古尔班通古特沙漠南缘典型沙地土壤水分动态及模拟
文献类型：学位论文
| 作者 | 董义阳 |
| 答辩日期 | 2017-05-01 |
| 文献子类 | 硕士 |
| 授予单位 | 中国科学院大学 |
| 授予地点 | 新疆乌鲁木齐 |
| 导师 | 赵成义 |
| 关键词 | Laio 土壤水分动态随机模型 土壤水分动态 土壤水力学参数 古尔班通古特沙漠 Stochastic model of soil moisture of Laio Dynamics of soil moisture,Soil hydraulic parameters Gurbantunggut Desert |
| 学位专业 | 理学硕士 |
| 英文摘要 | Soil moisture is the mainly limiting factor for the plant growth, vegetation succession and pattern change in arid desert area. The dynamics of soil moisture is affected by kinds of uncertainties, e.g., physical-chemical-biological processes,climate change, soil and vegetation differences. With randomness, it is more practical to simulate soil moisture evolution throughout time and space using a model based on probabilistic framework. Here, we selected the typical interdune at the southern edge of Gurbantunggut Desert as the study area in this thesis. This study was designed to investigate the soil moisture dynamics based on the field monitoring, laboratory experiment and model simulation. The relationship between the soil moisture dynamics and the precipitation characteristics was also analyzed. Using the measured soil moisture movement parameters, long-term soil moisture datasets and precipitation datasets, we simulated the soil moisture probability density function by stochastic Laio Model. The main conclusions are listed as follows.(1) Soil hydraulic parameters conformed to soil moisture dynamic chracteristics. Our results found that both the two models(VG and G) fit well with the measured soil water characteristic curves in this region. The saturated hydraulic conductivity of aeolian sandy soil in interdune was 1424.16 mm/d, which was determined using the one-dimensional horizontal infiltration method. There presented a monotonically increasing relationship between the unsaturated soil water diffusivity D(θ) and the soil water content θ.(2) Precipitation in the study area was dominated by small precipitation events(0-5 mm), accounted for 85.2% of the total events, and up to 44.7% of the total precipitation amount. The precipitation interval was dominated by 0-5 days,accounted for 53.2% of the total days without rainfall. And there showed 29.0% and 24.4% of intervals between precipitation events were from 11 days to 20 days and from 6 days to 10 days, respectively. As the precipitation intervals increased, the frequency of precipitation events decreased. (3) Soil moisture was relatively high at root-zone(0-100 cm) in the early growing season. With the temperature rising gradually, soil moisture decreased and reached the lowest basically(0.025 cm3 /cm3) at the end of the growing season. There were two distinct soil layers in the 400 cm depth. Soil water contents was significant variability in the upper 0-50 cm, and remained stable in 50-400 cm. (4) The soil moisture in sandy root-zone layer probability obeyed the T distribution with scale parameter and positional parameter in growing season. The distribution of probability density was basically unimodal, with a narrower width compared to the humid area. The peak value, position and scope of p(s) obtained by Laio model were similar to that of the measured values. Laio model had a good applicability in our study areas. For the thirteen parameters of Laio model, soil porosity, root depth, amount of precipitation intercepted by canopy cover for each rainfall event, soil moisture level below which plants begin closing their stomata, average daily evapotranspiration rate under unrestricted siol moisture conditions, average daily evaporation rate at permanent wilting point, mean of depth of rainfall events, arrival rate of rainfall events, soil moisture level below which water can not be extracted from the soil through evaporation and permanent wilting point were more sensitively, and mainly impacted the peak value of p(s) than paramater defining, along with saturated hydraulic conductivity, the relationship between soil moisture and hydraulic conductivity when an exponential law was used, saturated hydraulic conductivity, soil field capacity. |
| 学科主题 | 自然地理学 |
| 语种 | 中文 |
| 源URL | [http://ir.xjlas.org/handle/365004/14869]  |
| 专题 | 新疆生态与地理研究所_研究系统_荒漠环境研究室 |
| 作者单位 | 中国科学院新疆生态与地理研究所 |
| 推荐引用方式 GB/T 7714 | 董义阳. 古尔班通古特沙漠南缘典型沙地土壤水分动态及模拟[D]. 新疆乌鲁木齐. 中国科学院大学. 2017. |
入库方式： OAI收割
来源：新疆生态与地理研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。