Image: Aqua satellite captures striking cloud towers

Dec 12, 2013
Credit: NASA

(Phys.org) —In a view from high altitude, height can be a difficult thing to gauge. The highest of clouds can appear to sit on a flat plane, as if they were at the same elevation as the ocean or land surface. In this image, however, texture, shape and shadows lend definition to mushrooming thunderheads over the Indonesian island of Flores. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite acquired this image on the afternoon of Dec. 2, 2013.

The towering clouds are so well defined that it is easy to visualize the rapidly rising air that is fueling them. "This looks like a classic example of island convection that is enhanced by topography," says NASA scientist Joseph Munchak.

During the day, sunlight heats the land more quickly than it heats the ocean. The warm air over land rises, creating an area of low pressure that pulls in cool air from the ocean. The result is a sea breeze. On this Indonesia island, the sea breeze from the Flores Sea on the north blows inland and clashes with the sea breeze blowing inland from the Savu Sea in the south. When the two breezes meet in the center of Flores, they push the air up. The rising air cools and condenses into a line of clouds.

Sea breeze convection is not the only force at work here. On Flores, cloud formation has help from the shape of the land. A line of tall volcanoes runs down the spine of the island, and their steep slopes also force air to rise. So, moist ocean air blows inland, hits the mountains and volcanoes and rises with the slope. Above the mountains, the rising air meets the rising sea breeze from the other side, and the upward motion is reinforced.

The combination of the two forces pushes high into the atmosphere, resulting in large towering clouds of the sort that usually produce thunderstorms. In fact, a weather station on Flores reported rain and thunderstorms on December 2. This type of convection is strongest in the early afternoon, says Munchak, just about the time when Aqua MODIS acquired the image. The clouds were just beginning to form when Terra MODIS passed over earlier in the day.

Explore further: NASA sees Tropical Storm Francisco becoming extra-tropical

add to favorites email to friend print save as pdf

Related Stories

Image: Cloud streets over the Bering Sea

Jul 30, 2013

In early April 2013, clouds stretched in parallel rows for hundreds of kilometers over the Bering Sea. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this natural-color ...

Clouds over the southern Indian Ocean

Mar 20, 2013

(Phys.org) —Marine stratocumulus clouds stretched across the southern Indian Ocean in early March 2013. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite acquired this natural-color ...

Recommended for you

Canada to push Arctic claim in Europe

2 hours ago

Canada's top diplomat will discuss the Arctic with his Scandinavian counterparts in Denmark and Norway next week, it was announced Thursday, a trip that will raise suspicions in Russia.

Severe drought is causing the western US to rise

8 hours ago

The severe drought gripping the western United States in recent years is changing the landscape well beyond localized effects of water restrictions and browning lawns. Scientists at Scripps Institution of ...

A NASA satellite double-take at Hurricane Lowell

8 hours ago

Lowell is now a large hurricane in the Eastern Pacific and NASA's Aqua and Terra satellites double-teamed it to provide infrared and radar data to scientists. Lowell strengthened into a hurricane during the ...

User comments : 0