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Centre for Atmospheric Science University of Cambridge. AMMA-UK: Work Package 5 Centre for Atmospheric Science University of Cambridge Glenn Carver Andrew Robinson Nicola Warwick (pretending to be John Pyle and Neil Harris). Work packages. - PowerPoint PPT PresentationTRANSCRIPT
AMMA-UK: Work Package 5
Centre for Atmospheric ScienceUniversity of Cambridge
Glenn CarverAndrew RobinsonNicola Warwick
(pretending to be John Pyle and Neil Harris)
Centre for Atmospheric ScienceUniversity of Cambridge
Work packages
WP5.1 Use observations of the convective outflows in the TTL regions to analyse the chemical and dynamical processes occurring in such outflows.
WP5.2 Use modelling techniques to assess global transport and impacts of species from WAM & estimate impacts on lower stratosphere.
OWP5 TTL chemistry balloons. Two stratospheric balloons deployed during SOP2 to gain observations of the TTL region in the vicinity of the MCS events.
WP4.5 Investigate global impact on burden of ozone of biogenic emissions from the WAM region.
p-TOMCAT Chemical Transport Model
p-TOMCAT is a global offline chemical transport model Includes a fairly detailed gas-phase / photolysis tropospheric
chemistry scheme. Also includes parametrizations for cloud mixing, boundary layer
mixing, wet & dry deposition, emission inventories for surface and aircraft & lightning emissions.
Driven by ECMWF analyses (operational and ERA40) Standard configurations are 6x6 degree and 3x3 degree
horizontal resolutions with 31 levels Used for many studies of tropospheric chemistry; including
budget studies, field campaign support roles. Recent technical development has seen a move to much higher
resolutions.
Tropical Tropopause Layer tracer studies
Work done by James Levine (Cambridge)
Motivation Study troposphere to stratosphere transport to determine (any)
preferred regions of entry. Planning of SCOUT-O3 tropical campaigns
Studies used tracers in p-TOMCAT designed to allow the exchange of TTL air to lower strat. to be quantified.
TTL regions
1 = Africa 5 = C. Pacific2 = Indian O. 6 = E. Pacific3 = Indonesia 7 = S. America4 = W. Pacific 8 = Atlantic
Release of trop. tracers
T-tracers released one box below the tropopause
(weighted-average of min-T and 2 PVU surfaces)
Conversion to strat tracers
T-tracers converted to S-tracers as a function of TTL origin and entry into the stratosphere
Entry into the stratosphere
Tropopause: min-T and 2 PVU
2000-01
Entry into the stratosphere
Tropopause: min-T and 2 PVU
1997-8
High Resolution Chemical Modelling
Motivation
Emission datasets have global resolution of 1 degree or better : how does this impact on CTM simulations?
Improved representation of long-range transport and comparison with observations
Improved comparisons with aircraft data
Major technical changes to p-TOMCAT to achieve 1x1 and 0.5x0.5 degree global horizontal resolutions with full chemistry
High resolution chemical modelling
NO2 around model’s tropospause.
Taken from short test run of the 0.5x0.5 version of p-TOMCAT.
Transport and chemistry only.
High resolution chemical modelling
QuickTime™ and aPNG decompressor
are needed to see this picture.
NO2 has strong diurnalvariation. Destroyed by sunlight
Resolution
640 x 320
0.56 degree
Approx. 60km at equator
Aircraft .v. model comparisons
Achieving a quantitative comparison of model .v. aircraft data is difficult because of the difference in scales
Fiona O’Connor used high resolution advection to demonstrate this improved comparisons with aircraft data
Ozone and CO were advected (no chemistry) for short periods using horizontal resolutions of 1x1 and 3x3 degrees for comparison with ACTO flights.
In most cases there was significant improvement in the comparison, due to the improved representation of the synoptic situation in the model
Aircraft .v. model comparison
3x3 degrees
Aircraft .v. model comparison
1x1 degrees
Aircraft .v. model comparison
3x3
1x1
Improvements to p-TOMCAT (1)
Addition of Isoprene (Paul Young / Guang Zeng) Mainz Isoprene Scheme (MIM) (Pöschl et al., 2000)
~40 isoprene-related reactions and 16 isoprene-related species:
Emission inventory from GEIA
Sensitivity studies using the Met. Office Unified Model
Current chemistry scheme: NOx-CO-CH4-NMHCs (52 species)
The MIM C5H8
ISO2
OH
MACRO2
OH
NALD
OH
OH
HACETMGLYCH3CO3
NO
ISON
NO3
MACRISO2HOH
NOHO2
MACRO2H
MPAN
OH
HO2
± NO2
CH3C(O)OOH / CH3C(O)OH
PAN OH
HO2
± NO2
OHOH / NO3
HCHO + CO + NO2
OH
Isoprene-Related Species
1. C5H8 - isoprene2. ISO2 - hydroxy-peroxy radicals from C5H8+OH3. ISOOH - beta-hydroxy hydroperoxides from ISO2+HO24. ISON - hydroxy-alkylnitrates from ISO2+NO and alkyl nitrates from C5H8+NO35. MACR - methacrolein and MVK and other C4-carbonyls6. MACRO2 - hydroxy-peroxy radicals from MACR+OH7. MACROOH - hydroxy-hydroperoxides from MACRO2+HO28. MPAN - peroxymethacrylic nitric anhydride and other higher peroxyacyl nitrates9. HACET - hydroxyacetone and other C3-ketones10. MGLY - methylglyoxal and other C3-aldehydes11. NALD - nitrooxy-acetaldehyde (from decomposition of ISON)12. MeCOOOH - peroxyacetic acid13. MeCOOH - acetic acid14. HCOOH - formic acid15. PAN16. acetyl radical (MeCO3)
Improvements to p-TOMCAT (2)
Addition of Bromine (Xin Yang / Nicola Warwick) Bromine chemistry scheme: gas-phase and heterogeneous reactions
on cloud particles and background aerosols
Br emissions from biogenic bromocarbons and sea-salt aerosol
Aim: to determine the influence of bromine chemistry on tropospheric ozone
BrO
Br
BrONO2
HOBr
Br2
O3
NO, OH, RO2, BrO
NO2
HO2,RO2
HO2, RO2, HCHO, RCHO
hv
hv, OH
hv
hv
Ocean/land
BrNO2
CH3Br, CHBr3,CH2Br2, CH2BrCl,CHBr2Cl, CHBrCl2
OH hv
NO2 hv
hv
HBrOH
BrO
HBr, HOBr, Br2
wet or dry deposition
Bromine cycling scheme used in the p-TOMCAT model
Br
Cloud particles/ aerosols
Sea-salt
Heterogeneous or aqueous reactions ??
Particles
hv
~0.62 TgBr/yr
~3.1 TgBr/yr
Emissions of BromoformGlobal CHBr3 Flux
(GgCHBr3/yr)Derived from: Reference
210 Loss rate and global average concentration (0.4 pptv)
WMO, 1999
300 Tropical atmospheric measurements and calculated lifetimes
Dvortsov et al., 1999
220 Reviews of algal halocarbon emissions and biomass estimates
Liss and Carpenter, 2000
826 Published concentration data, global climalogical parameters and information on coastal and biogenic sources
Quack and Wallace, 2003
Bromine Source Studies
Top-down estimates of bromoform emissions depend on location of emission:
latitude (lifetime)
local/non-local source
Vertical Profiles of Bromoform
Red – Scenario 3 (400 Gg/yr) Red – Scenario 4 (595 Gg/yr)
Modelled Zonal Mean Total Bromine
Zonal mean total organic and inorganic bromine in emission Scenario 6 (595 Gg CHBr3 / yr)
Impact of bromine chemistry on tropospheric ozone
Figure by Xin Yang
Objectives
(1) Define the scope of the chemistry (in collaboration with Leeds/UEA)
(1) Include additional organics (e.g. isoprene, halocarbons)
(2) Others? (e.g. oxygenates)
(3) WAM emissions?
(2) Define range of model experiments
(1) Verification of new chemistry
(2) Comparisons with measurements (high res. simulations)
(3) Budget studies (global transport studies of emissions – impact on O3 in troposphere and lower stratosphere)
Acknowledgements
p-TOMCAT: Glenn Carver, Fiona O’Connor, Nick Savage
TTL tracer studies : James Levine, Nick Savage
High resolution modelling : Glenn Carver
Aircraft / model comparisons : Fiona O’Connor
Aircraft campaign support : James Levine, Peter Cook, Nick Savage, Fiona O’Connor
1 'O(3P)' 1 'FM' 'Ox' F F F 'Atomic oxygen (ground state)' 'pptv' 2 'O(1D)' 1 'FM' 'Ox' F F F 'Atomic Oxygen (excited state)' 'pptv' 3 'O3' 1 'FM' 'Ox' T F F 'Ozone' 'ppbv' 4 'NO' 1 'FM' 'NOx' T F F 'Nitric Oxide' 'pptv' 5 'NO3' 1 'FM' 'NOx' T T F 'Nitrate Radical' 'pptv' 6 'NO2' 1 'FM' 'NOx' T F T 'Nitrogen Dioxide' 'ppbv' 7 'N2O5' 2 'TR' ' ' T T F 'Dinitrogene Pentoxide' 'ppbv' 8 'HO2NO2' 1 'TR' ' ' T T F 'Peroxynitric Acid' 'ppbv' 9 'HONO2' 1 'TR' ' ' T T F 'Nitric Acid', 'ppbv'10 'OH' 1 'SS' ' ' F F F 'Hydroxyl Radical' 'pptv'11 'HO2' 1 'SS' ' ' F T F 'Hydroperoxyl Radical' 'pptv'12 'H2O2' 1 'TR' ' ' T T F 'Hydrogen Peroxide' 'ppbv'13 'CH4' 1 'TR' ' ' F F T 'Methane' 'ppbv'14 'CO' 1 'TR' ' ' T F T 'Carbon Monoxide' 'ppbv'15 'HCHO' 1 'TR' ' ' T T T 'Formaldehyde' 'ppbv'16 'MeOO' 1 'SS' ' ' F T F 'CH3OO' 'ppbv'17 'H2O' 1 'CF' ' ' F F F 'Water Vapour' 'ppbv'18 'MeOOH' 1 'TR' ' ' T T F 'CH3OOH' 'ppbv'19 'HONO' 1 'TR' ' ' T T F 'HONO' 'ppbv'20 'C2H6' 1 'TR' ' ' F F T 'Ethane' 'ppbv'21 'EtOO' 1 'SS' ' ' F F F 'EtOO' 'ppbv'22 'EtOOH' 1 'TR' ' ' T T F 'EtOOH' 'ppbv'23 'MeCHO' 1 'TR' ' ' T F T 'CH3CHO' 'ppbv'24 'MeCO3' 1 'SS' ' ' F F F 'Acetaldehyde' 'ppbv'25 'PAN' 1 'TR' ' ' T F F 'Peroxyacetyl Nitrate' 'ppbv'26 'C3H8' 1 'TR' ' ' F F T 'Propane' 'ppbv'
27 'n-PrOO' 1 'SS' ' ' F F F 'n-PrOO' 'ppbv'28 'i-PrOO' 1 'SS' ' ' F F F 'i-PrOO' 'ppbv'29 'n-PrOOH' 1 'TR' ' ' T T F 'n-PrOOH' 'ppbv'30 'i-PrOOH' 1 'TR' ' ' T T F 'i-PrOOH' 'ppbv'31 'EtCHO' 1 'TR' ' ' T F F 'EtCHO' 'ppbv'32 'EtCO3' 1 'SS' ' ' F F F 'EtCO3' 'ppbv'33 'Me2CO' 1 'TR' ' ' F F T 'Acetone' 'ppbv'34 'MeCOCH2OO' 1 'SS' ' ' F F F 'CH3COCH2OO' 'ppbv'35 'MeCOCH2OOH' 1 'TR' ' ' T T F 'CH3COCH2OOH' 'ppbv'36 'PPAN' 1 'TR' ' ' T F F 'PPAN' 'ppbv'37 'MeONO2' 1 'TR' ' ' F F F 'CH3ONO2' 'ppbv'38 'O(3P)S' 1 'FM' 'Sx' F F F 'Stratospheric Ground State Atomic Oxygen' 'ppbv'39 'O(1D)S' 1 'FM' 'Sx' F F F 'Stratospheric Excited State Atomic Oxygen' 'ppbv'40 'O3S' 1 'FM' 'Sx' T F F 'Stratospheric Ozone' 'ppbv'41 'NOXS' 1 'TR' ' ' T F F 'Stratospheric NOx' 'pptv'42 'HNO3S' 1 'TR' ' ' T T F 'Stratospheric Nitric Acid' 'ppbv'43 'NOYS' 1 'TR' ' ' T T F 'Stratospheric Reactive Nitrogen Species' 'ppbv'44 'SPECH' 1 'TR' ' ' F F F 'Advected Specific Humidity' 'g/g'45 'PT' 1 'TR' ' ' F F F 'Advected Potential Temperature' 'K'46 'ISOPRENE' 1 'TR' ' ' F F T 'Isoprene' 'ppbv'47 'C2H4' 1 'TR' ' ' F F T 'Ethene' 'ppbv'48 'C2H2' 1 'TR' ' ' F F T 'Ethyne' 'ppbv'49 'H2' 1 'CT' ' ' F F F 'Hydrogen' 'ppmv'50 'CO2' 1 'CT' ' ' F F F 'Carbon dioxide' 'ppmv'51 'O2' 1 'CT' ' ' F F F 'Oxygen' 'ppmv' 52 'N2' 1 'CT' ' ' F F F 'Nitrogen' 'ppmv'
Current p-TOMCAT Species
Global Bromoform Distribution - Surface
bromoform/pptv bromoform/pptv
Scenario 3 (400 Gg/yr) Scenario 4 (595 Gg/yr)
Creating an Emission Dataset for Methyl Bromide
Six model emission scenarios:
Methyl Bromide Seasonal Cycles
Measurements from NOAA/CMDL (Montzka et al., 2003)
CHBr3 Emissions (GgCHBr3/yr/km2)
Dataset 1: 826 Gg/yr distributed according to Q&W (2003)
Dataset 2: 210 Gg/yr distributed according to Q&W (2003)
Total Global Emissions:
71% in coastal regions
29% in open ocean
Tracer expt: sensitivities
• Sensitivity to level of T-tracer release: insensitive
Sensitivity to dates of T-tracer release?
Continued emission vs. release at start of run?
Differentiation between types of TST Sensitivity to definition of the tropopause?
Sensitivities to model resolution and convection?