Description: Atmospheric and Climate Science ETH, Winterthurerstr. 190, CH-8057 Zürich, Switzerland. Current day operational ensemble weather prediction systems generally rely upon perturbed atmospheric initial states, thereby neglecting the eventual effect on the atmospheric evolution that uncertainties in initial soil temperature and moisture fields could bring about during the summer months. The purpose of this study is to examine the role of the s...
Description: Observatoire Midi-Pyrénées, Toulouse, France. We review the basic approximations underlying magnetohydrodynamic (MHD) theory, with special emphasis on the closure approximations, i.e. the approximations used in any fluid approach to close the hierarchy of moment equations. We then present the main closure models that have been constructed for collisionless plasmas in the large-scale regime, and we describe our own mixed MHD-kinetic model, which is desi...
Description: Group of Nonlinear Physics, Faculty of Physics, University of Santiago de Compostela. E-15782 Santiago de Compostela, Spain. The response of a simplified global atmospheric circulation model (PUMA) to spatiotemporal stochastic forcing is analyzed using the statistical measures originally developed for ensemble forecast evaluation. The nontrivial effects of time and length correlations of the stochastic forcing on the ensemble scores (e.g....
Description: CSIRO Land and Water, Canberra, Acton, ACT, 2601, Australia. Knowledge about the scaling properties of soil water storage is crucial in transferring locally measured fluctuations to larger scales and vice-versa. Studies based on remotely sensed data have shown that the variability in surface soil water has clear scaling properties (i.e., statistically self similar) over a wider range of spatial scales. However, the scaling property of soil water storage...
Bhattacharaya, R. N., Gupta, V. K., and Waymire, E. C.: The Hurst effect under trends, J. App. Probab., 20, 649–662, 1983.; Arneodo, A., Audit, B., Decoster, N., Muzy, J. F., and Vaillant, C.: Wavelet based multifractal formalism: Application to DNA sequence, satellite images of cloud structure, and stock market data, in: The Science of Disasters, edited by: Bunde, A., Kropp, J., and Schellnhuber, H. J., Springer-Verlag, NY, 29 pp., 2002.; Biswas, A. and Si, B. C.: Scale...
Description: Dipartimento di Matematica ed Informatica, Salerno University, via S. Allende, I-84081 Baronissi (SA), Italy. We apply Independent Component Analysis (ICA) to seismic signals recorded at Stromboli volcano. Firstly, we show how ICA works considering synthetic signals, which are generated by dynamical systems. We prove that Strombolian signals, both tremor and explosions, in the high frequency band (>0.5 Hz), are similar in time domain. This seems to give...