A.K. Baker 1, C.A.M. Brenninkmeijer 1, D. Oram, D. O Sullivan,3, F. Slemr 1, T.J. Schuck 1, P. van Velthoven 1 Max Planck Institute for Chemistry, Mainz, Germany University of East Anglia, Norwich, UK 3 Now at Met Office, Exeter, UK KNMI, de Bilt, the Netherlands 9 June
CARIBIC: Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container Based aboard a Lufthansa Airbus 3 6 commercial jet. flights since May 5 Container deployed monthly for consecutive flights. TRAC: 8 flask sampler HIRES: 88 flask sampler (since May ).
Sampling flasks and GC system TRAC:.7L glass flasks filled to ~.5bar Alkenes not stable HIRES: 1L stainless steel flasks filled to ~bar 1L (STP) aliquot for analysis: dried, pre concentrated, cryofocused. GC FID : HP 689 GC with 15m Petrocol DH column GAW VOC audit in 9 Baker et al., (AMT) LOD Precision Ethyne 1.9% Ethane 1.% Propane 1.8% i Butane 1.1% n Butane 1.3% i Pentane 1.3% n Pentane 1.% methyl Pentane 1.3% 3 methyl Pentane 1.% n Hexane 1 1.5% Benzene 3.3% Cyclohexane 1.6% TMP 1 3.1% n Heptane 1.3% Toluene 1 1.6% n ane 1.% Ethylbenzene 3.1% m+p Xylene 3.6% o Xylene 3 5.%
Results Overview Upper Troposphere Lowermost Stratosphere Compound Mean (± 1σ) Min Max %BDL Mean (± 1σ) Min Max %BDL Ethyne 9 ± 3 18 31 ± LOD 117 5 Ethane 575 ± 17 1717 35 ± 16 88 67 Propane 7 ± 58 8 385 35 ± 31 LOD 3 i Butane 9 ± LOD 65 7 3 ± 3 LOD 13 51 n Butane 1 ± 17 LOD 113 3 6 ± LOD 33 15 i Pentane 6 ± 8 LOD 67 33 ± LOD 9 7 n Pentane ± 5 LOD 35 17 3 ± 1 LOD 8 3 methylpentane 3 ± LOD 7 8 3 ± 3 LOD 15 9 3 methylpentane ± LOD 85 1 ± 1 LOD 95 n Hexane ± LOD 5 ± 1 LOD 6 56 Benzene ± 18 LOD 179 5 ± 8 LOD 3 Cyclohexane ± 3 LOD 16 93 1 ± 1 LOD 96 i ane ± 1 LOD 5 96 3 ± 3 LOD 8 96 n Heptane ± 1 LOD 13 5 ± 1 LOD 6 65 Toluene 5 ± 11 LOD 19 9 ± 1 LOD 8 7 n ane 1 ± 1 LOD 7 81 ± 1 LOD 5 88 Ethylbenzene ± LOD 7 95 m+p Xylene ± LOD 19 9 o Xylene 3 ± LOD 8 98
Europe WAS 188 samples (~15% of all CARIBIC) 1 upper troposphere (UT UT) 78 tropopause layer or lowermost stratosphere (TP/LMS TP/LMS) Strat. influence identified by: Elevated PV, O 3 LMS distinguished as having PV > 9 8 7 6 5 3 1 3.5, O3 > 15 and Θ > Θ TPtop No longitudinal trends Decreasing altitudinal trend for TP/LMS samples. Altitude (km) Latitude ( N) May 5 Aug 5 Nov 5 Feb 6 May 6 Aug 6 Nov 6 Feb 7 May 7 Aug 7 Nov 7 Feb 8 May 8 Aug 8 Nov 8 Feb 9 May 9 Aug 9
Trends in the UT NMHC C H C 6 H 6 n C H C 3 H 8 C H 6 ΣNMHC [ppbc] 6 5 6 6 5 6 7 8 9 Back trajectories primarily from North America (~85%) Some European and African/Mediterranean ~/3 of back trajectories below 5 hpa in previous 8 days Majority from Gulf of Mexico region No significant trend for most compounds (and for total NMHC) Decrease in benzene (~5%)
Seasonal Profiles (TP/LMS) C H 6 C 3 H 8 n C H C 6 H 6 Seasonal profiles of NMHC suggest influence of the UT on the composition of the LMS through cross tropopause exchange: TP mixing ratios follow the UT trend 5 LMS mixing ratios show an increase in spring LMS similar to UT and TP values during summer. Presence of shorter lived NMHCs in spring & summer. ΣNMHC [ppbc] 3 1 Feb Mar May June Aug Sept Nov Dec Feb Mar May June Aug Sept Nov Dec
TP/LMS Vertical Profiles 6 6 6 5 C H 6 5 C 3 H 8 5 n C H O 3 [ppb] 3 3 O 3 [ppb] 3 6 6 8 6 5 15 3 O 3 [ppb] 5 3 C 6 H 6 3 5 5 3 total NMHC [pptc] 3 Extension to higher O 3 values during the spring and summer months No obvious differences in NMHC mixing ratios between seasons Expect lower in summer, based on photochemistry
8 Asian Summer Monsoon December 8. First in situ measurements of a number of trace species, including NMHCs. Characterization of monsoon (Indian) outflow. 15 hpa Schuck et al., (ACP) Baker et al., (submitted, ACPD) (from Park et al., 6, JGR)
8 Asian Summer Monsoon 8 C H 6 6 8 C 3 H 8 May June Aug Sept Nov Dec May June Aug Sept Nov Dec 15 n C H 15 5 5 i C H 6 May June Aug Sept Nov Dec May June Aug Sept Nov Dec 8 n C 5 H 1 6 i C 5 H 1 May June Aug Sept Nov Dec May June Aug Sept Nov Dec C H 15 5 3 C 6 H 6 ΣNMHC [ppbc].5. 1.5 1..5 May June Aug Sept Nov Dec May June Aug Sept Nov Dec May June Aug Sept Nov Dec May June Aug Sept Nov Dec.5..3..1 fraction reactive NMHC
8 Asian Summer Monsoon NMHC/CO, NMHC/NMHC to understands sources in India CH /C H 6 to look at CH emissions during monsoon n C H C H 6 8 6 15 5 slope = 11. ±.7 r =.67 slope =.3 ±. r =.7 slope =. ±.93 r =.7 slope =.7 ±.15 r =.56 8 1 8 C 3 H 8 i C H methane [ppbv] 19 185 18 June [m =.8 ±.19, r =.9] [m =.9 ±.6, r =.86] August [m =.38 ±.55, r =.91] September [m =.316 ±.18, r =.8] C H n C 5 H 1 5 3 1 15 5 slope =.6 ±.6 r =.11 slope =.8 ± 1. r =.8 slope =.3 ±.9 r =.1 slope = 1. ±. r =.78 6 5 3 1 5 3 i C 5 H 1 C 6 H 6 175 3 5 6 7 8 9 6 8 6 8 ethane CO [ppbv] CO [ppbv]
Future Analysis of case studies: biomass burning outflow, volcano emissions, etc. Continue making monthly flights now with our newly upgraded container Increased sample resolution with addition of HIRES Combination with CARIBIC I data (1997 ) Thank you for your attention! www.caribic.de
Trends in the UT NMHC C H C 6 H 6 n C H C 3 H 8 C H 6 6 5 6 Long term trend fit to: [HC] t π = a + b cos ( t c ) e 365 Negligible growth observed for all but benzene, which exhibits a slight decrease. Back trajectories indicate westerly flow at midlatitudes (~85%) dt 365 ΣNMHC [ppbc] 6 Very consistent picture of CARIBIC NMHC in this region over the last 5 years. 5 6 7 8 9
8 Asian Summer Monsoon June August September C H 6 8 6 15 5 C 3 H 8 n C H 15 5 15 5 i C H 6 6 n C 5 H 1 i C 5 H 1 6 C H 15 5 5 3 C 6 H 6 ΣNMHC [ppbc] 3..5. 1.5 1..5. 15 5 3 35 15 5 3 35 15 5 3 35 Latitude [ N] 15 5 3 35.6.. fraction reactive NMHC