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Posts tagged Cloud Streets

Thick Dust Blowing Over Cape Verde Islands – February 9th, 2012

16.0N 24W

February 9th, 2012 Category: Dust Storms, Image of the day

Dust Over Cape Verde - February 7th, 2012

Dust from the Sahara Desert blows off the west coast of Africa and over the Cape Verde Islands. The dust is so thick that it obscures several of the islands, although some interesting cloud patterns are visible through the veil of dust as it thins out.

These patterns are cloud vortex streets, also known as von Karman vortices. They are roughly symmetrical patterns of swirls created by low-level winds rushing over the Cape Verde Islands. As a prevailing wind encounters the island, the disturbance in the flow propagates downstream of the island in the form of a double row of vortices which alternate their direction of rotation.

Cloud Streets Behind Cape Verde Islands – January 30th, 2012

16.0N 24W

January 30th, 2012 Category: Clouds, Image of the day

Cape Verde - January 19th, 2012

The roughly symmetrical patterns of swirls and curves in the clouds in this image are cloud vortex streets, also known as von Karman vortices. They were created by low-level winds rushing over the Cape Verde Islands off the coast of northwestern Africa.

Von Karman vortices form nearly everywhere that fluid flow is disturbed by an object. In this image, the “object” that is disturbing the fluid flow is the group of Cape Verde islands. As a prevailing wind encounters the island, the disturbance in the flow propagates downstream of the island in the form of a double row of vortices which alternate their direction of rotation.

Cloud Streets Over Gulf of Mexico – November 6th, 2011

27.3N 94.3W

November 6th, 2011 Category: Clouds, Image of the day

Mexico - October 29th, 2011

This image shows clouds streets over the Gulf of Mexico, by the coasts of Lousiana, Texas and Mexico (counter-clockwise from upper right). Cloud streets are bands or lines of cumulus cloud that are oriented almost parallel to the low-level wind direction (with a slight angle of about 10 to 20 degrees to the left).

They usually form within the lower one to three kilometers of the atmosphere known as the planetary boundary layer and are caused by convection when the wind direction is relatively constant with height.

Multiple sources of thermals and a constant wind speed often give rise to a series of longitudinal roll vortices visible as cloud streets. This effect may be accentuated when a temperature inversion is capping the convection. The space between the cloud streets (the non-cloud streets) is about two or three times the depth of the convective layer.

Usually cloud streets have a well defined start point often following coast lines, but the end points tend to tail off as the air moves away from the source of convection. Cloud streets may from over seas as relatively cool air streams over relatively warm water, as is the case in this image, or they may be form over land as relatively unstable air streams over an obstacle and convection is caused by friction or shear.

Cloud Streets Over Lake Superior, Canada and USA

48.7N 87.6W

January 21st, 2011 Category: Clouds, Lakes

USA and Canada - January 21st, 2011

The dark blue line curving across this image is the northern shoreline of Lake Superior, bounded to the north and northeast by the Canadian province of Ontario, to the northwest by the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan.

The rest of the lake appears crossed by parallel white lines that gradually curve from the north to the southeast. These lines are cloud streets: long rolls of counter-rotating air that are oriented approximately parallel to the ground in the planetary boundary layer.

Also visible in the image is Lake Nipigon, in the upper left quadrant. Its surface is frozen and thus appears solid white. The lake drains into the Nipigon River and thence into Nipigon Bay of Lake Superior.

Oil Continues to Gush in Gulf of Mexico, Endangering Marine Life

29.0N 88.5W

May 11th, 2010 Category: Environmental Disasters

Oil Spill, Gulf of Mexico - May 7th, 2010

Oil Spill, Gulf of Mexico - May 7th, 2010

Cloud Streets Near Spill - May 8th, 2010

Cloud Streets Near Spill - May 8th, 2010

Oil Spill Highlighted by Sun Glint - May 8th, 2010

Oil Spill Highlighted by Sun Glint - May 8th, 2010

Radar Image of the Oil Spill - May 9th, 2010

Radar Image of the Oil Spill - May 9th, 2010

May 11th is the 22nd day of a Gulf of Mexico oil spill that began with an explosion and fire on April 20 on the drilling rig Deepwater Horizon, owned by Transocean Ltd. and leased by BP PLC, which is in charge of cleanup and containment of the environmental disaster. The blast killed 11 workers.

Since then, oil has been pouring into the Gulf from a blown-out undersea well at about 210,000 gallons per day. At least 4 million gallons of oil have spilled since the explosion on the Deepwater Horizon. At that pace, the spill will surpass the 11 million gallons spilled in the Exxon Valdez disaster by Father’s Day.

The spill can be seen in the bottom right corner of the main image thumbnail, taken on May 7th, although it is best viewed by opening the full version due to the slight difference in color between the black oil and the navy blue gulf waters making it difficult to discern. Easier to see is the city of New Orleans to the northwest. However, the spill is easily spotted in the May 8th image details due to sun glint, causing it to appear much lighter than the surrounding waters. These images also show several parallel lines of clouds, an atmospheric phenomenon known as cloud streets, in the skies near the spill.

Top hats and junk shots are on the list of possible next steps to contain the gusher as BP, casting about after a 100-ton containment box failed, settles in for a long fight to stop its uncontrolled oil gusher a mile under the Gulf of Mexico. Engineers at BP PLC were wrestling with a shopping list of ways to plug the well or siphon off the spewing crude, including a smaller containment box, dubbed a top hat, and injecting debris into the well as a stopper, called a junk shot.

Helicopters dropped large sandbags in Louisiana to try to protect the Lafourche Parish marshes from the massive oil slick. The spill began creeping farther west of the Mississippi River last week. About 300, one-ton sandbags were expected to be used as a makeshift boom to protect the coast.

Battered by hurricanes, weakened by erosion and flood-control projects, the sprawling wetlands that nurture Gulf of Mexico marine life and buffer coastal sites from storm surges now face another stern test as a monster oil slick creeps ever closer. About 40 percent of the nation’s coastal wetlands are clumped along southern Louisiana, directly in the path of oil that was still gushing Monday from a ruptured underwater well. Roughly 4 million gallons have escaped in the three weeks since the oil rig explosion, and some is bearing down on the marshes as workers rush to lay protective boom.

BP  said Monday the spill has cost it $350 million so far for immediate response, containment efforts, commitments to the Gulf Coast states, as well as settlements and federal costs. The company did not speculate on the final bill, which most analysts expect to run into tens of billions of dollars.

Early finger-pointing began among companies involved in the oil rig explosion on the eve of the first congressional hearings into the accident. A top American executive for BP, Lamar McKay, said a critical safety device known as a blowout-preventer failed catastrophically. Separately, the owner of the rig off Louisiana’s coast said that BP managed it and was responsible for all work conducted at the site. A third company defended work that it performed on the deepwater oil well as “accepted industry practice” prior to last month’s explosion.

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