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区域土壤侵蚀评价研究中的月降雨分解
张 少 伟
Subtype硕士
2011-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword区域土壤侵蚀评价 降雨分解 理论分布函数 降雨强度数值分布特征
Abstract

土壤侵蚀研究中降雨因素是主要动因之一,在区域尺度上进行侵蚀评价研究
时必须考虑时间-空间尺度相匹配的问题,一般认为月时段是与区域尺度相匹配
的时间尺度。然而利用月时间尺度进行计算造成降雨数据过于宏观,使得侵蚀评
价的结果误差增大,为了解决这一矛盾有必要讨论适合于区域土壤侵蚀评价的月
降雨分解方法。月降雨分解是指将月总降雨量分解产生一组降雨强度数值序列,
该序列能够反映真实降雨强度的分布特征,并具有和真实降雨相近似的统计特
征。这一方法的基础是利用理论分布函数来描述降雨强度数值的理论分布模型,
因此本文探讨了适合于陕北黄土高原降雨特征的理论分布函数形式,并以此为基
础讨论了区域尺度研究中月降雨分解的具体方法,主要结论如下:
1、利用历史降雨强度数据,通过最大似然法进行参数拟合,LOGN、GAMA 和
WBL 三种理论分布函数能够较好地再现月降雨强度分布。理论分布对降雨强度峰
值有一定的低估,低估的范围约15%左右。
2、WBL 分布对降雨强度数值序列整体的再现能力接近90%,而对降雨强度峰
值的再现能力在70%左右,可见该分布函数适合在陕北黄土高原土壤侵蚀评价研
究描述月降雨强度特征。
3、月降雨强度分解方法能够较好的实现由月降雨总量到月降雨强度序列的
转化,转化结果和真实降雨强度的统计特征相近,大多数月份的降雨分解后的雨
强序列与真实序列的统计特征相差在30%以内。
4、月降雨历时(小时数)是降雨分解过程中的重要参数,本文中采用月降
雨历时-降雨量关系来模拟计算降雨历时,本研究区的月降雨历时-降雨量之间的线性关系明显,二者的决定系数R2 在0.7 左右,因此该方法适用于该区域。
5、用理论分布函数进行降雨强度分解得到估计月降雨强度数值序列,大多
数(70%)以上的月份,降雨历时和月平均降雨强度误差约平均误差在20-30%之
间。真实降雨强度峰值的平均值在8.8mm/h 左右,估计序列的降雨强度峰值平均
值约8.2mm/h,总体趋于低估但误差不大,另外估计的降雨强度数值序列的分布
趋势更加集中。
关键词:区域土壤侵蚀评价;降雨分解;理论分布函数;降雨强度数值分布特征

Other Abstract

In the study of soil erosion , rain factor is one of the main agent. It is a necessity
to consider the matching of spatial and temporal scale when carrying out the study of
Soil Erosion Evaluation. It is generally thought a period of ten days to a month is the
temporal scale that matches the regional scale. However, using the temporal scale of a
period of ten days to a month to calculate gave rise to the generalization of rainfall
data and then exaggerate the error of erosion evaluation result. To solve one of the
contradiction, it is necessary to discuss monthly rainfall disaggregation method which
is suitable for regional soil erosion evaluation. Monthly rainfall disaggregation means
exploding and producing a group of rainfall intensity numerical sequence that enable
it to reflect true rainfall intensity and have the statistical characteristics similar to the
true rainfall. The base of this method is using theoretical distribution function to
describe the distribution characteristics of rainfall intensity numerical array. This
essay discussed the monthly rainfall disaggregation method based on the theoretical
distribution function appropriate for rainfall characteristics of Northern Shaanxi Loess
Plateau. The main conclusions are as follows :
(1)Three theoretical distribution functions of WBL、LOGN and GAMA are able
to represent monthly rainfall intensity distribution better with the use of historical
rainfall intensity data and parameter matching of maximum likelihood
method .Theoretical distribution have a low parameter estimation of the rainfall
intensity peak and the range of underestimation is 15% or so.  (2)The representation ability of WBL distribution to the rainfall intensity
numerical sequence approaches 90%, while to the rainfall intensity peak is about 70%.
Thus is visible that this distribution function is suitable for describing monthly rainfall
intensity characteristics in the study of soil erosion on the Northern Shaanxi Loess
Plateau.
(3)Monthly rainfall disaggregation method can better realize the transformation
from monthly total rainfall to monthly rainfall intensity sequence. The transformation
result is close to statistical characteristics of true rainfall intensity. The difference
between the rainfall intensity sequence after rainfall disaggregation of most month
and statistical characteristics of true sequence is within 30%.
(4)Monthly rainfall duration (hourage) is the important parameter in the process
of rainfall disaggregation. This essay adopt monthly rainfall duration-rain capacity
relation to imitate and calculate rainfall duration ,which is evident in this study area.
Furthermore, the coefficient of determination R2 of them is about 0.7.As a result ,this
method suits for this area.
(5)The error in rainfall duration and monthly average rainfall intensity of most
month(about 70%)is between 20% and 30% when using theoretical distribution
function to conduct rainfall intensity disaggregation and acquired the estimated
monthly rainfall intensity numerical sequence.The average value of true rainfall
intensity peak is 8.8mm/h or so ,while of the estimated array is about 8.2mm/h. The
total tends to underestimation but the error isn't to a great extent. Besides, the
distribution trend of estimated rainfall intensity numerical sequence is more
concentrated.
Key Words:Regional Soil Erosion Evaluation; Rainfall Disaggregation; Theoretical
Distribution Function; Rainfall Intensity Numerical Distribution Characteristics

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8889
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
张 少 伟. 区域土壤侵蚀评价研究中的月降雨分解[D]. 北京. 中国科学院研究生院,2011.
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