Journal of the Atmospheric Sciences 61 (2004) 1726-1739
Physica D: Nonlinear Phenomena 190 (2004) 153-166
A granular permutation-based representation of complex numbers and quaternions: elements of a possible realistic quantum theory
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 460 (2004) 1039-1055
CLIMATE IN HISTORICAL TIMES: TOWARDS A SYNTHESIS OF HOLOCENCE PROXY DATA AND CLIMATE MODELS (2004) 365-382
CLIMATE IN HISTORICAL TIMES: TOWARDS A SYNTHESIS OF HOLOCENCE PROXY DATA AND CLIMATE MODELS (2004) 13-41
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 129 (2003) 2401-2423
FIRST CHAMP MISSION RESULTS FOR GRAVITY, MAGNETIC AND ATMOSPHERIC STUDIES (2003) 441-446
Appl Opt 42 (2003) 5891-5896
A number of techniques to track rainfall patterns by use of radar observations have been developed over the years. We present a method for radar-echo tracking based on Hu invariant moments. The method has been tried on several sequences of test images, and the derived displacement fields were in good agreement with the real motions of the tested objects. For the real data obtained from the conventional meteorological radar in Legionowo the method occasionally failed when changes in the radar echo between observations were too large.
REALIZING TERACOMPUTING (2003) 1-18
Extratropical low-frequency variability in a three-level quasi-geostrophic atmospheric model with different spectral resolution
Journal of Geophysical Research D: Atmospheres 108 (2003)
Apart from variations of external forcing components and interactions between climate subsystems, natural atmospheric fluctuations with periods of years, decades and centuries can also be generated by inherent atmospheric dynamical instabilities of the flow. The objective of this study is to investigate the spatial and temporal structure of internal low-frequency atmospheric variability of the Northern Hemisphere using a minimum-complexity model of the extratropical circulation. Here, the main focus is the influence of varying spectral horizontal resolution on the formation of dominant patterns of variability. For this purpose, a three-level quasi-geostrophic atmospheric model with idealized thermal and orographic forcing has been integrated over 1,000 years under perpetual winter conditions with T5, T10, T15, and T21 resolutions. It has been shown that for the crude resolution T5 a rather strong bias occurs, whereas starting with T1O resolution, the nonlinear feedback between large- and small-scale features is reasonably well described. At this resolution a sort of plateau in the model performance has been reached, in respect to both the model climatology and the spatiotemporal structure of variability. Ultralow-frequency variability is most pronounced in the model's stratosphere and is associated with changes in the polar vortex strength and shape caused by vertically propagating planetary waves. Rossby wave trains in the lee of the model large-scale orography are the most dominant structures of long-period fluctuations in the middle troposphere. The results show that interannual- and decadal-scale variations can, in substantial part, be considered as a manifestation of the natural variability of the extratropical atmosphere. The inclusion of a seasonal cycle of the model's diabatic heating increases the interannual and interdecadal variability.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 128 (2002) 747-774
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 128 (2002) 1641-1670
A nonlinear dynamical perspective on model error: A proposal for non-local stochastic-dynamic parametrization in weather and climate prediction models
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 127 (2001) 279-304
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 127 (2001) 685-708
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 127 (2001) 709-731
JOURNAL OF CLIMATE 14 (2001) 3212-3226
Atmospheric Science Letters 2 (2001)
In order to investigate whether climate models of different complexity have the potential to simulate natural atmospheric circulation regimes, 1000-year-long integrations with constant external forcing have been analysed. Significant non-Gaussian uni-, bi-, and trimodal probability density functions have been found in 100-year segments. © 2001 Royal Meteorological Society.
Niederfrequente Variabilität großräumiger atmosphärischer Zirkulationsstrukturen in spektralen Modellen niederer Ordnung. Reports on Polar Research.
AWI (2000) 356