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25-788: [REDACTED] Look up dawes in Wiktionary, the free dictionary. Dawes may refer to: Places [ edit ] Dawes (Parish), New South Wales , Australia Dawes Point, New South Wales , Australia Dawes Arboretum , in Newark, Ohio, U.S. Dawes County, Nebraska , U.S. Dawes Township, Thurston County, Nebraska , U.S. Other uses [ edit ] Dawes (band) , an American rock band Dawes (lunar crater) Dawes (Martian crater) Dawes (surname) Dawes Act of 1887, US law regarding allocation of Native American tribal land Dawes Commission Dawes Rolls Dawes Cycles ,

50-414: A semi-arid climate except that its high evapotranspiration , or its aridity, makes it a desert climate . is almost unpopulated, with less than two inhabitants per square kilometer. This Far West geography article is a stub . You can help Misplaced Pages by expanding it . Evapotranspiration Evapotranspiration is defined as: "The combined processes through which water is transferred to

75-514: A British bicycle manufacturer Dawes Plan , a 1924 plan to resolve the World War I reparations See also [ edit ] Daw (disambiguation) Dawe (disambiguation) Daws (disambiguation) Simon Dawes , an American rock band Dawes' limit , a formula to express the maximum resolving power of a microscope or telescope Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

100-408: A large contribution to atmospheric moisture even under standard conditions. Levels of evapotranspiration in a given area are primarily controlled by three factors: Firstly, the amount of water present. Secondly, the amount of energy present in the air and soil (e.g. heat, measured by the global surface temperature ); and thirdly the ability of the atmosphere to take up water ( humidity ). Regarding

125-524: A surface and the ability of the surface to supply moisture, then PET is a measure of the demand side (also called evaporative demand ). Surface and air temperatures, insolation , and wind all affect this. A dryland is a place where annual potential evaporation exceeds annual precipitation . Often a value for the potential evapotranspiration is calculated at a nearby climatic station on a reference surface, conventionally on land dominated by short grass (though this may differ from station to station). This value

150-414: Is a reflection of the energy available to evaporate or transpire water, and of the wind available to transport the water vapor from the ground up into the lower atmosphere and away from the initial location. Potential evapotranspiration is expressed in terms of a depth of water or soil moisture percentage. If the actual evapotranspiration is considered the net result of atmospheric demand for moisture from

175-419: Is a remote rural locality and civil parish of Yungnulgra County in far North West New South Wales . The Parish has an arid landscape and the nearest town is Whitecliffs . The parish also has extremely hot summers and mild winters . Summers would usually exceed 36 °C. Winters are usually around 17 °C. The annual average rainfall is about249.7 millimetres (9.8 in) which would make it

200-419: Is areas with high water tables , where capillary action can cause water from the groundwater to rise through the soil matrix back to the surface. If potential evapotranspiration is greater than the actual precipitation, then soil will dry out until conditions stabilize, unless irrigation is used. Evapotranspiration can be measured directly with a weighing or pan lysimeter . A lysimeter continuously measures

225-446: Is by calculating the energy balance. λ E = R n − G − H {\displaystyle \lambda E=R_{n}-G-H\,\!} where λE is the energy needed to change the phase of water from liquid to gas, R n is the net radiation, G is the soil heat flux and H is the sensible heat flux . Using instruments like a scintillometer , soil heat flux plates or radiation meters,

250-418: Is called the reference evapotranspiration (ET 0 ). Actual evapotranspiration is said to equal potential evapotranspiration when there is ample water present. Evapotranspiration can never be greater than potential evapotranspiration, but can be lower if there is not enough water to be evaporated or plants are unable to transpire maturely and readily. Some US states utilize a full cover alfalfa reference crop that

275-460: Is lost or intentionally destroyed by clearing and burning, soil moisture is reduced by wind, and soils are easily eroded by high wind and rainfall events. In areas that are not irrigated, actual evapotranspiration is usually no greater than precipitation , with some buffer and variations in time depending on the soil's ability to hold water. It will usually be less because some water will be lost due to percolation or surface runoff . An exception

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300-622: Is the Penman equation . The Penman–Monteith variation is recommended by the Food and Agriculture Organization and the American Society of Civil Engineers . The simpler Blaney–Criddle equation was popular in the Western United States for many years but it is not as accurate in wet regions with higher humidity. Other equations for estimating evapotranspiration from meteorological data include

325-523: The Makkink equation , which is simple but must be calibrated to a specific location, and the Hargreaves equations . To convert the reference evapotranspiration to the actual crop evapotranspiration, a crop coefficient and a stress coefficient must be used. Crop coefficients, as used in many hydrological models, usually change over the year because crops are seasonal and, in general, plant behaviour varies over

350-434: The water balance equation for a given area:. The water balance equation relates the change in water stored within the basin ( S ) to its input and outputs: Δ S = P − E T − Q − D {\displaystyle \Delta S=P-ET-Q-D\,\!} In the equation, the change in water stored within the basin ( ΔS ) is related to precipitation ( P ) (water going into

375-497: The Earth's surface) in a set unit of time. Globally, it is estimated that on average between three-fifths and three-quarters of land precipitation is returned to the atmosphere via evapotranspiration. Evapotranspiration does not, in general, account for other mechanisms which are involved in returning water to the atmosphere, though some of these, such as snow and ice sublimation in regions of high elevation or high latitude, can make

400-511: The atmosphere from open water and ice surfaces, bare soil and vegetation that make up the Earth’s surface." Evapotranspiration is a combination of evaporation and transpiration, measured in order to better understand crop water requirements, irrigation scheduling, and watershed management. The two key components of evapotranspiration are: Evapotranspiration is typically measured in millimeters of water (i.e. volume of water moved per unit area of

425-406: The basin), and evapotranspiration ( ET ), streamflow ( Q ), and groundwater recharge ( D ) (water leaving the basin). By rearranging the equation, ET can be estimated if values for the other variables are known: E T = P − Δ S − Q − D {\displaystyle ET=P-\Delta S-Q-D\,\!} A second methodology for estimation

450-692: The components of the energy balance can be calculated and the energy available for actual evapotranspiration can be solved. The SEBAL and METRIC algorithms solve for the energy balance at the Earth's surface using satellite imagery. This allows for both actual and potential evapotranspiration to be calculated on a pixel-by-pixel basis. Evapotranspiration is a key indicator for water management and irrigation performance. SEBAL and METRIC can map these key indicators in time and space, for days, weeks or years. Given meteorological data like wind, temperature, and humidity, reference ET can be calculated. The most general and widely used equation for calculating reference ET

475-502: The liquid water in fog or low clouds onto their surface, which eventually drips down to the ground. These trees still contribute to evapotranspiration, but often collect more water than they evaporate or transpire. In rainforests, water yield is increased (compared to cleared, unforested land in the same climatic zone) as evapotranspiration increases humidity within the forest (a portion of which condenses and returns quickly as precipitation experienced at ground level as rain). The density of

500-558: The plant and leaves. Another example is that conifer forests tend to have higher rates of evapotranspiration than deciduous broadleaf forests, particularly in the dormant winter and early spring seasons, because they are evergreen . Transpiration is a larger component of evapotranspiration (relative to evaporation) in vegetation-abundant areas. As a result, denser vegetation, like forests, may increase evapotranspiration and reduce water yield. Two exceptions to this are cloud forests and rainforests . In cloud forests, trees collect

525-595: The second factor (energy and heat): climate change has increased global temperatures (see instrumental temperature record ). This global warming has increased evapotranspiration over land. The increased evapotranspiration is one of the effects of climate change on the water cycle . Vegetation type impacts levels of evapotranspiration. For example, herbaceous plants generally transpire less than woody plants , because they usually have less extensive foliage. Also, plants with deep reaching roots can transpire water more constantly, because those roots can pull more water into

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550-620: The title Dawes . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Dawes&oldid=1250941011 " Categories : Disambiguation pages Place name disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Dawes (Parish), New South Wales Dawes Parish, New South Wales in Central Darling Shire

575-465: The vegetation blocks sunlight and reduces temperatures at ground level (thereby reducing losses due to surface evaporation), and reduces wind speeds (thereby reducing the loss of airborne moisture). The combined effect results in increased surface stream flows and a higher ground water table whilst the rainforest is preserved. Clearing of rainforests frequently leads to desertification as ground level temperatures and wind speeds increase, vegetation cover

600-541: The weight of a plant and associated soil, and any water added by precipitation or irrigation. The change in storage of water in the soil is then modeled by measuring the change in weight. When used properly, this allows for precise measurement of evapotranspiration over small areas. Because atmospheric vapor flux is difficult or time-consuming to measure directly, evapotranspiration is typically estimated by one of several different methods that do not rely on direct measurement. Evapotranspiration may be estimated by evaluating

625-419: The year: perennial plants mature over multiple seasons, while annuals do not survive more than a few , so stress responses can significantly depend upon many aspects of plant type and condition. Potential evapotranspiration (PET) or potential evaporation (PE) is the amount of water that would be evaporated and transpired by a specific crop , soil or ecosystem if there was sufficient water available. It

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