DUST STORM IN MIDDLE EAST

Dust hovered over western Iran and the Persian Gulf on June 19, 2009. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite took this picture the same day. The dust follows a nearly vertical line east of the Iraq-Iran border. Aside from a subtropical climate along the coast of the Caspian Sea, Iran has a mostly arid or semiarid climate, but these dust plumes are likely a continuation of the dust storm in Iraq the previous day. The fine sediments of the Tigris and Euphrates floodplains regularly give rise to dust storms.

THE SAHARAN DUST STOM

Saharan dust crossed the Atlantic Ocean on June 24, 2009. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite observed the dust in two overpasses. The right third of this picture shows the image acquired in the first overpass at 14:50-14:55 UTC. The left two-thirds of this picture show the image acquired in the second overpass at 16:25-16:30 UTC. The dust remains discernible over a thousand kilometers west of Cape Verde. The gray stripe is where the satellite acquired no data.
Saharan dust often travels across the Atlantic thanks to a hot, dry, dusty layer of air known as the Saharan Air Layer. Extreme daytime heating of the Sahara creates instability in the lowest layer of the atmosphere, lofting dust particles into the air. The dust-laden air layer continues warming as it travels westward across the Sahara. As the Saharan Air Layer moves off the west coast of Africa, it passes over a cooler, wetter layer of air. This temperature inversion (air usually cools with altitude) prevents mixing, enabling dust to travel across the ocean intact. Across the Atlantic, dust brings problems and benefits: respiratory illness and coral bleaching, but also rich soils.
The high-resolution version of this image has a resolution of 1 kilometer.
References
Prospero, J.M., Carlson, T.N. (1972). Vertical and areal distribution of Saharan dust over the Western Equatorial North Atlantic Ocean. Journal of Geophysical Research, 77(27), 5255-5265.

HAZE OVER EASTERN CHINA

Thick haze blew eastward off the coast of China, over Bo Hai and the Yellow Sea in late June 2009. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image on June 25, 2009. The haze appears as a dingy blue-gray veil extending over land and water.
The haze likely results from urban and industrial pollution. China is the world’s most populous nation and as it has industrialized, air quality has suffered. Seventy-five percent of all urban residents live below the country’s air-quality standard.

Tropical storm nangka

Tropical storm nangka passed through the Philippines in late June 2009, bringing floods, landslides, and tornadoes. The tropical depression strengthened to a tropical storm on June 23 and headed northwest in the direction of mainland China. According to a bulletin from the Joint Typhoon Warning Center issued on June 25, the storm had sustained winds of 74 kilometers per hour (40 knots), with gusts up to 93 kilometers per hour (50 knots), and it could produce waves up to 4.3 meters (14 feet) high.
This image shows rainfall in the vicinity of the South China Sea between June 18 and June 25, 2009, made with data from the Tropical Rainfall Measuring Mission (TRMM) satellite. The greatest amounts of rainfall—up to 400 millimeters (15.7 inches)—appear in deep blue. Superimposed onto the rainfall amounts is a storm track for Nangka. The color shift on the storm track indicates where the storm intensified from a tropical depression to a tropical storm, with wind speeds of at least 65 kilometers per hour (35 knots).
By June 25, 2009, eight casualties had been reported, and eleven more people were missing, according to news reports. Four fishermen died when their boat was caught in a tornado, two died from drowning, and two more perished in landslides.
References
Joint Typhoon Warning Center. (2009, June 25). Tropical Storm 04W (Nangka) Warning Number 13. Accessed June 25, 2009.
Earth Times Online. (2009, June 25). Eight killed, 11 missing after storm Nangka in Philippines. Accessed June 25, 2009.
NASA image by Jesse Allen, using near-real-time data provided courtesy of TRMM Science Data and Information System at Goddard Space Flight Center. Caption by Michon Scott.

FLOODS

Floods from Cyclone Aila in India and Bangladesh
download large image (3 MB, JPEG) acquired May 28, 2009
download large image (3 MB, JPEG) acquired May 11, 2009
Cyclone Ailia was not a strong storm, but its heavy rains and storm surges were enough to swamp the Mouths of the Ganges River in Bangladesh and India. Some islands in the Bay of Bengal and the mangrove forests of the Sundarbans region were inundated and still cut off from relief and rescue workers as of May 29, 2009. Clean drinking water was an acute problem: tidal surges continued to wash salty water inland over damaged levees, and salt water cannot be decontaminated with regular water purification tablets, according to reports from BBC news.
This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite shows the flooding on May 28, 2009 (top), compared to the conditions on May 11, prior to the storm. Made from a combination of visible, shortwave-, and near-infrared light, the image highlights standing water, which appears blue. Vegetation is neon green, and bare ground is tan. Clouds are light blue or white.
Even prior to the storm, pockets of standing water appear in the Sundarbans and other low-lying areas; the first storms of the rainy season (generally June-September) may have already begun. But a dramatic increase in flooded areas is obvious in the post-storm image, despite the patchy clouds. Distributaries in the Sundarbans are wider and coastal areas of Orissa state (lower left) and West Bengal state (northeast of Orissa) in India were pale blue, rather than the light tan they were in the pre-storm image.
The large images provided above are at MODIS’ maximum spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides twice-daily images of the area in a variety of resolutions and formats, including photo-like natural color.