Global-scale emissions of carbonaceous aerosol from fossil fuel usage have been calculated with a resolution of 1° × 1°. Emission factors for black and organic carbon have been gathered from the literature and applied to domestic, transport, and industrial combustion of various fuel types. In addition, allowance has been made for the level of development when calculating emissions from a country. Emissions have been calculated for 185 countries for the domestic, industrial, and transport sectors using a fuel usage database published by the United Nations [1993]. Some inconsistencies were found for a small number of countries with regard to the distribution of fuel usage between the industrial and domestic sectors. Care has been taken to correct for this using data from the fuel use database for the period 1970–1990. Emissions based on total particulate matter (TPM) and submicron emission factors have been calculated. Global emissions for 1984 of black carbon total 6.4 TgC yr−1 and organic carbon emissions of 10.1 TgC yr−1 were found using bulk aerosol emission factors, while global black carbon emissions of 5.1 TgC yr−1 and organic carbon emissions of 7.0 TgC yr−1 were found using submicron emission factors. Use of the database is quite flexible and can be easily updated as emission factor data are updated. There is at least a factor of 2 uncertainty in the derived emissions due to the lack of exactly appropriate emission data. The emission fields have been introduced into the ECHAM4 atmospheric general circulation model and run for 5 model years. Monthly mean model results are compared to measurements in regions influenced by anthropogenic fossil fuel emissions. The resultant aerosol fields have been used to calculate the instantaneous solar radiative forcing at the top of the troposphere due to an external mixture of fossil fuel derived black carbon and organic carbon aerosol. Column burdens of 0.143 mgBC m−2 and 0.170 mgOC m−2 were calculated. Because of secondary production of organic carbon aerosol, it is recommended that the burden of organic carbon aerosol be doubled to 0.341 mgOC m−2. The resultant forcing when clouds are included is +0.173 W m−2 for black carbon and −0.024 W m−2 for organic carbon (×2) as a global annual average. The results are compared to previous works, and the differences are discussed.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999JD900187

Construction of a 1° × 1° fossil fuel emission data set for carbonaceous aerosol and implementation and radiative impact in the ECHAM4 model

[1] Atmospheric distributions of carbonaceous aerosols are simulated using the Geophysical Fluid Dynamics Laboratory SKYHI general circulation model (GCM) (latitude-longitude resolution of ∼3° × 3.6°). A number of systematic analyses are conducted to investigate the seasonal and interannual variability of the concentrations at specific locations and to investigate the sensitivity of the distributions to various physical parameters. Comparisons are made with several observational data sets. At four specific sites (Mace Head, Mauna Loa, Sable Island, and Bondville) the monthly mean measurements of surface concentrations of black carbon made over several years reveal that the model simulation registers successes as well as failures. Comparisons are also made with averages of measurements made over varying time periods, segregated by geography and rural/remote locations. Generally, the mean measured remote surface concentrations exceed those simulated. Notwithstanding the large variability in measurements and model simulations, the simulations of both black and organic carbon tend to be within about a factor of 2 at a majority of the sites. There are major challenges in conducting comparisons with measurements due to inadequate sampling at some sites, the generally short length of the observational record, and different methods used for estimating the black and organic carbon amounts. The interannual variability in the model and in the few such measurements available points to the need for doing multiyear modeling and to the necessity of comparing with long-term measurements. There are very few altitude profile measurements; notwithstanding the large uncertainties, the present comparisons suggest an overestimation by the model in the free troposphere. The global column burdens of black and organic carbon in the present standard model integration are lower than in previous studies and thus could be regarded as approximately bracketing a lower end of the simulated anthropogenic burden due to these classes of aerosols, based on the current understanding of the carbonaceous aerosol cycle. Of the physical factors examined, the intensity and frequency of precipitation events are critical in governing the column burdens. Biases in the frequency of precipitation are likely the single biggest cause of discrepancies between simulation and observations. This parameter is available from very few sites and thus lacks a comprehensive global data set, unlike, say, monthly mean precipitation. Several multiyear GCM integrations have been performed to evaluate the sensitivity of the global mean black carbon distribution to the principal aerosol parameters, with due regard to variability and statistical significance. The most sensitive parameters, in order of importance, turn out to be the wet deposition, transformation from hydrophobic to hydrophilic state, and the partitioning of the emitted aerosol between the hydrophobic and hydrophilic varieties. From the sensitivity tests, it is estimated that the variations of the global mean column burden and lifetime of black carbon are within about a factor of 2 about their respective standard values. The studies also show that the column burdens over remote regions appear to be most sensitive to changes in each parameter, reiterating the importance of measurements in those locations for a proper evaluation of model simulation of these aerosols.

/pdf/a-general-circulation-model-study-of-the-global-carbonaceous-4h3u9jgwuu.pdf

A general circulation model study of the global carbonaceous aerosol distribution

This paper is an overview of an intensive period of data collection performed as part of the Western Atlantic Ocean Experiment (WATOX) during early 1986. The objective of WATOX-86 was to determine the flux and fate of a variety of atmospheric materials that are advected eastward from North America to the atmosphere of the western North Atlantic Ocean (WNAO). WATOX-86 used two National Oceanic and Atmospheric Administration aircraft, a twin engine King Air and a four engine WP-3D, to collect gases and aerosols off the east coast of North America from Florida to Newfoundland. The WP-3D was based at McGuire Air Force Base, New Jersey, during the first 10 days of January 1986. The King Air was based at Hanscom Field, Massachusetts, during periods in January and February 1986 and on Bermuda during May 1986. Measurements were made of a variety of gases including SO2, NOx, NOy, peroxyacetyl nitrate, CO, O3, C2−C6 hydrocarbons, N2O and dimethyl sulfide. In addition, aerosols were collected and analyzed for black carbon, SO4=, NO3−, NH4+ and trace metals. The individual papers of this special issue provide details on the results and analysis of the individual measurement programs. This paper provides a brief summary of each program. During WATOX-86, there were large regions of the WNAO atmosphere that had elevated concentrations of the measured gas and aerosol species. The elevated concentrations were the result of transport of the products of anthropogenic activities from North America to the WNAO atmosphere. The high degree of correlation among the concentrations of the different species indicated that these materials were transported in “clouds” of polluted air that covered thousands of square kilometers. The WATOX-86 data on sulfur and nitrogen oxides are analyzed in the context of atmospheric budgets for WNAO. Approximately 25 to 35% of the sulfur and 15 to 25% of the nitrogen oxides emitted to the eastern North American atmosphere are advected eastward to the WNAO atmosphere. Of this material, about half of the sulfur and most of the nitrogen oxides are deposited to the WNAO. For both sulfur and nitrogen oxides, wet and dry deposition are of approximately equal importance.

Watox-86 overview and western North Atlantic Ocean S and N atmospheric budgets

Trace elements in daily collected aerosols at a site in southeast England

During the second Arctic Gas and Aerosol Sampling Program conducted in April 1986, we performed measurements of the optically absorbing carbonaceous component of the ambient aerosol from the NOAA WP-3D aircraft operating between sea level and 10 km altitude. We collected the aerosol of filters that were exposed for several hours; we also operated the aethalometer to measure the concentration of aerosol black carbon in real time. The filter analyses represent averages over the altitude range and time span during which the filter was collecting. The real-time results were sorted by altitude to calculate vertical profiles of black carbon concentration. Values typically ranged from 300 to 500 ng m−3 at lower altitudes, decreasing gradually to 25 to 100 ng m−3 at 8–10 km. Strong stratification at lower altitudes was frequently observed. The magnitude of these concentrations suggests that the sources are distant regions of considerable fuel consumption. The presence of this material in the tropospheric column and its probable deposition to the high-albedo surface may result in perturbations of the solar radiation balance. The concentrations measured at the highest altitudes may mean that particulate carbon and accompanying emissions for which it is a tracer are mixing into the stratosphere.

Aerosol black carbon measurements in the Arctic haze during AGASP-II

During the aircraft operations phase of the Western Atlantic Ocean Experiment (WATOX) program conducted in January 1986 off the eastern seaboard of the United States, we performed measurements of the optically absorbing carbonaceous component of the ambient aerosol. We collected the aerosol on filters that were exposed for several hours; we also operated the aethalo meter to measure the concentration of aerosol black carbon in real time. The filter analyses represent averages over the altitude range and time span during which the filter was collecting. The real-time results were sorted by altitude to calculate vertical profiles of black carbon concentration. Values typically ranged from 200 to 500 ng/m3 in the boundary layer, decreasing to 50 to 100 ng/m3 at higher altitudes. By multiplying the mean concentration profile by the offshore air flux, we may estimate the export of aerosol black carbon from the coast to be of the order of 5 × 1010 g/yr.

A. D. A. Hansen

Papers

Aerosol black carbon measurements over the western Atlantic Ocean