近40a来若尔盖盆地沙丘时空变化

Spatial and Temporal Patterns of Sand Dunes in Zoige Basin in Last 40 Years

在野外考察基础上对1966年地形图和1977年、1994年、2001年、2006年遥感影像进行目视解译,并以沙丘面积增加/减少数量、沙丘面积年均增长率、沙丘分布重心等指标来分析1966—2006年间沙丘时空变化。结果显示,沙丘扩张,分布重心向东南偏移。沙丘扩张主要源于沙源扩展,包括河漫滩与江心洲出露面积增加、草地退化沙质土壤出露、湖泊干涸湖底裸露、沼泽疏干。气象数据与人文统计数据分析表明,沙源扩展与近年来气温升高、降水减少、人口增长、牲畜增加有关。沙丘分布重心向东南偏移是因为起沙风主导风向为西风、北风及西北风。

Spatial and temporal patterns of sand dunes in Zoige Basin are analyzed based on combination of remote sensing data during 1966 2006 and field survey.The area of sand dunes expanded and spatial distribution center shifted to the southeast from 1996 to 2006.The expansion of the area of sand dunes related to expansion of sand sources,comprising newly exposed part of flood plain and river central island,degraded rangeland,dry lakes and dry marshes.The expansion of the sand sources related to air temperature rising,precipitation reducing,population increasing and livestock multiplying.The moving southeastward of the spatial distribution center of sand dunes is resulted from the predominant wind directions of west,north and northwest.