Modelling Activities
1. Specific objectives & working program
The specific contribution to the proposed project concerns 1d and 3d model studies of the radiative effects due to Arctic tropospheric aerosols. The importance of including aerosol properties in models that simulate arctic climate is investigated. For a realistic estimation of the climatic effect of Arctic haze, it is necessary to incorporate aerosol in a 3d climate model. A regional atmospheric climate model, called HIRHAM, is used over an Arctic integration area covering the whole Arctic north of 65 N. HIRHAM will be integrated over such seasons, where Arctic haze typically occurs, i.e. over spring seasons. It will be investigated which influence exerts the aerosol on the radiative budget and to what extent the possible changes of the heating rates do influence the monthly mean atmospheric structures due to changed vertical exchange processes. Due to the high horizontal resolution of the model it is possible to simulate both the influence on the large-scale and on the meso-scale atmospheric structures. The dependence of the aerosol climate signal on the optical properties of the aerosols and on clouds will also be investigated on the basis of a variety of sensitivity studies.
Specific objectives
- 1d radiative transport modeling studies for the point Ny Alesund
- implementation of the Global Aerosol Data Set (GADS) into HIRHAM
- HIRHAM spring simulations of the Arctic circulation
- study the aerosol influence on the atmospheric circulation
- incorporation of a newly developed (by ASTAR2000 campaign) Arctic aerosol dataset into HIRHAM
- simulations for the ASTAR2000 period
GADS:
Koepke, Hess, Schult, Shettle, 1997: Global Aerosol Data Set. Report No. 243, Max-Planck-Institut für Meteorologie, Hamburg.
2. Model description
3. Publications
Papers
Dethloff, K., A. Rinke, R. Lehmann,J. H. Christensen, M. Botzet, B. Machenhauer, 1996: Regional climate model of the Arctic atmosphere. J. Geophys. Res. 101, 23401-23422.
Rinke, A., K. Dethloff, 2000: On the sensitivity of a regional Arctic climate model to initial and boundary conditions. Clim. Res. 14 (2), 101-113.
Posters
Fortmann,Rinke,Dethloff,Christensen, 2000: The direct influence of Arctic aerosol during early spring in a regional climate model. EGS 2000, poster presentation.