Page1 PAGE 1 The influence of MM5 nudging schemes on CMAQ simulations of benzo(a)pyrene concentrations and depositions in Europe Volker Matthias, GKSS.

PAGE 1Page1

The influence of MM5 nudging schemes on CMAQ simulations of benzo(a)pyrene

concentrations and depositions in Europe

Volker Matthias, GKSS Research Center, Geesthacht, Germany

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Introduction

MM5 nudging schemes

Comparison to measurements

CMAQ model results for B(a)P and PM10

Conclusions

Outline

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

PAHs imperil humans and ecosystems– highly bioaccumulative (food chain)– persistent in various environmental compartments – significant adverse effects already at low doses

• carcinogenic• impair immune system• impair reproduction

Why PAHs ?

B(a)P

Object of international reduction conventions(Target values for air concentrations -

EU: 1 ng/m3 (annual average), UK: 0.25 ng/m3)

Emissions are likely to increase wood burning, ship traffic

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

18x18 km2 grid

54x54 km2 grid 30 vertical layers up to 100 hPa

Model domains

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

MM5 parameterizations

The use of MM5 at GKSS:

Kain Fritsch 2 convective cloud scheme MRF (Hong and Pan) PBL scheme Reisner 2 microphysics scheme Noah LSM ERA40 6-hourly boundary conditions (FDDA grid nudging with ERA40 fields)

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Checking meteorological fields

Comparison to ascents from 88 radiosonde station from the igra data base (Durre et al., 2006).

RS data is interpolated to model levels. Mean deviation and correlation are calculated for each profile.

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Test of nudging schemes

Cases:

•No nudging (no nudging)•No nudging, periodic restart (periodic)•Nudge only winds (nudge wind)•Nudge winds and temperature (nudge uvt)•Nudge winds, temperature and humidity (nudge all)•Nudge all, but use no LSM (nudge no LSM)•Nudge all with variable SST (nudge vsst)•Use subsets of layers (nudge all, 9L (12 L))

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Test of nudging schemes: temperature

root mean square error / K mean difference / Knudge allperiodicnudge windno nudgingnudge uvtnudge no LSMnudge vsstnudge all, 9L (12 L)

0

5 3

-3

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Test of nudging schemes: rel. humidity

root mean square error mean differencenudge allperiodicnudge windno nudgingnudge uvtnudge no LSMnudge vsstnudge all, 9L (12 L)

-0.2

0.4

0

0.2

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Monthly mean of correlation and bias sorted by station: Rel. Humidity

Year 2000, mean correlation (Rel. Hum.)

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

U-wind V-wind

high temporal correlations at all heights (0.85 - 0.99)

Annual mean of vertical wind profiles

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Comparison to wind-profiler data (CWINDE) mean vertical profiles (year 2000)

Lindenberg/D

Data from Myles Turp, UK Met Office

Pendine/UK

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

1000 100 10 1Period [hrs.]

1x10 -5

1x10 -4

1x10 -3

1x10 -2

1x10 -1

1x10 0

1x10 1

1x10 2

1x10 3

1x10 4

1x10 5

S(f

) UU

observationm odel, fu ll nudging

U -W ind, C am borne, 910 m , days 100 to 169, m 420

-5/3

Maximum-Entropy-spectra of the U-wind component

U-wind spectra from wind profilers vs. model results

Model/oberservations

1000 100 10 1Period [hrs.]

1x10 -5

1x10 -4

1x10 -3

1x10 -2

1x10 -1

1x10 0

1x10 1

1x10 2

1x10 3

1x10 4

1x10 5

S(f

) UU

m odel, C am borne, no nudging, 910 mm odel, C am borne, fu ll nudging, 910 mm odel, C abauw , nudging, 980 mm odel, C abauw , no nudging, 18 km grid , 980 m

U -W ind, days 92 to 121, m 360

-5/3

Model: influence of resolution and nudging

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Effects on B(a)P concentrations

full nudging periodioc simulations

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Effects on B(a)P depositions

full nudging periodioc simulations

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Annual PM10

Time series of daily means at Neuglobsow/Germany, year 2000

mean bias -7.4 g/m3

corr coeff 0.52

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Chemical composition at Melpitz/Germany

Sec. Organic Aer. underestimated, particularly in summer

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

Frequency distribution of PM10 measurements is log-normal.

Model results reveal the same distribution function.

PM10 frequency distribution function

Neuglobsow / Germany

Payerne/Switzerland

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Volker Matthias, GKSS Research Center, Geesthacht,

Germany

MM5 results were tested with different nudging schemes

Full nudging of T, RH, U and V permits close agreement with observations

Depending on horizontal grid scale, intraday variability of wind comp. is not resolved by the model

Deposition patterns can be highly sensitive to nudging/no nudging in MM5

PM10 results imply significant underestimation of organic aerosol in summer

Good results for sec. inorganic aerosols in Central Europe

Conclusions