ستون های گرد و غبار بر فراز دریا ی سرخ Dust Plumes over the Red Sea

Dust plumes blew off the coast of Africa and over the Red Sea through mid-July 2011. Dust was still blowing eastward on July 20, 2011, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terrasatellite acquired this natural-color image.

The dust blowing off the coast of Sudan is thick enough to completely hide the land and water surface below, but the thickest dust stops short of reaching Saudi Arabia. Farther south, between Eritrea and Yemen, a thin dusty haze hangs over the Red Sea.

Dust storms and drought are the hazards most frequently affecting Sudan, according to the CIA World Factbook. Less than 10 percent of Sudan’s land is arable, and less than 1 percent of the country’s land supports permanent crops.

1.   References

2.   CIA World Factbook. (2011, July 11). Sudan. Accessed July 21, 2011.

NASA image courtesy MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Michon Scott.

Instrument: 

Terra - MODIS

آتش سوزی در جنگلهای خاورروسیه Fires in Eastern Russia

A thick curtain of smoke hangs over the forests of Siberia in this natural color image taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on July 18, 2011. Several large forest fires had been burning throughout Siberia in previous days. As of July 17, fire was burning on 1,341 hectares (3,314 acres), reported RIA Novosti. The fires burning on July 18 are marked in red.

The fires shown in this image surround the Lena River, which is hidden under the smoke. Fires are common in the forests of Russia during the summer. The majority of those burning near populated areas are started by people.Though some of these fires are burning near settlements, none are threatening populated areas, said RIA Novosti. Sakha (Yakutia), the district shown in the image, was one of the three districts most affected by fire in mid-July.

1.   References

2.   EMERCOM of Russia. (2011, July 15). Fire situation on the territory of the Russian Federation. Accessed July 18, 2011.

3.   RIA Novosti. (2011, July 17). Siberian forest fire area shrinks by 50 pct over past 24 hours. Accessed July 18, 2011.

NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.

آسما ن های آفتابی بر فراز شمالگان – قطب شمال – Sunny Skies over Arctic Sea Ice

Clear skies allowed the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite a largely unobstructed view of the Arctic in early July 2011. This scene is a mosaic of observations acquired by MODIS on July 11, 2011. This natural-color mosaic shows Arctic sea ice and the brilliant white ice cap on Greenland.

High-pressure weather systems tend to bring sunny skies and high temperatures. The National Snow and Ice Data Center (NSIDC) reported that a high-pressure system occurred over the central Arctic and the Beaufort Sea in June, and high-pressure conditions persisted over the Beaufort Sea in the first half of July. Over the North Pole, and the Laptev and East Siberian Seas, temperatures were higher than normal in the first half of July, although they were lower than normal over the Kara Sea.

The same tilt in Earth’s axis that brings about seasonal changes also brings the Arctic maximum sunlight around late June and early July. When clear skies persist over the region at the same time, this can reinforce summertime sea ice melt. In parts of the Arctic, spring sea ice melt began earlier than usual, NSIDC stated.

On July 18, 2011, NSIDC reported that Arctic sea ice had declined at a rapid pace during the first half of July, and is currently tracking below the trend line for 2007. In September 2007, Arctic sea ice set a record low. Whether 2011 will set a new record, however, is yet to be seen.

The large version of this image has a resolution of 1 kilometer.

1.   References

2.   Arctic Sea Ice News and Analysis. (2011, July 6). Sea ice enters critical period of melt season. National Snow and Ice Data Center. Accessed July 20, 2011.

3.   Arctic Sea Ice News and Analysis. (2011, July 18). Early sea ice melt onset, snow cover retreat presage rapid 2011 summer decline. National Snow and Ice Data Center. Accessed July 20, 2011.

NASA image courtesy MODIS Rapid Response Team at NASA GSFC. Caption by Michon Scott.

Instrument: 

فوران جنبای آتشفشا ن زیر دریایی Active Eruption of NW Rota-1 Submarine Volcano

Introduction

Three years ago scientists visited NW Rota-1, an erupting submarine volcano near the Island of Guam. Upon returning they found that the volcano had been in near continuous eruption and that large numbers of shrimp, crab, limpets and barnacles now inhabit the volcanos. Many of these creatures are adapting to life on the volcano and some are new-to-science species only observed here. The pressures of the ocean deep significantly reduces the strength of volcanic blasts and that enabled the scientists to observe the volcano closely with Jason, their remotely-operated vehicle. 

Submarine Volcano Near Guam

Scientists who have just returned from an expedition to an erupting undersea volcano near the Island of Guam report that the volcano appears to be continuously active, has grown considerably in size during the past three years, and its activity supports a unique biological community thriving despite the eruptions. 

An international science team on the expedition, funded by the National Science Foundation (NSF), captured dramatic new information about the eruptive activity of NW Rota-1. 

The Only Deep-Sea Volcano Observed in Eruption

"This research allows us, for the first time, to study undersea volcanoes in detail and close up," said Barbara Ransom, program director in NSF's Division of Ocean Sciences, which funded the research. "NW Rota-1 remains the only place on Earth where a deep submarine volcano has ever been directly observed while erupting." 

Scientists first observed eruptions at NW Rota-1 in 2004 and again in 2006, said Bill Chadwick, an Oregon State University (OSU) volcanologist and chief investigator on the expedition. This time, however, they discovered that the volcano had built a new cone 40 meters high and 300 meters wide. 

باران های تابستانه در شمال خاور بنگا لادش Summer Monsoon Transforms Northeastern Bangladesh

Bangladesh typically experiences a mild winter from October to March; a hot, muggy summer from March to June; and a warm, rainy monsoon from June to October. By early July 2011, rains had already transformed northeastern Bangladesh.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured the top image on May 26, 2011. MODIS on NASA’s Aqua satellite captured the bottom image on July 10, 2011. Both use a combination of visible and infrared light to increase contrast between water and land. Vegetation is green. Clouds are pale blue-green or off-white and cast shadows. Water ranges from electric blue to navy. The light, silvery color of the water in the July image likely results from sunlight reflecting off the water surface.

During the summer monsoon, parts of the country are routinely flooded, and this image pair shows the rising water inundating large areas. A network of rivers and lakes fills northeastern Bangladesh. By July 10, many water bodies have merged, isolating relatively elevated land areas.

1.   References

2.   CIA World Factbook. (2011, July 5). Bangladesh. Accessed July 12, 2011.

توفان ِ ریزذره ها ی رقصان در هوا در صحرا ی الجزیره و مالی Dust Storm in the Sahara

A dust storm blew through parts of Algeria and Mali in early July 2011. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on July 10, 2011.

In places, the airborne dust forms a camel-colored cloud thick enough to completely hide the land surface below, especially near the Algeria-Mali border. The dark land surface northeast of the storm is the relatively high, rocky ground of Tassili n’Ajjer National Park where stone forests stretch skyward.

Source points for the dust storm are not obvious in this image, but a massive sand sea known as Erg Chech covers parts of northeastern Mali and western Algeria. The shifting dunes of this region provide plentiful material for dust storms.

آبگیرهای یخاب بر رویه ی دریای یخ در اقیانوس شمالگان – قطب شمال – در آلاسکا Ponds on the Ocean

If you have never been north of the Arctic Circle, it is easy to imagine that the “ice cap” at the top of the world is a uniform sheet of white. The reality, particularly during the spring and summer melt, is a mottled landscape of white, teal, slate gray, green, and navy.

The sea ice atop the Arctic Ocean can—as shown in this photograph from July 12, 2011—look more like swiss cheese or a bright coastal wetland. As ice melts, the liquid water collects in depressions on the surface and deepens them, forming melt ponds. These fresh water ponds are separated from the salty sea below and around it, until breaks in the ice merge the two.

Researchers on the NASA-funded ICESCAPE mission—Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment—have been examining melt ponds, the ice around them, and the waters below for three weeks, with three more to go. Carried by the U.S. Coast Guard Cutter Healy, a team of oceanographers, marine biologists, and glaciologists are investigating how changing conditions in the Arctic affect the ocean's chemical and biological makeup.

The science team collects water samples to examine water chemistry and to observe the colonies of plankton growing in the water and on the surfaces of the ice. Other instruments are used to assess how much and how far sunlight is penetrating into—and warming—the Arctic Ocean. Still others are measuring the current systems that move water from the depths to the surface, as well as horizontally across the Beaufort and Chukchi Seas.

Incidentally, the crew members in the photo are not harvesting data; they are collecting supplies. A C-130 airplane flew by earlier in the day, dropping a parachuted canister of hardware for fixing instruments and other machinery on the icebreaker.

NASA science writer Kathryn Hansen is blogging daily from the ICESCAPE cruise. Click here to learn some science, see what people are eating, and sample life on an Arctic icebreaker. You can also get a daily glimpse of the ice in the Arctic by clicking on the MODIS rapid response page.

NASA photograph by Kathryn Hansen. Caption by Mike Carlowicz.

Instrument: 

Photograph