%0 Journal Article %1 Talbot1996 %A Talbot, R. W. %A Bradshaw, J. D. %A Sandholm, S. T. %A Smyth, S. %A Blake, D. R. %A Blake, N. R. %A Sachse, G. W. %A Collins, J. E. %A Heikes, B. G. %A Anderson, B. E. %A Gregory, G. L. %A Singh, H. B. %A Lefer, B. L. %A Bachmeier, A. S. %D 1996 %I Amer Geophysical Union %J Journal of Geophysical Research-Atmospheres %K BIOMASS-BURNINGEMISSIONS;TROPOSPHERICOZONE;EQUATORIALAFRICA;METHANEFLUX;NITROGEN;PRECIPITATION;AEROSOL;CARBON;FOREST;HYDROCARBON %N D19 %P 24187--24202 %T Chemical characteristics of continental outflow over the tropical South Atlantic Ocean from Brazil and Africa %U http://www.agu.org/journals/jd/v101/iD19/95JD03630/ %V 101 %X The chemical characteristics of air parcels over the tropical South Atlantic during September - October 1992 are summarized by analysis of aged marine and continental outflow classifications. Positive correlations between CO and CH3Cl and minimal enhancements of C2Cl4 and various chlorofluorocarbon (CFC) species in air parcels recently advected over the South Atlantic basin strongly suggest an impact on tropospheric chemistry from biomass burning on adjacent continental areas of Brazil and Africa. Comparison of the composition of aged Pacific air with aged marine air over the South Atlantic basin from 0.3 to 12.5 km altitude indicates potential accumulation of long-lived species during the local dry season. This may amount to enhancements of up to two-fold for C2H6, 30% for CO, and 10% for CH3Cl. Nitric oxide and NOx were significantly enhanced (up to similar to 1 part per billion by volume (ppbv)) above 10 km altitude and poorly correlated with CO and CH3Cl. In addition, median mixing ratios of NO and NOx were essentially identical in aged marine and continental outflow air masses. It appears that in addition to biomass burning, lightning or recycled reactive nitrogen may be an important source of NOx to the upper troposphere. Methane exhibited a monotonic increase with altitude from similar to 1690 to 1720 ppbv in both aged marine and continental outflow air masses. The largest mixing ratios in the upper troposphere were often anticorrelated with CO, CH3Cl, and CO2, suggesting CH4 contributions from natural sources. We also argue, based on CH4/CO ratios and relationships with various hydrocarbon and CFC species, that inputs from biomass burning and the northern hemisphere are unlikely to be the dominant sources of CO, CH4, and C2H6 in aged marine air. Emissions from urban areas would seem to be necessary to account for the distribution of at least CH4 and C2H6. Over the African and South American continents an efficient mechanism of convective vertical transport coupled with large-scale circulations conveys biomass burning, urban, and natural emissions to the upper troposphere over the South Atlantic basin. Slow subsidence over the eastern South Atlantic basin may play an important role in establishing and maintaining the rather uniform vertical distribution of long-lived species over this region. The common occurrence of values greater than 1 for the ratio CH3OOH/H2O2 in the upper troposphere suggests that precipitation scavenging effectively removed highly water soluble gases (H2O2, HNO3, HCOOH, and CH3COOH) and aerosols during vertical convective transport over the continents. However, horizontal injection of biomass burning products over the South Atlantic, particularly water soluble species and aerosol particles, was frequent below 6 km altitude.

@article{Talbot1996, abstract = {The chemical characteristics of air parcels over the tropical South Atlantic during September - October 1992 are summarized by analysis of aged marine and continental outflow classifications. Positive correlations between CO and CH3Cl and minimal enhancements of C2Cl4 and various chlorofluorocarbon (CFC) species in air parcels recently advected over the South Atlantic basin strongly suggest an impact on tropospheric chemistry from biomass burning on adjacent continental areas of Brazil and Africa. Comparison of the composition of aged Pacific air with aged marine air over the South Atlantic basin from 0.3 to 12.5 km altitude indicates potential accumulation of long-lived species during the local dry season. This may amount to enhancements of up to two-fold for C2H6, 30% for CO, and 10% for CH3Cl. Nitric oxide and NOx were significantly enhanced (up to similar to 1 part per billion by volume (ppbv)) above 10 km altitude and poorly correlated with CO and CH3Cl. In addition, median mixing ratios of NO and NOx were essentially identical in aged marine and continental outflow air masses. It appears that in addition to biomass burning, lightning or recycled reactive nitrogen may be an important source of NOx to the upper troposphere. Methane exhibited a monotonic increase with altitude from similar to 1690 to 1720 ppbv in both aged marine and continental outflow air masses. The largest mixing ratios in the upper troposphere were often anticorrelated with CO, CH3Cl, and CO2, suggesting CH4 contributions from natural sources. We also argue, based on CH4/CO ratios and relationships with various hydrocarbon and CFC species, that inputs from biomass burning and the northern hemisphere are unlikely to be the dominant sources of CO, CH4, and C2H6 in aged marine air. Emissions from urban areas would seem to be necessary to account for the distribution of at least CH4 and C2H6. Over the African and South American continents an efficient mechanism of convective vertical transport coupled with large-scale circulations conveys biomass burning, urban, and natural emissions to the upper troposphere over the South Atlantic basin. Slow subsidence over the eastern South Atlantic basin may play an important role in establishing and maintaining the rather uniform vertical distribution of long-lived species over this region. The common occurrence of values greater than 1 for the ratio CH3OOH/H2O2 in the upper troposphere suggests that precipitation scavenging effectively removed highly water soluble gases (H2O2, HNO3, HCOOH, and CH3COOH) and aerosols during vertical convective transport over the continents. However, horizontal injection of biomass burning products over the South Atlantic, particularly water soluble species and aerosol particles, was frequent below 6 km altitude.}, added-at = {2009-06-08T21:16:48.000+0200}, author = {Talbot, R. W. and Bradshaw, J. D. and Sandholm, S. T. and Smyth, S. and Blake, D. R. and Blake, N. R. and Sachse, G. W. and Collins, J. E. and Heikes, B. G. and Anderson, B. E. and Gregory, G. L. and Singh, H. B. and Lefer, B. L. and Bachmeier, A. S.}, biburl = {https://www.bibsonomy.org/bibtex/2cc09b70580ddde8b09be48152b12be71/claas}, c1 = {NASA,LANGLEY RES CTR,HAMPTON,VA 23681.EOLEOLUNIV CALIF IRVINE,DEPT CHEM,IRVINE,CA 92717.EOLEOLGEORGIA INST TECHNOL,SCH EARTH & ATMOSPHER SCI,ATLANTA,GA 30332.EOLEOLLOCKHEED ENGN & SCI CO,HAMPTON,VA 23681.EOLEOLUNIV RHODE ISL,CTR ATMOSPHER CHEM STUDIES,NARRAGANSETT,RI 02882.EOLEOLNASA,AMES RES CTR,MOFFETT FIELD,CA 94035.}, citedreferences = {ANDREAE MO, 1988, J GEOPHYS RES, V93, P1509 ; ANDREAE MO, 1992, J GEOPHYS RES, V97, P6137 ; BARTLETT KB, 1988, J GEOPHYS RES, V93, P1571 ; BARTLETT KB, 1990, J GEOPHYS RES-ATMOSP, V95, P16773 ; BLAKE DR, 1996, J GEOPHYS RES-ATMOS, V101, P1763 ; CACHIER H, 1985, J ATMOS CHEM, V3, P469 ; CACHIER H, 1989, NATURE, V340, P371 ; CACHIER H, 1991, NATURE, V352, P228 ; CAHOON DR, 1992, NATURE, V359, P812 ; CICERONE RJ, 1988, GLOBAL BIOGEOCHEMICA, V2, P299 ; CRUTZEN PJ, 1979, NATURE, V282, P253 ; CRUTZEN PJ, 1990, SCIENCE, V250, P1669 ; DELMAS R, 1982, GEOPHYS RES LETT, V9, P761 ; ELLIOTT WP, 1984, J CLIM APPL METEOROL, V23, P434 ; FISHMAN J, 1991, SCIENCE, V252, P1693 ; GREENBERG JP, 1984, J GEOPHYS RES-ATMOSP, V89, P1350 ; GREGORY GL, 1990, J GEOPHYS RES, V95, P16903 ; GREGORY GL, 1996, J GEOPHYS RES-ATMOS, V101, P1727 ; HARRISS RC, 1994, J GEOPHYS RES, V99, P1659 ; HEIKES BG, 1992, J GEOPHYS RES-ATMOSP, V97, P18001 ; HEIKES BG, 1996, J GEOPHYS RES-ATMOS, V101, P1891 ; HELAS G, 1992, J GEOPHYS RES-ATMOSP, V97, P6187 ; KIRCHHOFF VWJ, 1990, J GEOPHYS RES, V96, P10899 ; KIRCHHOFF VWJH, 1994, ATMOS ENVIRON, V28, P69 ; KLEINMAN LI, 1991, J GEOPHYS RES-ATMOSP, V96, P991 ; KRISHNAMURTI TN, 1993, J GEOPHYS RES-ATMOSP, V98, P10621 ; KUHLBUSCH TA, 1991, NATURE, V351, P135 ; LACAUX JP, 1992, J GEOPHYS RES-ATMOSP, V97, P6195 ; LESLIE ACD, 1981, NUCL INSTRUM METHODS, V181, P345 ; LOBERT JM, 1991, GLOBAL BIOMASS BURNI, P289 ; MCKEEN SA, 1993, GEOPHYS RES LETT, V20, P2363 ; MOODY JL, 1991, J GEOPHYS RES-ATMOSP, V96, P20769 ; NEWELL RE, 1988, J ATMOS CHEM, V6, P61 ; PAERL HW, 1985, NATURE, V315, P747 ; PAERL HW, 1993, CAN J FISH AQUAT SCI, V50, P2254 ; PICKERING KE, 1992, J ATMOS CHEM, V14, P297 ; PICKERING KE, 1994, MON WEATHER REV, V122, P864 ; RUDOLPH J, 1992, J GEOPHYS RES-ATMOSP, V97, P6181 ; SINGH HB, 1992, GASEOUS POLLUTANTS C, P177 ; SPIRO PA, 1992, J GEOPHYS RES, V97, P6023 ; STEELE LP, 1992, NATURE, V358, P313 ; TATHY JP, 1992, J GEOPHYS RES-ATMOSP, V97, P6159 ; THOMPSON AM, 1993, J GEOPHYS RES-ATMOSP, V98, P23051}, file = {Talbot1996.pdf:Talbot1996.pdf:PDF}, ga = {VQ493}, interhash = {fbdefa5eae66e5ee5da295622580a11f}, intrahash = {cc09b70580ddde8b09be48152b12be71}, j9 = {J GEOPHYS RES-ATMOS}, ji = {J. Geophys. Res.-Atmos.}, journal = {Journal of Geophysical Research-Atmospheres}, keywords = {BIOMASS-BURNINGEMISSIONS;TROPOSPHERICOZONE;EQUATORIALAFRICA;METHANEFLUX;NITROGEN;PRECIPITATION;AEROSOL;CARBON;FOREST;HYDROCARBON}, la = {English}, month = {#oct#}, nr = {43}, number = {D19}, pa = {2000 FLORIDA AVE NW, WASHINGTON, DC 20009}, pages = {24187--24202}, pg = {16}, pi = {WASHINGTON}, publisher = {Amer Geophysical Union}, rp = {Talbot, RW, UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,MORSEEOLEOLHALL,DURHAM,NH 03824.}, sc = {Meteorology & Atmospheric Sciences}, sn = {0148-0227}, tc = {48}, timestamp = {2009-06-08T21:16:48.000+0200}, title = {Chemical characteristics of continental outflow over the tropical South Atlantic Ocean from Brazil and Africa}, url = {http://www.agu.org/journals/jd/v101/iD19/95JD03630/}, ut = {ISI:A1996VQ49300053}, volume = 101, year = 1996 }