Export efficiency of black carbon aerosol in continental outflow: Global implications Export

@article{citeulike:230106, abstract = {We use aircraft observations of Asian outflow from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) mission over the NW Pacific in March\&\#8211;April 2001 to estimate the export efficiency of black carbon (BC) aerosol during lifting to the free troposphere, as limited by scavenging from the wet processes (warm conveyor belts and convection) associated with this lifting. Our estimate is based on the enhancement ratio of BC relative to CO in Asian outflow observed at different altitudes and is normalized to the enhancement ratio observed in boundary layer outflow (0\&\#8211;1 km). We similarly estimate export efficiencies of sulfur oxides (SO_<i>x</i> = SO₂(g) + fine SO₄ ^2\&\#8722;) and total inorganic nitrate (HNO₃ ^<i>T</i> = HNO₃(g) + fine NO₃ ^\&\#8722;) for comparison to BC. Normalized export efficiencies for BC are 0.63\&\#8211;0.74 at 2\&\#8211;4 km altitude and 0.27\&\#8211;0.38 at 4\&\#8211;6 km. Values at 2\&\#8211;4 km altitude are higher than for SO_<i>x</i> (0.48\&\#8211;0.66) and HNO₃ ^<i>T</i> (0.29\&\#8211;0.62), implying that BC is scavenged in wet updrafts but not as efficiently as sulfate or nitrate. Simulation of the TRACE-P period with a global three-dimensional model (GEOS-CHEM) indicates that a model timescale of 1 \&plusmn; 1 days for conversion of fresh hydrophobic to hydrophilic BC provides a successful fit to the export efficiencies observed in TRACE-P. The resulting mean atmospheric lifetime of BC is 5.8 \&plusmn; 1.8 days, the global burden is 0.11 \&plusmn; 0.03 Tg C, and the decrease in Arctic snow albedo due to BC deposition is 3.1 \&plusmn; 2.5\%.}, author = {Park, Rokjin J. and Jacob, Daniel J. and Palmer, Paul I. and Clarke, Antony D. and Weber, Rodney J. and Zondlo, Mark A. and Eisele, Fred L. and Bandy, Alan R. and Thornton, Donald C. and Sachse, Glen W. and Bond, Tami C.}, citeulike-article-id = {230106}, citeulike-linkout-0 = {http://www.agu.org/pubs/crossref/2005/2004JD005432.shtml}, citeulike-linkout-1 = {http://dx.doi.org/10.1029/2004JD005432}, day = {1}, doi = {10.1029/2004JD005432}, journal = {Journal of Geophysical Research}, keywords = {aerosol, carbon, global, measurement, transport, tropospheric}, month = {June}, pages = {D11205+}, posted-at = {2005-06-16 19:46:34}, priority = {3}, title = {Export efficiency of black carbon aerosol in continental outflow: Global implications}, url = {http://dx.doi.org/10.1029/2004JD005432}, volume = {110}, year = {2005} }

TY - JOUR ID - citeulike:230106 L3 - citeulike-article-id:230106 N2 - We use aircraft observations of Asian outflow from the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) mission over the NW Pacific in March&#8211;April 2001 to estimate the export efficiency of black carbon (BC) aerosol during lifting to the free troposphere, as limited by scavenging from the wet processes (warm conveyor belts and convection) associated with this lifting. Our estimate is based on the enhancement ratio of BC relative to CO in Asian outflow observed at different altitudes and is normalized to the enhancement ratio observed in boundary layer outflow (0&#8211;1 km). We similarly estimate export efficiencies of sulfur oxides (SO_<i>x</i> = SO₂(g) + fine SO₄ ^2&#8722;) and total inorganic nitrate (HNO₃ ^<i>T</i> = HNO₃(g) + fine NO₃ ^&#8722;) for comparison to BC. Normalized export efficiencies for BC are 0.63&#8211;0.74 at 2&#8211;4 km altitude and 0.27&#8211;0.38 at 4&#8211;6 km. Values at 2&#8211;4 km altitude are higher than for SO_<i>x</i> (0.48&#8211;0.66) and HNO₃ ^<i>T</i> (0.29&#8211;0.62), implying that BC is scavenged in wet updrafts but not as efficiently as sulfate or nitrate. Simulation of the TRACE-P period with a global three-dimensional model (GEOS-CHEM) indicates that a model timescale of 1 &plusmn; 1 days for conversion of fresh hydrophobic to hydrophilic BC provides a successful fit to the export efficiencies observed in TRACE-P. The resulting mean atmospheric lifetime of BC is 5.8 &plusmn; 1.8 days, the global burden is 0.11 &plusmn; 0.03 Tg C, and the decrease in Arctic snow albedo due to BC deposition is 3.1 &plusmn; 2.5%. JF - Journal of Geophysical Research TI - Export efficiency of black carbon aerosol in continental outflow: Global implications VL - 110 SP - D11205 KW - aerosol KW - carbon KW - global KW - measurement KW - transport KW - tropospheric AU - Park, Rokjin AU - Jacob, Daniel AU - Palmer, Paul AU - Clarke, Antony AU - Weber, Rodney AU - Zondlo, Mark AU - Eisele, Fred AU - Bandy, Alan AU - Thornton, Donald AU - Sachse, Glen AU - Bond, Tami PY - 2005/06/01/ UR - http://dx.doi.org/10.1029/2004JD005432 ER -