Scientists have reported during the last 6 years curious findings of water vapor at concentrations as much as twice than previously thought in and around cirrus clouds, a discovery that could change our understanding about radiation and energy exchange between atmosphere, Earth, and space.

Cirrus clouds, wispy sheets of ice crystals, are found at 6 -10 miles (10-16 km) height into the atmosphere.

"Based on our current knowledge, it (the water vapors phenomena) shouldn't exist," said Marcia Baker, a University of Washington professor of Earth and space sciences.

"Part of the problem is that many atmospheric scientists have dismissed the findings as erroneous because the current understanding of atmospheric conditions and cirrus clouds would make the water vapor anomaly impossible", Baker said.

Clouds, particular gases and aerosols (solid particles) in the atmosphere are important in regulating the Earth's temperature because they determine the atmosphere's albedo (how much of the sun's energy is reflected back into space) and they store solar radiation reflected by the Earth's surface.

Cirrus clouds are also important in the circulation of water vapors, an important greenhouse gas in the upper troposphere but the cirrus clouds themselves play no role in albedo and greenhouse effect.

"We have thought our models of the formation and evolution of cirrus clouds are generally adequate in how they portray the role of cirrus clouds in regulating water vapor, but if the recent findings are accurate and high humidities are widespread, our assumptions could need significant adjustment," Baker said.

"The point is to bring this to the more general science audience as a broad puzzle, but also to lay the groundwork for research to solve the puzzle," she stated.

Cirrus clouds form in the upper troposphere and are important in the circulation of water between the troposphere (0-10 km) and the stratosphere (10-30 km).

Vapor in the upper troposphere can rise into the stratosphere but tiny ice crystals fall back toward the surface.

Outside the clouds, there are water vapors and aerosols, but no ice crystals.

Scientists thought that new ice crystals will begin to form in aerosols when vapor levels rise to the point at which they are 60 % above equilibrium with the surrounding air.

But new measurements have shown that vapor levels can reach 90 % to 100 % above equilibrium without forming new ice particles.

Inside the clouds, it is expected that water as a gas cannot be maintained above equilibrium, yet proofs show that often, vapor levels are as much as 30 % above equilibrium in large areas of clouds.

Scientists have speculated about what causes these anomalies.

"It is possible the aerosols might have as-yet undiscovered properties that prevent crystals from forming in some conditions, or there could be some kind of coating on the aerosols that prevents ice from forming," Baker said.

Maybe undiscovered ice crystals' features prevent them from forming in some conditions.

"There could be a different phase of ice at the temperatures and pressures in cirrus clouds that has a higher equilibrium for vapor," Baker said.