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Differential reflectivity, correlation coefficient and specific differential phase along reflectivity factor of Essen C-band radar from 2016-06-24. The data is filtered by a 35db signal-to-noise threshold and excludes data from radials, which may contain hail or are in the shadow of hail. Presence of hail aloft was checked by estimating specific attenuation and presence of anomalously high specific differential phase.


By: Matthias B. Schmidt, Meteorological Institute, University of Bonn
Date: 03/09/2017 - 01/10/2017
Locations: Norman, Oklahoma, USA

Differences in scattering behavior between S- and C-band radars is known to exists. However, comparing polarimetric variables (like reflectivity factor Z, differential reflectivity ZDP, crosscorrelation coefficient ρhv and specific differential phase KDP) calculated by a T-matrix backscattering simulation fed with disdrometer data, a severe discrepancy between the two radar systems is observed: Big drops (with reflectivity factors above 45 dBZ) in C band seem to look like ice particles considering the simulated polarimetric variables. For reflectivity factors of 45 dBZ and above, ρhv drops in C band, while it does not in S band. Also, differential reflectivity ZDP increases up to 8 dB and KDP drops too. Considering this effect, distinguishing liquid and frozen particles in hailstorms can become difficult in C band, as big drops usually occur close to hail in hailstorms.

To investigate this topic, picked events of the German radar network of the German weather service (DWD) will be looked into for such scattering behavior. Events where no hail was reported have been selected to investigate scattering of big drops. Also, a C-band and an S-band radar in Alabama, which are only 43km apart and therefore almost collocated, are utilized as well. In radials around hail, where big drops should be very likely, the theoretical predicted change in variable values should be quite visible in C band, while S band should clearly show rain characteristics. This will be monitored by observing KDP.

By: Philipp Pohlig (B1)
Date: 18/09/2017 – 19/09/2017
Locations: Karlsruhe Institute of Technology (KIT)

The autumn school “Moisture measurement in porous mineral materials” was organised and led by PD Dr. Katja Emmerich, Competence Center for Material Moisture (CMM), Karlsruhe Institute of Technology (KIT). It took place in Karlsruhe from September, 18 to 19. It covered a broad range of topics concerning water content measurements on different scales. The talks were presented by speakers with different scientific backgrounds ranging from physicists, chemists, geoscientists as well as civil, material or electrical engineers. The reason for me to attend the autumn school was due to the fact that I have had to measure and analyse lots of soil moisture data so that the topics of the autumn school fitted very well to my recent working field within my TR32 subproject.

hongjuan zhang

Cosmic ray probe (CRP) site: Kall. Left y-axis is soil moisture and right y-axis is parameter tau value. Blue line is SMAP soil moisture of the grid where Kall site drops. Red line is soil moisture from CRP. Yellow line is area average of TerrSysMP model soil moisture over the SMAP grid. Light blue dash line is tau value. In the title there are properties of this site.
(Please feel free to use this photo)


By: Hongjuan Zhang
Date: 26/03/2017 - 31/05/2017
Locations: Cambridge, MA, USA

The main objective for this two-month visit was trying to integrate the SMAP-data in our model TerrSysMP. Satellite SMAP was launched in January, 2015 to measure the amount of water in the top 5 cm (2 inches) of soil everywhere on Earth’s surface and to produce global maps of surface soil moisture. In the course of its observations, SMAP will also determine if the ground is frozen or thawed in colder areas of the world. SMAP is designed to measure soil moisture over a three-year period, every 2-3 days. This permits changes, around the world, to be observed over time scales ranging from major storms to repeated measurements of changes over the seasons. The data from SMAP will help to monitor the drought, predict floods and forecast the weather condition.

During my study in MIT, I processed the SMAP data for Rur Catchment. SMAP has 4 levels of datasets with various grid resolutions. We used the level 3 data with 9km grid resolution. Firstly, I cut the SMAP data for the Rur Catchment. Then I compared the soil moisture results from cosmic ray sites, SMAP soil moisture and our TerrsSysMP model prediction. Cosmic ray probes provided point scale measurements, SMAP data was for spatial scale (9km) and TerrSysMP model was also for spatial scale (0.5km). I calculated the SMAP grids which included the cosmic ray sites, and in which model grids were averaged. Then the three types of data were compared. We found that SMAP data was generally drier than cosmic ray data (almost all cosmic ray sites, except for a forest site ‘Wildenrath’), while soil moisture from model was always over saturated.

By: Thirza van Laar IGMK Cologne (C4)
Date: 03.09.2017-08.09.2017
Locations: Ascona, Switzerland

The week in Switzerland started on the Sunday afternoon with an introductory talk by Christopher Bretherton. Unfortunately we missed the largest part of this talk due to a cancelled flight in the morning. Luckily the rest of the talks during the summer school were just as interesting. There were a couple of different sessions, the topics they covered were: high-resolution observations, high-resolution models: processes and projections, extreme events, and exploitation of emerging hardware architectures. The presentation of my poster was scheduled in the session on high-resolution modelling and turned out to be very well visited (Presentation title: What controls the cloud size distribution of continental shallow cumulus cloud populations?).

By: Thirza van Laar, Tobias Marke
Date: 22.06.-23.06.2017
Locations: Institute for Geophysics and Meteorology - Cologne, RWTH Aachen

In the framework of the IRTG invited speaker program we were glad to invite Jordi Vila for a visit in Cologne and in Aachen during the TR32 General Meeting. Jordi is professor of Meteorology and Air Quality at Wageningen University in the Netherlands.

At the Institute of Marine and Atmospheric Research in Utrecht, Jordi did his PhD on the role of atmospheric turbulence on chemical reactions from 1989 to 1992. He then started to work with mesoscale models like WRF. Since 1999 Jordi works in the Meteorology and Air Quality section at Wageningen University, also as a lecturer for Bachelor, Master and PhD students.

His work focuses on Large-Eddy Simulations (LES) of boundary layer processes including clouds, mesoscale phenomena and the interactions between the land surface and the atmosphere. The scientific approach is to bridge different fields (chemistry, atmospheric dynamics, biology) to study these processes on different scales, based on simple conceptual models to complex LES and mesoscale models, which are also validated by field observations.

Event name: PhD Symposium on subsurface hydrology in land surface models
Event dates: 25th Nov. 2016
Event location: Forschungszentrum Jülich, Building 14.6, Room 241

Prof. Dr. Sascha Oswald and Dr. Rafael Rosolem were invited to give talks at the PhD Symposium of Roland Baatz on ‘Subsurface hydrology in land surface models’. The presentation stressed the relevance of field scale observations for improved understanding of land surface processes. The talks were introduced by Prof. Dr. Harrie-Jan Hendricks Franssen (FZ Jülich) head of the research group on ‘Stochastic analysis of terrestrial systems’.

Prof. Dr. Sascha Oswald is a full professor at the Institute for Earth and Environmental Sciences at University of Potsdam. He received his Ph.D. in Environmental Sciences from the ETH Zürich in 1999. After working as physicist at Colenco Power Engineering, research fellow at University of Sheffield, senior assistant at the Institute for Terrestrial Ecology at ETH Zürich, he became senior researcher at the Helmholtz Center for Environmental Science, UFZ Leipzig, in 2004. From 2009 onwards, Sascha Oswald became Professor for Water and Matter Transport in Landscapes at the University of Potsdam.

Dr. Rafael Rosolem is Lecturer in Water and Environmental Engineering at the University of Bristol. He received his Ph.D. in Hydrology from the University of Arizona in 2010. He became research associate and research assistant Professor at the University of Arizona and worked on the COsmic-ray Soil Moisture Observing System (COSMOS) project. From March 2013 onwards, Rafael Rosolem joined the Faculty of Engineering at the University of Bristol.

For further information, please contact:


tn328 54d609d0981ab

Nadine Heinrichs

IRTG Coordinator

University of Cologne
Institute for
Geophysics and Meteorology

D-50923 Cologne
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