water and carbon -processes driving change in the water cycle

Question 1

what are the 6 flows that drive change in the water cycle?

Answer 1

.evapotranspiration
.condensation
.precipitation
.cloud formation
.cryospheric processes
.runoff generation

Question 2

what is evapotranspiration?

Answer 2

.the transfer of water from liquid to gas
.it can occur from open water or from wet surfaces
.water is also lost from the surface when water vapour is transpired by vegetation

Question 3

what does evaporation rates depend on?

Answer 3

.the amount of solar energy
.the availability of water
.the humidity of the air - the closer the air is to saturation point, the slower the rate of evaporation
.the temperature of the air - warmer air can hold more water vapour than cold air

Question 4

what is condensation?

Answer 4

.as warm air cools it holds less water vapour
.if air is cooled sufficiently then it will get to a temperature at which it becomes saturated -it cant hold any more water -this is the dew point temperature

Question 5

what is needed for water to condense?

Answer 5

.condensation nuclei -tiny particles (smoke, salt, dust etc.) or surfaces (leaves, grass stems, windows etc.) that are below the dew point temperature

Question 6

what is precipitation?

Answer 6

.atmospheric moisture is returned to the terrestrial system through precipitation

Question 7

what is the direct cause of precipitation?

Answer 7

.condensation is the direct cause of all forms of precipitation

Question 8

how does precipitation form?

Answer 8

.it takes place when the temperature of air is reduced to dew point but the volume remains constant -this occurs when warm moist air passes over a cold surface
.it can also occur when the volume of air increases but there is no addition of heat (adiabatic cooling)

Question 9

what is cloud formation?

Answer 9

.clouds form when evaporated water condenses onto a condensation nuclei -the more condensation nuclei in the air, the more clouds there will be

Question 10

what is needed for clouds to form?

Answer 10

.high temperatures are needed for water to evaporate and rise and global atmospheric circulation is also responsible for cloud formation

Question 11

how do cryospheric processes drive change in the water cycle?

Answer 11

.during the last major glacial period sea level was 120m lower -this caused an interruption in the water cycle .accumulation is higher than ablation, so water is removed from the atmosphere and stored in the cryosphere
.there were also interglacial periods when global ablation exceeded accumulation (more melting than freezing)

Question 12

what is runoff generation?

Answer 12

.runoff is the atmospheric moisture that is transferred to the oceans on the surface or as groundwater flow

Question 13

how does runoff generation drive change in the water cycle?

Answer 13

.runoff generation will differ in magnitude spatially and temporally