Rain-fall

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.

Most of the surface drainage due to rain falling on roofs, roadways, etc. will be normal, acceptable floodwater and... 

The rain falling on the people and the lake probably has a pH of about 5.5. Acid rain contaminated by S03 has a pH of about 3.0. 

With cattle kept in open yards it is impossible to provide enough straw to absorb both the liquid manure and the rain falling into the yard, with the result that if the N and K are to be saved then drainage and storage of the liquid has to be provided. 

The purify of the water changes constantly during the water cycle. As rain falls through the air, for example, the water dissolves some atmospheric gases such as oxygen, carbon dioxide, and in industrial regions also such air pollutants as sulfur dioxide and oxides of nitrogen. Still more carbon dioxide... 

Field studies have shown that the first 5-6 mm of rain falling on a heated desert surface evaporate almost immediately, whilst single storms with more than 20 mm rain lose a major part of it by lateral runoff. Hence, it is estimated that from the already low rainfall in the arid zone an important part is lost for weathering and soil formation. The importance of this runoff... 

Not all lakes that are exposed to acid rain become acidified. In areas where there is plenty of limestone rock, lakes are better able to neutralize acid. In areas where rock is mostly granite, the lakes cannot neutralize acid. Unfortunately, much of eastern Canada—where most of the acid rain falls—has a lot of granite rock and therefore a very low capacity for neutralizing acids. 

The soil acts as a temporary storage reservoir for the landmine signature chemicals, releasing them when dew or rain falls, and collecting more as soil water evaporates. 

Dried Puddles Concentrate Molecules In our common experience, we have all observed the formation of puddles after a rain. We realize, without much analysis, that the puddle is not formed from rain that fell in only that location. It contains water that fell nearby and flowed to that area, which is at the locally lowest elevation. If the rain falls on an area that has buried sources of explosive molecules, then some of those that were sorbed to the surface particles above the source will be dissolved and carried into the puddle. When puddles dry they leave a concentration of molecules on the surface soil particles. Thus, an irregularly shaped area of relatively high concentration of molecules may appear some distance from any buried source. See the discussion on Figure 8.2 p 182. 

In the name of God I walked on in that garden, and after a while I arrived at a little square, each side being about six rods long. It was surrounded by rose-bushes, and the roses therein were very beautiful. There was some rain falling, and the sun shone very bright, and a beautiful rainbow appeared. I was about to turn away from there. . . when I saw that the wall had entirely disappeared, and in its place there was only a low fence of twisted twigs, and near that rose-garden I saw the... 

If growing indoors, take the plants outdoors when it is warm enough, and let rain fall on them. This will prevent mineral salts from building up in the soil and killing your plant... 

Take of balsam 1 lb., pitch 5 lbs., oil of eggs and quicklime equal parts, (in all) 10 parts. Grind the lime with the oil so as to make one mass. Smear with this mixture the stones, herbs and any growing things, during the dog days. Bury them in manure under ditches in that place. At the first autumn rain falls, the earth will take fire and its fire will bum the inhabitants, for Aristotle asserts that the fire of this lasts nine years. ... 

Most aluminum-containing compounds do not dissolve much in water unless the water is acidic. However, when acid rain falls, aluminum compounds in the soil may dissolve and enter lakes and streams. Since the affected bodies of water are often acidic themselves from the acid rain, the dissolved aluminum does not combine with other elements in the water and settle out as it would under normal (i.e., non-acidic) conditions. In this situation, abnormally high concentrations of aluminum may occur. For more information on aluminum in the environment, see Chapter 5. 

By distillation she returns to the earth the moisture of which vegetation, or heat, have deprived it. Sublimation is made by the elevation of vapours in the air, where they are condensed into clouds. The second is made by rain and dew. Fair weather succeeds rain, and rain fair weather, alternately a continual rain would inundate everything perpetual fair weather would wither all. Rain falls drop by drop, because if poured down too abundantly it would destroy all, as a gardener who would water his grains by bucket full. Thus Nature distributes her benefits with weight, measure and proportion. 

In Pacific Northwest cities like Seattle and Portland, there isn t hardly a single day when no rain falls. 

Presentations of the U-shape model in the literature do not specify the location of rain or snowmelt water and do not discuss the resulting recharge distribution. Commonly, rain falls over the entire area of an unconfined system, as depicted in the cross-section shown in Fig. 2.20. Runoff, too, is all over, but with an uneven distribution, as it runs fast from the topographic highs and accumulates and flows relatively slowly at the topographic lows. Thus recharge takes place all over the surface, but is intensified in the... 

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