Physical geography of Central Asia

Central Asia is a physiographic country in the heart of Eurasia. Its nature is shaped by two main factors: its great distance from the oceans and the high mountains in the south-east. Distance from the ocean makes the climate dry and extremely continental, so deserts cover the plains; the high mountains catch moisture, hold glaciers and give rise to rivers. Uzbekistan lies at the centre of this region, so the topic is the key to understanding Uzbekistan’s own nature. Exams ask about relief, rivers, lakes and climate, and the reasons behind them.

§1. Position and development of the territory

The region stretches from the Caspian Sea in the west to the Tien Shan and the Pamirs in the east, and from the Kazakh Uplands in the north to the Kopet Dag and the Afghan border in the south. It includes Uzbekistan, Turkmenistan, Tajikistan, Kyrgyzstan and southern Kazakhstan.
It lies thousands of kilometres from every ocean; moist ocean air hardly reaches it, and what does arrive has lost its moisture on the way. This is the root cause of its natural features.
Geological history. Seas once covered today’s plains, and their sedimentary layers accumulated oil, gas and salts. The mountains formed long ago, were worn down, and were uplifted again during the Alpine–Himalayan mountain building; they are still rising. So the region is seismically active, with strong earthquakes such as the 1966 Tashkent earthquake.

§2. Relief and minerals

Plains occupy the west and centre, mountains the south-east.

• Turan Lowland: the Kyzylkum lies between the Amu Darya and the Syr Darya; the Karakum lies south-west of the Amu Darya (in Turkmenistan); the Ustyurt plateau lies between the Caspian and the Aral, bounded by steep escarpments called chinks.
• Mountains: the Tien Shan (Western, Northern, Inner and Central), the Pamir-Alai and the Kopet Dag. The highest point is Ismoil Somoni Peak in the Pamirs (7,495 m). The highest peak of the Tien Shan is Pobeda (Victory) Peak.
• Intermontane basins: the Fergana, Issyk-Kul and Zarafshan basins — densely populated valleys.
• The plains contain residual mountains (Tamdytau and Bukantau in the Kyzylkum), worn-down remnants of ancient ranges.

The general rule holds here too: gas and oil in the sedimentary layers of the plains, ores (gold, copper) in the mountains and residual mountains.

Worked example

In the Fergana Valley (about 500 m) it is +30 °C in July. What is the temperature on Ismoil Somoni Peak (7,495 m) at the same time, if it falls by 6 °C per km?

1. Height difference: 7,495 − 500 = 6,995 m ≈ 7 km.
2. Fall: 7 · 6 = 42 °C.
3. Summit: 30 − 42 = −12 °C. Answer: about −12 °C — which is why the peaks stay under snow and ice all summer.

§3. Climate

Central Asia’s climate is extremely continental and dry:

• summers are long, very hot and dry, as tropical continental air forms over the region;
• winters are fairly short but cold, because Arctic air enters freely from the north and brings hard frosts;
• the temperature range, both daily and yearly, is large.

Precipitation on the plains is low (about 100–200 mm a year) and falls mainly in winter and spring with cyclones from the west; summer is almost rainless. The western, windward slopes of the mountains receive far more. Potential evaporation is many times greater than precipitation, so farming is possible only with irrigation.
Winds: the garmsil (hot and dry), the Kokand and Bekabad winds (at the entrance and exit of the Fergana Valley) and the "Afghan" wind (in the south, bringing dust storms).

Worked example

A lowland city has −6 °C in January and +30 °C in July. What is the annual range, and what does it show?

1. Range: 30 − (−6) = 36 °C.
2. A range above 30 °C is a sign of a continental climate.
3. Answer: 36 °C; the climate is extremely continental because of the distance from the ocean.

§4. Waters

The region’s rivers have inland drainage: they never reach the ocean but end in lakes such as the Aral and Balkhash, or vanish in the desert. They rise in the mountains and are fed by snow and glaciers, so high water comes in summer — exactly the irrigation season.

• The Amu Darya forms where the Panj and the Vakhsh, rising in the Pamirs, meet; it has the greatest flow in Central Asia and flows towards the Aral (it now barely reaches it).
• The Syr Darya forms in the Fergana Valley where the Naryn and the Kara Darya meet; it is the region’s longest river.
• The Zarafshan, Chu, Murghab and Tejen are rivers that "disappear in the desert" because their water is used for irrigation.
• Lakes: the Aral (shrinking since the 1960s), Issyk-Kul (tectonic, deep and ice-free in winter), Balkhash (fresh in the west, salty in the east), Sarez (formed in the 1911 earthquake when a landslide dammed a river) and the Aydar-Arnasay lake system.
• Glaciers: the Fedchenko Glacier in the Pamirs is one of the largest mountain glaciers.

Worked example

Why do Central Asian rivers have high water in summer, while European lowland rivers have it in spring?

1. Central Asian rivers are fed by snow and glaciers in high mountains.
2. In high mountains snow and ice melt fast only in the hottest summer months.
3. European lowland rivers are fed by lowland snow, which melts in spring.
4. Answer: the source of feeding and the time it melts are different.

§5. Soils, vegetation and natural zones

The plains belong to the desert zone: sandy deserts (saxaul, kandym, cherkez), clay and takyr deserts and salt flats; soils are sandy, takyr and solonchak, with grey serozems at the foot of the mountains. In spring ephemerals — plants that grow, flower and wither quickly — briefly carpet the ground.
The mountains show altitudinal zones: adyr foothills (serozem, ephemerals, tulips) → mountain forest (brown soils, juniper, walnut and pistachio) → yaylov pastures (subalpine and alpine meadows) → snow and glaciers.
Wildlife: in the deserts goitered gazelle, kulan, saiga, monitor lizard, snakes and rodents; in the mountains snow leopard, argali and mountain goat. Many species are in the Red Book.

Desert life is adapted to drought. Plants reach deep water with very long roots, their leaves are tiny or absent (in saxaul green twigs carry out photosynthesis) and many are thorny. Animals avoid the daytime heat, are active at night and live in burrows; some, like the Central Asian tortoise, sleep through the hottest and coldest periods.

§6. Natural resources and environmental problems

The region is rich in gas, gold, uranium and other minerals, in solar energy and in the hydropower of mountain rivers. The main problem is water shortage: most river flow is taken for irrigation. The results are the shrinking of the Aral Sea, salt-and-dust storms from the dried sea bed, salinisation of land and desertification. Solutions include water-saving irrigation, lining canals with concrete, planting saxaul on the dry Aral bed and joint management of transboundary rivers.

Check yourself

1. The highest point of Central Asia?

2. Which rivers join to form the Syr Darya?

3. Between which rivers is the Kyzylkum?

4. Which mountain lake does not freeze in winter?

5. In which seasons does most precipitation fall on the plains?

6. What kind of landform is the Ustyurt?

7. January −10 °C, July +28 °C. Annual range?

8. How did Lake Sarez form?

Common mistakes

• Writing that the Amu Darya rises in the Tien Shan — it rises in the Pamirs.
• Placing the Karakum between the Amu Darya and the Syr Darya — that is the Kyzylkum.
• Calling Central Asia’s climate temperate maritime — it is extremely continental.
• Thinking most precipitation falls in summer — summer is almost dry; rain comes in winter and spring.
• Mixing up the rivers: the Amu Darya has the greatest flow, the Syr Darya is the longest.