Evaporation and Transpiration Questions and Answers

Answer: A

The formula using only temperature and day length is the Blaney Criddle formula.

The Blaney-Criddle method estimates consumptive use from the mean monthly temperature and the percentage of annual daytime hours in the month, multiplied by a crop coefficient. It needs only these two climatic inputs, which made it popular where data are scarce.

The Penman method combines energy balance and aerodynamic terms and needs radiation, humidity and wind speed as well. The Christiansen formula uses several climatic factors, including radiation or pan evaporation, humidity and wind.

Answer: C

A lysimeter is used to measure Evapotranspiration.

A lysimeter is a tank of soil with growing vegetation, set in the field so that its conditions match the surroundings. By measuring the water added (rain and irrigation) and the water draining out, and weighing the tank, the water lost by evaporation and transpiration is found.

Humidity is measured with a hygrometer or psychrometer, infiltration with an infiltrometer, and wind speed with an anemometer.

Answer: A

The process is Evaporation.

Evaporation turns liquid water into vapour, and it takes place from open water surfaces (oceans, lakes, rivers, reservoirs) as well as from moist land and soil surfaces, which is exactly what the question describes.

Transpiration is loss of water through plant leaves, not from water or bare land surfaces. Precipitation falls from the atmosphere, and runoff flows over the land; neither occurs 'from' a water surface.