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Question 1

The water balance of a mountain lake is given as:
E = P + Q_i - Q_o + ΔS/Δt

E = monthly evaporation from the lake
P = monthly precipitation on the lake
Q_i = the monthly water inflow to the lake
Q_o = the monthly water outflow from the lake
ΔS/Δt = the monthly change in water storage in the lake; ΔS is positive if the storage increases; ΔS is negative if the storage decreases.
All variable values are in mm month^-1.
In April the water level in the lake increases; in August the water level in the lake decreases.
The water balance equation E = P + Q_i - Q_o + ΔS/Δt is

a) incorrect for both months.

b) only correct for the month of April (incorrect for the month of August).

c) only correct for the month of August (incorrect for the month of April).

d) correct for both months.

Question 2

The average precipitation over the globe is estimated as 1000 mm per year, and the amount of water vapour in the earth's atmosphere is estimated to equal a liquid water layer of 25 mm. The average residence time of water vapour in the earth's atmosphere in days therefore equals

a) 40

b) 14

c) 9

d) 3

Question 3

The persistence of either wet or dry conditions on a multi-year timescale, such as the multi-year droughts in the Sahel region of Africa, is due to a

a) positive feedback mechanism; the Bergeron-Findeisen process is a negative feedback mechanism.

b) negative feedback mechanism; the Bergeron-Findeisen process is a positive feedback mechanism.

c) positive feedback mechanism; the Bergeron-Findeisen process is a positive feedback mechanism.

d) negative feedback mechanism; the Bergeron-Findeisen process is a negative feedback mechanism.

Question 4

The Coriolis effect is related to

a) the earth's rotation.

b) the process of cooling of ascending air.

c) infiltration and percolation in the unsaturated zone.

d) the existing hydrostatic pressure at the water table.

Question 5

When the relative humidity of the air is

a) very low, the open-water evaporation in mm(!) from a small evaporation pan is significantly less than the open-water evaporation from a large lake.

b) very low, the open-water evaporation in mm(!) from a small evaporation pan is significantly more than the open-water evaporation from a large lake.

c) very high, the open-water evaporation in mm(!) from a small evaporation pan is significantly less than the open-water evaporation from a large lake.

d) very high, the open-water evaporation in mm(!) from a small evaporation pan is significantly more than the open-water evaporation from a large lake.

Question 6

The albedo gives the fraction of

a) short wave radiation that is absorbed by the earth's surface.

b) long wave radiation that is absorbed by the earth's atmosphere.

c) short wave radiation that is reflected by the earth's surface.

d) long wave radiation that is reflected by the earth's atmosphere.

Question 7

The latent heat flux density (latent heat transfer) is the energy per unit area and time (MJ m^-2 day^-1) used for

a) evaporation.

b) heating the air at the earth's surface.

c) heating the soil.

d) heating both the soil and the air at the earth's surface.

Question 8

The open-water evaporation increases when the saturation deficit

a) increases and the wind speed increases.

b) increases and the wind speed decreases.

c) decreases and the wind speed increases.

d) decreases and the wind speed decreases.

Question 9

The aerodynamic resistance determines the rate of

a) transpiration.

b) drainage.

c) discharge.

d) interception loss.

Oxford University Press, Online Resource Centre, Chapter 2.

Chapter 2

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