乌兰布和沙漠东北缘磴口县沙尘天气变化规律及其对防护林体系建设的响应

利用磴口县1970年～2000年31年的风沙天气发生日数资料和1977～2000年24年防护林建设资料,分析了沙尘天气的季节变化和年际变化,并通过线性回归和多项式回归分析了沙尘暴和扬沙日数的长期趋势变化,结果表明,大风、扬沙和沙尘暴日数呈总体下降趋势,1970～1985年沙尘发生日数相对较高,1985年以后明显下降;沙尘天气发生日数在防护林体系建设前期最高,在不同建设阶段各指标均明显下降,尤其是第三阶段各指标下降幅度可达73.0～94.0%。方差分析表明四个阶段沙尘天气差异极显著;相关回归分析表明风沙天气指标(年均大风日数、扬沙日数和沙尘暴日数)与防护林指标(防护林面积、防护林林木蓄积量)存在着显著的线性相关关系,同期扬沙、沙尘暴与大风日数的比值变化明显,说明防护林体系建设加强了其对沙尘天气的防护功能。

The Change of Sand-wind Climate and Response to the Shelter belt System Construction in the Northeastern Ulanbuh Desert

Based on the sand-wind climate data of 1970～2000 and the shelter belt system construction data of 1977～2000 of the Dengkou County, the monthly and yearly variation characteristics of strong wind and sand-blowing and sand storm weather were analyzed, and the long-term trend were studied with linear and polynomial regression analysis. The results are as follows: the days of strong wind and sand-blowing and sand storm weather had a decline trend in recent 31 years, and the days in 1970～1985 are more than that of 1985～2000, and obviously decrease after 1985.The days of strong wind and sand-blowing and sand storm are most before the shelter belt construction prophase, and reduce in different stage of shelter belt construction, especially, the days of different wind-sand weather decline to 73.0～94.0%. The results of anova analysis and F test show that the days of different wind-sand weather had an markedly differnce, the regression equations between wind-sand weather index(strong wind days, sand-blowing days and sand storm days) and shelter belt index(shelter belt areas and cumulation quantity of forest ) have notability liner correlation relation and significance of difference. Under the discussion of the strong wind transform rate, it showed that the 3 periods shelter belt system had evident difference in ecological protecting ability at the northeastern of Ulanbuh Desert. The total protecting effect of the system was increasing gradually.