PhD defense by Alexander Kurganskiy – Niels Bohr Institute - University of Copenhagen

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PhD defense by Alexander Kurganskiy

Title: Integrated modelling of physical, chemical and biological weather

Integrated modelling of physical, chemical and biological weather has been widely considered during the recent decades. Such modelling includes interactions of atmospheric physics and chemical/biological aerosol concentrations. Emitted aerosols are subject to atmospheric transport, dispersion and deposition, but in turn they impact the radiation as well as cloud and precipitation formation.

The present study focuses on birch pollen modelling as well as on physical and chemical weather with emphasis on black carbon (BC) aerosol modelling.

The Enviro-HIRLAM model has been used for the study. This is an online-coupled meteorology-chemistry model where chemical constituents and different types of aerosols are an integrated part of the dynamical model, i.e., these constituents are transported in the same way as, e.g., water vapor and cloud water, and, at the same time, the aerosols can interactively impact radiation and cloud micro-physics.

The birch pollen modelling study has been performed for domains covering Europe and western Russia. Verification of the simulated birch pollen concentrations against in-situ observations showed good agreement obtaining the best score for two Danish sites: Copenhagen and Viborg. It was verified that the birch pollen emissions and concentrations, as expected, depends strongly on the air temperature, relative humidity, wind speed and precipitation emphasizing the importance of accurate meteorological forecasts in order to perform operational birch pollen forecasts.

The BC modelling study was performed for a modelling domain covering most of the Northern Hemisphere with focus on the EU and Arctic regions.  Verification of BC concentrations against observations showed a good agreement for the EU air quality measurement sites. However, the Arctic region turned to be much more challenging.  The aerosol feedbacks to the physical atmosphere were also studied, and the model simulations indicated that the aerosol feedbacks induced the following changes: reduction of the net downward short-wave surface radiative fluxes, reduction of near surface air temperature, increase of total cloud cover and cloud water and a decrease in precipitation amount.

Link for the thesis: