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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) are being explored as well as the interaction between them. Typical for the research studies are elaborate measurement campaigns in the field, frequently under harsh conditions.

Within the 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 ring down spectroscopy, Paul trap, differentiel optical absorption spectroscopy, 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.

Recent announcements:

Bachelor students might select single topics from the course in the framework of the Advanced Physics Lab (PFP2), whereas Master students (Environmental Physics) have to attend the complete course (MVENV5).

With the summer term 2011, the EP-MA Field Course will be completely established with all experimental topics and full capacity for for the students. Currently, four out of seven topics are implemented (F50, Fxx, Fxx). 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 (PFP1/PFP2).

Enrollment:

Enrollment and scheduling for individual topics is accomplished via the Advanced Physics Lab:

in the framework of PFP2 (Bachelor)

in the framework MVENV5 (Master)

Topics:

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 (Martin Wieser, Sarah Marlene Görger, Tillmann Kaudse)

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 (Jens Buchner, Patrick Klenk)

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 (Rene Winter, Felix Friedel)
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 (Christoph Elsässer, Helene Hoffmann, Mario Ruckelshausen)

In preparation:

Measurement of atmospheric photon path lengths by DOAS
Measurements of atmospheric absorption of O₂ and O₄ in scattered sun-light as a function of solar zenith angle by Differential Optical Absorption Spectroscopy (DOAS). Analysis of optical spectra using DOAS. RT calculations for AMF's. Analysis of weather maps for cloud bottom and top heights. Attribution of O₂ and O₄ absorption to photon path length.

CRD (Cavity Ring Down) and CEA (Cavity Enhanced Absorption) Measurements of Atmospheric Gases
Characterization of the properties of an optical cavity. Measurements of atmospheric trace gases (NO₃ and H₂O). Analyze folding time for an empty versus a filled cell, as well as analysis of measured spectra as a function of ambient conditions.

Paul Trap
Solving Mathieu-DEQ. Stability of the cavity. Evaporation of liquids. Mie-Scattering. Particle sizes. Rainbow scattering. Liquid-solid phase transition.

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