干旱区环境绿洲化驱动机制浅析

Analysis on Driving Mechanism of Oasification in Arid Regions

基于树轮代用指标记录,重建了1368—2005年黑河流域气候干湿指数变化序列。结果表明,黑河流域中下游地区多数时段处在气候湿润期,气候干旱时期比较短暂。流域气候干湿指数存在3~5年和22年准周期,主要受ENSO和太阳活动影响。对黑河流域绿洲演化机制分析得出,历史时期绿洲面积变化与气候干湿变化趋势以及人口数量增减存在明显的对应关系,气候变干和人口数量减少是绿洲面积缩小的必要条件;气候变湿润时期和人口数量增加时期会限制绿洲面积减少。可见自然因素和人为因素共同作用影响了流域绿洲演变的历史过程。

Based on the tree-ring proxy index records, the dry-wet index of climate change in Heihe River Basin from 1368 to 2005 was reconstructed. The results showed that most of the time in the middle and lower reaches of the Heihe River Basin were in the wet period, while the dry period is relatively short. There are 3-5 years and 22 years cycles of dry-wet index over basin regions, which were mainly affected by ENSO and solar activities. Based on the analysis of the evolution mechanism of Heihe River Basin, it was concluded that the change of oasis area in historical period has obvious corresponding relation with the change of climate and population. Climate drying and population reduction were the necessary conditions for oasis area reduction;humid climate and increasing population would restrict the decrease of oasis area. It can be seen that natural and human factors have influenced the historical process of oasification over the basin region.