jan 2000), … , ‘dms200012.nc’ (Dec 2000) /dust_ncf DMS data /other_ncf_2000 all other emissions for the year 2000 - BC-biofuel ‘BC1bfuel.nc’ - BC-fossil fuel ‘BC1ff.nc’ - BC-veg.fire ‘GFED_2000_BC.nc’ - POM-vwg.fire ‘GFED_2000_POM.nc’ - SO2-veg.fire ‘GFED_2000_SO2_nc’ - POM-biofuel ‘POMbfuel.nc’ - POM-fossil fuel ‘POMff.nc’ - SO2-domestic ‘SO2_Domestic_2000bau.nc’ - SO2-industry ‘SO2_Industry_2000bau.nc’ - SO2-ships ‘SO2_International_Shipping_2000bau.nc’ - SO2-off raod ‘SO2_Off-road_2000bau.nc’ - SO2-powerplant ‘SO2_Powerplants_2000bau.nc’ - SO2-traffic ‘SO2_RoadTransport_2000bau.nc’ - POM-SOA ‘SOA.nc’ - volc. degassing ‘continuous_volc.nc’ - volc, explosive ‘explosive_volc.nc’ /other_ncf_1750 all other emissions for the year 1750 - BC-biofuel ‘BC1_1750_bfuel.nc’ - BC-veg. fire ‘GFED_1750_BC.nc’ - POM-veg. fire ‘GFED_1750_POM.nc’ - SO2-veg. fire ‘GFED_1750_SO2_nc’ - POM-biofuel ‘POM_1750_bfuel.nc’ - SO2-domestic ‘SO2_Domestic_1750bau.nc’ - POM-SOA ‘SOA.nc’ - volc. degassing ‘continuous_volc.nc’ - volc, explosive ‘explosive_volc.nc’ 22 Appendix B Regional aspects of AeroCom emissions For a quick reference on regional contributions of BC, (P)OM and SO2, annual AeroCom emissions are stratified into 18 regions according to the IMAGE project, as illustrated in Figure B1 (courtesy of Bas Eickhout at RIVM, Netherlands). Figure B1. Regional choices for continental regions by the IMAGE project (by Bas Eickhout) Regional AeroCom emissions by species and source are summarized for current conditions (year 2000) in Table B1 and for pre-industrial conditions (year 1750) in Table B2. Hereby, differences between year 2000 and year 1750 emissions provide estimates on anthropogenic contributions. 23 Table B1. Regional distributions of AeroCom emissions for the year 2000 category BC ofire BC biof BC fos.f BC all OM ofire OM biof OM fosf OM SOa OM all SO2 ofire SO2 v.ex SO2 v.co SO2 hom SO2 road SO2 pow SO2 off-r SO2 ship SO2 indu SO2 all CANADA USA C AMERICA S AMERICA N AFRICA W AFRICA E AFRICA S AFRICA OECD EU EAST EU F. USSR MID EAST SOUTH ASIA EAST ASIA SE ASIA OCEANIA JAPAN GREENLAND OCEAN 0.01 0.07 0.13 0.73 0 0.73 0.25 0.56 0.01 0.01 0.08 0 0.04 0.01 0.20 0.23 0 0 0 0.01 0.06 0.03 0.08 0 0.18 0.08 0.07 0.03 0.03 0.02 0.01 0.40 0.41 0.15 0 0 0 0.07 0.03 0.27 0.06 0.22 0.05 0.01 0.01 0.05 0.25 0.1 0.17 0.12 0.18 1.01 0.14 0.03 0.14 0 0.21 0.05 0.40 0.22 1.03 0.05 0.92 0.34 0.69 0.28 0.14 0.27 0.13 0.61 1.42 0.50 0.26 0.15 0 0.27 0.18 1.11 1.5 8.3 0 7.65 2.65 5.81 0.11 0.12 1.81 0 0.38 0.21 2.24 2.56 0.01 0 0 0.05 0.45 0.18 0.5 0.03 0.97 0.44 0.4 0.21 0.28 0.14 0.06 2.14 2.03 0.8 0.02 0 0 0.39 0.02 0.2 0.14 0.24 0.06 0.04 0.01 0.09 0.17 0.1 0.17 0.24 0.14 0.93 0.19 0.02 0.09 0 0.35 0.69 1.23 0.62 6.58 0.03 2.53 0.7 0.94 0.33 0.08 0.98 0.12 0.69 0.69 1.49 0.97 0.05 0 0.4 0.95 2.99 2.45 15.6 0.12 11.2 3.80 7.24 0.81 0.58 3.10 0.42 3.35 3.87 4.72 3.57 0.15 0 1.14 0.02 0.11 0.14 0.85 0 1.01 0.35 0.83 0.01 0.01 0.15 0 0.05 0.02 0.21 0.33 0 0 0 0 0.22 0.23 0.47 0 0.02 0.17 0.03 0.08 0 0.14 0.03 0 0.02 0.44 0.11 0.22 0 1.83 0 1.01 2.24 4.76 0 0 0.02 0.02 0 0 0 0 0 0 0.79 4.52 2.57 0 9.29 0.07 0.31 0.04 0.16 0.05 0.14 0.09 0.12 0.44 0.67 1.16 0.49 0.59 4.75 0.38 0.01 0.07 0 0 0.01 0.17 0.08 0.22 0.07 0.04 0.01 0.05 0.14 0.03 0.06 0.25 0.44 0.12 0.15 0.04 0.04 0 0 0.54 12.4 1.84 0.54 0.68 0.06 0.03 1.79 3.47 4.2 5.61 2.8 3.49 8.76 1.05 0.85 0.25 0 0 0.05 0.11 0.08 0.12 0.01 0.03 0.01 0.02 0.19 0.04 0.12 0.06 0.13 0.44 0.06 0.04 0.04 0 0 0 0 0 0.01 0 0 0 0 0.08 0 0 0.07 0 0 0.02 0 0 0 7.58 1.19 3.12 1.36 1.61 0.64 0.14 0.08 0.64 2.05 1.01 3.99 2.44 2.89 15.2 1.6 0.81 0.48 0 0 1.88 17.5 6 8.72 1.45 1.43 0.77 3.5 6.47 5.96 11.2 6.14 7.6 29.3 4.7 6.71 3.66 0 18.7 WORLD 3.04 1.63 3.04 7.72 34.7 9.09 3.2 19.1 66.1 4.1 4 25.2 9.55 1.92 48.4 1.56 7.75 39.2 142. Table B2. Regional distributions of AeroCom emissions for the year 1750 category BC ofire BC biof BC fos.f BC all OM ofire OM biof OM fosf OM SOa OM all SO2 ofire SO2 v.ex SO2 v.co SO2 hom SO2 road SO2 pow SO2 off-r SO2 ship SO2 indu SO2 all CANADA USA C AMERICA S AMERICA N AFRICA W AFRICA E AFRICA S AFRICA OECD EU EAST EU F. USSR MID EAST SOUTH ASIA EAST ASIA SE ASIA OCEANIA JAPAN GREENLAND OCEAN 0.04 0.00 0.01 0.23 0 0.22 0.08 0.20 0.00 0.00 0.09 0 0.01 0.01 0.06 0.06 0 0 0 0 0.01 0 0.01 0.01 0.04 0.04 0.03 0.01 0.01 0.02 0.01 0.06 0.10 0.03 0 0.01 0 0.07 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.04 0.02 0.01 0.24 0.01 0.27 0.12 0.22 0.01 0.01 0.11 0.01 0.07 0.10 0.10 0.07 0.01 0 0 0.85 0.06 0.15 2.57 0 2.39 0.88 2.05 0.04 0.01 2.10 0 0.08 0.10 0.74 0.78 0.01 0 0 0 0.06 0.01 0.03 0.02 0.11 0.11 0.07 0.05 0.03 0.13 0.02 0.29 0.46 0.13 0.01 0.03 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.69 1.23 0.62 6.58 0.03 2.53 0.7 0.94 0.33 0.08 0.98 0.12 0.69 0.69 1.49 0.97 0.05 0 0.4 1.54 1.35 0.78 9.17 0.06 5.03 1.68 3.06 0.41 0.12 3.21 0.15 1.06 1.26 2.36 1.77 0.08 0 0.40 0.07 0.01 0.01 0.28 0 0.32 0.12 0.29 0 0 0.17 0 0.01 0.01 0.06 0.10 0 0 0 0 0.22 0.23 0.47 0 0.02 0.17 0.03 0.08 0 0.14 0.03 0 0.02 0.44 0.11 0.22 0 1.83 0 1.01 2.24 4.76 0 0 0.02 0.02 0 0 0 0 0 0 0.79 4.52 2.57 0 9.29 0 0 0 0 0 0 0 0 0.01 0 0 0 0.03 0.05 0.01 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.07 1.24 2.49 5.51 0 0.34 0.31 0.34 0.10 0 0.31 0.03 0.04 0.08 1.30 4.72 2.79 0 11.1 WORLD 1.03 0.39 0 1.41 12.8 1.56 0 19.1 33.5 1.46 4.00 25.2 0.12 0 0 0 0 0 30.8 24 A central role, when back-scaling current emission to obtain estimates on pre-industrial emissions has been the population ratio of the HYDE data-set (www.rivm.nl/hyde). For the 18 IMAGE regions (see Figure B1) these population ratios are listed in Table B3. Table B3. Population by region for the years 1750 and 2000 (by HYDE) – and ratios Canada USA C.America S.America N.Africa W-Africa E-Africa S-Africa OECD-Europe E-Europe F.USSR M-East S-Asia E-Asia SE-Asia Oceania Japan world year 1750 year 2000 (in million) (in million) 0.3 2.1 5.5 5.0 4.5 22.1 8.0 10.7 113.7 31.6 25.3 9.3 172.0 268.9 28.5 0.3 24.9 722.3 27.8 254.1 145.1 292.8 118.2 242.0 151.8 117.5 377.1 122.2 289.6 192.4 1132.1 1247.1 442.0 26.4 123.5 5301.8 2000 / 1750 pop - ratio 93 121 26 59 26 11 19 11 3.3 3.9 11 21 6.5 4.6 16 88 5.0 7.34 1750 / 2000 pop - ratio 0.011 0.0083 0.038 0.017 0.038 0.091 0.053 0.091 0.30 0.26 0.087 0.048 0.15 0.22 0.065 0.011 .20 .136 25 Appendix C Background to the sizing of primary aerosol from biomass burning Biomass burning is one of the main sources for carbonaceus aerosol in the atmosphere. Globally it contributes to about 40% of CO, 32% of CO, 38% of tropospheric ozone, 7% of total particulate matter and 39% of particulate organic carbon. The majority of biomass aerosol (ca 80%) occurs in tropics as seasonal event (e.g. Aug-Oct: S. Africa and S.America). To provide background on choices for the sizing of freshly emitted (young) biomass aerosol, Luisa Marelli (JRC) has compiled a summary of measurements (Allen and Miguel, 1995; Anderson et al., 1996; Andreae and Merlot, 2001; Cachnier et al., 1996, LeCanut et al., 1996, Radke et al., 1991; Scholes et al., 1996, Suscott et al., 1991). Measured size distributions have been fitted to a multi-model lognormal distribution, which is defined by dN d log r (ln r ln rm ) 2 N ln 10 exp 2(ln ) 2 2 ln where N is total particle number, rm is the mode radius and is the standard deviation. A comparison of fits is presented in Figure C1. normalized number distributions of biomass in different burning areas Brazil - aged Africa - aged 1.E+01 Africa - young 1.E+00 N.Americaflaming N.Americasmoldering N. Americayoung Brazil-young 1.E-01 1.E-02 1.E-03 Brazil - aged 1.E-04 South Atlantic aged Canada - aged 1.E-05 Brazil - aged 1.E-06 10 100 1000 10000 100000 Diameter (nm) Figure C1. Multi-modal log-normal fits to measured biomass size samples 26 The accumulation size-mode (radii smaller than 0.5m) usually contains more then 90% of the biomass burning aerosol mass. Figure C2 presents the log-normal parameters data-pairs for rm (actually the diameter is shown) and of only the accumulation size-mode associated with the size distributions of Figure C1. Accumulation mode diameter vs standard deviation 350 300 250 200 150 y = -426.51x + 837.27 R2 = 0.882 100 50 0 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 standard deviation from lognormal fitting Figure C2. Relationship between (number-) mode diameter (in nm) and standard deviations from log-normal fits to the size-distributions of Figure A1. Data points in the lower right refer to young biomass aerosol while pairs towards the upper left refer to aged biomass aerosol. Data points in the lower right of Figure C2 indicate log-normal parameters from fits to young biomass aerosol. As the biomass aerosol ages, the mode radius increases and the distribution width narrows, resulting in an increase to effective radius (from 0.10 to 0.15m), which is small in the context of orders of magnitudes among different aerosol sizes. As biomass burning emissions are associated with young aerosol, recommendations are 0.04m for (number-) mode radius rm and 1.8 for standard deviation (as listed in Tables 1 to 3). These values are consistent with estimates of volatility analysis on young aerosol emitted by a North American fires (Reid et al, 2003), where sampled aerosol (rm =0.55m, =1.7) has been preheated to 310° C, to bake off volatile compounds (organics, sulfate, nitrate, water etc.), resulting in core aerosol (mainly BC and low volatility organics) of rm =0.32m and1.9. 27 Appendix D Comparison of available wildland fire inventories By 2003, three different global large-scale wildland fire inventories had been developed (van der Werf et al, 2003; Generoso et al, 2003; Hoelzemann et al, 2004). When comparing the inventories on a regional basis, as for POM in Figure D1, there is good agreement in a relative sense, although estimates by Hoelzemann (GWEM 1.2) are smaller, especially in South America. This lower estimate is erroneous and associated with a failure in the underlying area burnt satellite product, so that the impact of small but intense fires is underestimated in that region. A more recent version of GWEM (version 1.4) is now more consistent with the other inventories. For more discussion on the uncertainty of the POM/EC inventories, the reader is referred to the description of SPEW (Bond et al 2004). A particular problem is the uncertainty of emission factors, which for BC can exceed an order of magnitude (C. Liousse, private communication). Thus, the certainty for carbonaceous emissions can not be expected to be better than a factor of 2. Comparisons of POM estimates 35 POM in Tg of OM/yr 30 25 GLOBAL Africa 20 South America Central America North America Oceania Europe + Russia South East Asia 15 10 East Asia 5 0 1 2 1 : S.Generoso 2 : J.J. Hoelzeman 3 3 : G. van der Werf Figure D1. Comparison of three different global large-scale burning (wildland fire) inventories for regional POM emission estimates by S.Generoso et al. (2003), J.J.Hoelzemann et al. (2004) and G.van der Werf et al. (2003). 28