Compound extreme events (e.g., simultaneous occurrence of hot and dry days) are likely to have a big impact on society. In our paper, we propose a new method to analyze the temporal succession of compound extreme events, an aspect that has been largely neglected so far. We analyze past and future changes and identify regions within Europe, which are probably susceptible to a future change in the succession of heavy precipitation and cold days in winter and hot and dry days in summer.

Particle filters in their basic form have been shown to be unusable for large geophysical systems because the number of required particles grows exponentially with the size of the system. We have applied the ideas of localized analyses at each model grid point and use ensemble weight smoothing to blend each local analysis with its neighbors. This new local particle filter (LPF) makes large geophysical applications tractable for particle filters and is competitive with a popular EnKF alternative.

This work investigates the possible correlations between the integral scale of the turbulent stratified flows in the atmospheric boundary layer and parameters characterizing topological features of the wind velocity field, such as fractal dimension and its stability properties, studied through the bulk Richardson number. Fractal dimension and the integral scale of the horizontal (u') and vertical (w') velocity fluctuations have been calculated using the mean wind direction as a framework.

We devise a model of a fault system and study the conditions under which it can generate a sequence of seismic events. We also point out the conditions determining the order of the events in a sequence. A significant conclusion of our analysis is that the features of seismic sequences originated by a given fault system (order of events, duration of the sequence, duration of interseismic intervals) typically change from one sequence to another, due to the complexity of fault interaction.

The land-based hydrological cycle is one of the key processes controlling the growth and wilting of plants and the amount of carbon vegetation can assimilate. Recent studies have shown that many land surface models have biases in this area. We optimized parameters in one such model (JSBACH) and were able to enhance the model performance in many respects, but the response to drought remained unaffected. Further studies into this aspect should include alternative stomatal conductance formulations.

We have obtained new evidence of the existence of strain waves in the Earth based on a statistical analysis of the dynamics of seismicity along the northern boundary of the Amurian plate and the data derived from in situ GPS experimental observations. Our results (the periodicity of the seismic components, spatial cycles of the seismicity maxima and migration rate of earthquakes) allow us to identify the dynamics of seismicity along the northern boundary of the Amurian plate as a wave process.