Rain, rainfall

After three hours of moderate rain, rainfall reached 10.8 mm, percentage of Pp > 60% is rise to 9.42% then after an hour of heavy rain, the cumulative rainfall reached 20.8 mm, percentage of Pp> 60% is increased to 10.27%, the Pp increments of the two stages are very close. It means a relatively small rainfall intensity, with long enough rainfall time will also affect slope stability. 

The reason why the losses occurred is simply because it rained . The more rain that fell in the period after application, the more labelled nitrogen was lost. The critical period seemed to be the first three weeks after application this was the period that showed the closest relationship between the losses and the rainfall (Figure 2). ... 

Fig. 9.1. Rain falls when the water droplets in clouds turn to ice. This con only happen if the clouds are below 0°C to begin with. If the droplets are clean, ice can form only in the unlikely event that the clouds cool down to the homogeneous nucleation temperature of -40°C. When dust particles are present they can catalyse nucleation at temperatures quite close to 0°C. This is why there is often heavy rainfall downwind of factory chimneys.

In the eastern United States, acid rain consists of 65% sulfuric acid, 30% nitric acid, and 5% other acids. In the West, windblown alkaline dusts buffer the acidity in rains occurring over many rural areas, whereas in urban areas 80% of the acidity is due to nitric acid (28). Average pH in rainfall over the eastern United States for the period April 1979-March 1980 was less than 5.0, with some areas less than pH 4.2 (29). The lowest annual pH recorded was 3.78 at De Bilt, The Netherlands, in 1967, and the lowest in an individual rainfall was 2.4 at Pitlochry, Scotland, on April li) 1974 (30). 

A 1999 study by the Institute of Terrestrial Ecology predicts that tropical rain forests will be able to continue to absorb carbon dioxide at the current rate of 2 billion tons per year until global temperatures rise by 8°F (4.5°C). At this point, evaporation rates will be high enough to decrease rainfall for the forests, leading to the collapse of tropical ecosystems. This collapse will decrease the amount of carbon... 

Weathered ventilators need to have a complex air path in order to prevent rain entry so they therefore provide a restricted airflow. To overcome this, multifunctional ventilators are often used providing a direct air path during dry weather and a restricted one during rainfall. 

Exposure to external atmospheres The rate of corrosion will depend mainly on the type of metal or alloy, rainfall, temperature, degree of atmospheric pollution, and the angle and extent of exposure to the prevailing wind and rain. 

The second case (Table 2) illustrates a hypothetic urban stream receiving both metals and nutrients mainly via urban runoff. Since urban runoff is directly linked with rainfall episodes, metal inputs and exposure will be variable under base-flow during a rainy period and very low under a situation of water scarcity (low rain and low-flow). In this case, a sudden flow increase after strong rains may cause contrasting effects on water metal transport depending on the previous situation. If previous rains have already washed the metals retained in land and sediments, the... 

First evidences of the impact of heavy rainfall on the epidemiology of enteric pathogens were obtained from studies on the presence of various faecal organisms, both pathogens and indicators in water. Increased numbers of pathogens and indicators in different water bodies, including drinking water, had been reported after heavy rains. 

Very little evidence associating water scarcity and an increase in outbreaks of faecal-oral water-borne infectious diseases exists in developed countries. A recent retrospective study performed in England provides some evidence that both low rainfall and heavy rain precede many drinking water outbreaks [3]. Yet, as stated earlier in this review, the situation is potentially different in developing countries [5-7, 9-12], where water scarcity, including droughts, leads to different circumstances that have a clear incidence in the occurrence of both water-borne and water-washed infectious diseases. 

Samples of rainfall in Iowa have been analyzed for levels of pesticides (Nations and Hallberg 1992). Samples collected in April, May, and June of the three years in the study period of 1987-1990 had the highest levels of methyl parathion, corresponding to the application to crops. Methyl parathion was found in 4 of the 318 rain samples analyzed at a maximum concentration of 2.77 pg/L. In a study of... 

A change in pH of one unit reflects a tenfold change in hydronium ion concentration Normal rainfall has pH 5, but acid rain has ten times larger hydronium ion concentration, pH 4. 

In regions of rain-fed agriculture, the test plots must receive 110% of the monthly historical rainfall. Differences in this total should be reconciled every 10 days. If the plots do not receive 110% of historical monthly rainfall, the study may be severely compromised. 

The rainfall regime in arid areas is characterized by low, irregular and unpredictable precipitation, often concentrated in a few rainstorms, creating humid conditions in the soil for a short period and over a limited area. In many arid areas, several years may elapse between successive rainfalls. The moisture supplied to the soil from rain is offset by evaporation, that is related to air temperature, air humidity and intensity of solar radiation. Because of the irregular rainfall distribution, mean precipitation values have little meaning, if not also the range of variation is indicated. 

Dry subhumid areas (0.50 < P/PET < 0.65) less than 25% interannual rainfall variability and rain-fed agriculture is widely practiced (Fig. 1.2). 

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