Photochemistry in biomass burning plumes and implications for tropospheric ozone over the tropical South Atlantic
Mauzerall, DL; Logan, JA; Jacob, DJ; Anderson, BE; Blake, DR; Bradshaw, JD; Heikes, B; Sachse, GW; Singh, H; Talbot, B
| HERO ID | 1508905 |
|---|---|
| In Press | No |
| Year | 1998 |
| Title | Photochemistry in biomass burning plumes and implications for tropospheric ozone over the tropical South Atlantic |
| Authors | Mauzerall, DL; Logan, JA; Jacob, DJ; Anderson, BE; Blake, DR; Bradshaw, JD; Heikes, B; Sachse, GW; Singh, H; Talbot, B |
| Journal | Journal of Geophysical Research |
| Volume | 103 |
| Issue | D7 |
| Page Numbers | 8401 |
| Abstract | Photochemistry occuring in biomass burning plumes over the tropical south Atlantic is analyzed using data collected during the Transport and Atmospheric Chemistry Near the Equator-Atlantic aircraft expedition conducted during the tropical dry season in September 1992 and a photochemical point model. Enhancement ratios (Delta Y/Delta X, where Delta indicates the enhancement of a compound in the plume above the local background mixing ratio, Y are individual hydrocarbons, CO, O-3, N2O, HNO3, peroxyacetyl nitrate (PAN), CH2O, acetone, H2O2, CH3OOH, HCOOH, CH3COOH or aerosols and X is CO or CO2) are reported as a function of plume age inferred from the progression of Delta non-methane hydrocarbons/Delta CO enhancement ratios. Emission, formation, and loss of species in plumes can be diagnosed from progression of enhancement ratios from fresh to old plumes. O-3 is produced in plumes over at least a 1 week period with mean Delta O-3/Delta CO = 0.7 in old plumes. However, enhancement ratios in plumes can be influenced by changing background mixing ratios and by photochemical loss of CO. We estimate a downward correction of similar to 20% in enhancement ratios in old plumes relative to Delta CO to correct for CO loss. In a case study of a large persistent biomass burning plume at 4 -km we found elevated concentrations of PAN in the fresh plume. The degradation of PAN helped maintain NOx mixing ratios in the plume where, over the course of a week, PAN was converted to HNO3. Ozone production in the plume was limited by the availability of NOx, and because of the short lifetime of O-3 at 4 -km, net ozone production in the plume was negligible. Within the region, the majority of O-3 production takes place in air above median CO concentration, indicating that most O-3 production occurs in plumes. Scaling up from the mean observed Delta O-3/Delta CO in old plumes, we estimate a minimum regional O-3 production of 17 x 10(10) molecules O-3 cm(-2)s(-1). This O-3 production rate is sufficient to fully explain the observed enhancement in tropospheric 03 over the tropical South Atlantic during the dry season. |
| Doi | 10.1029/97JD02612 |
| Wosid | WOS:000073172100016 |
| Url | http://www.agu.org/pubs/crossref/1998/97JD02612.shtml |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Source: Web of Science WOS:000073172100016 Journal:JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2169-897X |
| Is Public | Yes |