سپیده ی موشکی در نروژ
The aurora borealis and aurora australis—the northern and southern lights—are visible manifestations of a connection between the Sun and Earth. Blasts of energy and magnetically charged particles from the Sun are constantly flowing out into space and crashing into the magnetic fields of Earth and other planets. At Earth, that energy stirs up the particles and energy trapped in Earth’s space, or magnetosphere, creating the auroras and disturbing the upper reaches of our atmosphere. Photographers captured these digital photos of a four-stage Black Brant XII sounding rocket and the aurora borealis (inset) on December 12, 2010, during the NASA-funded Rocket Experiment for Neutral Upwelling (RENU). The rocket was launched from Andøya Rocket Range near Andenes, Norway, and carried instruments about 200 miles (320 kilometers) into the atmosphere to observe the aurora and the associated flow of heat, particles, and electromagnetic energy. The photograph of the aurora was taken from the Kjell Henrickson Observatory in Svalbard, which was under the apogee, or peak, of the rocket’s arc through the sky. The rocket landed in the ocean about 900 miles (1450 km) from the launch site. The goal of RENU was to measure the flow of particles and heat both into and out of Earth’s upper atmosphere near the North Pole during an auroral event. The solar wind stirs up Earth’s magnetic field and creates electrical currents in the ionosphere. Such disturbances can also heat the atoms of the thermosphere and other atmospheric layers, expanding them and creating extra drag on satellites and spacecraft, shortening their lifespan. Around Earth’s poles, the magnetic field stretches out from the core of the planet into space and tucks back in at the opposite pole. The place where most of those field lines bunch up poke out of the Earth usually aligns in an auroral oval, where particles and energy from space precipitate and smash into the oxygen and nitrogen in the atmosphere to make the reds, greens, and whites of auroras. The funnel-shaped area inside that auroral oval—the polar cusp—is mostly open to space. RENU launched right into that cusp region to observe the flows of particles and energy both inbound and outbound. 1. Further Reading
3. Kjell Henrickson Observatory (2010, December 12). The Waiting Game. Accessed January 3, 2011. Instrument:
Photograph
Dust over the Gulf of Alaska
Dust blew over the Gulf of Alaska in early November 2011. The Moderate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Terra satellite captured this natural-color image on November 2, 2011. Blowing toward the south-southwest, the dust plume remains discernible for roughly 100 kilometers (60 miles). The dust emerges from the Copper River Valley, which zigzags through the glacier-rich Chugach Mountains. The slow movement of glaciers over bedrock grinds the rock into glacial flour. This fine sediment is easily lofted into the air by winds blowing through mountain valleys. This image also shows swirls of iridescent green in the waters along the shore. The bright green probably results from sediment and phytoplankton. Dust can fertilize phytoplankton, prompting big blooms, but the microscopic organisms also thrive in high-latitude seas especially near coastlines, without dust. 1. References
2. University Corporation for Atmospheric Research. (2003). Forecasting dust storms. (Registration required). Accessed November 3, 2011.
گرد و خاک بر فراز خلیج آلاسکا
Dust Plumes over the Persian Gulf
One day after multiple dust plumes blew through Iraq, dust hovered over the Persian Gulf. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on July 1, 2011. As on the previous day, light and dark dust plumes blow in the direction of the Persian Gulf through southeastern Iraq. The dark plume, however, is much thinner than it was the day before.
Dust plumes blow over the Persian Gulf, and dust is especially thick off the coast of the United Arab Emirates. Although much of this dust may have traveled from Iraq, some dust may also have arisen in the Empty Quarter or Rub’ al Khali. This massive sand sea spreads over much of the southern Arabian Peninsula, including parts of Saudi Arabia, Yemen, Oman, and the United Arab Emirates.
گرد غبار بر فراز خلیج فارس
Dust Plumes over the Red Sea
ستون های گرد و غبار بر فراز دریا ی سرخ
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.
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.
توفان ریزذره ها ی رقصان در هوا در صحرا ی الجزیره و مالی
