According to the analysis to the climatic data of Xiao Tang in desert, Lun Tai in oasis during 1992 to 1997, the following viewpoints were noted: (1)The air temperature of desert is lower than the one of oasis in winter, the air temperature rise gradually from oasis to desert in summer. The diurnal range and annual range of air temperature in desert is wide than the one in oasis. (2)The precipitation of oasis is more than the precipitation of desert. The difference of seasonal precipitation is great in desert, the most of precipitation is in warm period, it is basic characteristics that mean-square diviations of precipitation are big in desert. Not only large-scale weather system affects the precipitation in desert, but also violent local thermal circulation can form the local unstable precipitation in desert. (3)The Humidity of desert is lower than humidity of oasis and the evaporation amount of desert is bigger than evaporation amount of oasis. The evaporation capableness of desert is mighty, the difference of seasonal evaporation amount is great in desert and the 77% of annual mean evaporation amount is in summer and spring.(4)The days of sand blown by wind weather in desert are more than the one of oasis. The wind speed in desert is faster than the one of oasis. These indicate that the difference is apparent between desert and oasis. This is caused by differences of Landscape and water amount. The exploitation and utilization on oasis enlarge this difference.
In this paper, the characteristics of climate change in the west Tianshan Mountains for last 40 years are discussed. The trend of climate change and its effect combined with the oasis climate effect in the irrigated areas are analyzed. The regional characteristics of climate change and the temporal and spatial distribution characteristics of sand-dust storms, floating dusts and strong winds are compared and analyzed based on the observed data collected from 14 meteorological stations in the source stream area of Aksu River, Aksu Irrigated Area and Yarkant River Irrigated Area during the period of 1961-2000. We concluded that both temperature and precipitation have increased in these regions since 1990’s. It is observed with higher precipitation in the area of Aksu River there are fewer days when sand-dust storms, floating dusts and strong winds happened. The interaction between the climate change and the oasis development is also discussed.
Using the observations from 8 weather stations in northern Xinjiang, eight weather stations in southern Xinjiang and 8 weather stations in Tianshan Mountains area, we analyzed changing features of sandstorm, floating dust, blowing-sand. The observations were collected from 1961-2000 in Xinjiang, China. The results show that southern Xinjiang was the area where sandstorm and blowing-sand occurred more often, and the occurrence was 3-5 times higher than those in northern Xinjiang. Days of floating-dust appearing in southern Xinjiang were 50 times more than those in northern Xinjiang; in Tianshan Mountains area sand-dust weather appeared less. In the last 40 years, the long-term change trend of these sand-dust weather in southern Xinjiang was similar to those in northern Xinjiang, that had been obviously decreasing since the 1990’s; the total days of sand-dust weather in southern Xinjiang in spring had a linear relationship with air temperature and precipitation of the same period, respectively.
The relationship between the change of stream flow and the human activities in the Tarim River watershed is investigated based on the observed data collected by 13 meteorological stations from 1961 to 2000 and 8 hydrologic stations in the watershed. It is preliminarily attempted to quantify the impact intensity of the human activities. The influence index of water consumption is put forward, and the impact trend of human activities to the mainstream of Tarim River is analyzed. It is considered that the increase amplitude of the impact of human activities was the highest during the period from the 1970s to the mid-1980s, and the increase amplitude of human activities has been slowed down to some extent during the recent 10 years. Moreover, the temporal and spatial distribution characteristics of the climate change, sand-dust storms, floating dusts and strong winds in all the areas of the source streams and the mainstream of Tarim River are compared and analyzed. It is pointed out that the precipitation in the Tarim River watershed has increased since the 1990s, especially in the areas of its main source streams, and the occurring days of sand-dust storms, floating dusts and strong winds have obviously reduced. The possible relationship between the climate change and the human activities is also discussed.