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Fiona Rochholz

Institution:University of Bremen
Room:UFT, room 1560
Phone:+49 421 218 - 65983
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Other webpage(s):Fionas's MARUM web page
Fiona Rochholz

PhD project:

Modelling and evaluating the response of the climate system to long-term astronomical cycles with cGenie Earth System Model

Earth System Models are widely used to depict the interactions and processes of the Climate System of our Earth. They associate physical, biological and chemical processes within the atmosphere, the ocean and on land to a globally connected system. To better rely on predictions about the future climate, it has become of use to investigate past climate changes using models to unravel effects and relationships within the system and to quantify the current and future climate change.

Long-term climate changes are affected by variations of the orbital parameters (Eccentricity, Obliquity and Precession), modulating the incoming solar radiation on Earth and thus the so called insolation. They take influence on the timing and duration of seasons and differences in solar radiation on the northern and southern hemisphere. Even though the orbital parameters can to a large extend modulate the long term climate changes (Glacial, Interglacial), they are most likely not the only cause to variations. The response of the system itself to orbital forcing seems to differ between warm, greenhouse conditions and cool, icehouse periods. Since all climate parameters are in one way or another linked to each other, specifying the correlation between the orbital parameters and other components (Carbon Cycle, Ocean Circulation, …) is prerequisite to fully understand the Earth’s climate variations.

This PhD is part of the ERC project EARTHSEQUENCING, that focusses on the development of a high- resolution and continuous record of geological events, ages and durations for the past 66 million years to extract properties of Earth’s and solar system orbital motion. Part of this approach is to seek and understand the climate and carbon cycle sensitivity to orbital forcing throughout the Cenozoic, where deep sea records indicate orbital changes. Within this framework, I will investigate climate changes in the Paleogene, that are well described by sediment records, such as the Eocene-Oligocene boundary, the Paleocene-Eocene-Thermal-Maximum.

My thesis project will quantify and identify the Earth’s system reaction to climate perturbation (greenhouse gas concentration changes, changes in continental configuration,..) under the forcing of orbital parameters. This can describe the Earth’s sensitivity and thus determine the dependency of the Earth’s Systems reaction to the environmental conditions (icehouse or greenhouse). This will be realized using an Earth System Model of Intermediate Complexity, the cGenie Earth System Model. For this model, I will develop experiments over long term amplitude modulation cycles which requires model runs of at least 500 ka – 1 Ma and test the hypothesis, that the Earth’s climate response to the same type of orbital forcing has varied e.g. between greenhouse and icehouse conditions.

Thesis committee:

Prof. Dr. Heiko PälikeUniversity of Bremen
Dr. Torsten BickertUniversity of Bremen
Dr. André PaulUniversity of Bremen
GLOMAR Research Theme A