Upload
walden
View
83
Download
0
Embed Size (px)
DESCRIPTION
Linking GEOS-Chem with CMAQ: Consistency in meteorology and chemistry. GEOS-Chem : Goddard Earth Observing System-CHEMisrty CMAQ : EPA ’ s Community Multiscale Air Quality modeling system. Daewon W. Byun, Nankyoung Moon, Heejin In, Chang-Keun Song. - PowerPoint PPT Presentation
Citation preview
Linking GEOS-Chem with CMAQ:Consistency in meteorology and chemistry
Linking GEOS-Chem with CMAQ:Consistency in meteorology and chemistry
Institute for Multidimensional Air Quality StudiesInstitute for Multidimensional Air Quality Studies(IMAQS)(IMAQS)
University University ofof Houston Houston
Institute for Multidimensional Air Quality StudiesInstitute for Multidimensional Air Quality Studies(IMAQS)(IMAQS)
University University ofof Houston Houston
Daewon W. Byun, Nankyoung Moon, Heejin In, Chang-Keun SongDaewon W. Byun, Nankyoung Moon, Heejin In, Chang-Keun SongDaewon W. Byun, Nankyoung Moon, Heejin In, Chang-Keun SongDaewon W. Byun, Nankyoung Moon, Heejin In, Chang-Keun Song
Harvard UniversityHarvard UniversityHarvard UniversityHarvard University
Daniel Jacob, Rokjin ParkDaniel Jacob, Rokjin ParkDaniel Jacob, Rokjin ParkDaniel Jacob, Rokjin Park
GEOS-Chem: Goddard Earth Observing System-CHEMisrtyCMAQ: EPA’s Community Multiscale Air Quality modeling system
IntroductionIntroductionOne of key problems of regional air quality models is finding accurate initial and boundary conditions (BCs)
Most popular method is running a coarse regional model with fixed profiles for a reasonable period to spin-up the coarse domain, then use nesting for fine scale simulations.
Profile BCs could be different at each side of domain reflecting certain regional differences but cannot account for changes caused by long-range air pollution transport events.
Key Issues linking global model output for regional models are differences in;
1. Chemical species2. Scales and grid structure
- Spatial interpolation of global data for regional BC
3. dynamic descriptions in Global and Regional Models
O3-NOX-Hydrocarbon chemistry : 24 species24 species
CMAQ
MAPPING Table
CB4O3-NOx-Hydrocarbon
chemistry
[NO2 ] [NOx ]-[NO]
[O3 ] [Ox ] - [NOx ]
[N2O5] [N2O5]
[HNO3] [HNO3]
[PNA ] [HNO4]
[H2O2] [H2O2]
[CO ] [CO ]
[PAN ] [PAN ] + [PMN ] + [PPN ]
[MGLY] [MP ]
[ISPD] [MVK ] + [MACR]
[NTR ] [R4N2]
[FORM] [CH2O]
[ALD2] [ALD2] + [RCHO]
[PAR ] [ALK4] + [C3H8] + [C2H6]
[OLE ] [PRPE]
[ISOP] [ISOP]
GEOS-CHEM
CB4 : 16 species16 species
Un-used species : ACET, ALD2
Chemical species:Currently, chemical mechanisms in global and regional models are not “consistent”: use species mapping
Mechanics of Linkage
Mapping Table
SAPRACO3-NOx-Hydrocarbon
chemistry
[NO2 ] [NOx ] – [NO]
[PAN] [PAN]
[CO] [CO]
[ALK3] [ALK4]+[ALK5 [ALK4]
[ISOPRENE ] [ISOP]
[HNO3] [HNO3]
[H2O2] [H2O2]
[ACET ] [ACET]
[MEK] [MEK]
[CCHO] [ALD2]
[RCHO] [RCHO]
[MRTHACRO] [MACR]
[MA_PAN] [PMN]
[MVK] [MVK]
[PAN2] [PPN]
SAPRACO3-NOx-Hydrocarbon
chemistry
[RNO3] [R4N2]
[OLE1] + [OLE2] [PRPE]
[ALK2] [C3H8]
[HCHO] [CH2O]
[ALK1] [C2H6]
[N2O5] [N2O5]
[HNO4] [HNO4]
[COOH ] [MP]
CMAQ
GEOS-CHEM
SAPRAC-99
Linkage of Chemistry
LAT-LON 2 degree X 2.5 degree
30 layers in Sigma P
LAMBERT CONFORMAL
108 km X 108 km
23 layers in Sigma Po
Initial & Boundary Condition
IO/API Format in 108 km resolution
GEOS-CHEM MODEL3 CMAQ(Multi-pollutant Air Quality model)
Mechanics of Linkage
Linkage of scales: grid structures of the global and regional models are not “consistent”
•Requires horizontal & vertical interpolationImplementation Example: Horizontal interpolation
Future – requires “geocentric” coordinates(from a flat-earth to a spherical earth, if not spheroid)
Comparison of wind field
This difference can be cause the uncertainty to regional air quality simulations.
MM5 NASA-GMAOGeneral patterns of wind fields are well
Some difference shows in circled area. - CMAQ/MM5 shows parallel to the grid - GEOS-CHEM/NASA-GMAO shows inflow
Let’s see how big the problem is:
MM5 GMAO
CMAQ O3 Boundary Flux (2wk avg, Aug 16-30, 2000)
Profile BCGEOS_CHEM BC
N
S
W
E
Solid: in-fluxDashed: out-flux
Current Progress B.C. by Height: GEOS-CHEM 4 x 5 Vertical interpolation
WN
E S
Current Progress B.C. by pressure: GEOS-CHEM 4 x 5Vertical interpolation
WN
SE
Current Progress Cf: B.C. by pressure : RAQMS 2 x 2.5 Vertical interpolation
E S
NW
Comparison of CMAQ O3 with AIRS
CMAQ vs. O3 RAOBS (GEOS-CB4 vs.Profile)
Profile BC
GEOS_CHEM BC
GEOS-3
Example with RAQMS: CMAQ/CB-4 vs. O3 RAOB
O3 metSITE # Location Nation LAT. LON. ALT.
STN021
EDMONTON/STONY PLAIN
CAN 53.55 -114.10 766.00
STN076
GOOSE BAY CAN 53.30 -60.36 40.00
STN077
CHURCHILL CAN 58.75 -94.07 35.00
STN107
WALLOPS ISLAND USA 37.90 -75.48 13.00
Stratospheric O3 data assimilation issues:Chemistry and dynamics tropopause heights
STN021
STN076 STN077 STN107
Note: other than Wallops island, the o3 zonde sites are different from those used in previous page
What is the best method to link global/regional scale dynamics? Comparison of wind fields among four different MM5 results.
Case 1; MM5 results with EDAS first guess
Case 2; MM5 results with EDAS first guess and GMAO objective analysis
Case 3; MM5 results with GMAO, 36-km single domain
Case 4; MM5 results with GMAO, 108/36-km nesting
~ trying to get closer wind fields to GMAO
~ typical MM5 simulation for regional air quality study
Study importance of the dynamic consistency Comparison of the first guess field used in MM5:
between EDAS and GMAO
PREGRID MYPREGRID
REGRIDDER
EDAS GMAO
GMAO MM5/Case-1
00z
GMAO & MM5/Case-1 vs. RAOBs (wind components)
Case 1&2 vs. GMAO (wind components) 00z
Case 2Case 1
Case 3 & 4 vs. GMAO (wind components)
Case 3 Case 4
00z
agreement with observation : CASE1 > CASE2 > CASE4 > CASE3agreement with GEOS-3 : CASE1 < CASE3 < CASE2 < CASE4 Is CASE2 the winner?
Conclusion
Conducted sensitivity CMAQ simulations with fixed profile data, GEOS-Chem BC, CB-4 and SAPRC99 mechanisms, and different MM5 outputs
•Boundaries for global-regional scale linking must be located where direct emission sources are minimum; e.g., US-continental domain (Pacific to Atlantic Oceans).
•Careful assessment of chemical species linkage and horizontal & vertical interpolation schemes required
•Optimal mesoscale meteorological input obtained with EDAS first guess and GMAO objective analysis
Studied chemical and meteorological consistency issues between the global and regional models.