http://www.sciencedirect.com/science/article/pii/S1674987110000113   总被引：3，自引：0，他引：3  

Xueqi Xi  Zhongfang Yang  Yan Liao  Yujun Cui  Yansheng Li 《地学前缘(英文版)》2010,1(1):125-132

<正>Against the current background of global climate change,the study of variations in the soil carbon pool and its controlling factors may aid in the evaluation of soil's role in the mitigation or enhancement of greenhouse gas.This paper studies spatial and temporal variation in the soil carbon pool and their controlling factors in the southern Song-nen Plain in Heilongjiang Province,using soil data collected over two distinct periods by the Multi-purpose Regional Geochemical Survey in 2005—2007, and another soil survey conducted in 1982—1990.The study area is a carbon source of 1479 t/km~2 and in the past 20 years,from the 1980s until 2005.the practical carbon emission from the soil was 0.12 Gt.Temperature,which has been found to be linearly correlated to soil organic carbon,is the dominant climatologic factor controlling soil organic carbon contents.Our study shows that in the relevant area and time period the potential loss of soil organic carbon caused by rising temperatures was 0.10 Gt,the potential soil carbon emission resulting from land-use change was 0.09 Gt,and the combined potential loss of soil carbon(0.19 Gt) caused by warming and land-use change is comparable to that of fossil fuel combustion(0.21 Gt).Due to the time delay in soil carbon pool variation,there is still 0.07 Gt in the potential emission caused by warming and land-use change that will be gradually released in the future.  相似文献   

Temporal stability of apparent soil electrical conductivity measured by electromagnetic induction techniques     

LIAO Kai-hua  ZHU Qing  James DOOLITTLE 《山地科学学报》2014,11(1):98-109

Assessing and managing the spatial variability of hydropedological properties are important in environmental,agricultural,and geological sciences.The spatial variability of soil apparent electrical conductivity（ECa） measured by electromagnetic induction（EMI） techniques has been widely used to infer the spatial variability of hydrological and pedological properties.In this study,temporal stability analysis was conducted for measuring repeatedly soil ECa in an agricultural landscape in 2008.Such temporal stability was statistically compared with the soil moisture,terrain indices（slope,topographic wetness index（TWI）,and profile curvature）,and soil properties（particle size distribution,depth to bedrock,Mn mottle content,and soil type）.Locations with great and temporally unstable soil ECa were also associated with great and unstable soil moisture,respectively.Soil ECa were greater and more unstable in the areas with great TWI（TWI 〉 8）,gentle and concave slope（slope 〈 3%; profile curvature 〉 0.2）.Soil ECa exponentially increased with depth to bedrock,and soil profile silt and Mn mottle contents（R2= 0.57）,quadratically（R2 = 0.47）,and linearly（R 2 = 0.47）,respectively.Soil ECa was greater and more unstable in Gleysol and Nitosol soils,which were distributed in areas with low elevation（〈 380 m）,thick soil solum（〉 3 m）,and fluctuated water table（shallow in winter and spring but deep in summer and fall）.In contrast,Acrisol,Luvisol,and Cambisol soils,which are distributed in the upper slope areas,had lower and more stable soil ECa.Through these observations,we concluded that the temporal stability of soil ECa can be used to interpret the spatial and temporal variability of these hydropedological properties.  相似文献   

Modeling of spatial distributions of farmland density and its temporal change using geographically weighted regression model   总被引：1，自引：1，他引：0  

Haitao Zhang  Long Guo  Jiaying Chen  Peihong Fu  Jianli Gu  Guangyu Liao 《中国地理科学(英文版)》2014,24(2):191-204

This study used spatial autoregression（SAR） model and geographically weighted regression（GWR） model to model the spatial patterns of farmland density and its temporal change in Gucheng County,Hubei Province,China in 1999 and 2009,and discussed the difference between global and local spatial autocorrelations in terms of spatial heterogeneity and non-stationarity. Results showed that strong spatial positive correlations existed in the spatial distributions of farmland density,its temporal change and the driving factors,and the coefficients of spatial autocorrelations decreased as the spatial lag distance increased. SAR models revealed the global spatial relations between dependent and independent variables,while the GWR model showed the spatially varying fitting degree and local weighting coefficients of driving factors and farmland indices（i.e.,farmland density and temporal change）. The GWR model has smooth process when constructing the farmland spatial model. The coefficients of GWR model can show the accurate influence degrees of different driving factors on the farmland at different geographical locations. The performance indices of GWR model showed that GWR model produced more accurate simulation results than other models at different times,and the improvement precision of GWR model was obvious. The global and local farmland models used in this study showed different characteristics in the spatial distributions of farmland indices at different scales,which may provide the theoretical basis for farmland protection from the influence of different driving factors.  相似文献   

备用分钟数据读取程序浅析     

廖其瑞  李肖平  樊俏丽  文秀 《气象研究与应用》2014,35(3):103-104

从逐分钟地面数据文件中读取正点前10分钟内任一分钟的分钟数据进行备用,以备在临近正点时自动气象站计算机系统出现故障的情况下作为电话口传报文之用,保证正点数据的及时有效传输,避免逾限报的发生。  相似文献   

两次副高边缘特大暴雨对比分析     

杨新  柯文华  张小荣  任文斌  廖胜石 《气象研究与应用》2014,35(4):1-4

利用常规资料、地面加密自动观测资料、NCEP/NCAR的1°×1°每6h再分析资料及多普勒雷达资料,对2011年6月16日（简称6.16过程）及2008年7月31日（简称7.31过程）发生在粤东南两次副高边缘特大暴雨进行对比分析。结果表明：6.16过程主要是受高空短波槽和偏南风急流共同影响而产生的,较厚的暖云层、深厚的湿层等使该过程降水范围更广;7.31过程主要是受对流中层扰动诱发产生的,为局地性强降水。雷达回波均表现为强的反射率因子,回波发展迅速且移动缓慢;6.16过程回波图上出现有界弱回波区（BWER）等超级单体风暴特征。  相似文献   

Fusion of high-resolution DEMs derived from COSMO-SkyMed and TerraSAR-X InSAR datasets   总被引：1，自引：0，他引：1  

Houjun Jiang  Lu Zhang  Yong Wang  Mingsheng Liao 《Journal of Geodesy》2014,88(6):587-599

Voids caused by shadow, layover, and decorrelation usually occur in digital elevation models (DEMs) of mountainous areas that are derived from interferometric synthetic aperture radar (InSAR) datasets. The presence of voids degrades the quality and usability of the DEMs. Thus, void removal is considered as an integral part of the DEM production using InSAR data. The fusion of multiple DEMs has been widely recognized as a promising way for the void removal. Because the vertical accuracy of multiple DEMs can be different, the selection of optimum weights becomes a key problem in the fusion and is studied in this article. As a showcase, two high-resolution InSAR DEMs near Mt. Qilian in northwest China are created and then merged. The two pairs of InSAR data were acquired by TerraSAR-X from an ascending orbit and COSMO-SkyMed from a descending orbit. A maximum likelihood fusion scheme with the weights optimally determined by the height of ambiguity and the variance of phase noise is adopted to syncretize the two DEMs in our study. The fused DEM has a fine spatial resolution of 10 m and depicts the landform of the study area well. The percentage of void cells in the fused DEM is only 0.13 %, while 6.9 and 5.7 % of the cells in the COSMO-SkyMed DEM and the TerraSAR-X DEM are originally voids. Using the ICESat/GLAS elevation data and the Chinese national DEM of scale 1:50,000 as references, we evaluate vertical accuracy levels of the fused DEM as well as the original InSAR DEMs. The results show that substantial improvements could be achieved by DEM fusion after atmospheric phase screen removal. The quality of fused DEM can even meet the high-resolution terrain information (HRTI) standard.  相似文献   

中坝隧道地下分水岭演化的数值模拟分析     

廖晓超  许模  蒋莉  赵瑞  苟敬 《地下水》2014,(1):48-49,52

由于铁路隧道的施工,地下水进入隧道,形成了新的排泄基准面,对区域地下水环境产生较大影响,故对该类问题进行深入研究具有重要的工程实践意义。以中坝岩溶隧道为例,采用Visual modflow对中坝隧道进行三维数值模拟,模拟中坝隧道开挖建设后,地下分水岭的演化过程,以此来探讨分析其对地下水环境的影响。  相似文献   

From flood control to flood adaptation: a case study on the Lower Green River Valley and the City of Kent in King County,Washington     

Kuei-Hsien Liao 《Natural Hazards》2014,71(1):723-750

Despite massive investment in flood control infrastructure (FCI), neither cities nor rivers have been well served—flooding continues to challenge cities around the world, while riverine ecosystems are degraded by FCI. Although new flood hazard management concepts have shifted the focus away from FCI, many cities continue to count on FCI to prevent flood damage. It is assumed that existing built-up areas can only count on FCI, as large-scale retreat is often impossible. However, flood adaptation—retrofitting the built environment to prevent damage during flooding—as an option is often ignored. This paper argues against the continual use of FCI to prevent flood damage by reviewing FCI’s established problems. The paper examines human–river interactions associated with FCI, focusing on the feedback mechanisms in the interactions, with a case study on the Lower Green River (LGR) valley in King County, Washington, USA. An urban ecology research model is employed to organize the case study, where interactions between floodplain urbanization, FCI, flow and sediment changes, flood risk, and riverine ecosystem are explored and two feedback mechanisms—river adjustment and flood risk perception—are explicitly addressed. The resulting complex dynamics, in terms of cross–scale interactions, emergence, nonlinearity, and surprises, are synthesized and limitations of FCI outlined. Flood adaptation is explored as a plausible alternative to flood control to nurture flood resilience. A management scenario of flood adaptation for the City of Kent—the largest municipality in the LGR valley—is developed to discuss the implications of flood adaptation on flood risk and river restoration.  相似文献   

Rural-urban governance toward Sustainable Development Goals     

Ye  Chao  Chen  Mingxing  Chen  Ruishan  Liao  Chuan 《地理学报(英文版)》2022,32(7):1405-1408

Journal of Geographical Sciences -  相似文献   

Numerical simulation of a dam break for an actual river terrain environment     

C. B. Liao  M. S. Wu  S. J. Liang 《水文研究》2007,21(4):447-460

A two‐dimensional (2D) finite‐difference shallow water model based on a second‐order hybrid type of total variation diminishing (TVD) approximate solver with a MUSCL limiter function was developed to model flooding and inundation problems where the evolution of the drying and wetting interface is numerically challenging. Both a minimum positive depth (MPD) scheme and a non‐MPD scheme were employed to handle the advancement of drying and wetting fronts. We used several model problems to verify the model, including a dam break in a slope channel, a dam break flooding over a triangular obstacle, an idealized circular dam‐break, and a tide flow over a mound. Computed results agreed well with the experiment data and other numerical results available. The model was then applied to simulate the dam breaking and flooding of Hsindien Creek, Taiwan, with the detailed river basin topography. Computed flooding scenarios show reasonable flow characteristics. Though the average speed of flooding is 6–7 m s^?1, which corresponds to the subcritical flow condition (Fr < 1), the local maximum speed of flooding is 14·12 m s^?1, which corresponds to the supercritical flow condition (Fr ≈ 1·31). It is necessary to conduct some kind of comparison of the numerical results with measurements/experiments in further studies. Nevertheless, the model exhibits its capability to capture the essential features of dam‐break flows with drying and wetting fronts. It also exhibits the potential to provide the basis for computationally efficient flood routing and warning information. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献