ATom’s NOAA-GMD Instrumentation /Dataset/Science Backdrop J. W. Elkins1 , F. L. Moore1, 2, E. J. Hintsa1, 2, J. D. Nance1, 2, G. S. Dutton1, 2, B. D. Hall1 1GMD/ESRL/NOAA and 2CIRES/GMD/ESRL/NOAA (Boulder CO USA)

PANTHER: (PAN and other Trace Hydrohalocarbon ExpeRiment,) 190 lb PANTHER: (PAN and other Trace Hydrohalocarbon ExpeRiment,) 190 lb., 6-channel GC (gas chromatograph). * 3 ECD (electron capture detectors), packed columns. * 1 ECD with a TE (thermoelectric) cooled RTX-200 capillary column. * 2-channel MSD (mass selective detector). 2 independent samples concentrated onto TE cooled Haysep traps, two temp programmed RTX-624 capillary columns. * Tunable diode laser hygrometer (May Comm Inst.) Currently in UCATS. Last Time on DC-8 was SOLVE-II Measures: N2O, SF6 , CFC-113, CFC-12, CFC-11, halon-1211(CBrClF2 ), H2, CH4 , CO, PAN, methyl halides CH3I, CH3Br, CH3Cl, the sulfur compounds COS, CS2, hydrochlorofluorocarbons HCFC-22 (CHClF2 ), HCFC-141b(C2H3Cl2F) , HCFC-142b(C2H3ClF2 ), and hydrofluorocarbon HFC-134a(C2H2F4 ), H2O

Measures: N2O, SF6 , H2 , CH4 , CO, adds H2O and O3. UCATS: (Unmanned aircraft Chromatograph for Atmospheric Trace Species), 60 lb. GC, TDL and Photometer. * 2-Channel ECD GC, packed columns. * Tunable diode laser hygrometer (May Comm Inst.) * Dual-beam ozone photometer (2B Inst. ) Measures: N2O, SF6 , H2 , CH4 , CO, adds H2O and O3. More complicated Rack configuration and second pump with Teflon inlet beyond what we had in SOLVE-II

Redundant data sets: Sample Volume and rate information: In situ ECD data have even higher data rate of 1 or 2 min ( 2-3 second sample width). (target 0.5% precision) O3 (0.1 Hz) (target 2% +2 ppb precision) H2O (1 Hz) (target 3% + 1 ppm precision) In situ MDS data are similar to flask data except for a higher 3 min. data rate and a sample width of box integration of ~ 150 sec , or about an 80% sample duty cycle. (target 1% precision, ( might do better in ATom) PFP Flask data is altitude targeted (on dives) with ~ 10-20 seconds of sample width. (24 to 36 flask samples per flight). (target precision 0.05% on up depending on species ) Correlate with Fast Data sets. Integrate over Fast Data sets. Redundant data sets:

NWAS: (NOAA Whole Air Sampler) 20 lb. per 12 flask pkg NWAS: (NOAA Whole Air Sampler) 20 lb. per 12 flask pkg., 2 to 4 NWAS pkg per flight, 6 in rack. * Total 0f 24 flask per flight, [two NWAS PFPs] Analyzed on * MSD ( analysis by HATS/ESRL flask lab - Steve Montzka et al.) * ECD, NDIR, FID and RGA ( analysis by CCGG/ESRL flask lab - Pat Lang et al.) * MSD ( analysis by INSTARR/CU isotopes flask lab - James White et al.) Measures: CO, CO2 CH4 and isotopes, H2 , SF6 , N2O, tetrachloroethylene (C2Cl4), CCl4 , CFC-11, CFC-12, CFC-13, CFC-113, CFC-114, CFC-115, HCFC-22, HCFC-124, HCFC-141b, HCFC-142b, HCFC-227ea, HFC-23, HFC-125, HFC-134a, HFC-143a, HFC-152a, HFC-365mfc, halon-1211, halon-1301, halon-2402, chloroform (CHCl3), methyl chloroform (CH3CCl3), chloroethane (CH3CH2Cl), dichloromethane (CH2Cl2), methyl halides (CH3Cl CH3I CH3Br), bromoform (CHBr3), dibromomethane (CH2Br2), acetylene (C2H2), propane (C3H8), benzene (C6H6), perfluoropropane (PFC-218), iso-pentane (C5H12), n-butane (C4H10), n-pentane (C5H12), n-hexane (C6H14), carbonyl sulfide (OCS), and carbon disulfide (CS2).

Stratospheric Tracers: Long lived ~ strat lifetime (years) CO2 > 500 SF6 > 500 Growth >> age of stratospheric air and transport time scales. CFC-115 > 500 CFC-13 > 500 N2O ~ 120 CFC-12 ~ 100 CFC-113 ~ 85 halon-1301 ~ 65 CFC-11 ~ 50 CCl4 ~ 35 halon-2402 ~ 20 halon-1211 ~ 16 O3 (stratospheric sources) Photolytic Loss >> distributed mass flux and Strat-chemistry 4 CFC-11 best signal to noise stratospheric signature in trop. CFC-11 strat-signature in the troposphere will only mix back up to tropospheric value.

Stratospheric Processing (loss)

Troposphere tracers: In rapid NH growth, SF6 > In rapid NH growth (surface source no loss.) Dominant Tropospheric Process : Hemispheric Exchange Tracer gradient gives: Latitudinal surface and temporal information Trop Age of air since equilibrating northern PBL. (Waugh et al.)

large tropical transport drives inter hemispheric exchange January large tropical transport drives inter hemispheric exchange Mean Stream function - NCEP-NCAR reanalysis ( I M Dima and JM Wallace 2002) SF6

April tropical transport slows down hemispheres homogenize SF6

June large tropical transport drives inter hemispheric exchange SF6

October tropical transport slows down hemispheres homogenize SF6

Defining Hemispheric Exchange is Key: Dominant Tropospheric Process : Defining the observed gradients for many tracers. Has Vertical structure: Exchange occurs primarily an upper troposphere. Seasonal structure: Turned on and off twice a year. Not looking at and average 1.3 year process but rather an oscillatory and faster process. Controls mass flux across the tropics where the chemistry (OH) has similar characteristics. i.e. vertical and temporal structure. : Strongly coupled and highly variable: “ transport <-> chemistry ” problem to decouple in ATom:

(long compared to hemispheric exchange) Replacement Molecules: Like SF6, are typically in rapid NH growth but with ……. Substantial OH loss in troposphere. (typically long stratospheric lifetimes > 50 years.) If we normalize each tracer to their respective growth rates. (pictorially shown through color code) Then in the absence of loss (OH) they would have the same inter hemispheric gradient. (driven by exchange process) …. Differences in these normalized gradient are then a measure of loss. SF6 HFC-134a ~ Trop lifetime 13 years (long compared to hemispheric exchange)

Gradients contain free trop chemistry. Troposphere tracers: In rapid growth, Strong and variable surface source and sinks Short lived due to OH, photolysis, etc.. SF6 > In rapid NH growth (surface source.) CO2 > Strong and variable surface source and sink. CH4 > “ plus weak OH chemistry. ~ total lifetime (years) HCFC-143a 47. (OH) HFC-125 28 HCFC-142b 17 HFC-134a 13 HCFC-22 12 HCFC-141b 9.2 CH3CCl3 5.0 HFC-152a 1.5 CH3Cl 1.0 CH3Br 0.8 CHCl3 0.4 CH2Cl2 0.4 CH2Br2 0.34 C2Cl4 0.25 Gradients contain free trop chemistry. OH Exchange time 1.3 Free troposphere OH, photolysis loss rates equivalent to… large scale bulk troposphere transport time scales.

Fine source structure Troposphere tracers: In rapid growth, Strong and variable surface source and sinks Short lived due to OH, photolysis, etc.. SF6 > In rapid NH growth (surface source.) CO2 > Strong and variable surface source and sink. CH4 > Strong and variable surface source and sink. ~ total lifetime (years) HCFC-143a 47. (OH) HFC-125 28 HCFC-142b 17 HFC-134a 13 HCFC-22 12 HCFC-141b 9.2 CH3CCl3 5.0 HFC-152a 1.5 CH3Cl 1.0 CH3Br 0.8 CHCl3 0.4 CH2Cl2 0.4 CH2Br2 0.34 C2Cl4 0.25 OH Fine source structure Free troposphere OH, photolysis loss rates Faster than large scale bulk troposphere transport time scales.

Troposphere tracers: In rapid growth, Strong and variable surface source and sinks Short lived due to OH, photolysis, etc.. SF6 > In rapid NH growth (surface source.) CO2 > Strong and variable surface source and sink. CH4 > “ plus weak OH chemistry. ~ total lifetime (years) HCFC-143a 47. (OH) HFC-125 28 HCFC-142b 17 HFC-134a 13 HCFC-22 12 HCFC-141b 9.2 CH3CCl3 5.0 HFC-152a 1.5 CH3Cl 1.0 CH3Br 0.8 CHCl3 0.4 CH2Cl2 0.4 CH2Br2 0.34 C2Cl4 0.25 Replacement: typically in rapid NH growth but …. molecules substantial OH loss in troposphere. long stratospheric lifetimes > 100 years. OH Free trop OH, photolysis loss rates equivalent or faster large scale bulk troposphere transport time scales.

The rest of the tracers: very short lived with life times as short as days to weeks. *strong variability in unique surface, land., ocean, and free troposphere source and sinks *often used for focused and or process oriented studies. ethyne benzene propane Isopentane N_butane N_pentane CH3I CHCl3 OCS CS2 H2 CO O3 H2O PAN O18, C14 (CO2), C13 (CH4) OCS Jan/Apr 4 O3 Apr/Jun PAN Jan/Jun

Vertical and Horizontal Profiles looking for: * Source/Sinks. Ocean/Land/Atmospheric with dependency on Pollution/Biology/Chemistry. * Coupled with transport. Inter-hemispheric Exchange. Upwelling and Mixing. Interactions between Boundary-Layer <-> Troposphere <-> Stratosphere. 4

Run 3D- Model Simulations and Satellite Validations: Challenge: Distributed and in most cases uncertain boundary source region. Coupled variable transport and in most cases variable chemistry. Data only exist on a sheet down the Pacific and Atlantic though with good seasonal coverage. Run 3D- Model Simulations and Satellite Validations: Propagate estimates of surface sources/sinks and atmospheric chemistry onto the ATom data set. Use agreement / disagreement to improve estimates of surface sources/sinks, chemistry and model transport. In HIPPO model studies of N2O, CH4, Br-loading, OH, SF6-Trop Age, PAN, H2 many resulting in publications.

Some papers published with NOAA data collected on HIPPO (model comparisons, satellite validation...): Hossaini, R., et al., The contribution of natural and anthropogenic very short-lived species to stratospheric bromine, Atmos. Chem. Phys., 12, 371-380, doi:10.5194/acp-12-371-2012. Hossaini, R., et al., Evaluating global emission inventories of biogenic bromocarbons, Atmos. Chem. Phys., 13, 11819-11838, doi:10.5194/acp-13-1189-2013. Kuai, L., et al., Characterization of Aura TES carbonyl sulfide retrievals over ocean, Atmos. Meas. Tech., 7, 163-172, doi:10.5194/amt-7-163-2014. Leedham Elvidge, E.C., D. E. Oram, J.C. Laube, A. K. Baker, S. A. Montzka, S. Humphrey, D. A. O’Sullivan, C. A. M. Brenninkmeijer, Increasing concentrations of dichloromethane, CH2Cl2, inferred from CARIBIC air samples collected 1998-2012, Atmos. Chem. Phys., 15, 1939-1958, doi:10.5194/acp-15-1939-2015. Park, M., et al., Global variability and trends of CHClF2 (HCFC-22) and CCl3F (CFC-11) estimated from ACE-FTS, HIPPO and WACCM4, in review, 2015. Patra, P.K., et al., Observational evidence for interhemispheric hydroxyl-radical parity, Nature, 513, 219-225, doi:10.1038/nature13721, 2014. Umezawa, T., et al., Methyl chloride in the upper troposphere observed by the CARIBIC passenger aircraft observatory: large-scale distributions and Asian summer monsoon outflow, J. Geophys. Res., 119, 5542-5558, doi:10.1002/2013JD21396, 2014. Waugh, D.W., et al., Tropospheric SF6: Age of air from the northern hemisphere mid-latitude surface, J. Geophys. Res., 118, 11429-11441, doi:10.1002/jgrd.50848, 2013. Xiang, B., et al., Global emissions of refrigerants HCFC-22 and HFC-134a: unforeseen seasonal contributions, Proc. Natl. Acad. Sci., 111(49) 17379-17384, doi:10.1073/pnas.1417372111, 2014. *Typically single species model runs. *Need to take advantage of added information available in correlated data sets generated.