water cycle

In this blog we will talk about the water cycle. We will tell you what is it, the processes to do this, effects on climate and finally the water uses.

The water cycle, also known as hydrologic cycle, is the continuous movement of the water on Earth.

The water on Earth has been the same over time, but it changes it’s state from solid, liquid and gas.

The water cycle involves the exchange of heat which makes the temperature changes.

The water cycle purify water, fills the land with freshwater and transport minerals from one part of the globe to another.

The water cycle also makes erosion, sedimentation and maintains the life in the Earth.

The sun heats the water in the oceans and the seas and evaporate it into steam. Ice and snow can mel tinto water too, or sublimate to steam. Evapotranspiration is when the water transpirate for plants and evaporate from the soil. The rising air currents take the steam up into the atmosphere where cooler temperatures transform them into clouds.

  Then the air currents move them around the world and make them colide and grow and then, they fall out of the cloud and fall as precipitation. This precipitation could be water, snow, hail or sleet and can accumulate as ice caps and glaciers and store frozen for thousand of years, or simply filter into the soil. The water can fall into the ocean too, or flow onto the land as a river or a surface runoff. Either the rivers and the runoffs flow down the valleys and the mountains towards the oceans or store into a lake. Some runoffs soak into the ground as infiltration and replenishes aquifers, which finds openings in the land and return to the ocean. Over time the water returns to the ocean, where the water cycle starts.
video water cycle

Processes:

Precipitation: The condensed steam that falls to the Earth’s  surface, the most precipitation falls as rain, but it also can fall as snow, hail, sleet, fog drip or graupel.

Canopy Interception: The precipitation that falls into the plants folliage eventually evaporates to the atmosphere.

Snowmelt: The runoff produced by the melting of the snow.

Runoff: The variety of ways by which water moves across the land, this includes channel runoff.

Infiltration: When the water soak into the ground.

Subsurface flow: The flow of water underground, it may return to the surface, or soak into oceans directly.

Evaporation: Is the transformation from liquid water to steam. The principal source of energy for evaporation is the solar radiation. It also includes the transpiration from plants, which is called evapotranspiration.

Sublimation: When the ice or snow changes directly from solid to gas.

Deposition: When the steam transform directly into ice or snow.

Advection: The movement of the water in the atmosphere.

Condensation: The transformation of the steam into liquid droplets in the air which forms clouds and fog.

Transpiration: The release of steam from plants and soil into the air.

Percolation: When the water moves horizontally because of the gravity.

Efects on climate:

The water cycle is powered from solar energy. 86% of the evaporation occurs in the ocean, reducing its temperature by evaporative cooling. Without this cooling, the surface temperature would beabout 67º.

Only the 2.5% of the water is freshwater while the remaining is salt water, about two thirds of the freshwater is locked up in the glaciers or in permanent snow cover.

Water sources are renewable, but freshwater is distributed unevenly around the world. Only 9 countries have the 60% of world’s available freshwater: Brazil, Russia, China, Canada, Indonesia, U.S. , India, Columbia and The Democratic Republic of Congo.

A fifth of the world relies on ancient aquifers, and those aret he only non-renewable source of water. Nowadays, a quarter of the world’s population is affected by water scarcity, mostly in northern Africa.

Humans influence significantly in water cycle, humans withdraw 8% of the total renewable freshwater, and appropriate 26% of evotranspiration and 54% of accessible runoff.

Water cycle is also modified by our cities, because water can’t soak into the gorund and we collect i tinto our sewers and return it to the nearest runoff or beach directly modifying the cycle. We also pollute the water with our pesticides and other pollutants.

Water uses:

Agriculture: Inthe most countries irrigation accounts for over 90% of water withdraw of availiable sources for use.

Industrial use: industries are the second user of water, for produce energy or for mining, etc.

Domestic use: Is essential for live because we need to drink, to wash ourselves and to prepare foods.