Regional aerosol modeling in Europe: Evaluation with focus on vertical profiles and radiative effects

• Main Author: Meier, Jessica
• Other Authors: Universität Leipzig,
• Format: Doctoral Thesis
• Language: English
• Published: Universitätsbibliothek Leipzig 2013
• Subjects: Aerosol; Europa; regionale Modellierung; aerosol; Europe; regional modeling; ddc:530
• Online Access: http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-113187; http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-113187; http://www.qucosa.de/fileadmin/data/qucosa/documents/11318/JMeier_Dissertation.pdf

In this thesis the occurrence and the properties of atmospheric particles within Europe are studied by means of the regional transport model COSMO-MUSCAT (Consortium for Small-scale Modeling - MultiScale Atmospheric Transport Model). The model is used to perform calculations for a summer (19-26 July 2006) and a winter (16-26 February 2007) period. Individual extinction coefficients are computed taking into account hygroscopic growth and mass extinction efficiencies of specific chemical compounds. The model study focuses on vertical backscatter profiles, aerosol optical depths, particle surface concentrations and radiative effects. Different descriptions of the vertical distribution of chemical compounds at the lateral model boundaries are tested. The results show that for the tested model setup the influence of the aerosol distribution at the model boundaries on European aerosol is limited. Information from lidar profiles may improve the description at the lateral model boundaries. This may be more important for smaller model domains. Space-based lidar (light detection and ranging) observations (CALIOP - Cloud-Aerosol Lidar with Orthogonal Polarization) observations are compared to the simulated backscatter profiles caused by the simulated anthropogenic aerosol. The model reproduces the shape and magnitude of the vertical backscatter profiles well for both time periods. Better agreements are found for night-time observations compared to day-time data. Satisfying agreements between the model results and experimental observations of ground-based vertical backscatter profiles, aerosol optical depths and particle surface concentrations are also found for the two time periods in Europe. Discrepancies between measurement and simulation highlight the difficulties to describe horizontal and vertical aerosol properties properly. The direct and semi-direct radiative effects of the absorbing aerosol are studied for both summer and winter period. For both periods, an increase of the solar heating rate due to the aerosol forcing is determined. This heating leads to an average decrease of the total cloud cover of 1.0% (summer) and of 0.7% (winter). This semi-direct radiative effect causes a positive forcing at the surface and at the top-of-atmosphere in the European domain.