Water Planet Lecture 9/19Video on Water Cycle -The sun heats up the earth surface-The water cycle is continuous -Evaporation= cools atmosphere as it occurs, desalinization, potable= drinkable-Heat from sun creates wind= condensation= releases heat back into atmosphere, how earth regulates its temperature -When water freezes it can hold particles of the atmosphere= scientists can later study this -Erosion= shaping of geological features, carrying of life sustaining minerals to plants and animals-Infiltration= aquifers -Transpiration= plant sweat -Evapo-transpiration= how humans affect the water cycle -The Ocean Conveyer Belt, Thermohaline Circulation EvaporationThe transfer of liquid water into a gaseous state and its diffusion into the atmosphere-Open water evaporation-Potential Evaporation: occurs over the land’s surface or would occur if the water supply was unrestricted (optimum conditions= humidity/soil/temperature)-Actual evaporation: what actually occurs, if there is not much water available AE<PE-Evaporation above a land surface occurs by (evapotranspiration=combo):1.actual evaporation2.Transpiration from plants -need an energy source/ atmosphere must be dry -heat energy must be absorbed or released = provided by Sun Heat Fluxes -Sensible heat: can be sensed by instruments (how we feel on a sunny day)-Latent heat: the heat either absorbed or released during a phase change( positive= gas liquid, negative= liquidgas) -Soil heat flux: heat released from the soil Short and Longwave Radiation (a lot stays back at the surface) -Shortwave radiation: incoming radiation that reaches the surface-Outgoing radiation can either be reflected shortwave radiation or energy radiated back by Earth’s surface= major source of energy for evaporationOther forms of Available Energy:-Heat stored in buildings-Adective energy that originates in some other place and has been transported to evaporative surface where it becomes available energy The Receiving Atmosphere-Once it becomes water vapor it must be absorbed into atmosphere surrounding that surface using what energy source is available-Need enough buoyancy to more water vapor away from surface Buoyancy-Atmospheric mixing= how well a parcel of air is able to diffuse into atmosphere surrounding it (wind speed and atmospheric mixing) -Stability= tendency of an air parcel to resist displacement or return to starting place= stable -Drying Clothes= works best on a warm dry, windy day Effect of Vegetation Canopy-Interception Losses: factors influencing= capacity of leaves to intercept rainfall,-Water that does not reach surface= interception, some places have as much as 40%Lysimeters-Similar to evaporation pan except that a lysimeter is filled with soil and vegetation as opposed to water (limited due to cost)**Add to this from slide Estimation of Evaporation= complicated 1. Thornthwaite estimated monthly PE as a function of average air temperature and latitude2. Penman estimated daily PE as a function of net radiation3.
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