Sir, The impact of raindrops has major consequences on the soil surface conditions. The effects of rain drop energy on erosion and infiltration have been investigated (Fernandes et al., 1997). Palmer (1965) found that a thin layer of water increases the effects of raindrop impact force on soil properties; this result has been confirmed by numerical simulation (Huang et al., 1983; Chang & Hills,...

Abstract. We are interested in simulating overland flow on agricultural fields during rainfall events. In this context, we definitely have to cope with dry/wet interfaces and water inflow on dry soil. The model considered is the Shallow Water system (or Saint-Venant equations) without infiltration. Moreover, the model has to be completed with friction terms. It is numerically solved by a finite...

Soil pH, soil acidity, and their effects on plants The pH scale, ranging from 0 to 14, is used to indicate acidity and alkalinity. pH is a measure of the concentration of hydrogen ions (symbol = H) in the water contained in the soil. A pH of 7.0 is neutral, values below 7 are acidic, and those above 7 are alkaline (basic). The lower the pH, the more acid the soil. Each unit pH drop indicates te...

Two simple heuristic model formulations for warm rain formation are introduced and their behavior explored. The first, which is primarily aimed at representing warm rain formation in shallow convective clouds, is a continuous collection model that uses an assumed cloud droplet size distribution consistent with observations as the source of embryonic drizzle drops that are then allowed to fall t...

State-of-the-art chemical bonding analyses show that water clusters have a bifunctional catalytic role in the formation of H2SO4 in acid rain. The embedded H2O monomers mitigate the change in the chemical bonding scenario of the rate-limiting step, reducing thereby the corresponding activation energy in accordance with Hammond's postulate. We expect that the insights given herein will prove use...

The present study deals with the development of a low-cost microwave device devoted to the measurement of average rain rates observed along Earth–satellite links, the latter being characterized by a tropospheric path length of a few kilometres. The ground-based power measurements, which are made using the Ku-band television transmissions from several different geostationary satellites, are base...

OBJECTIVE Describing water-related perceptions and practice and how slum dwellers lacking public service coverage in the town of Turbo in the Antioquia Department, Colombia, approach this. METHODS This study involved qualitative research from an ethnographic approach. Data was collected by means of interviews with slum dwellers and observing water-related activities. The information was encod...

Roads can experience runoff problems due to the intense rain discharge associated to severe storms. Two advanced tools are combined to analyse the interaction of complex water flows with real terrains. UAV (Unmanned Aerial Vehicle) photogrammetry is employed to obtain accurate topographic information on small areas, typically on the order of a few hectares. The Smoothed Particle Hydrodynamics (...

We demonstrate how, from the point of view of energy flow through an open system, rain is analogous to many other relaxational processes in nature such as earthquakes. By identifying rain events as the basic entities of the phenomenon, we show that the number density of rain events per year is inversely proportional to the released water column raised to the power of 1.4. This is the rain equiv...