1957-2014年翁牛特旗气候要素和沙丘活化指数的变化

目的]研究位于科尔沁沙地的内蒙古自治区翁牛特旗沙丘活化指数变化,为该区的沙漠化防治提供依据.方法]根据翁牛特旗1957-2014年的气候资料,分析近60 a来该旗影响沙丘活化和沙漠化发展的主要因子特征,计算多年沙丘活化指数的变化.结果]该旗气候呈现降水减少,气温升高,风速降低的趋势,且1998年以来变化更为剧烈;多年沙丘活化指数M值持续减小,1998年以来相对1997年以前减小了34％,其中春、秋、冬季分别下降了28％,32％和38％,夏季M值上升了7％以上,但绝对值仅为13,影响不显著.结论]沙丘活化指数的变化表明该区气候有利于沙丘在自然条件下的固定和沙漠化的逆转,但仍然远高于沙丘固定的阈值,满足沙丘完全活化的条件,气候暖干化也将进一步加剧水资源短缺的矛盾,需要人为的沙漠化防治工程的合理干预,才能实现沙区治理的目标.

Changes in Climatic Factors and Dune Activity Index at Ongniud Banner During 1957-2014

Objective] The historical change of dune activity index of Ongniud Banner in Horqin sandy land in Inner Mongolia was studied, aiming to provide guidance to control desertification in this area. Methods] The climatic factors influencing dune activity and desertification were analyzed, and the dune activity index was calculated based on historical meteorological records from 1957 to 2014. Results] The climatic condition had a clear changing trend which was more obvious since the year of 1998 with reducing precipitation, increasing temperature, and declining surface wind speed. The dune activity index after 1998 was 34% less than that before 1997 with seasonal changes of -28%, -32% and -38% during spring, autumn and winter. The summer index increased 7% after 1997 but had limited influence on the yearly trend due to its low absolute average value of 13. Conclusion] The changes in dune activity index indicated a more appropriate climate for fixing sand dunes and reversing desertification, however, sand dunes could still be fully activated under the current nature environment. The drier and warmer climate will further intensify the water shortage problem. Artificial desertification control measures need to be proposed to improve the natural environment in the Horqin sandy land.