Precipitation and evaporation Flashcards Preview

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Flashcards in Precipitation and evaporation Deck (21):
1

Short term precipitation

- moniitoring sever stroms
- weather forecasting
- flood monitoring and control

2

Medium term precipitation

water resource management
- nature conservation
- domestic use
- hydroelectric power generation
- irrigation management

3

Long term precipitation

- climate prediction
- hydrological planning

4

Atmospheric rivers

are relatively narrow regions in the atmosphere that are responsible for most of the horizontal transport of water vapour outside the tropics

5

Precipitation water

the depth of water in a column of the atmosphere, if all the water in that column were precipitated as rain

6

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

7

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

8

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

9

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

10

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

11

high precipitation

- regions with rising air
- near the equator and 60 degrees

12

low precipitation

- regions with descending air
- near the equator and 30 degrees (Deserts)

13

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

14

Precipitation formation

- moisture (Water vapour)
- condensation nuclei
- atmospheric cooling
- importation of water vapour

15

Aondensation nuclei

Provide a surface fro the eater vapour to condense into liquid water upon
- particles floating in the atmosphere
- < 1 micron

16

Atmospheric cooling

Through the uplift of warm air
- convectional rainfall
- relief rainfall
- cyclonic rainfall

17

Relief (Orographic) precipitation

- warm, moist air is forced to rise over high areas
- air cools, forming clouds
- air descends, warms and becomes drier
- note rain shadow region at leeward side

18

Storage gauge measurement

- measures total depth of rain
- manually read, often daily
- maintained as check gauge

19

Tipping bucket measurement

- measures rain intensity over time
- records time of bucket tip
- electronically logged or telemetered

20

Measurement accuracy

- spatial variability
- evaporation (loss)
- splash from surroundings (gain)
- wind turbulence (loss

21

Pathways through vegetation

- interception
- stemflow
- through-flow and canopy drip
- infiltration