Hydrologic Cycle

HYDROLOGIC CYCLE, GLOBAL WARMING, AND SEA LEVEL RISE Krisna Andhika - 1509050

The Cycle Hydrologic Cycle or a Water Cycle is a circulation that will never stops from the water on the earth where the water is moving from the ground into the air and go back into the ground again even stored under the surface in three phase (liquid, solid, and gas). Hydrological cycle is the example of the biogeochemical cycle. Hydrological cycle has an important role in weather, climate, and meteorological science/study. Although the balance of the water on the Earth remains constant, actually the water molecules can come and go, in and out of the atmosphere. The water moves from one place to another, such as from iver to the ocean, or from the ocean to the atmosphere, by the processes called evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. The water flows through different phases such as liquid, solid, and gas. Hydrologic cycle involves the exchange of heat, which causes a change in the temperature. For an example, in the process of evaporation, the water takes energy from the surroundings and cools the environment. Otherwise, in the process of condensation, water releases the energy to its surroundings, and warming the environment. The hydrological cycle is significantly contributed in the maintenance of life and the ecosystem on the Earth. Even in each reservoir, water plays an important role. Hydrological cycle added significance to the presence of water on the planet. With the transfer of the water from one reservoir to another, the cycle purifies water; recharge the soil with fresh water; and transporting minerals to other places in the world along the water. The hydrological cycle also involves with the heat exchange, and it affects the Earth’s climate conditions.

The Water Balance In the hydrological cycle, all the water in the world seems balance. Water balance is the flow of water in and out of a system. A water balance can be used to help manage water supply and predict where there may be water shortages. It is also used in irrigation, runoff assessment, flood control, and pollution control. Further it is used in the design of subsurface drainage systems which may be horizontal (using pipes, tile drains or ditches) or vertical (drainage by wells). The water that flow in the surface, subsurface, and in the atmosphere of the earth, will be equally in the same amount. If the water in the surface decreases, the amount of the water in the subsurface or in the atmosphere will increase. There are many things that influence the water balance on the earth.

Precipitation is the water vapor that falls to the surface of the earth. Most of the precipitation occurs as rain, but it also includes snow, hail, fog drip, graupel, and sleet. Approximately 505,000 km3 of water falls as precipitation each year, 398,000 km3 of it happen over the oceans. Runoff is the variety of ways by which water moves across the land. This includes both surface runoff and channel runoff. As it flows, the water may seep into the ground, evaporate into the air, become stored in lakes or reservoirs, or be extracted for agricultural or other human uses. Infiltration is the flow of water from the ground surface into the ground. Once infiltrated, the water becomes soil moisture or groundwater. Subsurface flow is the flow of water from the ground surface into the ground. Once infiltrated, the water becomes soil moisture or groundwater. Evaporation is the transformation of water from liquid to gas phases as it moves from the ground or bodies of water into the overlying atmosphere. The source of energy for evaporation is primarily solar radiation. Evaporation often implicitly includes transpiration from plants, though together they are specifically referred to as evapotranspiration. Condensation is the process by which water vapor changes it's physical state from a gas to a liquid. Water vapor condenses onto small airborne particles to form dew, fog, or clouds. Transpiration is the biological process that occurs mostly in the day. Water inside of plants is transferred from the plant to the atmosphere as water vapor through numerous individual leave openings. Evapotranspiration is the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and water bodies. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves. Soil water storage capacity is the total amount of water that is stored in the soil within the plant’s root zone. The soil texture and the crop rooting depth determine this. A deeper rooting depth means there is a larger volume of water stored in the soil and therefore a larger reservoir of water for the crop to draw upon between irrigations.

Water Balance and Sea Level Rise Sea level rise is a condition of the ocean that makes the mean sea level of the world is rising up. What make the sea level is rising? And weather it related with the water balance in the earth? One of the things that make the sea level is rising is global warming. Global Warming is the rise in the average temperature of Earth's atmosphere and oceans. Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980.

With the increase of the temperature of the earth, mean the temperature of the sea is increasing too. That cause the temperature in the air and the water near the North Pole and South Pole is increasing, so the ice in the Pole is melting. There are many cubic of ice in the Pole, so it makes the sea level in the world is rising. How come it has anything to do with water balance? The water balance is the amount of the water in the whole world in all the form of the water (liquid, gas, and solid). The amount of the water in the world will never change. It will only change the form of the water. For example, if the amount of water is 100% divide by liquid 50%, gas 25%, and solid 25%. Because something happen (in this case it is Global Warming), the percentage of the solid water is decreasing to 10%. With the water balance theory, the solid water is not vanish but it change formed. The solid water could change form into liquid or gas. The Global Warming is not hot enough to change it into gas so it turns to liquid. The equation becomes 60% liquid, 25% gas, and 15% solid. That what caused the sea level is rising. Otherwise, with the global warming, there will be other place that will become hotter than normal. So it will make the evapotranspiration increasing and will make other rain. The hotter the place, the soil in that place will become dryer. In some place it will become dryer, in other place it become wetter. It the place that become wetter, if rain is happening there, the soil won’t withstand the number of water that is coming. If rain is happening in that place, either the water will make a runoff or it can create a flood. In the end, the water will go to the ocean, but it will make the sea level rises. So after all is not the change of anything, it just a low of balance. If some water is change form, the other form will be made. It is not like we couldn’t predict about it. We could have the equation and we could prepare how to avoid it. But it is the ignorance of the people that live on the earth. We could prepare for it or we could change the way we live so it won’t become worst. Water is not increasing, but it change form.

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