Ruprecht-Karls-Universitšt Heidelberg

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Practical Course Environmental Physics

Supervisor: Dr. Udo Frieß

Contact: IUP room 310, phone: 54-5478, udo.friess@iup.uni-heidelberg.de



Practical Course Environmental Physics Background:

The various research groups at the Institute for Environmental Physics explore the Earth System by utilizing state-of-art physical and chemical methods. Nearly all research projects are embedded in national or international collaborations. One of the strengths of Environmental Physics in Heidelberg is that all compartments of the environment (atmosphere, hydrosphere, cryosphere, and lithosphere)as well as the interaction between them are being explored. Typical for the research studies are elaborate measurement campaigns in the field, frequently under harsh conditions.

In the framework of this Practical Course, the students benefit from the available knowledge and abilities of the different research groups in order to develop their experimental skills. The different experiments comprise general physical principles and methods of modern measurement techniques (e.g. cavity enhanced absorption spectroscopy, differential optical absorption spectroscopy, Paul trap, ground penetrating radar, time domain reflectometry, γ-spectroscopy, and UV spectroscopy). The different topics cover many relevant aspects in environmental sciences (air-sea interaction, cycle of matter and energy fluxes, physics and chemistry of the atmosphere, aquatic systems, and soil physics) and are closely connected to current research projects at the institute.

The student's work load is considered to be 30 hours (one credit point) per experimental topic and is roughly equal to the effort of one experiment of the Advanced Physics Lab Course (PFP1/PFP2). This practical course provides an insight in the different research topics in the field of environmental physics. Therefore it is highly recommended to carry out several experiments.

Enrolment:

Enrolment and scheduling for individual topics is accomplished via the webpage of the Advanced Physics Lab Course:

in the framework of PFP2 (Bachelor)

in the framework MVENV5 (Master)




Topics:

  • Cavity-Enhanced Differential Optical Absorption Spectroscopy of atmospheric trace gases
    CE-DOAS is a very sensitive method for the in situ measurement of atmospheric trace gases. Atmospheric absorbers are detected spectroscopically along folded light paths with effective path lengths of several kilometres using an optical cavity with a length of less than a metre. During this experiment, NO2, an important pollutant in the urban atmosphere, will be measured and its photochemistry will be investigated.
    Objectives:
    1. Characterisation of the optical cavity
    2. Characterisation of the spectrometer/detector system
    3. Determination of the cavity path length
    4. Measurement and interpretation of the diurnal cycle of NO2

    Instructions: CE-DOAS (F58)
    Institute of Environmental Physics, INF 229, Lab 230

  • Analysis of lake stratification and lake-groundwater interaction
    Measurements of vertical CTD (conductivity, temperature, density) profiles on a lake near Ludwgishafen (Willersinnweiher) and sampling for later 222Rn measurements in the Lab. Analysis of CTD-data, calculations of density and stability, and linking the results of CTD and tracer measurements.

    Note: field experiment with rubber boat, due to security reasons participants must be able to swim!
    Instructions: Limnology (F50/51)
    Institute of Environmental Physics, INF 229, Lab 202

  • Propagation of electromagnetic waves in soils: TDR and GPR
    Time Domain Reflectometry (TDR) and Ground Penetrating Radar (GPR) are two different methods for estimation of soil water content. To get familiar with the methodology TDR measurements are conducted in the lab, followed by field experiments where both techniques are applied. The two dielectric methods are based on the estimation of the permittivity by time of flight measurements of high-frequency radio waves. Using TDR a probe is installed in the soil along which the electromagnetic pulses propagate. Analyzing the reflected signal the permittivity of the soil is derived. By contrast, GPR radiates short pulses of high-frequency radio waves into the ground and the reflected signal is detected by an receiving antenna. Again, the permittivity is estimated by the time of flight of the pulses, enabling a calculation of the soil water content.

    Note: field experiment (Hirschacker).
    Instructions: Electromagnetic Methods in Applied Geophysics (F52/53)
    Institute of Environmental Physics, INF 229, Lab 204

  • Air-Sea Interaction: Gas transfer across the air-water interface
    Measurement of the gas transfer rate of carbon dioxide across the air-water interface utilizing conductivity and pH measurements at a circular wind-wave flume. The pH-value is estimated by optical absorption spectroscopy and pH-indicators.
    Educational objectives:
    1. Comprehension of the carbonate system of the Ocean
    2. Learn to handle state-of-the-art optical measurement techniques in Environmental Physics.
    3. Investigation of the influence of the reactivity of carbon dioxide on the transfer rate
    4. Understand the wind speed and wind-waves dependence of the gas transfer rate.

    Instructions: Air-Sea Interaction (F54)
    Institute of Environmental Physics, INF 229, "AEOLOTRON", Lab 165

  • Natural radioisotopes as environmental tracers
    The aim of this experiment is to learn about natural radioactivity in the environment and to the application of radioactive tracers in environmental research. Environmental samples (both a soil profile and an atmospheric aerosol sample) will be taken and analysed with respect to natural and anthropogenic radioisotopes using low-level gamma spectroscopy.
    The following tasks will be performed:
    1. Measurement of small activity concentrations of radioisotopes on top of the natural radioactivity background
    2. Estimation of the fallout in the Odenwald as a result of the Chernobyl reactor accident
    3. Natural radioisotopes as tracers for airmasses and aerosols

    Instructions: Radioactive tracers in environmental research (F56)
    Institut für Umweltphysik, INF 229, Lab U50

  • Atmospheric trace gases
    Differential Optical Absorption Spectroscopy (DOAS) is a widely used technique for the detection of atmospheric trace gases in the atmosphere. This experiment offers the opportunity to gain insight into spectroscopic remote sensing techniques, which are widely used to study the composition of the Earth's atmosphere.
    The topics covered by this experiment are:
    1. To gain insight in the chemistry of the troposphere and stratosphere, in particular regarding zone and NO2
    2. To become familiar with spectroscopy and spectroscopic analysis techniques
    3. To gain insight into the radiative transfer in the Earth's atmosphere
    4. To learn how to determine a trace gas concentration with DOAS

    Instructions: Atmospheric trace gases (F18/38)
    Institut für Umweltphysik, INF 229, Lab 238

  • Isotopic measurements of water samples and determination of fractionation coefficients in a Rayleigh process
    In this experiment, the fractionation processes of water as they occur in the hydrological cycle during phase transitions are observed qualitatively and quantitatively using state of the art spectroscopy technologies (Off-Axis Integrated Cavity Output Spectroscopy). The isotopic composition of various water samples and water vapor are determined and several applications of isotopic measurements in hydrology and climate science are motivated.
    Lab course objectives:
    1. Observation of isotopic fractionation during water evaporation
    2. Determination of fractionation factors in a Rayleigh process depending on temperature
    3. Measurement of unknown water samples and introduction to applications in climate science

    Instructions will follow soon...
    Institut für Umweltphysik, INF 229, Lab 516


 

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