17.4.4. Empirical Formulas

Try these first

1. 1.

   What is Meyer’s Formula?

   Hint

   Think about how wind and vapor pressures are used in the formula.

2. 2.

   What two variables are needed for Rohwer’s Equation?

   Hint

   Consider which variables influence the evaporation rate.

3. 3.

   What does Meyer’s Formula primarily estimate?

   • Soil moisture
   • Evaporation
   • Temperature

   Hint

   Think about evaporation processes and their mathematical representations.

4. 4.

   True or False: Rohwer’s Equation does not include temperature in its formulation.

   • True
   • False

   Hint

   Consider how temperature relates to evaporation.

5. 5.

   Using Meyer’s Formula, if you know that es = 20 kPa, ea = 10 kPa, and wind speed at 9m is 2 m/s, what is the estimated evaporation? (Assume K = 0.36)

   Hint

   Break down the formula step by step.

6. 6.

   In an area with 10 daylight hours and an average monthly temperature of 30°C, apply the Blaney-Criddle method to estimate evaporation.

   Hint

   Calculate p based on an understanding of annual daylight hours.