Aktuelle Projekte

Leitung:

Björn Maronga, Günter Groß, Siegfried Raasch, Gunther Seckmeyer

Bearbeitung:

Tobias Gronemeier, Matthias Sühring, Farah Kanani-Sühring, Robert von Tils, Michael Schrempf

Laufzeit:

2016-2019

Förderung durch:

BMBF

Kurzbeschreibung:

The goal of the project is the development of a new innovative urban climat model that is able to simulate the microclimate in densely-populated cities like Berlin with a spatial resolution of less than 10 m. The model will be developed as a user-friendly tool, which can be applied by both scientists and urban planners.

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Leitung:

Björn Maronga, Siegfried Raasch

Bearbeitung:

Helge Knoop

Laufzeit:

2016-2019

Förderung durch:

Deutscher Wetterdienst (DWD)

Kurzbeschreibung:

The project aims to improve the local forecast of atmospheric surface layer processes and quantities for airport areas with a focus on the precise forecast of critical events such as radiation and advection fog as well as wind gusts by using high-resolution large-eddy simulations (LES).

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Leitung:

Siegfried Raasch, Björn Maronga

Bearbeitung:

Katrin Scharf

Laufzeit:

2016-2019

Förderung durch:

BMBF

Kurzbeschreibung:

In nature, atmospheric state variables are modified by surface flux variations at all scales, which are induced by dynamic (vegetation growth, land use management) surface heterogeneities, and which feedback on larger scale atmospheric boundary layer (ABL) fluxes. ABL circulations driven by these heterogeneities modify the surface fluxes resulting in two-way feedbacks and impacts on even extended circulations. Sub grid-scale heterogeneity of land surfaces in climate models is usually tackled by the tile approach, which assumes a homogeneous atmosphere interacting with a heterogeneous land surface. In this approximation, the atmosphere is solely driven by grid-averaged fluxes at the surface. This project will quantify the effect of climate model sub-grid flux variability including induced boundary circulations within the scale of the climate model grid cell and their feedbacks on the fluxes on the uncertainty of regional climate predictions. The main intention is to explicitly resolve the near-surface processes both in order to gain a better physical understanding, and to quantify errors in the existing weather forecasting model ICON surface parameterizations and suggest improvements.

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Leitung:

Björn Maronga

Bearbeitung:

Johannes Schwenkel

Laufzeit:

2015-2017

Förderung durch:

DFG

Kurzbeschreibung:

In this project, high-resolution large-eddy simulations (LES) will be used to investigate the effect of turbulence on nocturnal radiation fogs. The LES model PALM will be used at very high resolution in the order of 1 m with both an Eulerian bulk cloud physics scheme and an embedded Lagrangian particle model that allows for explicitly resolving aerosols and fog droplets will be employed. This innovative approach allows for studying fog droplet-turbulence interactions for the first time with LES. The aim of this study is to achieve a comprehensive view on the key parameters that determine the life cycle of radiation fog as well as its three-dimensional macro- and microstructure. Moreover, the effect of a nocturnal fog layer on the morning transition and the daytime boundary layer will be studied. The effect of surface heterogeneity on nocturnal radiation fog will be investigated by means of LES with prescribed idealized regular and observed irregular surface heterogeneities.

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