其他摘要 | Studying the dynamic process of soil and water loss at regional scale was of
great importance to understanding the effects of soil erosion on environmental factors and
the relationship between global change and regional soil erosion. Meanwhile, it could
provide the basis for governmental planning and decision-making in soil and water
conservation. This study made improvement for Regional Soil and Water Loss Model,
explored the estimation methods of soil moisture and developed a computer module system
under ArcGIS environment and .NET Framework2.0, using C# programming language
based on theory analysis of soil erosion process and its influence factors. The result was
applied in watersheds and regional soil and water loess process was modeled. The results
were as follows:
(1) Explored the estimation methods of regional soil water content. Considering the
climatic factors (temperature), soil factors (soil bulk density), vegetation factor(land
use)and terrain factor(topographic wetness index, slope aspect), the water moisture was
simulated based on GIS, and the regression results were significant. By comparison, the
average error between simulated value and the surveyed value was 0.105, which means the
simulation accuracy was high. The result showed that the soil moisture could be modeled
based on surveyed soil moisture data considering topographic wetness index, slope aspect,
land use, rainfall, and temperature and soil bulk density. Modeled soil moisture could be
used in estimation of runoff in Regional Soil and Water Loss Model as antecedent soil
moisture. (2) Algorithm design of Regional Soil and Water Loss Model was improved. This
research considered antecedent soil moisture, evaporation, raindrop detachment , soil
cohesion and different runoff producing mechanisms et al , improved algorithms of the
rainfall-runoff process and the soil erosion and sediment yield process in regional soil and
water loss. Supported by GIS and computer model system, the process of runoff, sediment,
and accumulation were completed.
(3) Completed the simulation of regional soil and water loss process in research areas.
The model was tested based on data in Jihe River demonstration zone in July 2005 by
using different resolution and time step. The results showed that all of the modules
designed can function well. The output maps could characterize the soil erosion in Jihe
River demonstration zone properly; the spatial pattern and structure depicted by the map
were accordant with the practical situation. The soil erosion in Jihe River was mainly
influenced by land using and climatic factors at macro scale, and by terrain microrelief at
micro scale. The model was applied in Jihe River demonstration zone. The calculated
results of the total runoff and sediment were 6.73 billion m3 and 6.74×106 t , and the
modulus of runoff and modulus of erosion were 9.48×104m3/km2.a and 2978t/km2.a
respectively in Jihe River demonstration zone. The simulation results were comparatively
accordant with the practical situation. |
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