Topics for PhD theses in the framework of the IMPRS-ESM

PhD thesis at the MPI for Meteorology can only be written in the framework of the International Max Planck Research School for Earth System Modelling (IMPRS-ESM). Please check the school's website for more information including how to apply. Below is a list of potential PhD topics for candidates who are interested in atmospheric research topics. Candidates are encouraged to think of other topics in the scope of research at the atmosphere department of MPI-M.

 

Feedback mechanisms of the QBO to the tropical convection (working group: WDC; main supervisor: Marco Giorgetta)

Observations show that deep convective systems like the Madden-Julian oscillation are sensitive to the phase of the quasi-biennial oscillation (QBO), which is an oscillating equatorial wind system driven by convectively triggered waves. In this study the  goal is to gain understanding on the processes by which the QBO can modify tropical convection and the conditions when these processes are effective. The major tool will consist of model simulations, which allow for explicit deep convection, and account for different states of the QBO.

Precipitation partitioning between land and ocean (PC, Cathy Hohenegger)

General Circulation Models (GCMs) using coarse resolution and convective parametrization struggle to correctly partition precipitation between land and ocean. There is hope that the next-generation GCMs, using a grid spacing of O(1 km) so as to explicitly resolve convection, are able to correctly partition precipitation, but this remains unclear. The goal of this PhD project is to investigate the variations of the land-to-ocean precipitation ratio across resolution and understand the processes that control this partitioning.

 

The role of upper tropospheric stability for atmospheric circulation (GCC, Hauke Schmidt)

Convective mass flux and atmospheric overturning circulation are expected to decrease with global warming, which can be related to increasing tropical tropospheric stability. There is uncertainty on the development of this stability as the amplification of warming in the upper troposphere seems to be weaker in some satellite data sets than in GCM simulations. Upper tropospheric stability is furthermore affected, e.g., by variability in the tropopause region caused by stratospheric aerosols, ozone, or the QBO, which have been shown to influence circulation patterns. The aim of this thesis is to study such links between upper tropospheric stability and circulation using a hierarchy of circulation models.   

 

Volcanic impact on seasonal time scales (SFC, Claudia Timmreck)

Large volcanic eruptions can significantly affect global and regional climate within a few months. Every seasonal and decadal prediction would therefore become obsolete if a large volcanic eruption happens in the future. The goal of this PhD project is to investigate on one hand how strong large volcanic perturbations will effect seasonal climate, depended on the initial background climate state, and on the other hand how predictable this response is. Investigations will be carried out with the seasonal prediction system of DWD.

 

The faint young sun problem (SFC, Claudia Timmreck)

For the early Earth, the solar constant was about 25 % weaker as today. This should have result in a completely frozen world if all other parameters controlling Earth's climate would had been the same. There is, however, evidence of liquid water in the Archean (3.8 to 2.5 BP), so some effects must have counteract the faint young Sun. The goal of the PhD study is to investigate possible reasons for this "faint young sun problem" by looking in particular to thermodynamic and cloud adjustments  with RCE and aqua planet simulations.