福建省复杂地形下旬平均气温分布式模拟     

李威鹏  邱新法  曾燕  施国萍  徐金勤  王丹丹 《热带地理》2019,39(2):229-236

为建立高时空分辨率的福建省复杂地形下气温栅格数据集，利用福建省及其周边33个常规气象站观测资料，基于数字高程模型（DEM）数据，综合考虑海拔、太阳总辐射、地表长波有效辐射对旬平均气温的影响，模拟了福建省复杂地形下旬均温的空间分布。结果表明：1）常规站验证结果显示：各旬气温绝对误差平均值（MAE）最小为0.46℃，最大为2.3℃，全年平均为0.87℃；加密站验证结果显示，MAE最大为2.3℃，最小0.5℃，全年平均为0.96℃。2）模拟结果能反映旬均温的宏观分布规律与局地细节特征。宏观范围内，旬均温受纬度影响较大，由北至南气温逐渐升高，沿海地区旬均温整体高于内陆，山区旬均温明显较低；局地范围内，各坡向上气温差异显著，海拔越高、坡度越大，差异越明显；地形因子对旬平均温的影响具有季节差异，具体表现为冬季时地形因子对旬均温的影响最大，秋季次之，春夏季节中地形因子对旬均温的影响最弱。  相似文献   

Laboratory Experiments on an Internal Solitary Wave over a Triangular Barrier     

MU Haidi  CHEN Xu  LI Qun 《中国海洋大学学报(英文版)》2019,(5)

Laboratory experiments were conducted to investigate the evolution of interfacial internal solitary waves(ISWs) incident on a triangular barrier. ISWs with different amplitudes were generated by gravitational collapse. The ISW energy dissipation and turbulence processes were calculated as waves passed over the triangular barrier. Experimental results showed that ISWs were reflecting back off the triangular barrier, and shoaling ISWs led to wave breaking and mixing when waves propagated over the obstacle. Wave instability created the dissipation of energy as it was transmitted from waves to turbulence. The rate of ISW energy dissipation, the maximum turbulent dissipation, and the buoyancy diffusivity linearly increased with the increase in the incident wave energy.  相似文献   

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river     

Jing Liu  Jun Zhong  Hu Ding  Fu-Jun Yue  Cai Li  Sen Xu  Si-Liang Li 《水文研究》2020,34(12):2780-2792

To better understand the mechanisms relating to hydrological regulations of chemical weathering processes and dissolved inorganic carbon (DIC) behaviours, high-frequency sampling campaigns and associated analyses were conducted in the Yu River, South China. Hydrological variability modifies the biogeochemical processes of dissolved solutes, so major ions display different behaviours in response to discharge change. Most ions become diluted with increasing discharge because of the shortened reactive time between rock and water under high-flow conditions. Carbonate weathering is the main source of major ions, which shows strong chemostatic behaviour in response to changes in discharge. Ions from silicate weathering exhibit a significant dilution effect relative to the carbonate-sourced ions. Under high temperatures, the increased soil CO₂ influx from the mineralisation of organic material shifts the negative carbon isotope ratios of DIC (δ¹³C_DIC) during the high-flow season. The δ¹³C_DIC values show a higher sensitivity than DIC contents in response to various hydrological conditions. Results from a modified isotope-mixing model (IsoSource) demonstrate that biological carbon is a dominant source of DIC and plays an important role in temporal carbon dynamics. Furthermore, this study provides insights into chemical weathering processes and carbon dynamics, highlighting the significant influence of hydrological variability to aid understanding of the global carbon cycle.  相似文献   

Multivariate adaptive regression splines for estimating riverine constituent concentrations     

Hong Huang  Xiaoliang Ji  Fang Xia  Shuhui Huang  Xu Shang  Han Chen  Minghua Zhang  Randy A. Dahlgren  Kun Mei 《水文研究》2020,34(5):1213-1227

Regression-based methods are commonly used for riverine constituent concentration/flux estimation, which is essential for guiding water quality protection practices and environmental decision making. This paper developed a multivariate adaptive regression splines model for estimating riverine constituent concentrations (MARS-EC). The process, interpretability and flexibility of the MARS-EC modelling approach, was demonstrated for total nitrogen in the Patuxent River, a major river input to Chesapeake Bay. Model accuracy and uncertainty of the MARS-EC approach was further analysed using nitrate plus nitrite datasets from eight tributary rivers to Chesapeake Bay. Results showed that the MARS-EC approach integrated the advantages of both parametric and nonparametric regression methods, and model accuracy was demonstrated to be superior to the traditionally used ESTIMATOR model. MARS-EC is flexible and allows consideration of auxiliary variables; the variables and interactions can be selected automatically. MARS-EC does not constrain concentration-predictor curves to be constant but rather is able to identify shifts in these curves from mathematical expressions and visual graphics. The MARS-EC approach provides an effective and complementary tool along with existing approaches for estimating riverine constituent concentrations.  相似文献   

分形岩石裂隙中渗流扩散运动的试验研究     

崔溦  邹旭  李正  江志安  谢武 《岩土力学》2020,41(11):3553-3562

由于存在大量粗糙不规则裂隙，使得岩体中流体运动极为复杂。针对天然粗糙岩石裂隙渗流试验存在物理模型隐蔽性和不可重复性等难点，基于三维Weierstrass-Mandelbrot分形函数构建了粗糙节理面的裂隙通道，采用3D打印技术获得了透明精细的裂隙模型，使用微流体控制仪研究了不同试验条件下的裂隙渗流扩散运动，分析了裂隙通道流量与压力水头、裂隙宽度和分形维数之间的关系。研究结果表明：与平行板立方定律近似，在分形裂隙中，裂隙通道流量与压力水头成线性关系；单宽流量与裂隙通道的宽度成近似的三次方关系；考虑分形维数影响时，相同条件下流过裂隙通道的流量随着分形维数的增加而增加；粗糙裂隙渗流立方定律可采用与分形维数相关的幂指数函数进行修正。  相似文献   

福建武夷山桃棋矿区石墨矿床地质特征及成因探讨     

许志华  林香  张大伟 《化工矿产地质》2020,42(3):231-237

  相似文献   

Bibliometric Analysis of Research Progress on Coastal Surface Water and Groundwater Interaction     

Tianzheng Cao  Dongmei Han  Xianfang Song  Wei Liu  Di Du 《地球科学进展》2020,35(2):154-166

The interactions among surface water, groundwater and seawater are closely related in the coastal area with complex hydrological conditions. A series of impacts from human activities and climate change are also more significant in this region. In order to understand the key knowledge and research status of surface water and groundwater interaction in coastal area, it is a useful method to analyze literatures in this research scope in the core database of Web of Science by using CiteSpace. The research achievements in this field were systematically sorted and potential research hotspots were explored, which may provide references for subsequent researches. The results show the following. \mathrm{①} The number of highly cited articles and highly burst articles in this research field has increased significantly since 2010. At present, this field is still in the development stage and has a broad research prospect. \mathrm{②} The United States, Australia, China and Germany have done plenty of researches on this issue and achieved a lot. At present, the number of research achievements supported by National Natural Science Foundation of China is in the lead over the world. \mathrm{③} Seawater intrusion, submarine groundwater discharge, the relationship between tide and hydrological conditions are the main research direction in this field. Hydrochemistry and isotopic analysis, and numerical simulation are the most important research methods in this field. \mathrm{④} The potential development directions and breakthroughs in this field include submarine groundwater discharge, the evolution of coastal mangrove wetlands, the migration and transformation of nutrients, the influences of different hydrological factors on coastal areas, and the impact of climate change on coastal areas. Overall, the future development of surface water and groundwater research in coastal areas is inseparable from the cross-integration of various disciplines, mutual verification of multiple methods and the introduction of new technical means.  相似文献   

基于Citespace的无人机遥感研究知识图谱分析     

梁宇哲  郑荣宝  徐嘉源  郑至键 《热带地理》2019,39(2):309-317

为清晰了解国内外无人机遥感应用研究现状及发展态势，以Web of Science核心期刊为数据源，运用文献计量方法与Citespace可视化分析工具对无人机遥感研究的相关文献进行统计分析。结果表明：无人机遥感相关研究文献呈快速增长趋势，与遥感科学、工程学和影像科学摄影技术三门学科联系最为密切；美国、中国、西班牙等国家发文量较多，具备较强研究力量；中国科学院发文量最多，而西班牙最高科研理事会h指数最高，均有较大影响力；澳大利亚学者Lucieer A和西班牙学者Zarco-Tejada PJ的h指数较高，为该领域的代表性学者；无人机遥感技术包含多个研究方向，其中研究热点包括无人机遥感在农业科学和生态学等领域的应用研究、遥感影像分类方法的研究、摄影技术和计算机视觉技术的研究等三方面。  相似文献   

The evolution of the spatial-temporal patterns of global energy security since the 1990s     

Wang  Qiang  Xu  Linglin  Li  Na  Du  Xue  Wu  Shidai  Tian  Lanlan  Wu  Chenlu 《地理学报(英文版)》2019,29(8):1245-1260

Journal of Geographical Sciences - In this study, we developed an energy security evaluation model (ESEM) from three dimensions, energy supply-transport security, safety of energy utilization, and...  相似文献   

Primary investigation of statistical correlation between changes in ice volume and area of glaciers     

PuYu Wang  ZhongQin Li  ChunHai Xu  Ping Zhou  WenBin Wang  Shuang Jin  HongLiang Li 《寒旱区科学》2019,11(1):41-49

This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers. Using data from nine sample glaciers in the Tian Shan, the results show that a linear relation exists between changes in ice volume and area, with a correlation coefficient of 0.700. However, the accuracy estimation is difficult due to the limited number of samples. The correlation was not improved after adding eleven glacier samples in other mountains. Two reference glaciers are then analyzed in more detail. The linear correlation coefficient is higher than 0.800 when using the observed changes in ice volume and area during different periods on Urumqi Glacier No. 1, which suggests that the linear relation is valid for one glacier for different periods if its shape does not change noticeably and also for other glaciers of the same shape during the same period. The relation between changes in ice volume and area of Qingbingtan Glacier No. 72 is different during different periods due to change in the shape of the glacier tongue and the influence of the debris cover. Moreover, errors in glacier-change monitoring and-volume estimation have an important influence on the correlation results. Therefore, further study needs to focus not only on the distinction between glacier types and between different periods but also on the accuracy of volume estimation.  相似文献