Evaporation measurements

Question 1

What controls the net evaporation rate?

Answer 1

vapour pressure deficit
availability of water
turbulence
available energy

Question 2

What is a drawback of the evaporation pan?

Answer 2

edge effect- as wind blows over water surface the evaporation lessens as the vapour pressure deficit is higher at the edges, so the evaporation pan can’t work for large areas, also it can get too hot (made of metal)

Question 3

What are the benefits and drawbacks of a lysimeter?

Answer 3

it better replicates the surface of interest with vegetation, however is requires the accurate measurement of precipitation, change in storage and percolating water- tough cause errors can accumulate

Question 4

What are the benefits and drawbacks of a micromet?

Answer 4

includes aspects of turbidity and humdity and measures natural undisturbed surfaces but relies heavily on assumptions of the shape of the wind profile and works best on fkat surfaces

Question 5

What is the boundary layer?

Answer 5

is the atmospheric layer strongly connected to the surface, variation i s in the different heights of this layer causing graidents in water vapor and turbidity which result in evaporation.

Question 6

In situations with high turbulence does wind speed change with height? What about low turbulence?

Answer 6

high turbulence- wind speed doesn’t change with height
low turbulence- wind speed does