Morozov A.N.

Lecture 1. Natural environment of Uzbekistan

As for natural environment, Uzbekistan territory is unique. Wealth of alpine meadows and big glaciers high up in the mountains, archa bushes and gardens at medium belt of mountains, beautiful spring-fall ranges at low mountains piedmont chules (steppe), extremely rich irrigated lands at valleys of rivers, major says (flows) and undulated plains at piedmonts, horizonless steppes gradually join with deserts.

Most important attributes that determine human comfort and indeed practically most aspects of his activity are land topography and its climatic features. Land topography determines groundwater formation conditions, their mineralization and irrigation capability, and climate - defines many aspects of business activities, natural grows species and types and necessity of irrigation for crops cultivation.

Several maps can be found below where successively shown followings:

Uzbekistan administrative division, its view from aerospace with showing administrative division and without one.

Picture 1.1. Administrative division of Uzbekistan and of neighboring countries..

Picture 1.2. Aerospace view of Amu Darya and Syr Darya interfluve with showing borders of countries and oblasts.

Picture 1.3. Aerospace picture of Amu Darya and Syr Darya interfluves.

Natural features of Uzbekistan territory are seen rather good enough at Picture 1.3. Please, look at it carefully. The picture gives a glimpse of Uzbekistan territory topography and of adjacent areas of neighboring countries. White glaciers are clearly seen in the mountains. The mountains highlighted with dark color, irrigated areas colored with moss-green. Steppes and deserts have oatmeal- brown tincture.

About how strata formations under soil, groundwater flows formation, seepage flows and their salinity are dependent on surface topography we shall tell in our next lectures related to origin of soils salinity and taking over control this effect. Here, we shall tell only that groundwater depth and their mineralization have significant influence to forming of soil types and their fertility, and they mainly determine necessary regime of irrigations with their rate either.

For more detailed view on climate of various territories of Uzbekistan, as a graphical example and for comparison, monthly mean air temperatures, its relative humidity (drought) and precipitation amount are shown at Pictures 1.4 - 1.6

These data were given for several indicative observation points, including Sherabad town in Surkhandarya oblast, (the most hot observation point at the very south of Uzbekistan), Nukus town in Karakalpaia (that is one of the very North stations) and a meteorological station located at foothill of central zone of Uzbekistan - at Dzhizak town.

Picture 1.4. Comparison of meteorological precipitation amount (mm) between the three meteorological stations of Uzbekistan.

As it could see at Picture 1.4 most of all precipitation occurs during winter-spring and autumn periods. Precipitation are six times more at foothill area (e.g. Dzhizak meteorological station) than at north of the republic at Nukus town, and twice more than at south of the republic at Sherabad meteorological station.

It will be observed, that precipitation amount during summer months at all the stations is inappreciable, but water requirement is - maximal.

Picture 1.5. Comparison of monthly mean air temperatures between the three meteorological stations of Uzbekistan.

It can be seen at Picture 1.5 that monthly mean air temperatures are much higher at south of the republic, and substantially they are above freezing all year long. Winter period lowest temperatures are observed at north of the republic.

Picture 1.6. Comparison of monthly mean air relative humidity (drought) between the three meteorological stations of Uzbekistan.

The more air drought is, then the less moisture is in it (as a percentage of maximal possible moisture contents in the air in the form of steam at this temperature). As it can be seen at Picture 1.6 air drought is growing naturally from north to south. Air drought is the lowest at foothills during winter-spring period.

Let us have a look at Picture 1.7, we can see general view there - where and how much precipitation takes place at Uzbekistan territory during a year. It is clearly seen at the picture that most of all precipitation take place in mountainous areas, less - at foothills and quite small amount - at flat land

Picture 1.7. Distribution of atmospheric precipitation (annual) over Uzbekistan territory.

Most important climate indicators are, so called:

"evaporative capacity from water surface" and

"humidity deficit".

First indicator was obtained empirically by comparison of actual evaporation against above mentioned one (of temperature, relative humidity) and corresponded to water sheet which is evaporated from water surface during a month, and second indicator is difference between evaporation capacity from water surface and amount of atmospheric precipitation.

At Picture 1.8 we show values of "evaporative capacity from water surface", and at Picture 1.9 - "humidity deficit" for the same indicative meteorological stations.

Picture 1.8. Values of "evaporative capacity from water surface" and of "humidity deficit" for the same indicative meteorological stations.

Picture 1.9. Values of "water balance deficits" for the indicative meteorological stations.

As judged by climatic indicators, more than half of Uzbekistan territory is in arid climate zone. What it does mean can be read in the encyclopedia:

"Arid climate (A.C.), climate of deserts and semideserts. It is typical for A.C.: high day and annual air temperatures; almost a total absence or trace amount of precipitation (100 - 150 mm/year). All coming water is evaporated rapidly. Rivers, flowing from neighboring more damp fields and crossing desert, here are getting shallow and often end at drainless depressions with salt lakes. Naked earth surface meet with temperature dancing within 24 hours, and because of that even compact rocks are ruined and turn into sand. Wind shift huge amount of dry sand and forming rolling topography of sand barchans and shifting sands. A.C. is most typical for tropical and subtropical latitudes (Sahara, deserts of Arab Peninsula, of Australia). A.C. at more high latitude is connected with protective effect of mountain ranges which prevent from moisture transfer from oceans (deserts of North and South America), or with farness from oceans (deserts of Central Asia)

You will find an answer in the next articles of the website - what for we discussed the issue on climate features and showed Uzbekistan maps with topography of its territory.

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