Roland Potthast Webhome

Our Division for Data Assimilation (FE12) of the German Weather Service (DWD), a part of the German Ministery of Transport and Digital Infrastructure (BMVI), is working on data assimilation for numerical weather prediction (NWP). Our main task is to provide

• operational data assimilation for the global ICON NWP-model (13km resolution, 90 layers 75km height), run every 3 hours 24/7,
• with its mesoscale two-way-nesting area over Europe (6.5km resolution) and the
• high-resolution convection-permitting COSMO model over central Europe (2.8/2.2km resolution, 24km height) every hour 24/7.

This includes ensemble data assimilation for the ensemble prediction systems ICON-EPS (40/20km resolution) as well as COSMO-DE-EPS (2.8/2.2km resolution) and a mean (best) state estimator for the deterministic runs (13/6.5km and 2km). A core goal is to replace COSMO by the ICON-LAM model with 2/1km resolution over central Europe operationally in about 2020/21. We run a hybrid ensemble-variational data assimilation scheme (EnVar) globally and a Local Ensemble Transform Kalman Filter (4D-LETKF) for our reginal data assimilation.

Data Assimilation includes the use of a broad varity of both direct and remote sensing measurements from

• Ground Stations and Ships (SYNOP),
• Radio Sondes (TEMP) and dropsondes,
• Buoys,
• Air Planes (AMDAR, AIREP, ACAR, …),
• Atmospheric Motion Vectors (AMV),
• Scatterometers (SCAT),
• Infrared Sounders (IR),
• Microwave Sounders (MW) and Microwave Radiometers (MWR),
• LIDAR including Clound Bottom Height (CBH), Cloud Top Height (CTH), Backscatter Profiles, Line-of-Sight Winds (AEOLUS), Ceilometers,
• RADAR including RADAR Radial Winds, RADAR Reflectivity and RADAR Dual Polarization,
• GPS/GNSS including Radio Occultations (RO), Zenith Total Delay (ZTD), Slant Total Delay (STD),
• Cameras,
• Cars.

Geostationary satellites and polar orbiting satellites are used operationally, while a lot of research is going into the better use of hyperspectral observations (many thousand frequencies per observed atmospheric column) in particular over land and in cloudy situations. The observation and reconstruction of snow, ice, sea surface temperature, land surface temperature, coverage, emissivity and soil moisture is a very active area of research. Also, the observation and data assimilation of clouds and convective processes with high-impact phenomena such as thunderstorms, heavy rain and wind gusts with lead times from minutes to days is a special focus of our research.

The research of our group at the University of Reading, UK, is concerned with inverse problems and data assimilation in three areas:

• numerical weather prediction (NWP),
• cognitive neuroscience / neural field theory (NFT),
• inverse scattering problems / remote sensing.

These are extremely exciting areas scientifically and very important for society, for example for air traffic control, severe weather warnings and national energy supply, in medicine by medical imaging and for many industrial and environmental questions.

Due to Covid the activities of this year have been strongly reduced.

• Nov 2020: Karlsruhe Institute of Technology: PhD Co-Supervisor

• Oct 22, 2020: Workshop on the Destination Earth (DestinE) initiative – Elements of a Digital Twin on “Climate Change Adaptation”
• Oct 14, 2020: Mathematics of the Planet Earth CDT of Imperial College and Reading University, Invited Inaugural Talk –online–
• Oct 14, 2020: 5. NAFEMS DACH Conference 2020, Keynote talk –online–
• Oct 5-7, 2020: RealPEP Conference “Precipitation and Flash Flood Prediction from Minutes to Days” Co-Organizer Website
• Oct 6, 2020: Bilateral Discussions ECMWF - DWD

• Sept 28-Oct 3, 2020: Würzburg, Germany: EUMETSAT Conference, Scientific Planning Committees –cancelled–
• Sept 10, 2020: Shing-Tung Yau Center of Southeast University and The Nanjing Center for Applied Mathematic, Invited Seminar Talk –moved to online–
• Sept 9, 2020, Berlin: Science Barbecue for German Parliament Scientific Staff, Invited Expert
• Sept 2-12, 2020 Geneva, Switzerland: COSMO General Meeting –moved to online–

• July 2020: Imperial College, PhD Co-Supervisor
• July 22, 2020: Potsdam University, PhD Referee

• June 27-28, 2020 Toulouse, France: NWP-SAF Steering Committee Meeting –moved to online–
• June 8-12, 2020, Colorado, USA: International Symposium on Data Assimilation –moved to 2022–

• May 11-13, 2020, 5. NAFEMS DACH Conference 2020, Keynote talk –moved to October–
• April 12-18, 2020, Mathematical Research Institute Oberwolfach, Workshop on Data Assimilation –cancelled–

• March 3-8, 2020, Reading and London, Research Visit
• Feb 2-8, 2020, Reading, UK: ECMWF 4th workshop on assimilating satellite cloud and precipitation observations for NWP, invited talk.

• Jan 19-29, 2020, Japan, Sapporo: Research Visit to Hokkaido University

For more news see IP News and IP Events!
Previous News News RP 2019, News RP 2018, News RP 2017, News RP 2016.

My group consists of approximately 40 researchers on data assimilation and inverse problems in Frankfurt/Offenbach and Reading (UK), see group.

Thinking about faith and life has always been a passion for me. I have become a Christian and have started to explore the world as someone who follows Jesus - that has turned out to be quite an adventure and highly exciting. In my daily blog I explore thoughts and arguments about faith, and monitor how faith works on a daily basis: Jesus Network

Recent publications can be found on publications. A book Inverse Modeling by Nakamura and Potthast with an introduction into data assimilation and inverse problems has recently appeared at IOP.

Working in an operational center, our focus is to develop state-of-the-art inversion methods which can be run in a reliable way on a supercomputer in near real-time. It includes codes on scattering of waves, propagation of light and radiation, tomography, large-scale optimization and uncertainty quanitfication, ensemble and particle methods.

(Our supercomputers at Deutscher Wetterdienst are no 99 and no 130 on the TOP-500 Supercomputer List Web)

However, the development of insight into the scientific problems we need to solve is an indispensible ingredient of our daily work. Part of this insight is based on mathematical analysis and the testing of computational methods for purpuse-built small-scale demonstration systems.

COST Action 1303 “TOPROF” Website;

• Frontiers in Applied Mathematics and Statistics - Dynamical Systems
• Mathematical Inverse Problems

Web Statistics on my webpages
(including the Christian activities on jesusnetwork.eu and the professional pages on inverseproblems.info).

including http://scienceatlas.com, http://inverseproblems.info and http://jesusnetwork.eu.