Hydrological cycle and observation

Question 1

Water movement - one location to another

Answer 1

• precipitation: rainfall/snow
  -ground
  -soil(by infiltration)
  -runoff(river flow)
  -ocean

Question 2

Water movement- phase change

Answer 2

-condensing(vapour to rain droplets)
-melting(snow to rain)
-evaporating(water to vapour)
-sublimation(vapour to ice crystal/clouds)

Question 3

Water movement- energy exchange

Answer 3

Latent heat change

Question 4

What affects water - distribution

Answer 4

-dependant on climate zones
-huge variability I’m both space and time
-climate change

Question 5

Water quality

Answer 5

-interfered with human activities
-water supply and sanitation

Question 6

Main input precipitation

Answer 6

-evapotranspiration
-ground water recharge
-(environmental) outflow

Question 7

River catchment

Answer 7

The drain area of surface water affected by the local topography and geology

Question 8

Hydrological budget

Answer 8

I - O = ds/dt

Where…
I : precipitation, inflow at the boundary
O : outflow at the boundary(evaporation, transpiration)
S: groundwater, aquifer

Question 9

Units in calcs

Answer 9

Volume = flow rate x time
Depth = volume / area

USE MM - easier to compare

Question 10

Humidity

Answer 10

Measurement of water vapour in the air

Question 11

Absolute humidity

Answer 11

The mass of the water vapour per unit volume of the moist air in kg/m3

Question 12

Specific humidity

Answer 12

The mass ratio between the water vapour and the moist air, in g/kg

Question 13

Water vapour pressure

Answer 13

Partial pressure due to the existence and the movement of water vapour molecules ( e represents )

Question 14

Saturation water vapour pressure (es)

Answer 14

An equilibrium state meaning that it can contain no more water vapour molecules

Air can contain more water vapour as temp. increases

Question 15

Relative humidity (%)

Answer 15

Ratio between absolute humidity and specific humidity
- h = e/es
-takes into account effect of temp.

Question 16

Dew point temperature (td)

Answer 16

The temperature at which the water vapour begins to condense (dew will form at certain surfaces)
-by comparing the current temperature and the dew point, we can have an idea of how humid the air is

Question 17

Wet-bulb temperature (tw)

Answer 17

The resultant temperature when vapour saturation is reached by evaporating water into the air (therefore cooled down)

Question 18

Psychometric chart

Answer 18

Shows relationship between saturated water vapour pressure and temperature

Question 19

Bowen ratio

Answer 19

A ratio of the latent heat and sensible heat during phase change

Question 20

Measurement - temperature

Answer 20

-recorded by thermometers in open boxes (1.25m above ground)
-distribution of temp. is influenced by latitude, altitude, topography and vegetation

Question 21

Measurement - radiation

Answer 21

Incoming and net radiation measured using radiometers

Question 22

Measurement - wind

Answer 22

-speed and direction measured by anemometer and wind vane
-specify height at which measurement is taken…
u/u0 = (z/z0)^0.15
where…
-u/u0 is wind speeds at height z0
-higher level z