沙坡头地区气候变化特征及其功能谱分析

Climatic Change Characteristics and its Functional Spectral Analysis in Shapot ou Region

论文探讨了沙坡头地区气候要素的年际、年内变化特征，并采用功能谱分析方法，定量分析了气温、降水的周期性变化规律，得出气温年际变化具有８．４ａ、３．５ａ和２．８ａ的周期规律；降水年际变化具有８．４ａ、５～６ａ、３．５ａ和３ａ的周期性规律。采用交叉功能谱分析方法研究了气温与降水协同变化机制、周期性及其对人工植被的影响，得出降水和气温组合因子具有１０．５ａ、８．４ａ、３．５～３．８ａ的波动周期。

t\ \ The characteristics of climatic change within a year and between years in Shapotou region were studied. By means of functional spectral a nalysis we studied quantitatively the periodic oscillations of temperature and r ainfall. Using cross over functional spectral analysis method we studied the m echanism of coordinated changes, periodicity and their influences on planted vegetation of temperature and rainfall. The main conclusions are as follows: (1) The temperature of this region fluctuates to a large extent within a year, but little between years. Statistical data show that the average temperature of January is -6 7℃, and that of July is 24 1℃; the yearly fluctuation is betw een 8 8℃ and 10 2℃. The functional spectral analysis of temperature change s hows that its yearly change exhibits the periodicities of 7 2 years, 3 years an d 2 4 years. (2) The average rainfall in this region is 182 mm, and the distribution within a year is uneven: about 87% of total rainfall concentrates on the period of June to October, with peak in August. The yearly fluctuation of rainfall is violent and the largest coefficient of variation reaches 63%. The functional spectral analys is of yearly fluctuation of rainfall demonstrates that the average rainfall per year exhibits the periodicities of 8 4 years, 5 years, 3 5 years and 3 years. (3) The temperature and rainfall in this region coincides seasonally, forming dry cold winter and moist hot summer. The spring and autumn are relatively dry , so spring plants germinate late and stop growing early in autumn. The joint a ction of temperature and rainfall shortens the growth period of plants in this a rid region. The results of cross over functional spectral analysis of water and temperature show that the coordinated effect of water and temperature has peri odicities of 9 years, 7 2 years and 3￣3 2 years. The above conclusions are in accordance with observational results. Main conclusions provide quantitative basis for the efficient utilization of cl imatic resources and establishment of sand fixing vegetation in this region.