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Recent information regarding oral presentations, lessons etc. of Prof. Dr. Thomas Foken are available on this web page.

Lessons

Eötvös Loránd University, Budapest, 21.-22.11.2017, Lessons in Micrometeorology

1. The Monin-Obukhov Similarity Theory and its Limitations (21.11., 09:30-11:00

2. The Eddy-Covariance Method - Basics (21.11., 11:15-12:45)

3. The Eddy-Covariance Method - Flux calculation and general problems (22.11., 09:30-11:00)

4. The Eddy-Covariance Method - Data Quality control (22.11., 11:15-12:45)

5. The Eddy-Covariance Method - Discussion (22.11., 12:45-13:15)


Presentations

Hungarian Meteorological Service, November 21, 2017, 15-16

Dénes Berényi's Textbook "Mikroklimatology' (1967, in German) - From Geiger to the Modern Micrometeorology

Thomas Foken

Exactly 50 years ago Dénes Berényi’s textbook “Mikro-Klimatologie” was published in Hungary in German language. Wrongly, the book is only well-known to a small German speaking community of micro-meteorologists and micro-climatologists. It is not as famous as Geiger’s “Klima der bodennahen Luftschicht” (The climate near the ground), but it has a much better theoretical basis – mainly a hydrodynamic basis. Unfortunately, Berényi did not have seen the fundamentality of Monin and Obukhov’s similarity theory. Nevertheless, it is one of the important textbooks in the middle of the last century together with the books of Lettau, Sutton, and Geiger. The presentation gives a historical survey of this time and Berényi’s merits.



Hungarian Academy of Sciences, Meteorological Scientific Days, Budapest, November 23, 2017, 09:40-10:10

Present Status about Micrometeorology

Thomas Foken

Micrometeorology is a part of Meteorology that deals with observations and processes in the smaller scales of time and space, approximately smaller than 1 km and one day. Micrometeorological processes are limited to shallow layers with frictional influence. Well-known is the fundamental theory for the atmospheric surface layer published by Monin and Obukhov in 1954. During the last 40 years, significant progress has been made in the theoretical understanding of surface-layer processes and in the development of precision instruments. As a result, the number of available data sets has increased significantly, but scientific breakthroughs for a more realistic treatment of phenomena such as heterogeneous surfaces or stable boundary layers are still missing. There has recently been a tendency in ecological and other research to unify flux measurements through the use of nearly identical instrumentation and data calculations, as in the ICOS project. This is contrary to new findings about the complicated exchange processes in and above tall vegetation and in peat-land and for chamber measurements. Data under stable stratification and low wind conditions in particular are eliminated. New software tools used to investigate and analyze these complicated structures. Non-standard calculation methods like the wavelet analysis are able to determine accurate fluxes even under non-steady state conditions. For tall vegetation, the coupling between the atmosphere, the crown and the trunk space is important for studying the sources of the fluxes. This coupling has a daily and annual cycle and can be used to understand complicated exchange conditions, mainly for trace gases. But the heterogeneity of the vegetation and of the surrounding area can also have a significant influence on the measured fluxes. This may be a reason for the worldwide findings of an increased carbon uptake of ecosystems. Ongoing research issues are the phenomena like the not fulfilled energy balance closure at the earth surface and the calculation of footprints of a non-homogeneous area. Air pollution modelling and the support of emergency cases require meteorological information of some typical meteorological parameters such as wind velocities, air temperature, humidity, atmospheric stability, etc., which show temporal and spatial variations over heterogeneous surfaces. Micrometeorology is the science which provides the basic information for this applied fields of meteorology.



9. Tagung des Fachausschusses Biometeorologie der Deutschen Meteorologischen Gesellschaft, Stralsund, 28.11. - 30.11.2017

Zunahme der Netto-Kohlenstoffaufnahme in Waldgebieten

Thomas Foken, Wolfgang Babel, J. William Munger, Tiia Grönholm, Timo Vesela, Alexander Knohl

Seit etwa fünf Jahren wird in der Literatur berichtet, dass die Netto-Kohlenstoffaufnahme von Wäldern in den letzten 20 Jahren zugenommen hat. Als Ursachen wurden die Zunahme der Kohlendioxidkonzentration in den letzten 20 Jahren um ca. 10 % , die Verlängerung der phänologischen Phasen speziell im Frühjahr und die Temperaturzunahme um fast 1 Grad diskutiert. Derartige Zunahmen wurden auch für die im Vortrag näher untersuchten Flächen „Harvard Forest“ (MA, USA, Eiche-Ahorn-Tannen-Mischwald), „Hyytiälä“ (Finnland, boreale Kiefer) und „Waldstein-Weidenbrunnen“ festgestellt. Bei allen drei Messflächen zeigt die Zunahme der Netto-Aufnahme jedoch Sprünge, die durch die genannten Faktoren nicht erklärt werden können. Im Vortrag werden weitere Einflussfaktoren diskutiert, die vorrangig auf die Struktur des Bestandes abzielen. Struktur verändernde Faktoren sind dabei Schädlingsbefall und Windbruch, was sich auf die Dynamik des turbulenten Austausches auswirkt. Beim ohnehin heterogenen borealen Wald hat die Messhöhe durch den veränderlichen Footprint eine ausschlaggebende Bedeutung. In diesem Zusammenhang wird der Einfluss von Waldkanten und Änderungen in der kleinräumigen Bestandsstruktur diskutiert und durch Modellungen untermauert . Demgegenüber zeigt ein geschlossener Altbestand, „Hainich“ (Deutschland, Buche), wahrscheinlich bedingt durch sein Alter eine Abnahme der Netto-Kohlenstoffaufnahme. Abschließend werden Vorschläge unterbreitet, welche Größen erfasst werden müssen, um Trends in der Netto-Kohlenstoffaufnahme zuverlässig bewerten zu können.


http://www.springer.com/de/book/9783642254390

New book

Micrometeorology

Thomas Foken

Springer 2017, 2nd edition, XXI, 362 p., 90,94 € (D)

The book focusses on atmospheric processes, which directly affect human environments within the lowest 100–1000 meters of the atmosphere over regions of only a few kilometres in extent. The book is the translation into English of the third edition of the German book “Applied Meteorology – Micrometeorological Methods”. It presents, with selected examples, the basics of micrometeorology applied to disciplines such as biometeorology, agrometeorology, hydrometeorology, technical meteorology, environmental meteorology, and biogeosciences.


>>Link...

http://www.springer.com/de/book/9783319493879

New in March 2017

Energy and Matter Fluxes of a Spruce Forest Ecosystem

Edited by Thomas Foken

Springer 2017, XV, 532 p, 181,89 € (D)

Scientific results obtained over the last 20 years at the FLUXNET site DE-Bay (Waldstein-Weidenbrunnen) are shown together with methods developed at the site, including the application of footprint models for data-quality analysis, the coupling between the trunk space and the atmosphere, the importance of the Damköhler number for trace gas studies, and the turbulent conditions at a forest edge.

 


>>Link...
Projects

Springer Handbook of Atmospheric Measurements

Editor: Thomas Foken

The topic of measurements in the atmosphere is not only of interest to the meteorologist and for the purpose of weather forecasting and climate research but also increasingly important in environmental physics and ecology. The book covers more than just the classical meteorological measurements and is divided into five parts: basics of measurements, classical in-situ measurements, remote sensing techniques for ground-based and aircraft- or space-based application, and complex measurements and methods that use different techniques. As well, a short link is made to measurements in the soil, in the water, at plants, and in the urban and rural environment, which are more and more necessary for observation of the interfaces to other geosystems. The knowledge of many scientists who are specialists in this field or who have had a great influence on the development of these techniques will be made available for the reader of this book. The book will be absolutely essential for all students, researchers, and technicians making measurements in the atmosphere and the adjacent environments or interpreting data, or those using these data in modelling studies. It will include a large number of tables with physical data, sensors and system characteristics, as well as numerous figures and schematics.

The book will be published in 2019