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, TurkeyPaper , under review Atmos Environ, 2013

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INTRODUCTION• Nitrogen (N) and Sulfur (S) impact on:

– 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.

BACK

GRO

UN

D

Duce et al., Science, 2008

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Chl “a” distribution along Mediterranean

Europe’s Environment, 1998.

N/P ratio in seawater from 22-28 >> than the normal (18)

MO

TIVA

TIO

N

HNO3

NH3

NO3-

NH4+

Dry Deposition

Wet Deposition

NO3-

NH4+

Total Deposition

NO3-

NH4+

NOx NOy

Particulate Nitrogen500 m

1500 m

Sediment traps

Mesozooplancton

Phytoplanton

Bacteries

Cilies

MO

TIVA

TIO

N

0

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11 12Months

mmolN/(15d*m2)

Sediment trapsDry depositionWet deposition

Kouvarakis et al., GBC, 2001

MOTIVATION

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.

FOCUS ON MEDITERRANEAN & BLACK SEA

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METHODS – MODEL CONFIGURATION• 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.

WRF METEOROLOGICAL

MODEL

INITIAL/BOUNDARY CONDITIONS (TM4-

ECPL)

MOSSES ANTHROPOGENIC

EMISSIONS MODEL

CHEMISTRY AND TRANSPORT MODEL

(CMAQ)

NATURAL EMISSIONS (MEGAN

BIOGENIC+GOCART DUST)

NCAR FINN BIOMASS BURNING EMISSIONS

MODEL

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EMISSIONS

Sectors (tons/yr) NOx NH3 SO2

Anthropogenic 1.7E+7 5.7E+6 1.4E+7Biogenic 6.8E+5Biomass Burning 2.2E+3 8.7E+2 1.9E+2

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)

Im et al. (2013) AtmEnv. Under Review

ANNUAL TOTAL N & S EMISSIONS

ANNUAL SECTORAL N EMISSIONS

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OBSERVATIONS

Im et al. (2013) AtmEnv. Under Review

EMEP wet deposition: 45 stations, 2008http://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

Kocak et al., BioGeoSci, 2010: Erdemli, Turkey station, 2006-2007

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MODEL VALIDATION

r2 Bias NMB RMSE IOA MAGE NMENH4

+ 0.3 -198 -53 262 0.6 201 54NO3

- 0.4 -47 -17 146 0.8 110 39

NH4++NO3

- 0.4 -165 -47 226 0.7 170 48SO4

= 0.2 -125 -36 267 0.6 172 46Precip 0.5 -116 -12 417 0.8 318 33

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COMPARISON* WITH EMEP WET DEPOSITION, 2008

PRECIPITATION SO4=

NO3- NH4

+

*Statistics are based on daily mean dataACCENT 2013, September 2013, Urbino, Italy

ANNUAL DEPOSITION FLUXES

Normalized mean error between modeled &observed N deposition fluxes

(N*: Total N as in the observations)

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N DEPOSITION OVER EUROPE, THE MEDITERRANEAN & THE BLACK SEA

Nitrogen deposition (Tg-N yr-1)

Precip.(mm yr-1)

NitrogenEmis.(Tg-N

yr-1)Deposition Emission Dry Wet Total

SeaLand+Sea Sea

Land+Sea Sea

Land+Sea Sea Land+Sea

BS 0.23 0.12 0.36 415 0.52 0.7EM 0.81 2.88 0.29 0.85 1.10 3.73 349 405 2.88 1.3

WM 0.60 2.80 0.32 0.65 0.92 3.45 491 384 1.93 1.8Europe 4.14 5.65 0.75 2.03 4.89 7.68 504 555 9.26 0.8

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S DEPOSITION OVER EUROPE, THE MEDITERRANEAN & THE BLACK SEA

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Sulfur deposition (Tg-S yr-1)Precip.

(mm yr-1)Sulfur

Emis.(Tg-S yr-1)Deposition Emission Dry Wet Total

SeaLand+Sea Sea

Land+Sea Sea

Land+Sea Sea

Land+Sea

BS 0.16 0.01 0.17 415 0.40 0.4EM 0.52 1.37 0.32 0.70 0.84 2.07 349 405 2.88 0.7

WM 0.33 0.48 0.19 0.33 0.52 0.81 491 384 0.84 1.0Europe 1.59 2.51 0.49 1.37 2.07 3.88 504 555 5.08 0.8

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IMPORTANCE & IMPACTS OF N DEPOSITIONLAND• 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.

OCEAN

N (g-N m-2 yr-1)

Annual N deposition over forests

Atm=2.02 TgN yr-1

ASW=1.4 TgN yr-1 River=1.08 TgN yr-1

GW=0.3 TgN yr-1

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IMPACTS OF N DEPOSITION OVER MARINE ECOSYSTEMS

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).

Atm. N Dep.0.36 TgN yr-1

N

C

C production 2.4 TgC yr-1

Sedimentation 1.6 TgC yr-1Theodosi et al., BioGeoSciDisc, 2013

BLACK SEA

This workAtm. 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

This work

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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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THANK YOU

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ACKNOWLEDGEMENTS

U. ImN. DaskalakisM. Kanakidou

S. Christodoulaki

N. MihalopoulosK. Violaki

PEGASOS

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FOCUS ON MEDITERRANEAN & BLACK SEA• Pollution receptor regions, seasonality.• Semi-closed ecosystem• East Mediterranean Sea is oligotrophic

• 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.

Lelieveld et al., Science, 2002

MO

TIVA

TIO

N

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