DC-8 Flight 4 9-Mar-06

1. Outflow Mexico City Basin Overpass DC-8 Flight 4 9-Mar-06 DC-8 Flight 5 11-Mar-06 INTEX-B Phase-2 Asian emissions were detected throughout the troposphere and in the lower stratosphere on all flights during Phase-II starting with the 17 April flight from California to Hawaii. During this period, major dust storms were occuring in China and evidence of dust was observed on all flights. Lower depolarizationsin these layers indicated the presence of other non-depolarizing aerosols and often an O3 max was observed at a higher altitude. Some examples are shown below. DC-8 Flight 10 17-Apr-06 DC-8 Flight 17 9-May-06 DC-8 Flight 16 7-May-06 DC-8 Flight 13 28-Apr-06 Aerosol Attenuation Corrections A coarse aerosol attenuation correction has been applied to the DIAL aerosol profiles in the analysis of the INTEX-B data set. The Fernald solution is solved by forward integration for nadir profiles and backward integration for zenith profiles. Thus the correction increases the scattering ratio in the nadir and decreases it in the zenith. Shown here are uncorrected profiles in black and corrected profiles in red (1064 μ) or green (576 & 599 μ). Extinction-to-backscatter ratios (Sa) assumed were as follows: Phase-I Sa = 45 for 576 & 599 μ, Sa = 30 for 1064 μ Phase-II Sa = 35 for 576 & 599 μ, Sa = 30 for 1064 μ The change in Sa for Phase-II was to accommodate general differences in aerosol types encountered during the two phases. These data are now available in the archive as “Version-2”. Zenith Profiles Nadir Profiles 1064 μ 599 μ 576 μ 1064 μ Aerosol Characteristics Measured by DIAL During INTEX-BCarolyn Butler(1,2), Edward Browell(1), John Hair(1), Marta Fenn(1,2),Anthony Notari(1,2), Syed Ismail(1), Susan Kooi(1,2)(1)Atmospheric Sciences Research, NASA Langley Research Center, MS 401A, Hampton, Virginia, 23681,USA (2) SSAI, Hampton, NASA Langley Research Center, MS 927, VA 23666 USA INTEX-B Phase-I Heavy aerosol loading was observed below 5 km on flights out of Houston. Inside the Mexico City Basin (MCB), depolarizing aerosols with large aerosol scattering ratios and very low wavelength dependence. Although the depolarization clearly indicates the presence of dust, the 10 – 20% values observed are low for dust and suggest the presence of other non-depolarizing aerosols. Outside of the basin, the MCB plume was often difficult to distinguish from aerosols from the Yucatan fires. FSU trajectories indicate the DC8 encountered MCB air on the NE leg of 9 March at higher altitudes than peaks in aerosol scattering ratios and depolarizations (which were even higher than over Mexico City). Selected observations and their aerosol characteristics are shown in the table. Shown here are Asian Emissions from the NILU Atmospheric Backward Transport Analysis (using the FLEXPART model) by Andreas Stohl. They show peaks in Asian emissions on each of these 4 flights at many altitudes, mostly fresh (< 10 days) but some more aged (> 10 days).