Clouds From Space

The Earth is a cradle of the mind, but we cannot live forever in a cradle. - Konstantin E. Tsiolkovsky


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Shuttle astronauts are clearly fascinated by the topside view of Earth's atmospheric patterns that space flight provides, since every space shuttle crew takes a significant number of photographs of clouds. In the past two years, interest in clouds has increased considerably as scientists attempt to understand global warming and the greenhouse effect. Efforts to predict climatic changes associated with global warming have focused new attention on the warming and cooling properties of clouds. The picture is a complex one, involving competing feedback mechanisms, and is not fully understood at this time. All clouds block some fraction of the incoming solar radiation, and absorb some fraction of the heat radiated back from the Earth's surface, and the balance between these two processes is hard to quantify. However, contemporary thinking suggests that the lower altitude cumulus clouds (such as pictures Thunderstorms, Brazil and Cumulus Cloud Tops) have a net cooling effect on Earth's surface, reflecting heat back to space. Conversely, the higher, thin cirrus clouds (such as pictures Jet Stream Cirrus and Jet Stream Cirrus, Saudi Arabia) trap heat, reflecting it back to the surface of Earth.

Current data suggest that the cooling effects of great masses of cumulus storm clouds over the ocean at mid latitudes outweigh the heating effects of the upper-level cirrus clouds when considered on a global scale. Nevertheless, there is cause for concern because many models of global warming predict a decline in heavy mid-latitude cumulus storm clouds in the future. The amount of high-level cirrus cloud is predicted to rise as the cumulus decreases. If environmental and climatic changes result in altered weather and atmospheric patterns that adhere to these models, such changes will in turn induce accelerated global warming.


Images of Clouds From Space

Jet Stream Cirrus (GIF, 166K)
This photograph taken from about 320 kilometers (200 miles) above the Earth shows a band of cirrus clouds produced by a westerly jet stream that stretches across the Red Sea from Sudan to Saudi Arabia. The contained uniformity of the cloud formation reflects the narrow track of the jet stream moving from left to right across the frame. The shuttle photo shows that the cloud band comprises a series of distinct and precisely spaced roll clouds. These are created by a rolling motion in the upper level air current. (Courtesy LPI/NASA. Picture #13-32-1099)

Florida Squall Line (GIF, 201K)
The shuttle crew approached this storm system from its southern margin in the Gulf of Mexico. The margins are clearly defined. The clouds in the storm system rise to about 16,500 meters (55,000 feet). April squall lines of this type are often associated with tornado development across the southeastern states. (Courtesy LPI/NASA. Picture #13-40-2130)

Thunderstorms, Brazil (GIF, 217K)
These cumulus thunderheads near São Paulo, Brazil, where photographed from almost directly overhead by the STS 41-B crew. This perspective conveys something of the energy that drives these cloud columns to punch up into the atmosphere. The foreshortening resulting from the near-vertical viewing angle disguises the fact that the cloudheads so prominently in view are but the tops of massive thunderhead storm clouds that can tower up to 18,000 meters (60,000 feet) in the tropics. (Courtesy LPI/NASA. Picture #11-41-2343)

Cumulus Cloud Tops (GIF, 240K)
The STS 41-B crew shot this oblique photograph just moments after the previous picture was taken. Some more fully developed thunderheads can be seen in the same Brazilian storm. When the rising cumulus columns meet the tropopause, or base of the stratosphere, at about 15,000 kilometers (50,000 feet), they reach a ceiling and can no longer rise buoyantly by convection. The stable temperature of the stratosphere suppresses further adiabatic ascent of moisture that has been driven through the troposphere by the 5-6.8 degree/kilometer (8-11 degree/mile) lapse rate. Instead, ice clouds spread horizontally into the extended cirrus heads seen in this photograph, forming the "anvil heads" that we identify from the ground. The finer, feathery development around the edges of some of the thunderheads is glaciation - water vapor in the cloud is turning to ice at high altitude. (Courtesy LPI/NASA. Picture #11-41-2347)

Cloud Margin, Bering Sea (GIF, 169K)
All that can be seen in this photograph is cloud stretching several hundred kilometers to the limb of the Earth, yet it tells us a great deal about the water in the Bering Sea below. The line or cloud margin running diagonally across the frame with dense, thick cloud to the right and lighter, more broken cloud to the left reflects an ocean current margin. A difference in water temperature on either side of the margin is reflected in the cloud forms condensing above. This striking cloud boundary stretches for 800-960 kilometers (500-600 miles) in this photograph. (Courtesy LPI/NASA. Picture #17-41-058)

Coastal Current, Namibia (GIF, 233K)
Condensing moisture from ocean currents in some parts of the world creates clouds that stay uniformly in position above that current for months at a time. This example shows clouds hanging above the cold Benguela current, which travels northward along the Atlantic coast of southwestern Africa. It is interesting that while the ocean is densely cloud-covered and the clouds lap at the coast, they never cross the coastline. The pinkish-colored Namib Desert is one of the driest places on Earth, confirming that the cloud associated with the ocean current does not stry off its prescribed track. Indeed the Namib Desert is home to unique inhabitants - insects with leg hairs especially adapted to collect moisture from morning dew - a strange irony of life on Earth where moisture-laden clouds hang so close by. (Courtesy LPI/NASA. Picture #25-46-076)

Unique Cloud Lanes, Oman (GIF, 268K)
These wispy rows of cloud or "cloud lanes" are recognized as a "landmark" by successive shuttle crews. This unique cloud formation off Oman is virtually constant at certain times of year. The clouds are created by a small vortex in the low level wind current. There is little difference between the ocean and atmosphere temperatures here, but the air current may have been subjected to heating from the Somali Current. (Courtesy LPI/NASA. Picture #2-10-649)

Jet stream Cirrus, Saudi Arabia (GIF, 263K)
This series of cirrus clouds is know as "roll clouds" because they are sculpted into tight rolls by air currents from the jet stream over Saudi Arabia and the Red Sea. The crest-to-crest spacing of the cloud bands can be used to calculate the velocity of the jet stream. (Courtesy LPI/NASA. Picture #13-32-1159)

Jet Stream Convergence (GIF, 233K)
This photograph taken over Namibia reveals another effect of jet streams. Here two streams converge; cloud has formed in the corridor between the two streams. Turbulence along the margins of the jet stream may explain the sharp boundary. The point of convergence of the two air streams is precisely located by this photograph. Shadows mark the cloud edges against a sunlit Namibian backdrop. (Courtesy LPI/NASA. Picture #13-31-092)

Cloud Streets, Tiladumati Atoll, Maldive Islands (GIF, 275K)
Small cumulus clouds frequently form in parallel rows or "cloud streets" in stable air conditions. These cloud streets over the reefs of the Maldive Islands in the Indian Ocean denote the prevailing wind direction, the cloud streets lying parallel with the wind. Turbulent air lifted by the windward portions of the islands promotes cloud formation downwind. (Courtesy LPI/NASA. Picture #13-35-1459)

Island Wake, Hawaii (GIF, 251K)
The combination of warm water temperature and hundreds of square miles of ocean, uninterrupted by land masses, results in a regular cumulus and stratocumulus cloud formation. In the Pacific Ocean the Trade Winds propel the clouds from east to west across the ocean. When the air current is intercepted by a sufficiently high land mass, such as the Big Island of Hawaii, the stable cloud pattern is interrupted and the clouds divide to bypass the island in a wide arc forming an "island wake." In addition to illustrating how gracefully the clouds circumnavigate Hawaii's volcanic peaks, the photograph shows how the prevailing wind direction dictates that the north and northeast of the island are wetter than the western side of the island and frequently under cloud. The clouds deposit rain on the low ground before dividing and spinning out to sea when they meet the Kohala Mountains and Mauna Kea with its summit at 4,205 meters (13,796 feet). (Courtesy LPI/NASA. Picture #25-47-016)

Cloud Tail, Lake Tana (GIF, 236K)
Islands or high land, elevated above the surroundings and interrupting the air stream, can produce "tails" as well as "wakes." Shuttle astronauts have frequently observed Dek Island in Lake Tana in Ethiopia, the source of the Blue Nile, with a well-developed cloud tail. This occurs when the land mass disrupts the air flow, creating downwind turbulence that promotes condensation. The lake stands at 1,800 meters (6,000 feet) above sea level. (Courtesy LPI/NASA. Picture #27-38-003)

Open Cells over Ocean (GIF, 283K)
Open cell formations like this are frequently found over ocean. The cells are denser to the left of the frame than to the right, suggesting a gradual warming in water temperature. By looking at this photograph and studying the water color and cloud density, an expert could tell you which ocean you are looking at, the time of year, and the temperature of the water below. This picture was taken in the Indian Ocean, north of Australia. (Courtesy LPI/NASA. Picture #11-37-1875)

Anticyclonic Clouds (GIF, 277K)
This pinwheel of anticyclonic clouds was photographed by the STS 41-B crew over the southern hemisphere of the Pacific Ocean. The ground winds at the center of this cyclonic system reach 80 kilometers per second (50 miles an hour). Circular storms in the northern hemisphere produce spiraling clouds with a clockwise pattern, while southern latitude storms have a counterclockwise cloud motion. (Courtesy LPI/NASA. Picture #11-45-2834)

Eye of Hurricane Kamysi (GIF, 185K)
During the Solar Maximum Satellite Repair Mission, astronauts had an excellent opportunity to look down the eye of Hurricane Kamysi over the Indian Ocean. Clear blue water can be seen through the hurricane's eye, and the crew reported that they could see the ocean wave below. Unfortunately, the camera film could not pick them out. (Courtesy LPI/NASA. Picture #13-35-1499)

Typhoon Odessa (GIF, 272K)
Odessa is one of the strongest circular storm patterns seen by shuttle crews to date and has a superb tightly formed eye. The tighter the eye in a circular storm, the stronger the winds underneath. Mission STS 51-1 came to be known as the mission of all the hurricanes, tracking no less than four circular storms around the globe. Live pictures from Discovery of Hurricane Elena in the Gulf of Mexico were transmitted directly from Mission Control in Houston to the National Hurricane Center in Florida for correlation with conventional weather satellite and high level aircraft data. (Courtesy LPI/NASA. Picture #27-35-077)

Sunrise (GIF, 105K)
Space shuttle crews see a sunrise or sunset every 45 minutes as they circle the Earth at 27,300 kilometers (17,000 miles) per hour, crossing the surface at 6.4 kilometers (4 miles) per second. From their unique perspective they see clearly defined bands of color through the atmosphere as the sun rises. High-peaking cumulus clouds, topping out in anvil-head cirrus can be seen as black shadows against the sunlit horizon. The brightness of the colors in the atmosphere in this photograph taken over the South China Sea is due to concentrations of dust in the atmosphere. Greater concentrations of dust are found in equatorial regions. There are various sources for such upper level dust. Many dust storms in Africa, intensified by several years of drought, have been responsible for putting large amounts of dust into the atmosphere in recent times. Ash clouds from major volcanic eruptions can have a similar effect. Recent discussion of the climatic and environmental effects of a "nuclear winter" centering on upper atmosphere pollution has drawn from the atmospheric effects of catastrophic volcanic eruptions (Courtesy LPI/NASA. Picture #14-32-014)

Weather System Margin (GIF, 244K)
The Discovery crew photographed this very distinct stripe running through the clouds for several hundred miles. Two weather systems are sliding past each other like crustal plates on the Earth's surface. The one at the top of the photograph (geographical north) is moving up and curing away slightly to the north, while the system at the bottom of the frame is moving westward and curving gently to the south in conjunction with a cyclone located several hundred miles away. The miniature cold-water gyres on the fringes of the two weather systems indicate that a channel of colder water runs under the break in the clouds and is reflected above where colder air runs between the two cloud masses. (Courtesy LPI/NASA. Picture #25-31-011)



This material was abstracted from the slide set:

Jones, Pat. Shuttle Views the Earth - Clouds from Space. Planetary Image Center/Lunar & Planetary Institute.




Calvin J. Hamilton