Sébastien Verrier

Simulation of yearly rainfall time series at microscale resolution with actual properties: Intermittency, scale invariance, and rainfall distribution

Rainfall is a physical phenomenon resulting from the combination of numerous physical processes involving a wide range of scales, from microphysical processes to the general circulation of the atmosphere. Moreover, unlike other geophysical variables such as water vapor concentration, rainfall is characterized by a relaxation behavior that leads to an alternation of wet and dry periods. It follows that rainfall is a complex process which is highly variable both in time and space. Precipitation is thus characterized by the following features: rain/no-rain intermittency, multiple scaling regimes, and extreme events. All these properties are difficult to model simultaneously, especially when a large time and/or space scale domain is required. The aim of this paper is to develop a simulator capable of generating high-resolution rain-rate time series (15 s), the main statistical properties of which are close to an observed rain-rate time series. We also attempt to develop a model having consistent properties even when the fine-resolution-simulated time series are aggregated to a coarser resolution. In order to break the simulation problem down into subcomponents, the authors have focused their attention on several key properties of rainfall. The simulator is based on a sequential approach in which, first, the simulation of rain/no-rain durations permits the retrieval of fractal properties of the rain support. Then, the generation of rain rates through the use of a multifractal, Fractionally Integrated Flux (FIF), model enables the restitution of the rainfalls multifractal properties. This second step includes a denormalization process that was added in order to generate realistic rain-rate distributions.

Analysis of Boundary-Layer Statistical Properties at Dome C, Antarctica

The atmospheric boundary layer over the Antarctic Plateau is unique on account of its isolated location and extreme stability. Here we investigate the characteristics of the boundary layer using wind and temperature measurements from a 45-m high tower located at Dome C. First, spectral analysis reveals that both fields have a scaling behaviour from 30 min to 10 days (spectral slope

Multifractal analysis of African monsoon rain fields, taking into account the zero rain-rate problem.

\beta \approx 2

Multifractal analysis of oceanic chlorophyll maps remotely sensed from space

β≈2). Wind and temperature time series also show a multifractal behaviour. Therefore, it is possible to fit the moment-scaling function to the universal multifractal model and obtain multifractal parameters for temperature (

Study of rainfall intensities for micro-scales in a semi-arid zone (Tunis) by FIF model

\alpha \approx 1.51,\, C_1\approx 0.14

Generation of mono-site Rainfall time series from micro to large scale

α≈1.51,C1≈0.14) and wind speed (