| 摘要: |
| 【目的】提取浅沟特征参数，建立浅沟发生的临界关系式，研究立地类型对浅沟的影响。【方法】 以ArcGIS 9.2为操作平台，Quickbird遥感影像为数据源，提取黄土丘陵沟壑区合家沟封育流域的浅沟信息，确定浅沟参数（浅沟长度、浅沟沟间距、浅沟坡度、上坡汇流面积、坡面坡度）；按坡向（正阳坡、半阳坡、正阴坡、半阴坡）和坡度（缓坡、陡坡、极陡坡）划分为12种立地类型，分析立地类型对浅沟分布发育的影响。【结果】 研究区浅沟平均长度为56.5 m，平均沟间距为10.8 m，平均浅沟坡度为30.9°，其中坡度为30°~36°的浅沟占总数的53.3%，其分布临界关系式为S=0.74A-0.16（其中S为浅沟坡度，A为上坡汇流面积），可以此预测研究流域的浅沟侵蚀分布。同一种坡度条件下，平均坡面密度变化为正阳坡<半阳坡<正阴坡<半阴坡，同一种坡向的浅沟坡面密度随着坡度的增加而增大，且无论是阴坡还是阳坡，浅沟的沟头位置均随坡度的增加由坡面的中上部向坡顶移动，且阴坡沟头的移动幅度较阳坡大。【结论】 建立了研究区浅沟发生的临界关系式，确定了立地条件对该区浅沟分布的影响，为浅沟侵蚀预测提供了有益参考。 |
| 关键词: 浅沟 浅沟侵蚀 临界关系式 立地类型 陕北黄土区 |
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| 基金项目:国家“十一五”林业科技支撑计划项目（2006BAD03A0302） |
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| Distribution characteristics and relation with site type of ephemeral gully in Loess Plateau of Northern Shaanxi Province |
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| Abstract: |
| 【Objective】 The emphemeral gully characteristic parameters were extracted to establish the S-A critical relational expression and to research the influence of site type on ephemeral gully.【Method】 By using the ArcGIS 9.2 as the operating platform and the Quickbird image as the data source,we firstly extracted and then analysed the emphemeral gully characteristic parameters of Hejiagou banned basin in Loess hilly and gully region.【Result】 The average length of the emphemeral gully in Hejiagou basin is 56.5 m,the average spacing 10.8 m and the average gradient 30.9°,of which of the gradiant the emphemeral gully is between 30°-36°,accounting for 53.3% of the total.The S-A critical relation of the area is:S=0.74A-0.16,the relation can be used to predict the emphemeral gully erosion;Having analysed the site type of the area,we found that,under the conditions of the same slope gradient,the variation of the average slope surface density is:sunlit slopeS-A critical relation and determined the influence of site type on ephemeral gully,whhich also provides a reference for ephemeral gully erosion. |
| Key words: ephemeral gully ephemeral gully erosion critical relation site type Loess Plateau |
