What is Evaporation?
Evaporation is the process in which liquid changes into a gaseous state at boiling point is known as evaporation.Evaporation is one of the processes in the hydrologic cycle.In this article, we are going to learn about factors affecting evaporation losses.
This cycle causes evaporation losses.The hydrological cycle consists of precipitation, evaporation, infiltration, condensation etc…
According Daltons law
- V=wind velocity in km/hr
- Es=Saturation vapour pressure at the water surface
- Ea=Actual vapour pressure.
Factors Affecting Evaporation losses
The main factor affecting evaporation losses is due to solar radiation.Solar radiation is directly proportional to the rate of evaporation
2.Surface area of water
Greater the surface area more evaporation loss.The evaporation loss is directly proportional to the surface area of water.
3.Nature of soil
In wet soil evaporation is faster, the evaporation is more for black cotton soils than red soils.
4.Depth of water
As the depth of water in the catchment increases the rate of evaporation is lesser.Because the surface temperature is much lesser.As the depth increases, the heat from the solar radiation will transmit downwards(from the surface to the bottom of the water body).Thus the surface temperature is lesser and also evaporation loss will be lesser.
The evaporation rate of summer will be lesser than the winter due to the additional heat energy available, which is stored during the summer in deep waters.
Ad the humidity increases the evaporation loss will decrease, because of the excess water molecules present in the air.
Evaporation loss is directly proportional to the wind velocity.
7.Temperature of air
As the temperature of air increases the rate of evaporation increases.
Evaporation happens when the atmospheric pressure is more than the saturation pressure of water vapour molecules just above the water body.
- Ps>Pa – Evaporation happens
- Ps<Pa-Water molecules return to a water body
The last factor affecting evaporation loss is due to the presence of salts in water.The presence of dissolved salts present in the water decreases the evaporation.Thus sea water has lesser evaporation losses than the pure water at same conditions.