Present situation of environmental protection in Xinjiang

Xinjiang Uygur Autonomous Region is located in the northwest border of the motherland, at 73 20,41,-96 25,3415,-4910,45, in an extremely arid desert zone in the middle temperate zone. The whole region covers an area of 6.5438+0.6649 million square kilometers, accounting for one sixth of the national territory, and is the largest administrative province in China.

1. Geographical location and topographical structure far away from the ocean and mountains.

Xinjiang is located in the hinterland of Eurasia, 2500——4000km east of the Pacific Ocean, 6000——7500km west of the Atlantic Ocean, 0/700-3400 km south of the Indian Ocean/KLOC, and 2800——4500km north of the Arctic Ocean. Judging from the influence of atmospheric circulation, only a small amount of wet air from the Pacific Ocean can reach southern Xinjiang. It is difficult for the Indian Ocean airflow to cross the Qinghai-Tibet Plateau, and only the Atlantic Ocean and Arctic Ocean airflow can affect the western and northern parts of Xinjiang. This land-sea relationship far away from water vapor makes Xinjiang the arid center of Eurasia.

The topographic structure surrounded by high mountains has further exerted a far-reaching influence on the formation of arid environment. According to the large landform outline, structural features and sediment features, Xinjiang can be divided into six landform units from north to south, namely Altai Mountain, western mountainous area of Junggar, Junggar Basin, Tianshan Mountain, Tarim Basin and southern mountainous area, which constitute the overall outline of "three mountains and two basins". Inclined alluvial fans and alluvial plains are regularly distributed from the foothills to the center of the basin. The center of the basin is a vast and flat alluvial plain and lake plain, on which loose sediments are eroded by the wind to form a big desert. Specific layout: Altai Mountain traverses the northern edge of Xinjiang from northwest to southeast, with an average ridge line of less than 3,000 m and the highest Friendship Peak at an altitude of 4,373 m; The southern edge is Kunlun Mountain, and from west to east are the majestic Pamir Plateau, Karakorum Mountain, Kunlun Mountain and Altun Mountain, with an average ridge line of 5,000-6,000 meters. Between Xinjiang and Kashmir, the world's second highest peak is 8611m above sea level. Tianshan Mountains cross the central part of Xinjiang from east to west, dividing Xinjiang into north and south parts, with a ridge line of more than 4,000 meters, and the highest peak Tomur Peak is 7455 meters above sea level ... Between Altai Mountain and Tianshan Mountain is a semi-closed Junggar basin with an area of about 38× 104km2. To its west is Junggar Mountain. The central part is the Gurbantunggut Desert, which is dominated by fixed and semi-fixed sand dunes, covering an area of nearly 5× 104km2. There is Aiding Lake, the second lowland in the world, in the eastern Turpan Basin, with an altitude of 154m. Between Tianshan Mountain and Kunlun Mountain is Tarim Basin, the largest inland basin in China, with an area of 53× 104km2. The central part of the basin is Taklimakan Desert, with an area of 33× 100km2, which is the largest desert in China and the second largest mobile desert in the world. The Tarim River, the longest inland river in China, flows through the basin. The Qinghai-Tibet Plateau is in the southeast, and the southern branch of Tianshan Mountain and Pamir Plateau are in the west. Among the three mountain systems, there are several closed and semi-closed intermountain basins such as Turpan Basin, Hami Basin, Yanqi Basin, Baicheng Basin and Wushi Basin.

The vast territory and complex terrain have formed different regions with obvious climate differences, extensive distribution of water and heat and diverse natural conditions. According to the landform types, the proportion of mountainous areas, plain areas, Gobi areas and desert areas in Xinjiang is roughly 2: 1: 1. Restricted by the high altitude, low temperature, steep slope and extreme drought and water shortage in the middle of the basin, the main economic activity areas in Xinjiang are distributed in the inclined alluvial plain between the foothills and the middle of the basin. Restricted by the spatial distribution of water resources, it also shows the characteristics of oasis mosaic along the edge of the basin.

2. Typical continental climate

Xinjiang belongs to temperate continental climate. The foothills of Tianshan Mountains divide Xinjiang into south and north regions, which are located in the warm temperate zone and the middle temperate zone respectively. Affected by altitude and geographical location, Xinjiang has Turpan Basin, the hottest "Huozhou" in China, and Keketuo Sea, the second cold pole in China after Mohe County in Heilongjiang Province. The climatic characteristics are: drought, little rain and strong wind; Winter is cold and long, summer is hot and short, and the temperature changes sharply in spring and autumn; Abundant sunshine, etc.

The complex topography of the territory also has a significant impact on the climate. The height difference between mountains and plains causes obvious climate differentiation, and the surrounding and blocking of the basin by mountains forms a series of topographic and climatic differentiation and special local climate.

Seasonal characteristics of (1) climate

The climate varies greatly, especially in summer and winter. The summers in southern Xinjiang and Turpan basin are 4 months and 5 months respectively, while the summers in northern and western northern Xinjiang are only 2 months. Winter in northern Xinjiang can last for more than four months.

The temperature rises rapidly in spring, but it is extremely unstable. It is often attacked by cold waves, causing cold, and windy in spring and autumn, forming sandstorms and floating dust weather in southern Xinjiang. The temperature changes little in summer, and the precipitation accounts for two-thirds of the annual precipitation; In autumn, the temperature drops obviously, and the monthly average temperature drops by about 10oC. In winter, northern Xinjiang is cold and long, and there is abundant snow from the mountainous area to the edge of the basin. Due to the influence of inversion layer, the temperature in the middle and low mountainous areas is higher than that in the basin, and there are few strong winds except the tuyere area in winter.

(2) The temperature changes greatly.

The annual average temperature in southern Xinjiang is higher than that in northern Xinjiang. The annual average temperature in Tarim Basin is 65438±00oC, and that in Junggar Basin is 5oC-70oC.

There is a great difference between northern and southern Xinjiang in winter, and the average monthly temperature of 1 is below-10oC and-17oC respectively. In summer, there is little difference between northern and southern Xinjiang. In July, the average temperature in northern Xinjiang was 20℃-25℃, and that in southern Xinjiang was 25℃-27℃, which also showed the characteristics of high temperature in the year. The monthly average temperature changes sharply in spring and autumn, but it changes greatly in spring.

The daily temperature changes greatly, and the annual average daily range of all parts of Xinjiang is higher than 1 1oC, and its distribution is: southern Xinjiang is greater than northern Xinjiang, basins are greater than mountainous areas, and deserts are greater than oases. Therefore, there is a saying that "wear leather clothes early and gauze at noon" to describe the daily temperature changes in Xinjiang.

(3) Precipitation is scarce and unevenly distributed.

Precipitation in Xinjiang is scarce. The average annual precipitation in the whole region is 147mm, accounting for only 23% of the national average annual precipitation, of which150-200mm in northern Xinjiang and less than150-200mm in southern Xinjiang. The annual precipitation in Gongnaisi Forest Farm of Yili River can exceed 840mm, while the annual precipitation in Toksun County is less than10mm ... The precipitation is mostly concentrated in May-August, accounting for 70% of the whole year.

The uneven distribution of precipitation shows that northern Xinjiang is higher than southern Xinjiang, western Xinjiang is higher than eastern Xinjiang, mountainous area is higher than basin, basin edge is higher than basin center, and windward slope in mountainous area is higher than leeward slope. The total precipitation in mountainous areas accounts for 84.3% of the annual precipitation in the whole region.

The interannual variation of precipitation is large, with small variation in rainy areas and large variation in less rainy areas. In Altay, Tacheng and Yili areas with more precipitation, the difference between the highest precipitation and the lowest precipitation is 2-3 times, while in Turpan and Qiemo areas with less precipitation, the difference is about 15 times.

The snowfall in the mountainous areas of northern Xinjiang accounts for about one-third of the annual precipitation. The thickness of snow gradually increases from south to north, from east to west, and from basin to mountainous area. Altay, Tacheng and Yili are the areas with heavy snowfall, with the maximum amount of snow reaching 70-90 cm. The maximum thickness of the northern slope of Tianshan Mountain is 30-40cm. The thickness of snow in some mountain passes can reach more than1m.

(4) Strong evaporation and sufficient sunshine.

The annual average evaporation in the whole region is about 2,000-2,500mm, and it is1500-2,000mm in northern Xinjiang, 2,000-3,400mm in southern Xinjiang, and over 4000mm in Tangsan Lake and Naomao Lake in eastern Xinjiang. The annual evaporation in mountainous areas of northern Xinjiang is mostly below 1000mm, and that in mountainous areas of southern Xinjiang is below 2000 mm. The regional distribution law of evaporation in various places is as follows: southern Xinjiang is large and northern Xinjiang is small; Higashionishi is small; The plain is big and the mountain is small; The belly of the basin is larger than the edge of the basin; The windy area is larger than the windy area. Evaporation is the most vigorous in late spring and early summer, accounting for more than 70% in the five months from April to August.

Xinjiang basin and plain areas are rich in light and heat resources, and the annual total solar radiation is second only to the Qinghai-Tibet Plateau. The annual sunshine hours reach 2550-3500 h, and the regional distribution characteristics are as follows: (1) it decreases slightly from north to south; Increasing from west to east; From the basin to the mountainous area, northern Xinjiang shows a decreasing trend, while southern Xinjiang shows an increasing trend. The longest sunshine in a year occurs in July, and the shortest sunshine occurs in 65438+February-65438+1October.

(5) Strong winds and disastrous weather

Xinjiang is a windy area with strong winds. The wind speed in northern Xinjiang is higher than that in southern Xinjiang, and the wind speed in mountainous area is higher than that in plain. The northwest of northern Xinjiang, eastern Xinjiang and eastern southern Xinjiang are areas with high gale value. The number of sandstorm days in Tarim basin is generally more than 30 days, and most areas in northern and eastern Xinjiang are about 20 days. In the whole year, the wind speed is the largest in spring, followed by summer and the smallest in winter. Due to the abundant sand sources in southern Xinjiang, under the action of wind erosion, floating dust and sandstorm weather often appear from March to May every year.

The disastrous weather in Xinjiang includes drought, cold wave, strong wind, snowstorm, low temperature frost, hail, dry hot wind, rainstorm and flash floods, strong wind and sandstorm, etc. It is harmful to agricultural production and transportation in Xinjiang. In addition, there is inversion in winter in mountainous areas, which provides favorable conditions for livestock to overwinter; However, the inversion of temperature in valleys and basins is an important factor to restrain airflow diffusion and aggravate air pollution.

3. Land

Our region is vast and rich in land resources, but the utilization rate is low.

The land in the whole region is classified by topography. The mountainous area in our region is 565,438+0.4%, and the plain area is 48.6%. The mountainous area is divided by the contour line at an altitude of 2500m, and the mountainous area accounts for 29.60% of the total area. Although this area has the characteristics of convenient water source, it is short of heat, thin soil layer and large slope. Desert Gobi is mainly distributed in plain areas, accounting for 32.9% of the total area of Xinjiang. Although it has the characteristics of flat terrain and sufficient heat, it is located in an extremely arid area with little precipitation. Therefore, the area of fine soil plain available in our area is not large.

According to the investigation data of agricultural regionalization, the wasteland suitable for utilization in the plain area of the whole region is 2 1× 106 hm2, the first and second-class wasteland is 6.93x106hm2, and the first, second and fourth-class wasteland is 14× 106 hm2. The total area of wasteland resources suitable for utilization in the plain of the whole region is more in northern Xinjiang than in southern Xinjiang; The quality of wasteland in northern Xinjiang is better than that in southern Xinjiang, among which Yili is the best, and its ⅰ and ⅱ wasteland accounts for 96% of the suitable wasteland resources. The suitable wasteland distributed on both sides of the piedmont fine soil plain and the river alluvial plain has deep soil layer and sufficient heat. Although there is little precipitation, it is easy to draw water, but there are two same-sex problems: First, the problem of land salinization. The area of saline-alkali land in the wasteland in the whole plain is 8.67×106 hm2; Second, the soil fertility is low and there is a general lack of organic matter. The organic matter content of wasteland soil in Xinjiang is generally 0.5- 1%.

Our region is located in arid environment, which determines that the exertion of land resources advantages depends on the rational allocation, development and utilization of water resources.

Abundant sand sources and extensive saline-alkali land are the result of long-term natural conditions in arid areas. Under the climatic conditions of strong wind, windy and strong evaporation, there are serious hidden dangers of desertification in the land.

4. Hydrological characteristics

The geographical location far from the ocean determines the lack of water vapor sources in Xinjiang. The average annual precipitation is about 2400× 108m3, and the average annual precipitation is 145mm, accounting for only 23% of the national average annual precipitation.

The geographical distribution of precipitation is extremely uneven, and the mountainous areas accounting for 84.3% of precipitation in Xinjiang are desert areas.

Wetland Island in China has become the formation area of surface runoff in our region, which has bred more than 570 rivers, with an annual surface water resource of 793× 108m3, including foreign water, with a total runoff of 884× 108m3, accounting for 3% of the total runoff in China.

Xinjiang is the largest internal flow area in China, and all rivers belong to internal flow except Irtysh River, which finally flows into the Arctic Ocean. The whole region can be divided into Central Asia internal flow area, Junggar basin internal flow area, Tarim basin internal flow area and Qiangtang internal flow area, as well as two water systems originating from the southern foot of Kunlun Mountain. As far as the whole region is concerned, the density of river network in our region is small, which is characterized by drought and semi-drought.

According to the types of rivers and the characteristics of runoff changes, there are five types of river recharge sources in our region: 1, which originates from Tianshan Mountain, the northern slope of Kunlun Mountain and Pamir, and is replenished by glaciers, perennial snow and groundwater, with the characteristics of long flood season, concentrated water in summer and large amount of water. 2. Rivers originating from Altai Mountain and Tacheng Mountain are supplemented by seasonal snow and precipitation in middle and low mountains in summer, characterized by concentrated springs, short flood season, long dry season and relatively uneven distribution during the year. 3. Rainfall and groundwater recharge rivers, mostly small and medium-sized rivers, and their water sources depend on summer rainfall. Its characteristic is that the spring water is slightly larger than the autumn water, and the summer water is not as concentrated as the rivers supplied by snowmelt, and the flood peak fluctuates violently and is fierce. 4. Rivers with spring water and groundwater recharge throughout the year have the characteristics of stable water quantity and even distribution during the year, and the water quantity is less affected by meteorological factors. 5. Rivers that are usually dry and have runoff due to snowmelt or rainstorm.

Because the melting snow and ice in mountainous areas accounts for a certain proportion of the river recharge sources in our region, and there is complementary regulation between melting snow and ice and precipitation in middle and low mountains, the runoff changes little during the year. Among them, the rivers in Altai Mountain in the north change greatly, followed by the rivers in Kunlun Mountain in the south, and the rivers in Tianshan Mountain are smaller. The annual distribution of river runoff in the whole region is 65,438+07% from March to May, 56% from June to August, 9- 1 1 month, 65,438+08%,1February to February 9% of the following year.

The surface water quality has two zonal characteristics, that is, the total ion content and total hardness of river water gradually increase from north to south and from mountainous area to plain. In Xinjiang, except for some rivers in Altai area, the PH values of other rivers are higher than 8, and the PH values of rivers in southern Xinjiang are higher than those in northern Xinjiang. The annual average suspended sediment concentration of rivers also increases gradually from north to south. Rivers originating in Altai area are below 0. 1kg/m3, and rivers originating in Kunlun Mountain and South Tianshan Mountain can reach 2-5 kg/m3.

The natural pollution of water quality in some rivers is serious, for example, the arsenic and magnesium contents in Kezi River exceed the standard, and the fluorine content in water in Hami and Aksu areas is high.

Groundwater in Xinjiang has the following characteristics: rich recharge sources and stable water quantity, but uneven regional distribution. The topography of Xinjiang is conducive to the mutual transformation of atmospheric precipitation, surface water and groundwater. Water comes from mountainous areas, and human activities are at the edge of the basin. From the piedmont to the basin, there are natural "underground reservoirs" formed by Quaternary structures, with deep aquifers. Groundwater is abundant because there is more precipitation and runoff in the north and west. The climate in the east and south is dry, with little precipitation and poor groundwater.

5. Wild animal and plant resources

(1) plant resources

Xinjiang is located at the intersection of several phytogeographical regions, and the flora is diverse. The flora of Xinjiang is composed of Europe-Siberia, PaleoAsia-Mediterranean and Tianshan-Pamir.

There are about 3,569 species of plants in Xinjiang (the total number is estimated to be about 4,000 due to the lack of comprehensive investigation so far). For arid areas, plant species are relatively rich. According to the proportion of families and genera in plant taxonomy in China, they account for 32% and 22% respectively, while the number of species only accounts for 65,438+00%, indicating that most plants in Xinjiang belong to single family, single species or few genera, one species or one genus, which is rare in all provinces and regions of China, indicating that the flora of Xinjiang is complex.

The high content of effective substances is another feature of plants in Xinjiang. There are many kinds of feed plants with good quality, and other resource plants such as medicinal plants, fiber plants, aromatic plants, oil plants and special economic plants are also rich. There are many kinds of wild plants, which are only distributed in Xinjiang or a few provinces, but most of them are in Xinjiang. There are Abies sibirica, Pinus sibirica, Picea sibirica, Wild Apple in Xinjiang, Betula halophila, Walnut, Populus euphratica, Populus euphratica, etc. There are 2 1 species of plants listed in the national protection list. Ephedra, Glycyrrhiza uralensis and Apocynum venetum, which constitute desert vegetation, have a large distribution area and large reserves in our region.

② Wild animals

The natural conditions in our district are complex, sparsely populated and the traffic is inconvenient. There are many rare wild animals in a specific ecological environment, such as wild camels, wild yaks, wild donkeys, beavers and northern salamanders.

There are nearly 644 species of vertebrates in Xinjiang, including 136 species of mammals, 398 species of birds, 43 species of reptiles, 6 species of amphibians and 66 species of indigenous fish, accounting for 27.5%, 35.4%, 13%, 4. 1% and 2.3% of the national species respectively.

Adapting to the living environment, different animal species constitute desert fauna, alpine fauna, forest grassland dwellers fauna, oasis fauna and wetland fauna.

Rare vertebrates 1 13 species, accounting for 28.97% of the national key protected species.

The quality of the natural environment depends on the overall coordination of the basic elements of the ecosystem, such as the quantity and quality of light, heat, water, soil, animals and plants, and the combination in time and space. Due to the special geographical location and the arid climate conditions formed by the closed inland basin, the overall coordination degree of the above factors in Xinjiang is very poor. Due to more light and heat and less water, the structural function and input-output stability of various natural ecosystems in our region are low, and the balance of natural ecosystems is easy to be destroyed, which is difficult to recover after being destroyed, showing the characteristics of extremely fragile ecological environment.