Experimental analysis of microscale rain cells and their dynamic evolution

Abstract

This paper presents a detailed space‐time analysis of rainfall rate using two dense networks of rain gauges covering two microscale areas of some 100 km2 each and located in two distinct climatic areas in the United Kingdom and Spain. The study has been carried out with the main objective of addressing dynamic fade mitigation techniques and scatter interference problems in terrestrial and satellite communication systems. The two databases, using a total of 49 and 23 rain gauges, respectively, are described, and the continuous interpolated field used for the subsequent analyses is explained in detail. The suitability of the networks in terms of density, correlation distance, and fractal dimension are briefly addressed. A to‐scale comparison grid of the networks is also given. It has been found that when the maximum intensity reached during a rain event surpasses a certain threshold, different for each of the two areas, rainfall rates exhibit a spatial structure in the form of closed contours of thresholds referred to as cells. In statistical terms, the most probable diameter found is about 3.5 km, and distributions are presented. They are similar for the two sites but not so for the maxima reached inside the cells. Using cross‐correlation techniques, displacement and velocities are analyzed in detail. Cells “zigzag” around a dominant trend because of the global cloud movements (driven by winds at heights of about 700 hPa). Local topography strongly affects local behavior. Analytical approximations to the experimental statistical distributions and selected histograms of the results are presented.

Rainfall spatial organization and areal reduction factors in the metropolitan area of Barcelona (Spain)

“…Figure 6 shows the dependency of CV on duration when the whole network has registered rainfall. In particular for events with a return period higher than 5 years, the mean value of CV varies between 0.7 and 2 for a duration of 10 min and between 0.2 and 0.9 for 24 h. Dirks et al (1998) found similar values for longer durations using traditional interpolation methods as kriging, Thiessen, or inverse distance, whereas Enjamio et al (2005) found values between 0.4 and 0.7 analyzing four rainfall events using an interpolation algorithm based on biharmonic splines. We can conclude that the Barnes interpolation method reproduces correctly the actual rainfall spatial variations, giving better results the more extensive the rainfall is and a longer duration is taken into consideration.…”

Analysis of extreme rainfall in Barcelona using a microscale rain gauge network

“…A. ), a company that controls the sewer systems of Barcelona (Lorente and Redaño, 1990;Enjamio et al, 2005). The method of classification using the clusters analysis has been applied and the IP has also been calculated.…”

On the Space-Time Variations of Rain Attenuation

“…A number of other average rain cell diameters are reported in the literature, among them [36], [42] and [43]. In [36] the average rain cell diameter was found to be of order 6 km and the most probable diameter in statistical terms was found to be 3.5 km.…”

“…The maximum rainfall intensity depends on the dominant rainfall-generating mechanism associated with local climatologic features [36]. In addition, height difference in the terrain has an effect in the development of regional circulations and cloudiness features that result in strong localized enhancement of precipitation [37].…”