Atmospheric deposition of nitrogen
and sulfur over Southern Europe with
focus on the Mediterranean and the
Black Sea: WRF/CMAQ modeling
U. Im1,2, S. Christodoulaki1,3, K. Violaki1, P. Zarmpas1, M.
Kocak4, N. Daskalakis1,2, N. Mihalopoulos1, M. Kanakidou1
[1] Environmental Chemical Processes Laboratory, Department of Chemistry, University of
Crete, Voutes Campus, P.O.Box 2208, 71003, Heraklion, Greece
[2] Institute of Chemical Engineering Sciences, Foundation for Research and Technology
Hellas (FORTH), Patras, Greece
[3] Institute of Oceanography, Hellenic Center for Marine Research, P.O. Box 2214, 71003,
Heraklion, Crete, Greece
[4] Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin, Turkey
Paper , under review Atmos Environ, 2013
INTRODUCTION
• Nitrogen (N) and Sulfur (S) impact on:
BACKGROUND
– Atmospheric chemistry (O3 chemistry, SIA HNO3, H2SO4)
– Ecosystem (deposition: fertilization, acidification and accumulation)
• N and S have both anthropogenic and natural sources
• Emissions and deposition of N/S species will further
increase/decrease in the future.
Duce et al., Science, 2008
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MOTIVATION
Chl “a” distribution along Mediterranean
N/P ratio in seawater from 22-28 >> than the normal (18)
Europe’s Environment, 1998.
NO3-
HNO3 NO3-
NH4+
NH3 NH4+
MOTIVATION
Wet
Deposition
Dry
Total Deposition
Deposition
NO3NH4+
Bacteries
Cilies
Phytoplanton
Mesozooplancton
500 m
Particulate Nitrogen
Sediment traps
1500 m
NOx NOy
MOTIVATION
4
S e d im e n t tra p s
m m o lN /
D ry d e p o sitio n
2
(1 5 d * m )
W e t d e p o sitio n
3
2
1
0
1
2
3
4
5
6
7
8
9
10
11
12
M o n th s
Kouvarakis et al., GBC, 2001
FOCUS ON MEDITERRANEAN & BLACK SEA
 The results obtained during this study showed that
airborne DIN alone is more than sufficient to explain
new production in the East Mediterranean Sea. Dry
deposition alone accounts for about a factor of two of
the collected PON and both dry and wet deposition
account for about 370% of the PON.
 Observations have limited geographical coverage.
 CTMs provide integrated view (temporal and spatial
variations) (local to global).
 Few modeling studies dedicated to the atmospheric
deposition of N and S to the Mediterranean and the
Black Seas.
METHODS – MODEL CONFIGURATION
WRF
METEOROLOGICAL
MODEL
MOSSES
ANTHROPOGENIC
EMISSIONS MODEL
•
•
•
•
•
•
NCAR FINN BIOMASS
BURNING EMISSIONS
MODEL
INITIAL/BOUNDARY
CONDITIONS (TM4ECPL)
NATURAL EMISSIONS
(MEGAN
BIOGENIC+GOCART
DUST)
CHEMISTRY AND
TRANSPORT MODEL
(CMAQ)
•
•
•
•
WRF/CMAQ
171×123×23 grid cells
30 km horizontal resolution
Vertical extent ~16 km
CB-V chemical mechanism
(Yardwood et al., 2005)
AERO5 aerosol mechanism (Foley et
al., GeosciModDev, 2010)
NCEP meteorology for 2008
Monthly mean chemical boundary
conditions (global model TM4-ECPL:
Myriokefalitakis et al., ACP, 2011)
Model setup: Im and Kanakidou,
ACP, 2012 & Im et al STOTENV,
under review, 2013
Natural Emissions and Biomass
burning Emissions are calculated on
line.
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ACCENT 2013, September 2013, Urbino, Italy
EMISSIONS
Anthropogenic Emissions
•INERIS 10 km inventory for Europe
•CIRCE global emissions for remaining
parts around the Mediterranean and
Asia (Pozzer et al., ACP, 2012)
•2 km emissions for Istanbul (Markakis
et al., APR 2012) and Athens
(Markakis et al., WASP & APR, 2010)
ANNUAL TOTAL N & S EMISSIONS
ANNUAL SECTORAL N EMISSIONS
Sectors (tons/yr)
NOx
Anthropogenic
1.7E+7
Biogenic
6.8E+5
Biomass Burning
2.2E+3
NH3
SO2
5.7E+6
1.4E+7
8.7E+2
1.9E+2
Im et al. (2013) AtmEnv. Under Review
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OBSERVATIONS
EMEP wet deposition: 45
stations, 2008
http://www.emep.int/
Mihalopoulos unpublished
data: 2008. Finokalia station,
Greece, dry deposition
http://finokalia.chemistry.uoc.gr
Medinets and Medinets,
TurJFishAqua, 2012: Zmiinyi
station, Black Sea, 2008
Markaki et al., MarChem,
2010:5 stations 2001-2003
Im et al. (2013) AtmEnv. Under Review
Kocak et al., BioGeoSci,
2010: Erdemli, Turkey
station, 2006-2007
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MODEL VALIDATION
ANNUAL DEPOSITION FLUXES
SO4
PRECIPITATION
=
NO3-
NH4+
COMPARISON* WITH EMEP
WET DEPOSITION, 2008
r2
Bias
NMB RMSE IOA MAGE NME
NH4+
NO3-
0.3
0.4
-198
-47
-53
-17
262 0.6
146 0.8
201
110
54
39
NH4++NO3-
0.4
-165
-47
226 0.7
170
48
SO4=
0.2
-125
-36
267 0.6
172
46
Precip
0.5
-116
-12
417 0.8
318
33
Normalized mean error between
modeled &observed N deposition fluxes
(N*: Total N as in the observations)
*Statistics are based on daily mean data
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N DEPOSITION OVER EUROPE, THE
MEDITERRANEAN & THE BLACK SEA
Nitrogen deposition (Tg-N yr-1)
BS
EM
WM
Europe
Dry
Land
Sea +Sea
0.23
0.81 2.88
0.60 2.80
4.14 5.65
Wet
Land
Sea +Sea
0.12
0.29 0.85
0.32 0.65
0.75 2.03
Total
Land+
Sea
Sea
0.36
1.10
3.73
0.92
3.45
4.89
7.68
Nitrogen
Emis.(Tg-N
yr-1)
Precip.
(mm yr-1)
Sea
415
349
491
504
Deposition
Emission
Land+Sea
405
384
555
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0.52
2.88
1.93
9.26
0.7
1.3
1.8
0.8
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S DEPOSITION OVER EUROPE, THE
MEDITERRANEAN & THE BLACK SEA
BS
EM
WM
Europe
Sulfur deposition (Tg-S yr-1)
Dry
Wet
Total
Land
Land+
Land+
Sea +Sea
Sea
Sea
Sea
Sea
0.16
0.01
0.17
0.52 1.37 0.32
0.70
0.84
2.07
0.33 0.48 0.19
0.33
0.52
0.81
1.59 2.51 0.49
1.37
2.07
3.88
Precip.
Sulfur
(mm yr-1)
Emis.(Tg-S yr-1)
Land+
Sea
Sea
415
0.40
349
405
2.88
491
384
0.84
504
555
5.08
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Deposition
Emission
0.4
0.7
1.0
0.8
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IMPORTANCE & IMPACTS OF N DEPOSITION
Annual N deposition over forests
LAND
•
•
19% of total N (0.93 Tg-N yr-1) is deposited
over forests.
84% of the forested regions receive
fluxes larger than the critical
nitrogen load of 1 g-N m-2 yr-1.
Atm=2.02 TgN yr-1
N (g-N m-2 yr-1)
OCEAN
ASW=1.4 TgN
River=1.08 TgN yr-1
yr-1
GW=0.3 TgN yr-1
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IMPACTS OF N DEPOSITION OVER
MARINE ECOSYSTEMS
Atm. N Dep.
0.36 TgN yr-1
N
C
C production
2.4 TgC yr-1
Sedimentation
1.6 TgC yr-1
Theodosi et al.,
BioGeoSciDisc, 2013
BLACK SEA
Atm. N Dep.
0.8 g N m-2 yr-1
N
Sedimentation
0.16 gN m-2 yr-1
Kouvarakis et al., GBC,
2001
EAST MED. SEA
 The excess of N accumulates then in the water column and could explain the
anomalous N/P ratio observed in the Eastern Mediterranean (Christodoulaki et al.,
JMarineSys, 2013).
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CONCLUSIONS
• The Mediterranean Sea receives 2.02 Tg-N yr-1 and 1.36 Tg-S yr-1
while the Black Sea receives 0.36 Tg-N yr-1 and 0.17 Tg-S yr-1.
• Results compare reasonably with observations and previous model
studies over Europe although some underestimation is seen
depending on species and season.
• A significant amount of the deposited N and S is transported to the
Mediterranean basin.
• The critical nitrogen load (1 g-N m-2 yr-1) is exceeded in 84% of the
European forested areas.
• Atmospheric deposition plays a predominant role on the open
Mediterranean and Black Seas ecosystems functioning.
• Excess N accumulates in the East Med Sea due to atmospheric N
and is leading to high N/P ratios.
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ACKNOWLEDGEMENTS
U. Im
N. Daskalakis
M. Kanakidou
PEGASOS
S. Christodoulaki
N. Mihalopoulos
K. Violaki
THANK YOU
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FOCUS ON MEDITERRANEAN & BLACK SEA
MOTIVATION
• Pollution receptor regions, seasonality.
• Semi-closed ecosystem
• East Mediterranean Sea is oligotrophic
Lelieveld et al., Science, 2002
• Observations have limited geographical coverage.
• CTMs provide integrated view (temporal and spatial variations) (local
to global).
• Few modeling studies dedicated to the atmospheric deposition of N
and S to the Mediterranean
and the Black Seas.
ACCENT 2013, September 2013, Urbino, Italy
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