Dynamic Planet Key Terms + Concepts

Hydrologic (water) Cycle

The continuous circulation of water within the Earth and atmosphere system

Evapotranspiration

The process by which water moves from the Earth’s surface to the atmosphere - sum of movement of water through evaporation and transpiration (excludes sublimation)

Evaporation

A change in state from liquid to gas - in the water cycle, occurs when energy (typically from the sun) heats upper layers of bodies of water, allowing for hydrogen bonds to break and for water to turn into water vapor

Transpiration

The process of plants absorbing water from the soil and releasing water vapor through stomata on leaves - powered by water potential

Sublimation

A change in state from solid to gas - in the water cycle, ice recieves energy from the sun, which allows frozen water to break hydrogen bonds and form water vapor (less water from this process enters the atmosphere)

Condensation

A change in state from gas to liquid - in the water cycle, water vapor transforms into water droplets due to the lowered kinetic energy and heat within higher altitudes - allows for clouds to form

Convection

The vertical movement of energy - initial movement of water vapor within the water cycle, from surface to atmosphere

Advection

The transport of a substance through bulk movement - in the water cycle, water vapor moves horizontally through the atmosphere at bulk with wind currents and moisture gradients

Precipitation

Water released from clouds in the form of rain, freezing rain, sleet, snow, hail, etc. - fresh water released from clouds due to the condensing of larger water droplets

Infiltration

The process by which water from the ground enters the soil - initial entering of water

Runoff

Precipitation which is not absorbed into the ground (infiltrated) - appears in uncontrolled streams, rivers, drains, and sewers

Percolation

The (deeper) movement of water through soil and rock layers - water travels to water tables and aquifers

Flux

A process which moves water between pools, like evaporation, precipitation, discharge, recharge, or human use

Water Storage Reservoir

Places where water tends to accumulate and spend time in - examples include the ocean, glaciers, ice sheets, aquifers, groundwater, lakes, rivers, etc.

Atmosphere Estimated Residence Time

7-9 days

Soil Moisture Estimated Residence Time

14-28 days

Snow Estimated Residence Time

30-150 days

River Estimated Residence Time

Weeks-months

Groundwater Estimated Residence Time

months-10000 years

Glacier Estimated Residence Time

40-400 years

Lake Estimated Residence Time

100 years

Ocean Estimated Residence Time

3000-3500 years

Evapotranspiration Rate Formula

ET = E + T

(E = evaporation rate, T = transpiration rate)

Runoff Coefficient Rate Formula

C = R/P

(R = Runoff Rate, P = Precipitation Rate, C = Runoff Coefficient (in %)

Residence Time Formula

Residence Time = Reservoir Volume/Flow Rate

General Water Budget Equation

ΔS = inflows - outflows

(ΔS = change in water storage)

Complex Water Budget Equation

ΔS = P - R - ET - G

Residence Time

The amount of time water spends within a water storage reservoir

Water Budget

The combined rates of inflow, outflow, and changes in water storage within a given area (typically a watershed).

Critical Zone

Zone at Earth’s land surface extending from the top of the vegetation canopy through soil to subsurface depths at which fresh groundwater freely circulates