The Moderate Dimensions Of Oasis Expansion With Climate Change In Weigan River Basin

Oasis moderate dimensions is an important indicator that related to the balance of the s socio-economic's development and ecological system of oasis. It is mainly restricted limited by amount of water resources. In recent years, the rapid development of socio-economic in Xinjiang under the strong support of relevant national policies, people's demand for expand the scale of the oasis has become increasingly urgent. At the same time, global climate change makes enormous changes for water resources in Xinjiang. Therefore, it is very important to determine the moderate dimensions of oasis in the future based on the amount of water resources under climate change. Therefore, this research took the Weigan River watershed as a study subject, and determined water resources, the key factor of determining the oasis' suitable size, as the main line. Subsequently, we analyzed the variation in water resources, cultivated land resources. And studied the water consumption in different water use sector, then, making the forecast of cultivated land change, water supply and water consumption in under climate change in future. Calculated the suitable area of oasis and cultivated land in current(2005, 2010) and forecast years(2015, 2025, 2035) by by the model of the oasis moderate dimensions, that building under the water and heat balance principle. That all study with the help of remote sensing image, hydrological and meteorological information, social and economic data, urbanization construction planning of the state and the autonomous region, national counterpart aid for Xinjiang plan and other data. Finally, putting forward the "red line", "yellow line" and "minimum" of Weigan River basin scale and cultivated land in future. To provide theoretical support for the scientific development of Weigan River basin oasis. According to the present study, the conclusions of this study are as follow:(1)Area of different land use types in study area as follows: forest land > cultivated land > desert(unutilized land) > construction land > water area. Cultivated land area increased year by year, The rate of expansion through the process of �slow expansion- medium expansion- medium expansion�, the Extend mode through the process of "internal filling and exterior expansion- exterior expansion- internal filling�. The external contour fractional dimension of cultivated land increases early, but later stabilized, It's decreasing obviously overall. The centroid of cultivated land through the moving process that �South East- South East- North west�, it is showing a trend of spreading to the south. Cultivated land reclamation has been gradually shifted from the upper reaches of the lower mountain grassland to the lower reaches of the natural oasis. Water resources and population are the main driving forces of the change of cultivated land.(2)Uneven distribution of runoff within one year, which showed that summer > autumn > spring > winter, this trend in the future will be more obvious. There are three significant stages of inter annual runoff change that wet season from 1960 to 1976, normal season from 1976 to 1993 and drought season from 1994 to 2013. Runoff presented a growth trend in the whole period, especially in summer, however experienced a slight drop in winter..The Runoff in Weigan River would keep going up in nearly future. Temperature and precipitation increased in the last 54 years. The fluctuation points appeared in late 1970 s and early 1990 s, which are consistent with variation characteristics of runoff.(3)The climate model prediction, in the future, the temperature, precipitation and runoff showed a tendency of increase in Weigan River basin oasis. Expected 2015, 2025, 2035, the average temperature is14.17 �C,14.97 �C,15.52 �C. The average annual rainfall is 69.20 mm, 87.16 mm, 87.76 mm. Expected 2015, 2025, 2035, the runoff is 22.72�108 m3-41.76�108 m3?23.09�108 m3-45.85�108 m3?23.14�108 m3-87.76�108 m3.(4)In 2010 and 2005, the total water consumption is 58.66�108 m3?57.16�108 m3. In Weigan River basin oasis. In which,The non-vegetation water consumption was 5.10�108 m3?5.29�108 m3, and the vegetation water consumption was 53.56�108 m3?51.87�108 m3.If in accordance with the current development model and the law of water consumption continues to develop, it is expected that the total water consumption of 2015, 2025, 2035 will reach57.58�108 m3?59.87�108 m3?61.32�108 m3,in which, The water consumption of vegetation were 4.99�108 m3?5.82�108 m3?6.82�108 m3, vegetation water consumption were 52.59�108 m3?54.05�108 m3?54.50�108 m3.(5)In 2010 2005, the moderate dimensions of Weigan River basin oasis were6506.17 km2 and 7756.18 km2, the suitable area of cultivated land respectively was2927.78 km2 and 3490.28 km2. Which calculated by the model of the oasis moderate dimensions, that building under the water and heat balance principle. By artificial control measures,it is expected to 2015,2025 and 2035 the moderate dimensions of Weigan river basin oasis were 6021.94-8818.69 km2, 5686.59-8821.23 km2, and 5259.08-8411.80 km2. suitable cultivated land area were 3010.97-4409.35 km2, 2843.30-4410.61 km2, 2629.54-4205.90 km2.Currently,the actual size of Weigan River basin oasis have reached the appropriate size limit, the cultivated land area are beyond the suitable cultivated area.(6)In 2015,2025,2035.The "minimum" of Weigan River basin scale is 6021.94 km2?5686.59 km2 and 5259.08 km2.the "yellow line" is 6609.20 km2?6316.78 km2?5876.17 km2;the"red line" is 8818.69 km2?8821.23 km2?8411.80 km2.In 2015,2025,2035,The "minimum" of cultivated land is 3010.97 km2?2843.30 km2?2629.54 km2;the "yellow line" is 3304.60 km2?3158.39 km2?2938.09 km2;the �red line" is 4409.35 km2?4410.61 km2?4205.90 km2.