# Water evaporation, temperature, wind and heat capacity?

• Alfreds9
In summary, the conversation discusses the factors that influence water evaporation in a large pool, including wind, temperature, and water's heat capacity. The speaker mentions Penman's equation as a possible solution but is unsure if it applies to their specific example. They also express confusion about how surface water temperature affects evaporation and apologize for not having visual aids.

#### Alfreds9

Hi,

I'd like to know how I'd put together, either elegantly or at least in physical terms, that surely water evaporation in a large pool of V volume and S surface is influenced by wind (increased by it as opposed to having side barriers), temperature (increased by direct sunlight as opposed to shading due to the very same barriers shielding wind laterally) and water's heat capacity not being constant across its temperature range.

I am thinking about Penman's equation (or Shuttleworth's) fitting above needs however I am not sure if it'd still stand true for my example, since I don't fully grasp how much would superficial water heated more by sunlight than its shaded counterpart rise up the vapor pressure and hence speed up evaporation of water and also how to put that a wind side barrier would decrease the net evaporation by decreasing wind on water surface and also having sunrays hit directly water only about at zenith.

I apologize for the awful teeny drawings, I am on mobile without any graphic tablet or computer.

Thank you

Allison

You've Googled Penman's. What are the results?

Bystander said:
You've Googled Penman's. What are the results?

The results are that I unfortunately still don't see where does surface water temperature (due to high irradiation VS low irradiation) comes into play in either Penman's or Shuttleworth's formula. I am quite sure that, considering everything else equal, water at say 23°C evaporates more readily than water at say 13°C.

## 1. What is water evaporation?

Water evaporation is the process in which liquid water is converted into water vapor through the application of heat energy. This occurs when the temperature of the water reaches its boiling point and the water molecules gain enough energy to break free from their liquid state and become water vapor.

## 2. How does temperature affect water evaporation?

Temperature plays a crucial role in water evaporation. As the temperature of water increases, the water molecules gain more energy and are able to break free from their liquid state more easily, resulting in a faster rate of evaporation. On the other hand, colder temperatures slow down the movement of water molecules, leading to a slower rate of evaporation.

## 3. How does wind affect water evaporation?

Wind can greatly impact the rate of water evaporation. When wind blows over a body of water, it removes the layer of air above the water's surface, allowing for more water molecules to escape into the air. This increases the rate of evaporation as there is a constant supply of dry air to absorb the water vapor.

## 4. What is heat capacity and how does it relate to water evaporation?

Heat capacity is the amount of heat energy required to raise the temperature of a substance by a certain amount. Water has a high heat capacity, meaning it requires a large amount of heat energy to raise its temperature. This is why bodies of water are able to absorb and store heat without experiencing dramatic changes in temperature. Heat capacity also plays a role in water evaporation, as it requires a significant amount of heat energy for water to reach its boiling point and evaporate.

## 5. What factors can influence the rate of water evaporation?

Aside from temperature and wind, there are other factors that can affect the rate of water evaporation. These include humidity, air pressure, and surface area of the water. Higher humidity levels can slow down evaporation, as the air is already saturated with water vapor. Higher air pressure can also slow down the rate of evaporation, as it prevents the water molecules from escaping into the air. In terms of surface area, larger bodies of water have a higher rate of evaporation due to their increased exposure to heat and wind.