[ [[/|Welcome]] ][ [[Group]] ][ [[Research]] ][ [[Publications]] ][ [[CV]] ][ [[MISC]] ][ [[http://www.jesusnetwork.eu/en/|My Christian Blog]] ][ [[Church Stuff]] ] [[https://iopscience.iop.org/book/978-0-7503-1218-9|{{book_cover.png?143}}]]\\ Institute of Physics (IOP) {{20200203_122104.jpg?350}}\\ at ECMWF 2020 -- 4 weeks before Corona restrictions started ===== Workshop and Seminar News ===== ====2024==== === Oct-Dec === * Nov 28-29, 2024: ICON Board Meeting * Nov 2-9, 2024: Seoul, Korea, **KIAPS Workshop** and Scientific Advisory Committee (**SAC**) * Oct 21-25, 2024: International Symposium on Data Assmilation (**ISDA**), Kobe, Japan, Scientific Committee [[https://isda-online.univie.ac.at/]] {{csm_isdaonline_logo_c62185bd89.jpg?150 }}{{cloud_rea3.gif?150 }} === July-Sept === * Sept 30-Oct 3, 2024: European Working Group on Limited Area Modeling **EWG-LAM** Meeting in Prague, Talk on E-AI Programme * Sept 23-24, 2024: **DWD-DLR Coordination Group** Meeting * Sept 19-20, 2024: **ICON Seamless Meeting** in Hamburg, Seewetteramt * Sept 2-6, 2024: COSMO General Meeting (**COSMO GM**) in Offenbach, Germany. Organizer, Steering Committee * August 26-30, 2024: **Data Assimilation Summer School**, University of Hamburg, Lecturer/Co-Organizer === April-June === * June 15-28, 2024: Visit to **Reading, London and Oxford**, UK * June 5-6, 2024: E-AI **Workshop on AI/ML for Products and Services** in Weather, Climate and Environment * May 26-29, 2024: **Cineca**, Bologna, Italy, **GLORI4DE** Project Meeting * May 15, 2024: **LA24** SIAM Conference Linear Algebra 2024, Paris, Talk on Preconditioning for Data Assimilation, Participation in Minisymposium * April 25, 2024: **ESM-W Workshop**, Earth System Modeling on the Weather Scale * April 18, 2024: **Gauss Computing Centre** (GCS) Lenkungsausschuss [[https://www.gauss-centre.eu]] * April 22-23, 2024: **ITMS Project Meeting** in Karlsruhe * April 11-12, 2024: **DestinE** Meeting Bonn, GLORI Digital Twin, E-AI Programme working with DestinE and ECMWF {{wiki:natesm_small.png?150 }}{{:eumetsat_diverse.png?150 }} === January-March === * March 16-26, 2024: Personal Visit in **Libanon** * March 8, 2024: Kick-off of the Strategic Expert Team (**SET**) of the **E-AI EUMETNET** Programme on Artificial Intelligence in Weather, Climate and Environment * March 8-9, 2024, COSMO Steering Committee Meeting (**COSMO STC**) * March 4-8, 2024, **ICCARUS**: ICON COSMO ART User Seminar with about 250 participants in Offenbach, Germany * Feb 29, 2024 Koordination Group Numerical Weather Prediction at DWD (**KG NWV**) * Feb 27-28, 2024 National ESM Strategy Workshop **natESM** in Leipzig [[https://www.nat-esm.de/services/trainings/events/ws_february2024]], Steering Group * Febr 19-20, 2024, **EUMETSAT AI Workshop**, Darmstadt * Feb 2, 2024, Integrated Greenhouse Gas Monitoring System (**ITMS**) Project Meeting in Offenbach [[https://www.itms-germany.de/]] * Jan 30-31, 2024: Earth-System-Model **ESM-Meeting** DWD-MPI in Hamburg * Jan 29, 2024, COSMO Steering Committee Meeting (**COSMO STC**)[[https://www.cosmo-model.org]] * Jan 23-24, 2024: **EUMETNET Programme Manager** Meeting Brussels (hybrid) [[https://www.eumetnet.eu]] * Jan 10-13, 2024: Cineca Bologna, **GLORI4DE** Project Meeting, GLORI Digital Twin for Destination Earth * Jan 1, 2024: Start of the EUMETNET Programme on **"Artificial Intelligence and Machine Learning in Weather, Climate and Environment" (E-AI)**, Programme Management ==== 2023 ==== === October, November, December === * Nov 23-24, 2023: **ICON Board** in Person Meeting at Offenbach, Germany * Nov 20-22, 2023: ICON WarmWorld + ICON All-Hands + ICON gt4py Meeting * Nov 9-10, 2023: **KIAPS SAC** Science Advisory Committee Meeting, Seoul, Korea * Nov 6-8, 2023: **KIAPS International Symposium**, Seoul, Korea, from last year: [[http://kiaps-symposium.com/|2022 Symposium]] * Oct 26, 2023: Talk at NUIST, Nanjing, China: Data Assimilation of Nowcasted Observations * Oct 23+24, 2023: Informal Meeting of Western European NWP Directors at Offenbach, Germany * Oct 16-20, 2023: International Symposium on Data Assimilation (**ISDA 2023**) at Bologna, Italy. [[https://eventi.unibo.it/isda2023|ISDA]], see also ISDA Online [[https://isda-online.univie.ac.at/|Web]] * Oct 12-13, 2023: High-Performance Computing Center (**HLRZ Stuttgart/Karlsruhe**) Lenkungsausschuss, Stuttgart, Germany [[https://www.hlrs.de/|Web]] * Oct 5-6, 2023: KIT-DWD Research Coordination Steering Group [[www.cosmo-model.org|{{wiki/cosmo_countries.png?600}}]] [[https://isda-online.univie.ac.at/|{{wiki/bologna.jpeg?120}}]] [[http://kiaps-symposium.com/|{{wiki/kiaps.jpeg?110}}]] === July, August, September === * Sept 26-27, 2023: DLR-DWD Research Cooperation Steering Group * Sept 19-20, 2023: **RealPEP** (DFG Research Group) Meeting in Berlin, Germany [[https://gepris.dfg.de/gepris/projekt/320397309?language=en|DFG RealPEP]], [[https://www2.meteo.uni-bonn.de/realpep/doku.php?id=home|Web RealPEP]] * Sept 18-20, 2023: NHR Conference in Berlin, Germany [[https://events.uni-paderborn.de/event/487/|Web]] * Sept 11-15, 2023: COSMO General Meeting (**COSMO GM**) in Danzig, Poland [[https://cmm.imgw.pl/?page_id=28463|COSMO GM 2023]], see also [[https://www.cosmo-model.org/]] * Sept 11, 2023: **COSMO STC** Steering Committee in Danzig, Poland * Sept 4-8, 2023: Applied Inverse Problems (**AIP**) Conference at Göttingen, Germany [[http://www.aip2023.com/|Web]] * Aug 10-11, 2023: ICON-Seamless All-Hands Meeting in Offenbach, Germany plus Hybrid with the ICON Consortium developers [[https://www.dwd.de/EN/specialusers/research_education/seminar/2021/iccarus2021/presentations/monday_01_frueh.pdf?view=nasPublication&nn=745324|Roadmap]] * July 25-Aug 7, 2023: Scientific Visit to **Hokkaido University**, Sapporo, Japan. Working on Edition 2 of the[[https://iopscience.iop.org/book/mono/978-0-7503-1218-9|Inverse Modeling]] Book * July 24, 2023: Prof Adrian, President of DWD and WMO President retirement celebration at Offenbach, Germany [[https://www.dwd.de/EN/press/press_release/EN/2019/20190613_adrian_as_wmo_president_news.html|Web]] * July 14, 2023: LMU Munich, Visiting our HErZ Centre Branch, Cooperation with Panama ([[https://botschaft-panama.de/ger/botschafter/|Ambassador]], [[https://pancanal.com/en/ricaurte-vasquez/|CEO Canal Authority]], Director Citex [[https://pa.linkedin.com/in/juan-pimento|Juan Pimento]]) [[https://www.dkrz.de/en/dkrz-partner-for-climate-research?set_language=en|{{dkrz1.jpg?100}}]] [[https://www.dkrz.de/en/dkrz-partner-for-climate-research?set_language=en|{{dkrz2.jpg?80}}]] [[https://www.nhr-verein.de/en|{{wiki/nhr_logo.svg?100}}]] [[https://www2.meteo.uni-bonn.de/realpep/doku.php?id=home|{{wiki/realpep2022.png?200}}]] [[https://www.global.hokudai.ac.jp/|{{wiki/hokkaido.jpg?200}}]] === April, May, June 2023 === * June 14-15, 2023: **Leadership Conference** (FüKo) of DWD in Offenbach, Germany [[https://www.dwd.de/DE/derdwd/arbeitgeber/entwickeln/fuehrungskraefte.html|Web]] * June 12-13, 2023: International **GLORI Workshop** (Global-to-Regional ICON Digital Twin) at Karlsruhe Institute pf Technology (KIT), Karlsruhe, Germany * June 7, 2023: **ICON Board** meeting [[https://code.mpimet.mpg.de/projects/iconpublic|Web MPI]] [[https://www.dwd.de/EN/research/weatherforecasting/num_modelling/01_num_weather_prediction_modells/icon_description.html|Web DWD]] * June 6, 2023: National High-Performance Computing User Panel (**NHR**) Meeting [[https://www.nhr-verein.de/en/node/8|NHR Web]] Apply for computing time here [[https://www.nhr-verein.de/en/computing-time|NHR Resources]] * June 1, 2023: DWD-Google Inc. Consultation on AI for Weather Prediction at Offenbach, Germany (plus Hybrid New York, Colorado, San Francisco) * May 30, 2023: COSMO Steering Committee Meeting (**COSMO-STC**) [[https://www.cosmo-model.org/|COSMO Web]] * May 23-24, 2023: ECMWF **DestinE Member States Working Group**, Bonn, Germany. [[https://www.ecmwf.int/en/about/what-we-do/environmental-services-and-future-vision/destination-earth|Web]] * May 25, 2023: "Podium Discussion on **Randomness**" at Atelier Francfurt between Artists and Scientists [[https://www.atelierfrankfurt.de/de/|Web Atelier Frankfurt]] * May 8-10, 2023: ICON-Consolidated (**ICON-C**) Workshop in Hamburg at the German Climate Computing Centre (DKRZ), with the partners from Max-Planck-Institute for Meteorology (MPI-M), Karlsruhe Institute of Technology (KIT), DKRZ, C2SM and DWD [[https://www.dkrz.de/en/dkrz-partner-for-climate-research?set_language=en|Web]] ICON-C is our development theme for consolidation of the ICON model adapting it to emerging computing architectures. * May 4, 2023: Earth System Modeling (**ESM-W**) Workshop at DWD/ Hybrid with MPI-M and ICON Partners. The project jointly with GeoInfoDienst BW and the ICON Consortium partners aims at developing a coupled ICON atmospheric and ocean forecasting system on the weather scale. * April 27, 2023: Webinar Intelligent Cloud Operators for Numerical Weather Prediction (**ICamCloudOps**), see [[https://reuniwatt.com/en/2023/03/27/webinar_dwd_reuniwatt_icamcloudops_2023/|Contents]] * April 21, 2023: **ITMS Workshop**, Offenbach, Germany (International Greenhouse Gas Monitoring System) [[https://www.dwd.de/EN/climate_environment/climatemonitoring/greenhousegas/greenhousegas_node.html|Web]]. We develop a greenhouse gas data assimilation, monitoring, inversion and forecasting system. * April 19, 2023: Opening of the exhibition **70 Years between Nature and Society** at the **German Parliament** (Deutscher Bundestag), Paul-Löbe-Haus, Berlin * April 12-14 Exhibition Setup for 70 Years between Nature and Society at Deutscher Bundestag, Paul-Löbe-Haus, Berlin, Diorama of NWP from observations to forecasting * April 13, 2023: **ICON Board** Meeting [[https://reuniwatt.com/en/2023/03/27/webinar_dwd_reuniwatt_icamcloudops_2023/|{{wiki/icco_2023_banner_1000px.png?150}}]] [[https://www.dwd.de/EN/climate_environment/climatemonitoring/greenhousegas/greenhousegas_node.html|{{wiki/greenhousegas_picture.png?100}}]] [[https://www.dwd.de/DE/wetter/thema_des_tages/2023/4/30.html|{{wiki/paul_loebe_haus.jpg?130}}]] [[https://www.dwd.de/DE/wetter/thema_des_tages/2023/4/30.html|{{wiki/paul_loebe_haus2.jpg?110}}]] === January, February, March 2023 === * March 30-31, 2023: National Earth System Modeling (**natESM**) Strategy workshop (natESM) at Berlin, Germany, see [[https://nat-esm.de/]]. The ICON model is chosen as core component of the national ESM strategy. * March 21-24, 2023: Leadership meeting of Research and Development Department Heads at the Meteorological Observatory Lindenberg, Germany * March 17, 2023: DWD ITMS Workshop, Offenbach, Germany (International Greenhouse Gas Monitoring System) [[https://www.dwd.de/EN/climate_environment/climatemonitoring/greenhousegas/greenhousegas_node.html|Web]]. * March 15, 2023: Coordination Group Numerical Weather Prediction (**KG-NWV**) at DWD * March 9-11, 2023: **Village AI** at Global Industrie 2023 a Lyon, France, with Podium Discussion on AI Innovation and with a Presentation of our CONTRAILS AI Project [[https://global-industrie.com/en/home|Web]] * March 6-9, 2023: **ICCARUS Workshop** (=ICON COSMO CLM ART User Seminar) at DWD, Offenbach, Germany with a survey presentation on the NWP development at DWD [[https://www.dwd.de/EN/specialusers/research_education/seminar/2023/iccarus2023/iccarus_2023_en_node.html|Web]]. ICCARUS is our main research focussed development workshop for the ICON model. * Feb 30/March 3: **GLORI** (Global-to-Regional ICON) Digital Twin Workshop Bologna, Italy * Feb 27-29: **IDEA-S4S** German Italian Research Programme Workshop, Bologna, Italy [[https://www.dwd.de/DE/forschung/forschungsprogramme/idea_s4s/downloads/idea_s4s_konzept_20220318_en.pdf|Background]] Coordinating the GLORI activities with the European Destination Earth (DestinE) programme [[https://digital-strategy.ec.europa.eu/en/policies/destination-earth|DestinE EU]] * Feb 15-16, 2023: DWD Department Heads Retreat in Braunschweig, Germany * Feb 13-14, 2023: ICON Licence Working Group Meeting Munich * Feb 13, 2023: **ICON Board** Meeting * Jan 2023: 4-Weeks Redesign Exercise for variational Data Assimilation System of DWD [[https://www.dwd.de/EN/specialusers/research_education/seminar/2023/iccarus2023/iccarus_2023_en_node.html|{{seminare_iccarus_2023_logo_en.png?110}}]] [[https://global-industrie.com/en/home|{{wiki/global_industrie_2023.png?100}}]] [[https://digital-strategy.ec.europa.eu/en/policies/destination-earth|{{wiki/destine.jpeg?65}}]] [[nat-esm.de|{{wiki/natesm_small.png?100}}]] Previous News [[news_rp_2022|News RP 2022]], [[news_rp_2021|News RP 2021]], [[news_rp_2020|News RP 2020]], [[news_rp_2019|News RP 2019]], [[news_rp_2018|News RP 2018]], [[news_rp_2017|News RP 2017]], [[news_rp_2016|News RP 2016]]. ---- ===== Modeling, Data Assimilation and Inverse Problems ==== Our department FE1 for Numerical Weather Prediction (NWP) of the //German Weather Service// (DWD) consists of about 120 scientists at DWD headquarters in Offenbach close to Frankfurt/Main and in Potsdam close to Berlin, about 60 of them on funded R&D projects. The department consists of four sections, with 20-25 scientists each: * Data Assimilation and Predictability (FE11), * Observations Modeling and Verification (FE12), * Numerical Modeling (FE13), * Physical Processes and Dispersion (FE14). DWD is a part of the German //Ministery of Transport and Digital Infrastructure// (BMVI), but our work is carried out in intensive cooperation with * the //Max-Planck-Institute for Meteorology// [[https://mpimet.mpg.de/|MPI-M]], see also [[https://mpimet.mpg.de/wissenschaft/modellierung-mit-icon|ICON]], * the //German Climate Computing Center// [[https://www.dkrz.de/|DKRZ]], * the //Karlsruhe Institute of Technology// [[https://www.kit.edu/|KIT]], in particular with [[https://www.imk-tro.kit.edu/english/5925.php|ICON-ART]], * //ETH Zurich//, in particular [[https://c2sm.ethz.ch/|C2SM]], * the weather services of the [[http://cosmo-model.org/|COSMO Consortium]] (Italy, Switzerland, Russia, Poland, Romania, Greece and Israel), * the Meteorological Service of the German Armee [[https://www.bundeswehr.de/de/organisation/cyber-und-informationsraum/kommando-und-organisation-cir/kommando-cyber-und-informationsraum/zentrum-fuer-geoinformationswesen-der-bundeswehr|Geo BW]], see also [[https://www.bundeswehr.de/resource/blob/153544/b3cb4f4c8803999d00458803e8d7c9ca/download-geoinfobroschuere-data.pdf|PDF]], * the //Hans-Ertel Center// [[https://www.hans-ertel-zentrum.de/en/index.html|HErZ]] research branches at the Universities of Munich, Bonn, Frankfurt, Hamburg, Berlin and further international partners such as the * //European Centre for Medium Range Weather Forecasting// [[https://www.ecmwf.int/|ECMWF]] located in Reading, Bologna and Bonn. * EUMETSAT, in particular the [[https://nwp-saf.eumetsat.int/site/|NWP-SAF]] Consortium with the Partners MetOffice (UK), Meteo-France, ECMWF and DWD. We are working on [[http://www.dwd.de/EN/research/weatherforecasting/num_modelling/02_data_assimilation/data_assimilation_node.html|modeling and data assimilation for numerical weather prediction (NWP)]] and earth system simulation (ESM). Our main task is to provide operational data assimilation and forecasting with {{ cosmo_de4.png?200}} * ICON-global, i.e. a global NWP-model with 13km resolution, 120 layers 75km height, run every 3 hours 24/7, * ICON-EU, i.e. its mesoscale two-way-nesting area over Europe with 6.5km resolution and the * ICON-D2, i.e. high-resolution convection-permitting analysis and forecasts over central Europe with 2km resolution, 24km height analysis every hour 24/7, forecasts every three hours. We prepare a rapid update cycle (RUC) with forecasts every hour in integration with Nowcasting techniques. This system is called * ICON-RUC and SINFONY, see also [[https://www.dwd.de/EN/research/researchprogramme/sinfony_iafe/sinfony_en_node.html|SINFONY Webpage]]. Our development and services include ensemble data assimilation for the ensemble prediction systems * ICON-EPS global with 26 km resolution and 40 members and * ICON-EU-EPS with 13km resolution over Europe with 40 members as well as * ICON-D2-EPS with 2km resolution over central Europe, 40 members. * ICON-D1 and ICON-D05 with 1km resolution and 500m resolution is under development. We run a * hybrid ensemble-variational data assimilation scheme (EnVar) globally, i.e. a variational data assimilation scheme, coupled with an Localized Ensemble Transform Kalman Filter (LETKF). * For ICON-D2 we employ the four-dimensional version of the Localized Ensemble Transform Kalman Filter (4D-LETKF). Further, * Particle filters, in particular the Localized Adaptive Particle Filter LAPF and Localized Mixture Coefficients Particle Filter LMCPF are available for global and regional scale and are being used for research within the operational framework. * EnVar for convective-scale ICON-D2 is under development, * 4D-EnVAR for both global and regional systems * an ultra-rapid data assimilation scheme (URDA) based on our ensemble and also * a coarse EnVar (cEnVar) using our global ensemble for regional ensemble data assimilation world-wide are being developed and tested. 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. {{world_weather002.png?250 }} 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 [[http://www.inverseproblems.info/|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. ---- ===== Group ===== Since October 2020 I am heading the department on Numerical Weather Prediction (NWP) of DWD with about 120 researchers in-house (state July 2023). There are four division heads in this department to lead sections of approximately 20-35 researchers each, see [[group]]. [[group|{{group001.jpg?200}}]] [[group|{{group002.jpg?200}}]] [[group|{{group003.jpg?200}}]] ---- ===== My Christian Blog ===== 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: [[http://www.jesusnetwork.eu/en/|Jesus Network]] ===== Publications ===== [[https://iopscience.iop.org/book/978-0-7503-1218-9|{{book_cover.png?140 }}]] [[http://www.springer.com/mathematics/analysis/book/978-3-642-54592-4|{{springer_book_neuro.jpg?130 }}]] [[https://www.crcpress.com/Point-Sources-and-Multipoles-in-Inverse-Scattering-Theory/Potthast/p/book/9781584882527|{{potthast_book.jpg }}]] Recent publications can be found on [[publications]]. A book [[https://iopscience.iop.org/book/978-0-7503-1218-9|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 high-dimensional analysis and simulation methods which can be run in a reliable way on a supercomputer in near real-time. It includes codes simulating atmospheric processes, fluid-dynamics, physical parametrizations, scattering of waves, propagation of light and radiation, tomography, large-scale optimization and uncertainty quanitfication, ensemble and particle methods. With a SX-AURORA TSUBASA A412-8 of NEC our supercomputer at Deutscher Wetterdienst is no 140 (Nov 2020) [[https://www.top500.org/lists/top500/list/2020/11/?page=2|Web]] on the TOP-500 Supercomputer List (2017 with CRAY we were no 99 and 130 [[https://www.top500.org/lists/top500/list/2017/06/|Web]]). We have access to Cray XC40, Xeon E5-2695v4 of ECMWF, Mistral - bullx DLC 720, Xeon E5-2680v3 12C of DKRZ and Piz Daint - Cray XC50, Xeon E5-2690v3 12C 2.6GHz, Aries interconnect, NVIDIA Tesla P100 of CSCS in Switzerland. High-performance computing is our daily business, however, the development of **insight** into the scientific problems we need to solve is an indispensable 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" [[http://www.toprof.imaa.cnr.it/|Website]]; ===== Editorial Board ===== * [[http://journal.frontiersin.org/journal/applied-mathematics-and-statistics/section/dynamical-systems#|Frontiers in Applied Mathematics and Statistics - Dynamical Systems]] * [[http://mip.apacific.org/|Mathematical Inverse Problems]] \\ Prof. Dr. Roland Potthast\\ Deutscher Wetterdienst (DWD)\\ Frankfurter Strasse 135\\ 63067 Offenbach, Germany\\ Roland.Potthast@dwd.de\\ \\ Professor for Applied Mathematics\\ Department of Mathematics and Statistics,\\ Whiteknights, PO Box 220,\\ Reading RG6 6AX, UK \\ r.w.e.potthast@reading.ac.uk\\ https://twitter.com/roland_music\\ \\