摘要
文章提出用临界侵蚀积分值作为划分流域发育阶段的定量指标,是对经典理论的发展,主要表现在:1)将地貌发育阶段纳入开放系统的概念之中;2)避免高程积分法在划分发育阶段上的不确定性;3)建立地貌发育阶段与流域物质迁移之间的定量关系;4)区分自然侵蚀和加速侵蚀。用文中的临界侵蚀方程对黄土高原丘陵沟壑区分析计算,得到临界侵蚀积分值为0.30和0.70,即当侵蚀积分值小于0.30寸,流域处于侵蚀早期;当侵蚀积分值大于0.30,小于0.70时,流域处于侵蚀中期;当侵蚀积分值大于0.70时,流域处于侵蚀晚期。对于纯自然侵蚀过程,与临界侵蚀积分值相对应的年代及侵蚀模数为7万年前,7008t/km^2·a和距今7.2万年以后,7008t/km^2·a。目前黄土高原丘陵沟壑区加速侵蚀所占比例为30％。
This paper puts forward the integral value of erosion of threshold as a quantitative standard to divide the stages of geomorphological evolution which inherits and develops the classical theories in geomorphology. The advantages by using the integral value of erosion are as follows: (1) putting the stage of geomorphological evolution into the concept of open system; (2) avoiding the uncertainty 'Caused by Strahler's Area-Altitude analysis to divide the stages of geomorphological evolution; (3.) setting up the quantitative relation between the stages of geomorphological evolution and matter movement of drainage basins; and (4) distinguishing the natural and accelerating erosion of drainage basin.
By analyzising and calculating the drainage basins which belong to rolling gully area
on Loess Plateau, the conclusions are reached that the drainage basin enters maturity from youth, when the integral value of erosion equals 0.30, in which the evolutionary time was 70 thousand years ago and erosional modulus was 7008 t/km'. a; the drainage basin will enter old age from maturity when the integral value of erosion equals 0.70, in which the evolutionary time will be 72 thousand years later from now on and erosional modulus will be 7008 t/km2. a only for natural process. The percentage of accelerating erosion in rolling gully area on Loess Plateau is 30% now.
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
1990年第1期110-120,共11页
Acta Geographica Sinica
关键词
地貌
发育
定量研究
Integral Value of Erosion Integral Value of Erosion of Threshold Accele-rating Erosion
