21.2.2. Components of Penman Equation

Try these first

1. 1.

   What is net radiation?

   Hint

   Think about how solar energy is received and lost from the surface.

2. 2.

   What does albedo refer to?

   Hint

   Consider how much sunlight a surface reflects versus absorbs.

3. 3.

   What does net radiation determine in the Penman Equation?

   • Water retention
   • Energy availability for evapotranspiration
   • Soil moisture content

   Hint

   Think about what drives evaporation processes.

4. 4.

   True or False: Albedo has no effect on the amount of solar radiation absorbed.

   • True
   • False

   Hint

   Consider how surfaces vary in reflectivity.

5. 5.

   A crop is situated in an area receiving Rs = 30 MJ/m2/day, has an albedo of 0.25, and experiences Rnl = 4 MJ/m2/day. Calculate the net radiation and discuss its implications for evapotranspiration potential.

   Hint

   How does the energy balance impact the water cycle?

6. 6.

   In a region with high wind speeds, the saturation vapor pressure is determined to be 3.5 kPa, and the actual vapor pressure is 1.8 kPa. How does this affect the aerodynamic term and thus the overall evapotranspiration?

   Hint

   Analyze the relationship between atmospheric conditions and evapotranspiration rates.