Page1 PAGE 1 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

PAGE 2  Introduction  MM5 nudging schemes  Comparison to measurements  CMAQ model results for B(a)P and PM10  Conclusions Outline

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 3 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/m 3 (annual average), UK: 0.25 ng/m 3 ) Emissions are likely to increase wood burning, ship traffic

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 4 18x18 km 2 grid 54x54 km 2 grid 30 vertical layers up to 100 hPa Model domains

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 5 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)

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 6 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.

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 7 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))

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 8 Test of nudging schemes: temperature root mean square error / K mean difference / K nudge all periodic nudge wind no nudging nudge uvt nudge no LSM nudge vsst nudge all, 9L (12 L)

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 9 Test of nudging schemes: rel. humidity root mean square error mean difference nudge all periodic nudge wind no nudging nudge uvt nudge no LSM nudge vsst nudge all, 9L (12 L)

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 10 Monthly mean of correlation and bias sorted by station: Rel. Humidity Year 2000, mean correlation (Rel. Hum.)

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 11 U-windV-wind high temporal correlations at all heights ( ) Annual mean of vertical wind profiles

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 12 Comparison to wind-profiler data (CWINDE) mean vertical profiles (year 2000) Lindenberg/D Data from Myles Turp, UK Met Office Pendine/UK

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 13 Maximum-Entropy-spectra of the U-wind component U-wind spectra from wind profilers vs. model results Model/oberservations Model: influence of resolution and nudging

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 14 Effects on B(a)P concentrations full nudging periodioc simulations

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 15 Effects on B(a)P depositions full nudging periodioc simulations

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 16 Annual PM10 Time series of daily means at Neuglobsow/Germany, year 2000 mean bias -7.4  g/m 3 corr coeff 0.52

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 17 Chemical composition at Melpitz/Germany Sec. Organic Aer. underestimated, particularly in summer

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 18 Frequency distribution of PM10 measurements is log-normal. Model results reveal the same distribution function. PM10 frequency distribution function Neuglobsow / GermanyPayerne/Switzerland

Volker Matthias, GKSS Research Center, Geesthacht, Germany PAGE 19  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