21.2. Penman Method

Try these first

1. 1.

   What does ET stand for?

   Hint

   It combines two processes.

2. 2.

   Name one advantage of the Penman Method.

   Hint

   Think about its basis in physical principles.

3. 3.

   What does the Penman Method estimate?

   • Actual Evapotranspiration
   • Potential Evapotranspiration
   • Neither

   Hint

   Think about the water availability scenario.

4. 4.

   The albedo value of a surface affects what?

   • True
   • False

   Hint

   Consider the reflectivity of surfaces.

5. 5.

   Given the following data: Incoming solar radiation (Rs) = 20 MJ/m²/day, Albedo (α) = 0.2, Outgoing longwave radiation (Rnl) = 6 MJ/m²/day. Calculate the net radiation (Rn).

   Hint

   Use the formula discussed and plug in the values correctly.

6. 6.

   If a region has an average temperature of 25°C and a wind speed of 3 m/s, discuss how these factors would influence the accuracy of the Penman Method in that region.

   Hint

   Consider all factors from the equation and how they interrelate.