Why Doesn’T The Ocean Simply Reabsorb The Water That Evaporates?
The oceans don’t necessarily need to reabsorb the water that has evaporated because they are already abundant in water.
Why doesn’t the water in the ocean evaporate?
The complete evaporation of Earth’s water is an impossibility due to the planet’s two hemispheres (north and south). When it’s summer in one hemisphere, leading to evaporation from water bodies, it’s winter in the other, allowing for water storage. Moreover, evaporation in one area is offset by rainfall in another, maintaining a stable water level in the oceans.
Climate variations across the globe mean that while some regions may be experiencing hot, dry conditions conducive to evaporation, others might be receiving rain. Hence, the water evaporated is often replenished on the Earth’s surface due to these differing climatic conditions.
Additionally, water possesses a high specific heat of vaporization. This means that even the intense summer heat is insufficient to vaporize all the water on Earth’s surface. Although a significant volume of water does evaporate from the surface of water bodies, it eventually returns to Earth as precipitation, such as rain or snowfall.
What happens when ocean water evaporates?
The surface of the ocean is in a perpetual state of activity due to wind and variations in density or buoyancy. The physical properties of the ocean naturally change with depth. As you go deeper, the temperature drops as only the surface waters are heated by the sun. The warm water, being lighter or more buoyant than cold water, remains near the surface.
However, the surface water also experiences evaporation. As seawater evaporates, water dissipates leaving behind salt, resulting in relatively salty water. Despite its increased salinity, this water can remain afloat at the surface. For instance, in tropical regions, it stays afloat due to its warmth and buoyancy.
Why isn’t water vapor that comes from the ocean salty?
Occasionally, I’m asked why rain from tropical systems isn’t salty, given that these systems originate over the ocean and draw their moisture from it.
It’s undisputed that the bulk of the moisture forming the clouds and storms in hurricanes comes from the ocean. However, understanding the exact process of how this moisture is transferred from the ocean to the atmosphere, where the clouds and eventually the rain form, is crucial.
Unlike tornadoes, which can directly pull water up into the storm, depositing the salty water elsewhere, hurricanes don’t operate in the same way. The moisture that fuels the hurricane’s clouds is solely from evaporation.
When ocean water evaporates into water vapor, a gas, the salt is left behind in the ocean.
Consequently, what remains is pure water vapor, which eventually condenses back into a cloud droplet. Therefore, any rain that falls from this would also be free of salt.
Will the ocean eventually evaporate?
The gradual natural intensification of solar luminosity, a process quite slow and unrelated to current climate warming, will lead to a rise in Earth’s temperatures over the next several hundred million years. This will eventually culminate in the total evaporation of the oceans.
A team from the Laboratoire de Météorologie Dynamique (CNRS / UPMC / ENS / École polytechnique) has constructed the first three-dimensional climate model capable of simulating this event. The model forecasts that Earth will lose its liquid water in about one billion years, extending prior estimates by hundreds of millions of years.
Published in the journal Nature on December 12, 2013, this research not only enhances our comprehension of Earth’s evolution but also helps identify the conditions required for the existence of liquid water on other planets similar to Earth.
Due to the water cycle, the ocean does not reabsorb evaporated water. Evaporation is the process where water transforms into vapor and ascends into the atmosphere, where it eventually condenses and returns as rainfall.