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Meteorology

Masters theses

Here is a list of currently available topics for Masters theses in the Meteorology group. As a Masters student you are always invited to talk to us about your own ideas for a thesis topic.

1. How well do weather forecast models simulate precipitation variability at the sub-hourly time scale?

Precipitation from weather forecasting models typically provide data every hour or less, while the actual rain shower that hits you on the way home may only last some minutes. The central question of this thesis is, how do modelled and observed rainfall time characteristics compare? We have new high-resolution rainfall and precipitation phase instrumentation in place at GFI, measuring at 1 min resolution. The purpose of this thesis is to investigate the observed short-term precipitation statistics with simulations from the current operational AROME model run at Met Norway at  as sub-hour resolution obtained from operational weather forecast models. A possible result of this Masters thesis is to develop a more useful way to communicate precipitation forecasts.

Relevant literature: The AROME forecast model (Seity et al., 2011). Precipitation variability from MRR and Disdrometer (Jaffrain et al., 2011)

Contact: Harald Sodemann (Numerical Modeling, Atmospheric Water Cycle)

 

2. Origin of moisture observed from aircraft measurements of an atmospheric river near Iceland

Moisture is often transported along frontal regions of extratropical cyclones. In a vertically integrated perspective, the total column water appears to flow poleward similar to a river, therefore these features are sometimes called Atmospheric Rivers (ARs). In September and October 2016, aircraft measurements during the international NAWDEX/NEAREX/EPATAN campaign near Iceland sampled ARs during 3 cases. The task within this Masters thesis will be to simulate the moisture transport during a selected event with a mesoscale numerical weather prediction model equipped with water vapour source tracers. The sources, structure and evolution will be compared to aircraft measurements and satellite imagery, to investigate how moisture is "handed over" from one cyclone to another.

Relevant literature: Moisture transport in Atmospheric Rivers (Ralph et al., 2011). Sources of water vapour in Atmospheric Rivers (Sodemann and Stohl, 2013).

Contact: Harald Sodemann (Numerical Modeling, Atmospheric Water Cycle)

 

3. Evaporation "hot spots" and the Deuterium excess signature in high-resolution climate models

The atmospheric water cycle is a key component of weather forecasting and climate models. This work is about identifying the regions where strong latent heat flux, or evaporation occurs, and how this affects the Deuterium excess, a stable isotope indicator of evaporation conditions. We have 6-hourly data from several current climate models which allow to compare how the evaporation process is simulated in each of them. A possible outcome of the work is to better understand where uncertainties in the water cycle of models are located, and how we can use additional measurements to improve them.

Relevant literature: Deuterium excess in the global water cycle (Pfahl and Sodemann, 2014). The NorESM climate model's water cycle (Bentsen et al., 2012).

Contact: Harald Sodemann (Numerical Modeling, Atmospheric Water Cycle)

 

4. Moisture source variability during periods of low predictability

The aim of this thesis is to investigate what role moist processes play during periods of low predictability. A moisture source identification is applied to data from the ECMWF 51-member ensemble to examine the variability of moisture sources and transport in each member. A keen interest in learing and applying ensemble methods as well as advanced atmospheric diagnostics based on backward trajectories are needed for this project.

Relevant literature: The moisture source diagnostic of Sodemann et al. (2008). Application of the moisture source perspective to Central Europe (Sodemann and Zubler, 2010). Measuring uncertainty in the ECMWF ensemble prediction system (Buizza et al, 1999)

Contact: Harald Sodemann (Numerical Modeling, Atmospheric Water Cycle)

  

 

5. Validation of remotely sensed wind profiles against radiosoundings

The marine atmospheric boundary layer is in the altitudes relevant for state-of-the-art and future expected wind turbines (0-300 m) not yet well understood. To improve our understanding of the complex interaction between wind shear, atmospheric stability and turbulence characteristics offshore, the offshore measurement campaign OBLEX-F1 (Offshore Boundary Layer Experiment at FINO1) has been initiated. It is an intensive observational campaign within the German Bight and is carried out by NORCOWE and several international partner institutions. The data from the experiment allows for an intensive and detailed study of the marine atmospheric boundary layer under various synoptic conditions.
Within this master project, wind profiles from a scanning lidar system (Leosphere WindCube 100S) should be validated against radiosoundings from two sites in the vicinity, Schleswig and Norderney. It will include a  statistical analysis of the observed differences as function of the synoptic situation, in particular wind speed, wind direction, and atmospheric stability.
More information on the project can be found here.

Contact: Joachim Reuder (Boundary layer meteorology, Energy meteorology)