Why does the percentage of water vapor vary

What percentage of water vapor is found in the air? Chemistry Solutions Percent Concentration. Mar 5, It may vary from 0 to Explanation: The psychrometric chart is the document used to find the particular amount of water in the air under particular conditions. Water vapor moves heat from the equator toward the poles, distributing heat across the globe.

Heat absorbed by water molecules provides the energy for evaporation. That water vapor rises into the atmosphere, carrying the heat up into the atmosphere. As the water vapor rises, it eventually reaches levels where the atmosphere is less dense and the air colder. As the heat energy of the water vapor is lost to the surrounding colder air, the water vapor condenses.

When enough water vapor condenses, clouds form. Clouds reflect sunlight, helping cool the Earth's surface. Karen earned her Bachelor of Science in geology. She worked as a geologist for ten years before returning to school to earn her multiple subject teaching credential. Karen taught middle school science for over two decades, earning her Master of Arts in Science Education emphasis in geosciences along the way. What Does a Hygrometer Measure? Types of Hygrometers.

How to Calculate a Mixing Ratio. How to Read a Sling Psychrometer. How to Make a Galilean Thermometer. How to Convert hPa to Altitude. Water evaporates from the Earth's surface and rises on warm updrafts into the atmosphere. It condenses into clouds, is blown by the wind, and then falls back to the Earth as rain or snow. This cycle is one important way that heat and energy are transferred from the surface of the Earth to the atmosphere, and transported from one place to another on our planet.

Water vapor is also the most important greenhouse gas in the atmosphere. Heat radiated from Earth's surface is absorbed by water vapor molecules in the lower atmosphere. The water vapor molecules, in turn, radiate heat in all directions. Some of the heat returns to the Earth's surface. Thus, water vapor is a second source of warmth in addition to sunlight at the Earth's surface. There is also a possibility that adding more water vapor to the atmosphere could produce a negative feedback effect.

This could happen if more water vapor leads to more cloud formation. If the amount of solar warming decreases, then the temperature of the Earth would decrease. In that case, the effect of adding more water vapor would be cooling rather than warming. But cloud cover does mean more condensed water in the atmosphere, making for a stronger greenhouse effect than non-condensed water vapor alone — it is warmer on a cloudy winter day than on a clear one. Thus the possible positive and negative feedbacks associated with increased water vapor and cloud formation can cancel one another out and complicate matters.

The actual balance between them is an active area of climate science research. Careers Launch and grow your career with career services and resources.