Honeycomb clouds develop from atmospheric convection, which is air movement caused by warm air rising and cold air falling.The white parts of the honeycomb clouds reflect sunshine back into space, but the open spaces let energy through to warm up the planet.
This classic form of convection can be seen between two horizontal, flat plates separated by a thin liquid layer: Heat up the bottom and warm liquid rises, pushing cold liquid near the top downward. The updrafts and downdrafts mold the liquid into vertical walls. If the bottom heats uniformly, the flow causes the top surface to break up into hexagonal cells, looking like a honeycomb. A honeycomb structure, it turns out, is one of the most effective way to transfer heat.
This occurs on a large scale in our atmosphere from the surface up to a couple kilometers (less than two miles). But the earth’s ocean is not a uniform surface and it doesn’t warm the atmosphere evenly from below. That’s one reason why open-cell clouds do not organize into perfect hexagons.
Though the open-cell clouds always looked like a honeycomb, the individual cells deformed and reformed over a couple hours. To determine why they changed in this way, the team took the open-cell clouds and examined air flow and rain along the cell walls.
Strong updrafts coincided with the presence of the thick vertical walls, the scientists found. Over time, however, these regions accumulated enough water to rain, which caused downdrafts. When adjacent downdrafts approached the ocean surface, they flowed outward and collided — air converged and formed new updrafts. The air in the downdrafts cooled off initially by evaporation of raindrops, but warmed up again near the ocean, starting the updraft cycle again but shifted over in space.
This cycling of falling rain, downdrafts and updrafts caused cloud walls and their cells to disappear but reappear somewhere else in the field. The honeycomb-structure of the clouds remained, but cells shifted in space. The authors call these shifts oscillations in open cells.
image source : uwgb
content : science daily