THE HYDROLOGIC CYCLE A true cycle with no

THE HYDROLOGIC CYCLE

A true cycle with no beginning or end.

Nice and Simple. . .

The Hydrologic Cycle Defined as the movement of water on, above, and below the surface of the Earth. Describes condensation of water vapor and formation of cloud droplets and eventually precipitation.

Three Main Elements of H 2 O Cycle Evaporation Condensation Precipitation

EVAPORATION (Transpiration) The process of transforming liquid water from the oceans and the soil to water vapor. Water vapor is an invisible odorless gas that enters the atmosphere.

CONDENSATION The process of changing water vapor back to liquid water. The process of forming cloud droplets. As water vapor rises, temperature decreases in the atmosphere and condensation begins in the formation of tiny cloud droplets.

PRECIPITATION Cloud droplets collide and coalesce with neighboring cloud droplets. As they grow in size and weight, cloud droplets form precipitation which falls from the sky as liquid water particles (rain) solid water particles (snow and hail)

Other Processes. . . Freezing Melting Sublimation q Sublimation is the phase change from solid to gas minus the intermediate step of forming liquid. Ø For example: The change from snow or ice to gaseous water without the step of liquid water formation.

Cloud Formation Clouds are visible masses of condensed droplets or frozen crystals suspended in the atmosphere. Clouds are divided into two main categories Convective or Cumulus (in latin: piled up) Layered or Stratus (in latin: layer)

Location of Clouds in Atmosphere Cumulus and stratus clouds are divided into four more groups that distinguish the altitude location of the cloud. LOW (up to 6, 500 ft. ) Stratus, nimbostratus, cumulus and stratocumulus Characteristics of cumulus clouds Dense White and puffy (like cotton balls) Associated with good weather

Locations continued. . . LOW clouds (up to 6, 500 ft. ) Characteristics of stratus clouds Dark gray Low lying Uniformly stratified or layered covering the whole sky Usually associated with rain MIDDLE clouds (6, 500 -16, 500 ft. ) Begin with prefix “alto” Includes alto stratus and altocumulus

High Clouds Above 16, 500 ft. In the cold region of the troposphere Begin with prefix “cirro” or cirrus Often whispy or transparent At this altitude, water freezes so the clouds are almost always composed of ice crystals. High clouds include cirrus, cirrostratus, and cirrocumulus. Aircraft contrails form in this altitude range.

Questions? Activity: “It’s Time to Get Cirrus With Clouds”