NASA Terra Satellite- Cloud Streets Off of the Aleutian Islands

Image Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team

Strong winds polished the snow of southwestern Alaska and stretched marine stratocumulus clouds into long, parallel streets in early January, 2012.

After crossing Bristol Bay, the winds scraped the clouds across the tall volcanic peaks of the Aleutian Islands.

As the wind impacted the immobile mountains, the airflow became turbulent, swirling in symmetric eddies and carving intricate patterns into the clouds on the leeward side of the islands.

At the top of this image, the bright white color indicates a thick layer of snow overlying the land of southwestern Alaska.

The pristine white is broken by the rugged Ahklun Mountain Range in the east, which is partially covered by a bank of clouds.

Off the coast of Alaska, sea ice floats in Bristol Bay, cracked and chipped by the flow of the waters which lie underneath. A few cloud streets – parallel lines of clouds – can be seen in the far northwest over land.

The clouds increase over the sea ice and become thick over open water, where row upon row of clouds lie close in perfectly parallel formation.

The Aleutian Islands stretch from northeast to southwest across the image. Sea ice, which is bright white here, lies on the windward side of the islands. A few of the tallest volcanic peaks can be seen rising from the icy islands.

The character of the cloud streets change as they impact the Aleutians, especially near the center of the image, where two rows of beautifully symmetric swirls of eddies in the clouds stretch across the sky.

These swirling formations are known as von Karman vortex streets. This true-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite on January 11, 2012.

Deep Depression over Britain

This MODIS weather satellite view of Britain, taken on 14 June 2012 at about 1.30pm, a shows a huge storm moving towards the south-west

Picture: MODIS

NASA MODIS: Snow in Europe

In early February 2012, much of Europe shivered under the effects of a “Russian Winter” - intense cold and snow triggered by a strong Siberian anticyclone which hovered over northern Russia.

The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of the snowy landscape of France and the United Kingdom on February 11, 2012.

In the coldest parts of the year, when the intense cooling of the surface layers of air over northeastern Siberia occurs, the time is right for the formation of a Siberian anticyclone.

Also called a Siberian high, it is a semi-permanent system of high atmospheric pressure centered in northeastern Siberia.

The Siberian anticyclone is one of the principal sources of polar air masses, and outbreaks of polar air westward from the high-pressure area can cause severe cold spells in the European continent.

In early February, 2012, a strong anticyclone formed over northern Russia. On February 3, Mosfiloti Weather Service reported a high pressure of 1061 hPa in that area.

Set against a depression almost 70 hPa lower in southern Greenland, it was a driving force to push frigid temperatures across Europe.

On February 10, CNN reported that twenty-two countries had posted warnings for extreme cold temperatures and accumulating snow. Temperatures of -17 °C (1.4 °F) were reported in Romarantin and -16 °C (3 °F) in Bergerac, France on February 7.

The cold has reached as far south as Algeria, bringing a rare snowfall. The bitter cold and snow not only been inconvenient, tangling traffic and cutting off villages from essential services, especially in Eastern and Central Europe, but it has been deadly as well.

On February 14, the Telegraph reported at least 306 deaths across the continent. The Ukraine has been the hardest hit, with over 131 cold-related deaths reported.

NASA MODIS Image: New Island forming in Red Sea

An eruption occurred in the Red Sea in December 2011. According to news reports, fishermen witnessed lava fountains reaching up to 30 meters (90 feet) tall on December 19.


The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites observed plumes on December 20 and December 22.

Meanwhile, the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite detected elevated levels of sulphur dioxide, further indicating an eruption.

The activity in the Red Sea included more than an eruption. By December 23, 2011, what looked like a new island appeared in the region.

The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured these high-resolution, natural-color images on December 23, 2011 (top), and October 24, 2007 (bottom).

The image from December 2011 shows an apparent island where there had previously been an unbroken water surface.

A thick plume rises from the island, dark near the bottom and light near the top, perhaps a mixture of volcanic ash and water vapor.

The volcanic activity occurred along the Zubair Group, a collection of small islands off the west coast of Yemen.

Running in a roughly northwest-southeast line, the islands poke above the sea surface, rising from a shield volcano. This region is part of the Red Sea Rift where the African and Arabian tectonic plates pull apart and new ocean crust regularly forms.

1. References

2. Bauwens, J. (2011, December 22). Eruption in the Zubair Archipelago, in the southern Red Sea. Accessed December 27, 2011.
3. Gass, I.G., Mallick, D.I.J., Cox, K.G. (1973). Volcanic islands of the Red Sea. Journal of the Geological Society, 129(3), 275–309.
4. Global Volcanism Program. (2011, December 20). Weekly volcanic report, 14 December–20 December 2011. Smithsonian Institution. Accessed December 27, 2011.
5. Global Volcanism Program. Zubair Group. Smithsonian Institution. Accessed December 27, 2011.
6. Klemetti, E. (2011, December 19). Potential eruption off the coast of Yemen. Eruptions. Accessed December 27, 2011.
7. U.S. Geological Survey, National Park Service. (1999, January 14). Divergent plate boundaries. Accessed December 27, 2011.
8. Volcano Discovery. (2011, December 21). Volcanic eruption in the Red Sea (Yemen) reported. Accessed December 27, 2011.

NASA Earth Observatory image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott.

NASA MODIS Image: Tropical Cyclone Bingiza: Madagascar

Tropical Cyclone Bingiza made landfall on Madagascar on February 14, 2011.

The U.S. Navy’s Joint Typhoon Warning Center (JTWC) reported that, as of about noon Madagascar time on February 14, Bingiza had maximum sustained winds of 85 knots (155 kilometers per hour) and gusts up to 105 knots (195 kilometers per hour).

The storm was located roughly 250 nautical miles (465 kilometers) northeast of Antananarivo.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image at 10:00 a.m. local time on February 13, 2011. Bingiza’s eye approaches northern Madagascar, and a spiral arm grazes Antananarivo.

Although Bingiza would weaken somewhat over land, the storm was expected to re-strengthen after passing over northern Madagascar, thanks to high sea surface temperatures. The JTWC forecast that, on the western side of Madagascar, the storm would travel southward, roughly tracing the island’s west coast.

Hurricane Igor : Image

Hurricane Igor : Image of the Day

Hurricane Igor continued its westward trek across the Atlantic Ocean on September 14. At 11:00 a.m. Atlantic Standard Time (AST) on September 14, the U.S. National Hurricane Center (NHC) reported that Igor was located roughly 710 miles (1,140 kilometers) east of the northern Leeward Islands.

Igor remained a Category 4 hurricane, with maximum sustained winds of 135 miles (215 kilometers) per hour.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image of Hurricane Igor at 10:15 a.m. AST (14:15 UTC) on September 14, 2010. As it did the day before, the storm shows the characteristics of a powerful hurricane—spiral arms stretching across hundreds of kilometers, and a distinct eye.

On September 14, Igor was traveling slowly toward the west-northwest. The NHC warned of swells from the storm affecting the Leeward Islands and Puerto Rico over the next couple days, although no coastal watches or warnings were in effect.

The same day that MODIS acquired this image, observations by the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua satellite detected a 170-degree difference between the frigid cloud tops of Hurricane Igor and the warm sea surface below, which fueled the powerful storm.

NASA Modis Image: Dust Plumes off Western Africa

large image (2 MB, JPEG) acquired September 15, 2010

Multicolored dust plumes blew off the coast of western Africa in mid-September 2010. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image on September 15, 2010. An especially dense, dark plume blows over the Atlantic Ocean just south of the Western Sahara-Mauritania border. Around this plume are thinner, lighter plumes. The dust appears lightest in the north.

The varying colors of the plumes might result from different points of origin, or simply from different densities of dust. Source points for this dust storm aren’t obvious in this image, but sand seas sprawl over most of Mauritania, and the dust could have easily arisen from one or more localities in that country.

Dust clouds such as these can carry anthrax, which is endemic in the African soils, into Europe.

NASA MODIS: Tropical Storm Estelle

Tropical Storm Estelle strengthened from a tropical depression over the eastern Pacific Ocean on August 6, 2010.

By 2:00 a.m. Pacific Daylight Time on August 8, the storm had maximum sustained winds of 65 miles (100 kilometers) per hour, according the U.S. National Hurricane Center.

Estelle was roughly 355 miles (570 kilometers) south of the southern tip of Baja California.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image of Tropical Storm Estelle at 1:20 p.m. PDT (20:20 UTC) on August 8.

Estelle appears as a compact cloud mass with a few disconnected bands of clouds along its perimeter. Along the storm’s northeastern margin, a band of clouds casts shadows toward the northeast.

At 8:00 a.m. PDT on August 9, 2010, the NHC reported that Estelle was roughly 390 miles (630 kilometers) south-southwest of the southern tip of Baja California, with maximum sustained winds of 40 miles (65 kilometers) per hour.

The storm had moved westward, and was expected to continue along that track before turning toward the west-southwest.