HR: 11:35h
AN: A52A-06    [Abstracts]
TI: Combustion Iron Distribution and Deposition
AU: Luo, C
EM: cluo@uci.edu
AF: Department of Earth System Science, University of California, Irvine, Irvine, CA , United States
AU: * Mahowald, N
EM: mahowald@ucar.edu
AF: NCAR, 1850 Table Mesa DR., Boulder, CO , United States
AU: Bond, T
EM: yark@uiuc.edu
AF: Department of Civil and Environmental Engineering, University of Illinois, Champagne- Urbana, Urbana, IL , United States
AU: Chuang, P
EM: pchuang@ucsc.edu
AF: Department of Earth Science, University of California, Santa Cruz, Santa Cruz, CA , United States
AU: Artaxo, P
EM: artaxo@if.usp.br
AF: Instituto de Fisica, Universidade de Sao Paulo, Sao Paolo, Brazil
AU: Siefert, R
EM: siefert@usna.edu
AF: Chemistry Deparment, US Naval Academy, Anapolis, MD , United States
AU: Chen, Y
EM: ychen04@stanford.edu
AF: Geological and Environmental Sciences, Stanford University, Palo Alto, CA , United States
AU: Schauer, J
EM: jjschauer@wisc.edu
AF: Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI , United States
AB: Iron is hypothesized to be an important micronutrient for ocean biota, thus modulating carbon dioxide uptake by the ocean biological pump. Studies have assumed that atmospheric deposition of iron to the open ocean is predominantly from mineral aerosols. For the first time, we model the source, transport and deposition of iron from combustion sources. Iron is produced in small quantities during fossil fuel burning, incinerator use, and biomass burning. The sources of combustion iron are concentrated in the industrialized regions and biomass burning regions, largely in the tropics. Model results suggest that combustion iron can represent up to 50 percent of the total iron deposited, but over open ocean regions is usually less than 5 percent of the total iron, with the highest values (less than 30 percent) close to the East Asian continent in the North Pacific. For ocean biogeochemistry the bioavailability of the iron is important, and this is often estimated by the fraction which is soluble (Fe(II)). Previous studies have argued that atmospheric processing of the relatively insoluble Fe(III) occurs to make it more soluble (Fe(II)). Modeled estimates of soluble iron amounts based solely on atmospheric processing as simulated here cannot match the variability in daily averaged in situ concentration measurements in Korea, which is located close to both combustion and dust sources. The best match to the observations is that there is substantial direct emissions of soluble iron from combustion processes. If we assume observed soluble Fe/black carbon (BC) ratios in Korea are representative of the whole globe, we obtain the result that deposition of soluble iron from combustion contribute 20-100 percent of the soluble iron deposition over many ocean regions. This implies that more work should be done refining the emissions and deposition of combustion sources of soluble iron globally.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0412 Biogeochemical kinetics and reaction modeling (0414, 0793, 1615, 4805, 4912)
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly