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Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily
HOME > Lecture catalog / Research summary > Glossary > Hydrology
[ water cycle | soil ]
| The science which deals with the water of the earth, their occurrence, circulation and distribution on the planet, their physical and chemical properties and their interactions with the physical and biological environment, including their responses to human activity (UNESCO 1964) |
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 Water in the earth is always in movement, and the natural water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the blink of an eye and over millions of years. |
 H and O tracers of the hydrologic cycle |
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= water economy, and water balance General equation ΔS = P - R - G - E - T
ΔS: storage = P - (b - a)
a: amount of remaining water for dt or Δt = P - ΔS if ΔS = b - a |
Water balance in streamIdealP = R + E + T + G Practical P = R + E + T + G + ΔS ΔS: changes (increase or decrease) in water storage at a given time unit for the observation of runoff and/or precipitation in a watershed ΔS ≈ 0: possibly approximate when the unit of period is a year for treating the data
G ≈ 0: possibly apporximate for small watershed |
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Def. a branch of mechanics that deals with the behavior of materials and fluids that are considered to be continuous, rather than discrete Two main subjects Continuum mechanics (連続体力学, s.s.): mechanical behavior of solid materials |
Sub-subject Solid Mechanics (固体力学): studies how solid materials deform, move, and fail under forces, temperature changes and other external or internal influences Fluid dynamics (流体力学): the behavior of fluids (liquids and gases) in motion Rheology (レオロジー): how materials flow and deform under applied forces |
| Foundation to understand climatology and hydrology |
Magnus effect (マグナス効果): Magnus, Heinrich G (1802-1870) an observable phenomenon commonly associated with a spinning object moving through a fluid, including air applied to ball sports Def. Magnus force, FA = Δp·A = cA·ρ/2(u12 - u22)·A
cA: a scalar dependent on the rotating object |