The key difference between actual evapotranspiration and potential evapotranspiration is that actual evapotranspiration is the amount of water that is actually removed from a surface by evaporation and transpiration while potential evapotranspiration is a measure of the ability of the atmosphere to remove water from the surface through evaporation and transpiration.
Sufficient water is a key factor in crop growth and yield. Many crops are grown in environments that are naturally short of water. Hence, water resource management is an essential process in crop growth. Scientists consider both potential evapotranspiration and actual evapotranspiration for effective crop management. Actual evapotranspiration indicates the actual amount of water evaporated through the surface while potential evapotranspiration is the ability of the atmosphere to remove water from the surface by evaporation and transpiration. Potential evapotranspiration takes a higher value than the actual evapotranspiration. Hence, crop water need can be calculated by subtracting the actual evapotranspiration from the potential evapotranspiration.
CONTENTS
1. Overview and Key Difference
2. What is Actual Evapotranspiration
3. What is Potential Evapotranspiration
4. Similarities Between Actual Evapotranspiration and Potential Evapotranspiration
5. Side by Side Comparison – Actual Evapotranspiration vs Potential Evapotranspiration in Tabular Form
6. Summary
What is Actual Evapotranspiration?
Actual evapotranspiration is the quantity of water that is actually removed from a surface by the processes of evaporation and transpiration. Therefore, it explains the exchange of water and energy between soil, land surface and atmosphere. Actual evapotranspiration is difficult to measure. But it is an extremely important process in natural ecosystems. Moreover, it is a major component of the water cycle since it affects the water balance.
What is Potential Evapotranspiration?
Potential evapotranspiration is the measure of the ability of the atmosphere to remove water from the surface through both evaporation and transpiration. When measuring the potential evapotranspiration, it is assumed that there is no control in the water supply.
Figure 01: Evapotranspiration
In fact, potential evapotranspiration is a representation of the atmospheric demand for evapotranspiration, which is the sum of evaporation and transpiration. This process needs energy. The major sources of energy are sunlight and wind. Potential evapotranspiration utilizes 80% of its energy from the sun. Secondly, the process takes energy from the wind.
What are the Similarities Between Actual Evapotranspiration and Potential Evapotranspiration?
- Actual and potential evapotranspiration are two types of evapotranspiration processes.
- Scientists consider both processes for the practical purpose of water resource management.
- The crop water need can be calculated by subtracting actual evapotranspiration from the potential evapotranspiration.
- When there is an ample amount of water, actual evapotranspiration is believed to be to equal potential evapotranspiration.
- Both processes are important for the balance of water on earth.
- Sunlight and wind play major roles in both processes.
What is the Difference Between Actual Evapotranspiration and Potential Evapotranspiration?
Actual evapotranspiration is the amount of water that is actually removed from the surface by evaporation and transpiration. In contrast, potential evapotranspiration is a measure of the ability of the atmosphere to remove water from the surface by evapotranspiration when there is ample water. So, this is the key difference between actual evapotranspiration and potential evapotranspiration.
Moreover, potential evapotranspiration generally takes a higher value than actual evapotranspiration. However, when there is an ample amount of water, actual evapotranspiration is believed to be to equal potential evapotranspiration.
Below is a summary of the difference between actual evapotranspiration and potential evapotranspiration.
Summary – Actual Evapotranspiration vs Potential Evapotranspiration
Evapotranspiration is the transferring of water from the earth’s land and ocean surface to the atmosphere by evaporation and plant transpiration. Actual evapotranspiration is the actual amount of water that is removed by evaporation and transpiration. In contrast, potential evapotranspiration is the measure of the ability of the atmosphere to remove water from the surface by evaporation and transpiration when there is no control of water. Actual evapotranspiration is believed to be equal to potential evapotranspiration when there is ample water. Thus, this is the summary of the difference between actual evapotranspiration and potential evapotranspiration.
Reference:
1. “8(J) Actual And Potential Evapotranspiration”. Physicalgeography.Net, 2020, Available here.
2. “Evapotranspiration”. En.Wikipedia.Org, 2020, Available here.
Image Courtesy:
1. “Surface water cycle” By M. W. Toews – Own work (CC BY 4.0) via Commons Wikimedia