O ciclo da chuva

Robert Lamb

The water plays a central role in climate, despite responding for such a small proportion of the atmosphere. In some areas, the local atmosphere can contain up to 4% water while other regions contain no water into the atmosphere. Since water can exist as solid, liquid or gas under normal atmospheric conditions, she participates in the hydrological cycle . In this cycle, the water evaporates from the ocean in the form of water vapor and finally returns to the land and sea in the form of precipitation .

The hydrologic cycle keeps the water in constant circulation by Earth

Water vapor is invisible, but quickly becomes visible when cool and condense into contact with something. If you've noticed the moisture that comes in the windows of a warm car on a cold day, you see condensation in action. The hot water vapor touches the window and cold vapor back into a liquid state. Clouds are formed similarly. The atmosphere is filled with small particles of dust known as condensation nuclei , which comes from volcanic eruptions, dust storms, fires and pollution. When water vapor condenses to adhere these microscopic particles. If water vapor in the cooling air in sufficient volume, the particles accumulate and form the millions clouds . If the temperature is cold enough, the water turns to ice around the nuclei of condensation. To study the clouds deeper, read How clouds work (in English).

In a world without wind, these water droplets descend immediately to the surface, but the complex air high winds of the earth keeps the clouds in the air and carry them across vast distances, changing its shape in the process. If too much water can condense around one particle in the air or the air temperature falls, the water falls back to the surface. Liquid particles fall in the form of rain , while frozen particles fall as snow . If rain freezes to fall, it becomes freezing rain . In some instances, the rain rises at higher altitudes and in cold strength of the vertical wind; particles freeze and return to earth as hail .

Clouds come in various shapes and sizes and occur at varying altitudes. They may form near the ground, in the form of fog . This happens when warm, moist air near the ground cools quickly or is superssaturado water vapor.

But as you know, more substantial cloud formations of Earth happen in heaven. In the next section we will see how much water vapor rises.