Real-time rainfall prediction at small space-time scales using a two-dimensional stochastic advection-diffusion model

1993 ◽  
Vol 29 (5) ◽  
pp. 1489-1504 ◽  
Author(s):  
Kenji Jinno ◽  
Akira Kawamura ◽  
Ronny Berndtsson ◽  
Magnus Larson ◽  
Janusz Niemczynowicz
Keyword(s):  
Real Time ◽  
Diffusion Model ◽  
Time Scales ◽  
Space Time ◽  
Two Dimensional ◽  
Small Space ◽  
Rainfall Prediction ◽  
Advection Diffusion

Real-time tracking of convective rainfall properties using a two-dimensional advection-diffusion model

1997 ◽  
Vol 203 (1-4) ◽  
pp. 109-118 ◽  
Author(s):  
Akira Kawamura ◽  
Kenji Jinno ◽  
Ronny Berndtsson ◽  
Takashi Furukawa
Keyword(s):  
Real Time ◽  
Diffusion Model ◽  
Two Dimensional ◽  
Convective Rainfall ◽  
Advection Diffusion ◽  
Real Time Tracking

The spatial distribution of gyrotactic swimming micro-organisms in laminar flow fields

2011 ◽  
Vol 680 ◽  
pp. 602-635 ◽  
Author(s):  
R. N. BEARON ◽  
A. L. HAZEL ◽  
G. J. THORN
Keyword(s):  
Random Walk ◽  
Diffusion Model ◽  
Diffusion Models ◽  
Random Walk Model ◽  
Two Dimensional ◽  
Local Flow ◽  
Spatial And Temporal Scales ◽  
Advection Diffusion ◽  
Micro Organisms ◽  
Good Agreement

We compare the results of two-dimensional, biased random walk models of individual swimming micro-organisms with advection–diffusion models for the whole population. In particular, we consider the influence of the local flow environment (gyrotaxis) on the resulting motion. In unidirectional flows, the results of the individual and population models are generally in good agreement, even in flows in which the cells can experience a range of shear environments, and both models successfully predict the phenomena of gravitactic focusing. Numerical results are also compared with asymptotic expressions for weak and strong shear. Discrepancies between the models arise in two cases: (i) when reflective boundary conditions change the orientation distribution in the random walk model from that predicted by the long-term asymptotics used to derive the advection–diffusion model; (ii) when the spatial and temporal scales are not large enough for the advection–diffusion model to apply. We also use a simple two-dimensional flow containing a variety of flow regimes to explore what happens when there are localized regions in which the generalized Taylor dispersion theory used in the derivation of the population model does not apply. For spherical cells, we find good agreement between the models outside the ‘break-down’ regions, but comparison of the results within these regions is complicated by the presence of nearby boundaries and their influence on the random walk model. In contrast, for rod-shaped cells which are reorientated by both vorticity and strain, we see qualitatively different spatial patterns between individual and advection–diffusion models even in the absence of gyrotaxis, because cells are advected between regions of differing rates of strain.

Some Eulerian and Lagrangian statistical properties of rainfall at small space-time scales

1994 ◽  
Vol 153 (1-4) ◽  
pp. 339-355 ◽  
Author(s):  
Ronny Berndtsson ◽  
Kenji Jinno ◽  
Akira Kawamura ◽  
Magnus Larson ◽  
Janusz Niemczynowicz
Keyword(s):  
Time Scales ◽  
Space Time ◽  
Statistical Properties ◽  
Small Space

scholarly journals Micrographia of the twenty-first century: from  camera obscura to 4D microscopy

2010 ◽  
Vol 368 (1914) ◽  
pp. 1191-1204 ◽  
Author(s):  
Ahmed H. Zewail
Keyword(s):  
Electron Microscopy ◽  
Complex Systems ◽  
Real Time ◽  
Time Scales ◽  
Biological Function ◽  
First Century ◽  
Two Dimensional ◽  
Camera Obscura ◽  
Microscopic Imaging ◽  
Emergent Phenomena

In this paper, the evolutionary and revolutionary developments of microscopic imaging are overviewed with a perspective on origins. From Alhazen’s camera obscura , to Hooke and van Leeuwenhoek’s two-dimensional optical micrography, and on to three- and four-dimensional (4D) electron microscopy, these developments over a millennium have transformed humans’ scope of visualization. The changes in the length and time scales involved are unimaginable, beginning with the visible shadows of candles at the centimetre and second scales, and ending with invisible atoms with space and time dimensions of sub-nanometre and femtosecond. With these advances it has become possible to determine the structures of matter and to observe their elementary dynamics as they unfold in real time. Such observations provide the means for visualizing materials behaviour and biological function, with the aim of understanding emergent phenomena in complex systems.

Potential Urban Rainfall Prediction Measurement System

1984 ◽  
Vol 16 (8-9) ◽  
pp. 349-362 ◽  
Author(s):  
John L Vogel
Keyword(s):  
Real Time ◽  
The United States ◽  
Monitoring Systems ◽  
Climatic Region ◽  
Convective Storm ◽  
Rainfall Prediction ◽  
Water Quality Regulations ◽  
General Data ◽  
Real Time Information ◽  
Time Information

Continued growth of urban regions and more stringent water quality regulations have resulted in an increased need for more real-time information about past, present, and future patterns and intensities of precipitation. Detailed, real-time information about precipitation can be obtained using radar and raingages for monitoring and prediction of precipitation amounts. The philosophy and the requirements for the development of real-time radar prediction-monitoring systems are described for climatic region similar to the Midwest of the united States. General data analysis and interpretation techniques associated with rainfall from convective storm systems are presented.

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