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Scientific Progress through Interdepartmental Co-operation

Scientific Progress through Interdepartmental Co-operation. Hartmut Grassl Max Planck Institute for Meteorology Meteorological Institute, University Hamburg. Outline. Motivation Results (Examples) Improving GCM parameterizations by LES modelling

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Scientific Progress through Interdepartmental Co-operation

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  1. Scientific Progress through Interdepartmental Co-operation Hartmut Grassl Max Planck Institute for Meteorology Meteorological Institute, University Hamburg

  2. Outline • Motivation • Results (Examples) • Improving GCM parameterizations by LES modelling • Complex planetary boundary layers measured and modelled • Global distribution of semi-volatile organic compounds • Plans(Examples) • Tropospheric aerosols and the climate of the North Atlantic region • Persistent organic substances in and above the North Sea and • the Baltic Sea • Evaluation of all MPI Met models by ENVISAT data

  3. Motivation • Most scientific progress originates from new data that falsify and subsequently improve models • The experimental groups and the modellers have to co-operate • In addition corporate identity is strengthened

  4. LES for GCM Parameterizations (I)Chlond/Bäuml/Roeckner Goal: Development of a radiative transfer parameterization in the ECHAM5 model which accounts for the effect of horizontal sub-grid scale cloud variability Basis: Effective Thickness Approach (Cahalan, 1994): Optical thickness of clouds is reduced by a correction factor  • Method: • Determine reduction factor for different cloud types using Large-Eddy Simulations and radiative transfer calculations • Implement correction factor into standard two-stream scheme, diagnosing cloud type from phase and cloud thickness

  5. Geographical distribution of the mean winter albedo bias due to cloud inhomogeneity • Results: • Albedo is reduced by 1.8 % in the global annual mean (corres-ponding to an increase of net SW radiation by 6.2 W/m2) • Correction factors are in the range 0.4    1 for water clouds (depending on LWP),  = 0.9 for ice clouds

  6. LES for GCM Parameterizations (II)Chlond/Müller/Roeckner • Goals: • advance the understanding of the physical processes that determine the thermal and dynamical state of the cloud-topped boundary layer • evaluate and improve methods of representing shallow cloud systems in global climate models of the atmosphere • produce comprehensive 4-D data sets using LESs • use of LES data sets to investigate deficiencies in ECHAM using the Single Column Model (SCM) version as a test bed • correct and improve parameterizations in ECHAM

  7. LES vs SCM: Diurnal variation of LWP (FIRE) Result:ECHAM-SCM produces a too shallow boundary layer and predicts a too low liquid water path but with a timing in phase compared with the observations

  8. Observation and simulation of a double boundary layer over the Baltic SeaBösenberg/Jacob/Hennemuth • During PEP in BALTEX a double-layered PBL was observed over the central Baltic Sea (Gotland) by lidar and other sensors • REMO in the BALTEX version with 1/6° horizontal resolution is capable to simulate such structures • The model results indicate that the upper layer is the advected PBL over land • The occurrence of an elevated layer over the marine PBL further suppresses the vertical transport of sensible and latent heat from the surface layer into the free atmosphere • Concerning PBL structure the Baltic Sea is rather a big lake than an ocean

  9. Observation of the phenomenon

  10. Simulation of the phenomenon

  11. Profiles of Latent Heat Flux through Combination of an H2O-DIAL and a RADAR-RASSBösenberg/Peters/Wulfmeyer Objective: Determine the vertical transport of water vapour in the boundary layer. Approach: Eddy correlation technique using high resolution retrievals of vertical wind and water vapour. Advantages: No assumptions on turbulence structure. Representative for large area. Technique: RASS for vertical wind. DIAL for water vapour.

  12. Profiles of Latent Heat Flux through Combination of an H2O-DIAL and a RADAR-RASSBösenberg/Peters/Wulfmeyer Gotland 12/13 September 1996 P1 P2 P3 P4 From Wulfmeyer, Atmos. Sci.

  13. Vertical Structure of Aerosol Optical Properties over EuropeBösenberg/Feichter • MODEL SIMULATIONS • Relaxation of the GCM towards observed meteorology • Calculation of the distribution of the aerosol physical, chemical and optical properties • Atmospheric GCM ECHAM5-T63 (2ox2o horizontal resolution) including aerosol microphysics • EARLINET • Systematic measurements of aerosol • profiles at 22 stations in Europe • Quantitative lidar methods (Raman • lidar, multi-angle method) applied • Quality controlled • Products: backscatter and extinction • profiles, optical depth • Special measurements for diurnal • cycle, Saharan dust, forest fires • 2.5 years of measurements • More than 10000 profiles

  14. Intercomparison Observations - Model resultsRequirements for future cooperation • Realistic intercomparison requires: • Modelling of observable parameters: • Backscatter and extinction, optical depth • Calculation of statistical distribution • Improved representation of the PBL • Detailed comparison for typical situations • Improved microphysical retrievals • Improved temporal coverage

  15. Environmental fate of semivolatile organic compounds (SOCs), in particular persistent organic pollutants (POPs) Lammel/Feichter • Scientific objectives: • Understanding the fate of those substances which migrate between compartments on large spatial scales • Validation of model tools used in decision making (national and international chemicals legislation / conventions) • Methodological achievements: • Multicompartment chemistry-transport model • Characterization of environmental fate by novel and appropriate indicators • Results obtained: • The persistence and long-range transport potential of SOCs are strongly (and more than expected) dependent on the location and the time of entry into the environment.

  16. Environmental Fate as a Function of Location of Entry DDT emission fromChina (overall persistence Poverall = 10 years, effective spatial spreading SSeff = 750 km) Ocean Atmosphere Turkey(Poverall= 13 years, SSeff = 1900 km)

  17. HOAPS

  18. Direct and Indirect Aerosol EffectsOlaf Krüger, Johann Feichter • Emissions: Africa (Sahara), USA, Europe • Influence on ITCZ, NAO • Correlations between cloud water/precipitation and • cloud albedo • Evaluation of coupled global models with long satellite • time series (AVHRR, MODIS)

  19. EXPOSURE TO PERSISTENT ORGANIC SUBSTANCES AND EFFECTS IN THE NORTH SEA AND BALTIC SEA ATMOSPHERIC AND AQUATIC ENVIRONMENTS • INTERDISCIPLINARY: • INTEGRATED: exposure (environmental) and effects (wildlife, • humans) or: P+S+I # • GEOGRAPHIC FOCUS: German Bight (during the 1st phase) • PROCESS FOCUS: air-sea exchange (1st phase) • SUBSTANCE FOCUS: exploratory (1st phase) # D = driver P = pressure S = state I = impact R = response

  20. Conclusions • Development of new remote sensing tools (sensors + algorithms) and LES modelling has reached a level that allows global and regional model evaluation and improvement • Co-operation within the ZMAW will give us the capability of ecosystem model evaluation • Our hypothesis: There is a connection between NH anthropogenic aerosol load and ITCZ as well as NAO

  21. THE END

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