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Master theses: Derivation of temperature at the mesopause

Advertising institute: IEK-7 - Stratosphere
Reference number: D122/2012, Physics, Chemistry

We are seeking a Master student working on the derivation of temperature from satellite measurements of vibrationally excited hydroxyl.

Background

This work will improve our understanding of Earth's upper atmosphere energy balance. Although 80-90 km above the surface, this part of the atmosphere is often considered as a miner's canary of global change, because human induced changes such as the CO2 increase have a much larger effect in this part of the atmosphere than below. One of the key challenges is a sound understanding of the dynamical and radiative balance. Observation of airglow emitted from vibrationally excited hydroxyl can be used to infer several quantities relevant in this context. To measure airglow from ground- or satellite based instruments is a common technique. However, to derive atmospheric trace gases such as atomic oxygen or hydrogen from these emissions requires the knowledge of the ambient temperature as well as a thorough understanding of the excitation and of the energy flow within the hydroxyl molecule, which is very difficult to measure in a laboratory. Recent high resolution measurements by means of the Sciamachy and Mipas instruments on ESA's Environmental Satellite (Envisat) give an excellent and unique opportunity to quantify these processes.

The focus of this thesis lies in the derivation of temperatures from the rotational distribution of OH. This distribution can be simulated using Einstein coefficients and a Boltzmann distribution. Non-linear fitting procedures will be applied to obtain temperature data. This data will be analyzed an different time scales to learn about seasonal, annual, and long term changes.

About us

Forschungszentrum Jülich is the largest interdisciplinary research center in Germany with about 4500 employees. This work will be conducted in the Institute of Energy and Climate Research (IEK-7). There is a small team of 3 students and scientists working in this field.

Tools we use

The non-LTE model and the data processing are written in Python.

Prerequisites

This position is addressed to students of physics, chemistry, and related subjects. The candidates need an official supervisor from their university to supervise this work. Good programming skills are a prerequisite.

Contact

For more information, please contact Dr. Martin Kaufmann, email: m.kaufmann@fz-juelich.de


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