Impacts of aerosols in the CORDEX-Europe domain using the regional aerosol-climate model REMO-HAM

Transcription

1 Impacts of aerosols in the CORDEX-Europe domain using the regional aerosol-climate model REMO-HAM Armelle Reca C. Remedio (1), Claas Teichmann (1,2), Joni-Pekka Pietikäinen (3), Natalia Sudarchikova (1), Daniela Jacob (1), Guy Brasseur (1,2) (1) Climate Service Center 2.0, (2) Max Planck Institute for Meteorology, (3) Finnish Meteorological Institute 21st Century Challenges in Regional Climate Modelling Lund University, Sweden June 16, 2014

2 Aerosols in atmosphere Source: IPCC AR4,

3 Aerosols in atmosphere Source: IPCC AR5,

4 Motivation We attempt to quantify the aerosols-clouds interaction over Europe using a regional aerosol-climate model * within the framework of the EU FP7 PEGASOS Project Regional aerosol-climate model Experimental setup Preliminary Results Comparison between REMO-HAM and REMO Comparison between models and CRU Summary and conclusions 4

5 Regional aerosol-climate model REMO-HAM (J.P. Pietikäinen et al., 2012) based on the regional climate model REMO REMO (Jacob and Podzun, 1996; Jacob et al., 2013) Hydrostatic, three-dimensional atmosphere model Prognostic equations for cloud water, water vapor & cloud ice, empirical cloud cover scheme Cloud droplet number concentration is parameterized separately for continental and maritime climate and it is a function of height No aerosol module Aerosols based on the climatology: spatial distributions of the optical thickness of land, sea, urban, and desert aerosols, and well mixed tropospheric and stratospheric background aerosols 5

6 REMO-HAM REMO-HAM uses the HAM-M7 aerosol module structure similar to the global aerosol-climate model ECHAM5-HAM (Roeckner et al., 2003; Stier et al., 2005) nucleation Aitken BC soluble SU 0 O coarse DU DU O, SS SU, BC 0.05 DU - dust SU - sulfate DU O BC SU insoluble r, µm accumulation DU O, SS SU, BC O - organics SS - sea salt BC - black carbon 0.5 Includes most of the main aerosol processes: nucleation, condensation, thermodynamic equilibrium with water vapor and the inter model transfer Aerosol information is passed on to the cloud scheme (Lohmann et al., 2007) Indirect effects No coupling between HAM-M7 and radiation (similar to REMO) No direct / semi-direct effects Model evaluation on aerosols (J.P. Pietikäinen et al., 2012) comparable with observations 6

7 Cloud droplet number concentration (cm-3) Summer REMO,(Pfeifer, 2006) Solid line: continental clouds Dashed line: maritime clouds Winter Boundary conditions for REMO-HAM Mean daily concentrations at the lowest model layer 7

8 Model Setup CORDEX Europe 0.44 (Coarse) ~ 27 N 72 N, ~22 W 45 E Dimensions: 129x121x27 Initial and lateral boundary conditions: ERA-Interim Simulation period: REMOHAM: Emission dataset from AEROCOM 2000 inventory Experiments: REMO (from CORDEX Europe simulations) REMO-HAM Focus: Impact of aerosols to climatic variables (cloud cover, precipitation) 8

9 Preliminary results Summer and winter, Comparison between experiments: REMO-HAM and REMO Cloud cover Large scale precipitation Sub-grid resolved precipitation Comparison to CRU Observations Cloud cover Precipitation 9

10 REMO-HAM REMO Changes in cloud cover (fraction) Summer Decrease in cloud cover Winter Increase in cloud cover 10

11 REMO-HAM REMO Changes in large scale precipitation (%) Summer Winter Regions of increase mostly in land areas 11

12 REMO-HAM REMO Changes in subgrid-resolved precipitation (%) Summer Winter Increase in land areas 12

13 Mean bias to CRU Mean cloud cover bias (%) during summer REMO REMO-HAM 13

14 Mean bias to CRU Mean cloud cover bias (%) during winter REMO REMO-HAM 14

15 Mean bias to CRU Mean precipitation bias (%) during summer REMO REMO-HAM 15

16 Mean bias to CRU Mean precipitation bias (%) during winter REMO REMO-HAM 16

17 Summary and conclusions Impacts on precipitation and clouds using a regional aerosol-climate model during summer and winter of in the CORDEX Europe coarse resolution domain.we use REMO-HAM to analyze the indirect effects of aerosols: During summer: fraction of cloud cover decreases in REMO-HAM compared to REMO increase in precipitation During winter: regions of increase in fraction of cloud cover decrease in precipiation currently investigating: changes in the cloud droplet number concentration Posters: REMO-HAM (T1-18), CORDEX-Europe Initiative (T4-16) 17

18 Thank you for your attention! Contact: Armelle Reca C. Remedio Climate Service Center 2.0 Climate System Department Fischertwiete Hamburg armelle.remedio@hzg.de 18