1. Gas & Aerosol boundary conditions to Chimere from GEOS-Chem
With inputs from: Walter Di Nicolantonio and Alessandra Cacciari (CGS/CNR)

2. Boundary Conditions in regional CTMs
TOP
BCs are implemented as concentrations specified at domain edges and trasported inside by winds
Domain of the regional model (e.g. Chimere)
NORTH
Altitude
WEST
EAST
SOUTH
Latitude
Longitude
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

3. Standard BCs to Chimere CTM
MONTHLY mean climatologies from global models
Gas
LMDz-INCA
Aerosol
GOCART
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

4. What is the impact of BCs?
Test:
CTRL = reference run
NOBC = run w/ BC=0
Results for Ozone:
Influence of BC expands from boudaries to the center in about 10 days
BC contribute to a background of ppbv
Importance of BC depends on local photochemistry activity
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

5. Using GEOS-Chem hourly output for Chimere Boundary Conditions
GEOS-Chem v
GEOS-4, 4°x5° 30 levs
Dust emissions: scheme implemented by Duncan et al. [2007], with DEAD emissions
Saharan emissions reduced by a factor of 3 following Generoso et al. [2008]
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

6. Effect of hourly BCs on Chimere O3
EMEP average
Chimere w/ Monthly BCs
Chimere w/ Hourly BCs
Only marginal improvement:
Bias +0.3 ppb
RMS -0.2 ppb
r +0.02
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

7. Anthropogenic vs Natural PM10 in Europe (year 2003)
Anthropogenic PM10
Natural/Biogenic PM10
µg/m3
Chimere model results [Curci et al., in preparation]
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

8. Saharan dust event July 27-29, 2005 MODIS AOT 550 nm
24/07
25/07
26/07
27/07
28/07
29/07
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

9. Saharan dust event July 27-29, 2005 Images from SEVIRI/MSG
Sequence of RGB images composite with Brightness Temperatures Differences using InfraRed SEVIRI channels (IR 8.7, IR10.8, IR 12.0) : DUST appears Magenta
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

10. Saharan dust event July 27-29, 2005 GEOS-Chem hourly BCs to CHIMERE
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

11. Effect of hourly BCs on Chimere PM10 Comparison with EMEP ground obs
Viznar (ES) 03°W
Chaumont (CH) 07°E
EMEP average
27/07
28/07
Chimere w/ std BCs
Chimere w/ Monthly BCs
Ispra (IT) 09°E
Iskrba (SI) 14°E
Chimere w/ Daily BCs
29/07
30/07
Chimere w/ Hourly BCs
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

12. THANKS FOR YOUR ATTENTION!
Conclusions on preliminary results:
Regional ozone simulation not really sensitive to BC details
Regional PM simulation very sensitive to Saharan dust events  interesting to account for “natural” PM10 excedances
Follow ups of this work:
Comparison with ground data with PM speciation info (e.g. separate contribution from dust)
Comparison with AERONET: AOD at other wavelengths?
Test higher GEOS-Chem resolution (2°x2.5°)
More episodes and statistics on the longer term
THANKS FOR YOUR ATTENTION!
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila

13. Implementation of GEOS-Chem BCs to CHIMERE CTM
global CTM
Hourly or daily
GEOS-Chem timeseries
gas & aerosol
(binary format)‏
ts_YYYYMMDD.bpch
ts_YYYYMMDD.bpch
ts_YYYYMMDD.bpch
ts_YYYYMMDD.bpch
If .not. conse-cutive run
src/prep/
prep_boun.f90
Chimere
pre-processing
Hourly
Chimere BC at domain edges
(netCDF)‏
INI_CONCS.nc
BOUN_CONCS.nc
FILES
Chimere core
(Version 2008b)
LEGEND
Existing CODE
New CODE
Chimere BCs from GEOS-Chem
Harvard University, 24/06/2018
Gabriele Curci, CETEMPS - U. L'Aquila