October 29, 2013 - Central Asia


On October 20, 2013 NASA’s Aqua satellite flew over central Asia on a beautifully clear autumn day. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard that satellite captured this true-color image at 0805 UTC (2:05 p.m. local time) on that same day.

Black borderlines have been overlain on the image to delineate political boundaries. The land in the far north of the image is southern Russia, and snow covers the Altai Mountains on Russia’s southeast border with Kazakhstan (west) and China (south). On the western border of China, from the north to south, lie the countries of Kyrgyzstan, Tajikistan, Afghanistan and Pakistan. Uzbekistan lies on the left center edge of the image, with a portion of eastern Turkmenistan just to the south.

The tan color that predominates in this region indicates lack of vegetation, due both the arid climate and the drying and browning of plants that occurs at the end of the growing season in fall. Bits of green vegetation can be seen near water sources and at higher elevations. The darker browns in the upper section of the image have tinges of green scattered throughout. This marks the Kazakh Steppe – a broad area of grasslands, savannah and shrub lands that taper off into arid and desert regions to the south.

A brilliant milky-to-turquoise blue lake stretches across southern Kazakhstan. At 16,400 km2 (6,300 sq mi), Lake Balkhash is one of world’s largest lakes. It is unique, however, because the lake is filled with fresh water in the western section, while the eastern section is saline. A narrow strait joins the two sections, but is not wide enough to allow significant mixing of the waters. To the south, the deep blue waters in the northern Tianshan Mountains belong to Lake Issyk Kul. It is a salt-water lake, and is the second-largest saline lake in the world (only the Caspian Sea is larger).

The broad, light tan, oval in the southeastern section is the Taklamakan Desert. It is located in the Tarim Basin, the largest inland basin in China and is surrounded by the Tianshan Mountains, the Kalakunlun Mountains and the Kunlun Mountains. It is a temperate desert, with an average July temperature of 25°C, and in January about -9 to -10° C. Known as a shifting sand desert, the sand is easily lifted aloft even with mild winds, and sandstorms occur on approximately one-third of the days each year. Maximum wind speeds typically reach up to 300 m/s, causing heavy and blinding sandstorms. Although the skies over the rest of the region are brilliantly clear on this day, the skies above the Taklamakan Desert are lightly covered with a fine veil of sand.

Image Facts
Satellite: Aqua
Date Acquired: 10/20/2013
Resolutions: 1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC