Martin Göber

<p>Measuring submesoscale variability is the core task of the field campaign FESSTVaL (Field Experiment on Sub-Mesoscale Spatio-Temporal Variability in Lindenberg).  FESSTVaL focuses on three sources of submesoscale variability: cold pools, wind gusts and boundary layer pattern. It took place in the summer months of 2021 at the Meteorological Observatory Lindenberg – Richard-Aßmann-Observatory (MOL-RAO) of the German Weather Service (DWD) near Berlin and was initiated by the Hans-Ertel-Center for Weather Research (HErZ).</p><p>In order to capture phenomena at the submesoscale (500 m – 5 km), generally not captured by conventional measurement network, a hierarchical measurement strategy is adopted. This includes wind profiling stations with a coordinated scanning strategy of several Doppler Lidars, two mobile profilers to measure thermodynamic properties and precipitation, more than 100 stations with near-surface measurements of air temperature, pressure and soil moisture, more than 20 automatic weather stations, an X-Band radar, and a number of energy balance stations. This equipment is augmented by the extensive ground-based remote sensing array at the MOL-RAO, operated by DWD and by flights operated by Unmanned Aerial Systems. Complementing to this, the benefit of a citizen-science measurement network is investigated during the campaign with “Internet-of-things” based technology and low-cost sensors built and maintained by citizens. The measurements are supplemented by high-resolution large-eddy simulations (ICON-LES).</p><p>Originally planned for the summer 2020, FESSTVaL had to be postponed to 2021 and replaced by three local individual campaigns, conducted in Bayern, Lindenberg and Hamburg in 2020. Those three test campaigns demonstrated the ability of the envisionned measurement strategy and planned instruments to capture submesoscale variability and submesoscale weather phenomean. This talk will give a brief overview on the results of these three campaigns, as a foretaste to FESSTVaL, together with some of the very first measurements taken during FESSTVaL. </p>

The project KARE-citizen science established a layperson weather network with two schools in the Bavarian Prealps, Germany, to build up decision-relevant knowledge about weather and climate Over the summer of 2020, pupils collected weather data with self-assembled low-cost autonomous weather stations and reported weather impacts The project included a pre- and post-test of pupils' weather literacy and awareness of climate change and their expectation of local weather before summer and perception in hindsight The ongoing COVID-19 situation had a major impact on the intended activities A comprehensive analysis is therefore deferred to a full experiment planned in summer 2021 © owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4 0 International License (CC BY-NC-ND 4 0)

A statistical model to assess probabilities for the occurrence of fire brigade operations is presented. The model takes into account data from a nowcast system, operationally run at the German weather service (DWD), and information describing the local exposure by publicly available OpenStreetMap data. It is demonstrated, that the model is capable of providing spatial information on the likelihood of fire brigade operations occurrences. While water related operations (e.g. due to flooded basements) are found to be modelled rather well, tree related operations (e.g. the removal of wind throw) are more difficult to model. It is concluded that this is due to the fact that tree related operations can be caused by either severe precipitation or severe gusts. While precipitation is well captured by the nowcast data used to model the meteorological hazard, this is not the case for severe gusts.

Even when the behaviour of a system is very irregular only a small fraction of the phase space might be active. The (fractal) dimension provides a measure of complexity to quantify the number of dominant degrees of freedom. We performed a dimension analysis for different time series which are connected with the ENSO-phenomenon. The algorithm was tested using the output of a low-order model showing deterministic chaos. Moreover, the dimension analysis was applied to measured times series and to stochastic processes with the same Fourier-coefficients. In contrast to earlier investigations, no clear evidence of low dimensionality of the underlying dynamics has been found

The uncertainty of weather warnings is mostly expressed only in textual form (e.g., “thunderstorms are possible tomorrow afternoon”). Thus linguistic uncertainty might be added to the numerical uncertainty of the warnings. Two questions arise: can human forecasters estimate the uncertainty and how well is this done in verbal terms. Subjective and statistical forecasts of the probability of the occurrence of severe weather events for the city of Berlin were verified. Human estimates of the probability for the occurrence of thunderstorms and wind gusts > 14 m/s in Berlin were found to be reliable and possess significant skill in comparison to the statistical reference forecast. Additionally, the verbal description of warning uncertainty in an operational textual warning report was classified and objectively verified. Results indicate that forecasters actually are aware of the inherent uncertainty, yet express this by means of a multitude of verbal terms. In order to improve the com...

In an extension of a study by Fraedrich et al. (1979a, b) we show how the atmospheric processes generating a local climate state can vary from year to year and between two decades in Eastern Germany - an area which is frequently visited by mature cyclones. On the basis of homogeneous and long (1971-90) time series of 4 times daily radiosonde ascents of the GDR we investigated the interannual variability of monthly means, synoptic variability (variance/covariance with periods between 2 and 8 days, weather), low frequency variability (periods of 10-30 days), and high frequency variability (periods of less than one day, noise) of geopotential, temperature, zonal and meridional wind and specific humidity at 14 levels between 925 and 50 hPa. For the time interval 1971-90 we find that the already described significant increase of monthly mean tropospheric temperature and mean zonal wind is accompanied both by changes of different transports carried out by the time mean circulation and by significant changes of monthly variances and transports by eddies of different scales. Additionally we suggest for further studies of interannual variability of atmospheric processes based on radiosonde data applying a low pass filter on the data removing fluctuations with a period of less than one day before making any further operation with the data

In 2011, the German Federal Ministry of Transport, Building and Urban Development laid the foundation of the Hans-Ertel Centre for Weather Research [Hans-Ertel-Zentrum für Wetterforschung (HErZ)] in order to better connect fundamental meteorological research and teaching at German universities and atmospheric research centers with the needs of the German national weather service Deutscher Wetterdienst (DWD). The concept for HErZ was developed by DWD and its scientific advisory board with input from the entire German meteorological community. It foresees core research funding of about €2,000,000 yr−1 over a 12-yr period, during which time permanent research groups must be established and DWD subjects strengthened in the university curriculum. Five priority research areas were identified: atmospheric dynamics and predictability, data assimilation, model development, climate monitoring and diagnostics, and the optimal use of information from weather forecasting and climate monitoring f...

Even when the behaviour of a system is very irregular only a small fraction of the phase space might be active. The (fractal) dimension provides a measure of complexity to quantify the number of dominant degrees of freedom. We performed a dimension analysis for different time series which are connected with the ENSO-phenomenon. The algorithm was tested using the output of a low-order model showing deterministic chaos. Moreover, the dimension analysis was applied to measured times series and to stochastic processes with the same Fourier-coefficients. In contrast to earlier investigations, no clear evidence of low dimensionality of the underlying dynamics has been found

ABSTRACT Verification scientists and practitioners came together at the 5th International Verification Methods Workshop in Melbourne, Australia, in December 2011 to discuss methods for evaluating forecasts within a wide variety of applications. Progress has been made in many areas including improved verification reporting, wider use of diagnostic verification, development of new scores and techniques for difficult problems, and evaluation of forecasts for applications using meteorological information. There are many interesting challenges, particularly the improvement of methods to verify high resolution ensemble forecasts, seamless predictions spanning multiple spatial and temporal scales, and multivariate forecasts. Greater efforts are needed to make best use of new observations, forge greater links between data assimilation and verification, and develop better and more intuitive forecast verification products for end-users. Copyright © 2013 Royal Meteorological Society

... Martin Göber,a* Ervin Zsótérb and David S. Richardsonb a Deutscher Wetterdienst, Offenbach, Germany b European Centre for Medium-Range Weather Forecasts, Reading, England, UK ... References Accadia C, Mariani S, Lavagnini A, Speranza A. 2003. ...