Testing Fast Photochemical Theory During TRACE-P Based on Measurements of OH, HO2, NO2, and CH2O
Abstract
NASA's TRACE-P (Transport and Chemical Evolution over the Pacific) mission provided measurements of several key short-lived photochemical species from both the DC-8 and P-3B aircraft. Measurements also included the critical longer-lived constituents and physical parameters necessary to theoretically predict the concentrations of these short-lived species. Measurements of OH, HO2, and NO2 were conducted on both aircraft, while CH2O was measured only from the DC-8. Measurements of these species will be compared with box model calculations to assess our understanding of fast photochemical cycling. Onboard the DC-8, additional measurements of H2O2, CH3OOH, and oxygenated NMHCs were available. Calculations show the impact of oxygenated NMHCs on photochemical cycling to be significant only for the upper troposphere at altitudes above 8 km, thus, the examination of HOx (OH+HO2) measurements from the P-3B, which has a flight ceiling of 7 km, is not compromised by the absence of oxygenated NMHC measurements. There are some biases between model-predicted peroxides and measurements for the DC8, but a sensitivity analysis shows that magnitude of these discrepancies have minimal impact on HOx predictions. This suggests that although there are no peroxide measurements available on the P3B aircraft to use as model constraints, theoretical analysis of HOx on the P3B can still be examined with some confidence. Results will address both the broad level of model-measurement agreement as well as evidence for trends in agreement for special environments, e.g., in-cloud data, pollution plumes, and stratospheric air.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.A62A0111O
- Keywords:
-
- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0317 Chemical kinetic and photochemical properties;
- 0365 Troposphere: composition and chemistry;
- 0368 Troposphere: constituent transport and chemistry