Precipitation and evaporation Flashcards
Short term precipitation
- moniitoring sever stroms
- weather forecasting
- flood monitoring and control
Medium term precipitation
water resource management
- nature conservation
- domestic use
- hydroelectric power generation
- irrigation management
Long term precipitation
- climate prediction
- hydrological planning
Atmospheric rivers
are relatively narrow regions in the atmosphere that are responsible for most of the horizontal transport of water vapour outside the tropics
Precipitation water
the depth of water in a column of the atmosphere, if all the water in that column were precipitated as rain
Latitudinal distribution of energy
- geometrical relations of the earths orbit cause seasonal and latitudinal variation in the receipt of solar energy
- given energy is spread out over larger areas at high latitudes
- latitudinal effect is modified seasonally because the earths axis of rotation is tilted at 23.5 degrees
Net radiation
- positive for latitudes below 35 degrees
- total energy input and output must be in balance at all latitudes
- net poleward transfer of energy fluxes, accomplished by air and ocean currents
General circulation
- unequal latitudinal distribution of radiation plus need for conservation of angular momentum of the rotating earth l
- 3 cells (0-30, 30-60, 60-90) plus jet streams and typical surface wind directions
- less dominate in high latitudes where wind circulates in large scale horizontal eddies
General circulation result in (high and low pressure)
- low pressure: regions of rising are near equator and at latitudes of 60 degrees
- Higher pressure: region of descending air near 30 degrees latitude and the poles
- quasi stationary zones of H & L pressure cause moving cyclonic storms
- both dominate weather systems in latitudes
Distribution of precipitation
- equatorial belt is particularly pronounces because of warm easterly winds from both hemisphere
- these carry large amounts of moisture evaporated from tropical oceans that converge in this zone (ITCZ)
- peaks in mid-latitudinal zones, mainly linked to extra-tropical cyclonic storms, developing along polar fronts
high precipitation
- regions with rising air
- near the equator and 60 degrees
low precipitation
- regions with descending air
- near the equator and 30 degrees (Deserts)
Global precipitation patterns
- significant deviations from latitudinal distribution
- precipitation rates are influenced by topography, air temp, frontal activity and wind direction in relation to moisture sources
- mountain ranges cause high P, rain shadow leeward of prevailing winds
- interaction of circulation & topography causes monsoon in Asia
- teleconnections, ENSO
Precipitation formation
- moisture (Water vapour)
- condensation nuclei
- atmospheric cooling
- importation of water vapour
Aondensation nuclei
Provide a surface fro the eater vapour to condense into liquid water upon
- particles floating in the atmosphere
- < 1 micron
