Post on 16-Oct-2021
SIMULATING AMAZONIAN BIOGENIC EMISSIONS AND
TROPOSPHERIC CHEMISTRY USING A GEOS-CHEM NESTED GRIDMichael Barkley (U. Leicester, UK) + 17 others
Motivation:
Use model & satellite HCHO columns to constraint Amazonian isoprene emissions
Model version:v8-03-01
Meteorology:GEOS-5 1/2 lat x 2/3 lon
CONTRASTING ISOPRENE EMISSIONS INVENTORIES
MEGAN ( CANOPY-SCALE )
• E = EF × Activity Factors
• Use MODIS LAI for seasonal changes in vegetation
LPJ-GUESS ( LEAF-SCALE )
• E = J × ε × α × fi ( ≈ photosynthesis )
• Use LPJ-GUESS DVM for seasonal changes in vegetation
LPJ ( CRU )CRU meteorologyArneth et al. 2007,2010
MEGAN-Hybrid5-layer canopy model
Guenther et al. 1995,1999,2006
MEGAN-PCEEAParameterized model
Guenther et al. 2006
LPJ ( GC )GEOS-5 meteorology
Arneth et al. 2007,2010
CHEMICAL MECHANISM BOUNDARY LAYER MIXING
1) Standard 43 tracers
2) Caltech 56 tracers
1) Full mixing
2) Non-local
Compare with MEGAN-MOHYCANMuller et al. 2008 (uses ECMWF + detailed canopy model)
T2M & PAR PRECTOT, SWGNET & T2M
w & w/o OH recycling
Climate Research Unit @ UEA, UK
WHY WE NEED TOP-DOWN
ISOPRENE EMISSION ESTIMATES !
2005 2006 2007 2008
Hybrid 174 154 152 135
PCEEA 162 140 138 119
LPJ (GC) 73 75 69 73
LPJ (CRU ) 102 90 - -
MOHYCAN 102 100 - -
Units = Tg C
MODEL TYPICALLY OVERESTIMATES OBSERVED HCHO COLUMNSHybrid PCEEA Hybrid' LPJ(CRU) LPJ(GC) Hybrid PCEEA Hybrid' LPJ(CRU) LPJ(GC)
Submitted to JGR –with Editor for decision
Simulations based on Caltech chemical mechanism and with full boundary layer mixing
EXTRA
THE DIURNAL CYCLE OF ISOPRENE OXIDATION CHEMISTRY
HOW DOES THE MODEL PERFORM?
Hybrid (standard chemical scheme, full PBL mixing)
PCEEA (standard chemical scheme, full PBL mixing)
Hybrid (Caltech chemical scheme, non-local PBL mixing, inc OH-recycling)
Hybrid x 0.635 (standard chemical scheme, full PBL mixing)
SCIAMACHY vertical column + 1 sd
Truth: Troffee ground based measurements ~60W 2.6S NNW Manaus
COMPARISON WITH GABRIEL
OBSERVATIONS