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1.
降水空间化信息在很多领域都具有重要意义,而进行空间插值方法形成降水空间化信息是当代较为常用的方式。面对众多的插值方法其插值精度成为我们是否采用的关键,就kirging插值法与IDW(Inverse Distance Weighting)插值进行研究以探讨其插值效果,为此类科学研究提供依据。研究以漓江流域内各气象站点降水统计资料为基础分别采用上述两种方法进行插值处理,通过与预留实测站点比较评判方法的插值效果的优劣。结果表明,多年月平均降水量作为时间步长时,降水丰沛的月份使用kriging插值法较优于IDW插值法,而枯水月份则使用IDW插值法较优于kriging插值法。 相似文献
2.
北京西山鹫峰地区氢氧稳定同位素特征分析 总被引：4，自引：0，他引：4
以北京西山鹫峰低山区为研究对象,通过对降水、土壤水、泉水氢氧同位素的变化特征分析,研究低山区的降水-土壤水-泉水的转化关系。研究结果表明:该地区的雨季降水线与北京地区的地区降水线有明显区别,斜率和截距偏小;随降雨的进行氢氧同位素特征有时程变化和降雨量效应,而降雨的时程变化也对土壤水的同位素特征产生了影响;土壤水分同位素分布特征相对集中,蒸发线方程的斜率和截距相对于当地大气降水线和雨季降水线都偏小,栓皮栎混交林土壤水对于小雨量次降雨事件反应不敏感,而侧柏林的土壤水分运动较栓皮栎混交林快,说明林分类型和土壤特性对不同水体之间的转化有影响;泉水的同位素特征比较稳定,主要分布在地区降水线的右下方与雨季降水线的交点附近;不同水体中降雨的δD、δ18O变化范围较大,土壤水次之,泉水变化最小;而沿着大气降水-土壤水-地下水(泉水)这一水循环路径,水体中的δD、δ18O值总体上呈下降趋势。 相似文献
3.
Simulated rainfall experiments were performed on bare, undecomposed litter layer and semi-decomposed litter layer slopes with litter biomasses of 0, 50, 100 and 150 g m−2, respectively, to evaluate the effect of the undecomposed layer and semi-decomposed layer of Quercus variabilis litter on the soil erosion process and the particle size distribution of eroded sediment. The undecomposed layer and semi-decomposed layer of litter reduced the runoff rate by 10.91–27.04% and 12.91–36.05%, respectively, and the erosion rate by 13.35–40.98% and 17.16–59.46%, respectively. The percentage of smaller particles (clay and fine silt particles) decreased and the percentage of larger particles (coarse silt and sand particles) increased with an increased rainfall duration on all treated slopes, while the extent of the eroded sediment particle content varied among the treated slopes with the rainfall duration, with bare slopes exhibiting the largest variability, followed by undecomposed litter layer slopes and finally semi-decomposed litter layer slopes. The clay and sand particles were transported as aggregates, and fine silt and coarse silt particles were transported as primary particles. Compared with the original soil, sediment eroded from all treated slopes was mainly enriched in smaller particles. Furthermore, the loss of the smaller particles from the undecomposed litter layer slopes was lower than that from the semi-decomposed litter layer slopes, indicating that the undecomposed litter layer alleviated soil coarsening to some extent. The findings from this study improve our understanding of how litter regulates slope erosion and provide a reference for effectively controlling soil erosion. 相似文献
4.
北京山区林地土壤水分时间序列分析 总被引：4，自引：0，他引：4
采用时间序列分析法,对北京山区4种主要林分类型2010-03—10的土壤含水量与降水量之间的相关关系进行了研究。结果表明:降水序列无明显自相关性,而土壤含水量则具有高度自相关性,其中20～40 cm土层自相关性最大;降水与土壤含水量在时间上有显著的相关性,油松林地和刺槐林地受当月降水的影响最大,侧柏林地和栓皮栎林地则是受前一个月降水量的影响最大;不同土层土壤含水量与降水的相关性不同,说明不同土层受降水的影响有时间上的不同。 相似文献
5.
Spatial variability of soil nitrogen and phosphorus of a mixed forest ecosystem in Beijing,China 总被引：1，自引：1，他引：0
Spatial patterns of soil nutrient (N and P) were examined using geostatistical analysis in three different soil horizons (A,
B, C) in a mixed forest in Beijing China. Soil nutrients (total nitrogen or TN, total phosphorous or TP, and available nitrogen
or AN) were high near the surface and lower with depth. In general, the spatial correlation in soil nutrient content varied
by depth. Soil nutrient content was also strongly influenced by vegetation type and elevation. These results consist of a
set of simple statistical models that could provide information for the planning of the forest management and long-time research
in this area. 相似文献
6.
黄土区林草植被与降水对坡面径流和侵蚀产沙的影响 总被引：27，自引：0，他引：27
在一定地形地貌基础上,林草植被与降水是决定坡面产流产沙量的主要因素,而这些因素各因子之间合作用于坡地产流产沙,增加了影响机制的复杂性。为深入分析降水因子与林分结构因子对坡地降雨产流产沙的影响,为黄土区植被建设提供理论依据,对蔡家川流域典型样地的实验资料进行分析。结果表明,刺槐和油松林场降雨产流、产沙量与降雨量和降雨强度有较好相关性,但相关性随着林分郁闭度的增大而减小;当油松林林分郁闭度<0.6时,产流、产沙量与I30的相关性要更显著于与I10的相关性,而林分郁闭度在0.6以上时,则相反。在林分结构因子对坡面产流产沙的影响中,当林分覆盖度>40%时,林分减水减沙效益显著。林地枯落物和草本植物通过截持降水、增加地表糙率来削减坡面产流产沙量,刺槐和油松林地的枯落物年截流量占降雨总量的13.5%~22%。刺槐和油松林的稳渗速率随林分密度的增加而增大,但不与密度的增加幅度成正比,当刺槐、油松林的密度超过3 000株/hm2时,稳渗速率增加缓慢,从防蚀角度考虑,可将其作为林分密度的上限。在林分生物量>14.51 t/hm2时,植被具有极好的防护功能。通过对影响坡面产流产沙的影响因子的灰色关联分析,林分郁闭度和草本、枯落物生物量对坡面产流产沙影响显著,关联度值均>0.6。 相似文献
7.
Particulate matter(PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is a useful indicator for air PM pollution in road systems. To detect the relationships of foliar PM load with road structures, urbanization, and meteorology in road systems, we studied a widely-planted tree Sophora japonica L. in 100 roads and 10 yards of Beijing, China, and found that the foliar PM loads increased with the distances from the urban centre(DUC) linearly, while decreased with the road density. All-subsets regression analysis indicated that DUC, average monthly relative humidity, average monthly wind speed, and mean annual wind speed were the most important factors in predicting foliar PM load, rather than general situation of buildings and road cleanliness. The monthly relative humidity and monthly wind speed had a negative correlation to foliar PM, while the annual relative humidity and annual wind speed had a positive correlation to foliar PM. Suburban areas and these effective factors should be highlighted in PM control in Beijing. 相似文献
8.
Yuguo Han Xinxiao Yu Peiling Yang Bo Li Lei Xu Chengzhi Wang 《Environmental Earth Sciences》2013,69(1):289-296
Drought is a great concern in agricultural yield. Super-absorbent polymers (SAPs) can assist in easing water shortage. Therefore, it is significantly important to study the water absorbing and desorbing capacity of SAPs when applied into soil as well as their effective time. The aim of this study was to investigate the effect of different SAP types under the same moisture condition and the effect of the same SAP type under different moisture conditions on saturated soil water content, saturated soil hydraulic conductivity and soil water diffusivity. With SAP application, saturated soil water volumetric content increased significantly, up to 0.186 cm3 cm?3, while saturated hydraulic conductivity and diffusivity significantly decreased because the soil pores were blocked by SAP’s swelling volume during the repeated wetting and drying cycles. After SAPs were mixed in the soil, their capacity of absorbing and desorbing water showed a downward trend with time and outside water condition. Under a relatively stable water condition, such capacity reduced more slowly. As for the soil with SAP application, successful simulation for diffusivity D(θ, T) was also applicable to other parameters of the equation of water movement, which made it possible to study the water movement under the same condition. 相似文献
9.
目的：通过网络药理学方法筛选国医大师刘祖贻验方晕清降压方治疗代谢性高血压病的作用成分,并探讨其潜在作用机制。方法：从TCMSP及BATMAN-TCM数据库中筛选出晕清降压方的活性成分及作用靶点。从OMIM及GeneCards中筛选出代谢性高血压病的靶点。利用Bioinformatics & Evolutionary Genomics平台将晕清降压方成分靶点与代谢性高血压病的靶点进行映射,获得晕清降压方-代谢性高血压病的共同靶点,并将其导入STRING数据库获得蛋白-蛋白网络模型,构建“活性成分-靶点”网络,对共同靶点进行GO富集分析及KEGG富集分析。结果：晕清降压方有114种活性成分可能通过143个靶点发挥抗代谢性高血压病的作用;GO富集分析及KEGG富集分析显示,晕清降压方治疗代谢性高血压病主要通过PI3K-AKT信号通路、流体剪切力与动脉粥样硬化、AGE-RAGE信号通路、TNF信号通路、内分泌抵抗等发挥作用。结论：从晕清降压方的12味中药中筛选出114个具有抗代谢性高血压病的活性成分,这些活性成分通过多个靶点、多条通路发挥抗代谢性高血压病的作用。 相似文献
10.
Simulated multi-scale watershed runoff and sediment production based on GeoWEPP model 总被引：5，自引：2，他引：3
YU Xinxiao ZHANG Xiaoming NIU Lili Prof. Dr. Key Laboratory of Soil Water Conservation Desertification Combating Ministry of Education School of Soil Water Conservation Beijing Forestry University Beijing China Dr. China Institute of Water Resource Hydropower Research Beijing China Dr. ... 《国际泥沙研究》2009,24(4):465-478
The runoff and sediment yield data from the Qiaozidonggou, Qiaozixigou, and Lu＇ergou watersheds, in the Loess Plateau of China are used to calibrate and validate the runoff and sediment yield simulated by GeoWEPP model of the WEPP Model at watershed scale. The indices of relative error, R, correlation coefficient, Re, and Nash-Suttcliffe efficiency coefficient Ens are used to evaluate the model fit. The eco-hydrological responses in the Luoyugou and Lu＇ergou watersheds are also forecast based on the WEPP Model. Meanwhile, the relation between vegetation pattern changes and sediment yield in the watershed is discussed, and the responses of runoff and sediment yield in the watersheds concerning forest growth stages are studied. The results show that the relative errors of simulated values of runoff and sediment yield are below 30%, the correlation coefficients axe above 0.90, and the Nash-Suttcliffe efficiency coefficients axe above 0.80. The simulation results present satisfactory performance, thus, the model could be used to simulate the runoff and sediment yield in these small watersheds. It is also observed that soil erosion tended to become severe as precipitation increased in the watershed, while soil erosion has a decreasing trend as forest cover increases and vegetation pattern is optimized. When the watershed is fully covered by forest, erosion and sediment yield are minimized. When the forest cover is about 30% and evenly distributed in the watershed, the erosion intensity is lower than if the forest cover is collectively distributed in the watershed. Erosion varies with different forest growth stages in the watershed; it is more serious at the young and near planting stage and is the smallest at the mature forest stage. 相似文献