不同发展模式下资源环境承载力评价——以海南省为例     

牛方曲  杨欣雨  孙东琪 《热带地理》2020,40(6):1109-1116

文章关注于产业、人口与资源环境要素的作用关系，建构了资源环境承载力综合评价框架，并以海南省为案例区开展应用研究。该框架首先对区域产业重要性进行评价并分级，为产业结构调整提供依据；其次解析了区域产业、人口资源消耗与污染排放强度，最后，基于产业评价结果设定不同的产业结构调整情景，结合产业和人口的资源消耗与污染排放强度评价不同产业结构下的资源环境承载力，即产业和人口的规模上限。结果表明：2016年海南省的经济规模并未超载，产业有进一步发展空间。其中土地资源成为海南省发展的首要限制因素，其次是水环境；海南经济效益较高的支柱产业和基础性产业多为高耗水、高污染的产业，亟需加强水资源的集约利用，并降低污染排放强度。为提升经济发展规模上限，需要培育低能耗、低排放的产业。文章建构的资源环境承载力评价方法将产业、人口与资源环境相联系，其评价结果政策意义更为明确，可为优化产业结构调整、控制产业及人口发展规模提供决策参考。  相似文献   

Effects of Anthropogenic Disturbance on Sediment Organic Carbon Mineralization Under Different Water Conditions in Coastal Wetland of a Subtropical Estuary     

Xiaojie Mou  Xingtu Liu  Zhigao Sun  Chuan Tong  Jiafang Huang  Siang Wan  Chun Wang  Bolong Wen 《中国地理科学(英文版)》2018,28(3):400-410

The changes in soil organic carbon(C) mineralization as affected by anthropogenic disturbance directly determine the role of soils as C source or sink in the global C budget. The objectives of this study were to investigate the effects of anthropogenic disturbance(aquaculture pond, pollutant discharge and agricultural activity) on soil organic C mineralization under different water conditions in the Minjiang River estuary wetland, Southeast China. The results showed that the organic C mineralization in the wetland soils was significantly affected by human disturbance and water conditions(P 0.001), and the interaction between human disturbance activities and water conditions was also significant(P 0.01). The C mineralization rate and the cumulative mineralized carbon dioxide-carbon(CO_2-C)(at the 49th day) ranked from highest to lowest as follows: Phragmites australis wetland soil aquaculture pond sediment soil near the discharge outlet rice paddy soil. This indicated that human disturbance inhibited the mineralization of C in soils of the Minjiang River estuary wetland, and the inhibition increased with the intensity of human disturbance. The data for cumulative mineralized CO_2-C showed a good fit(R~2 0.91) to the first-order kinetic model C_t = C_0(1 – exp(–kt)). The kinetic parameters C_0, k and C_0 k were significantly affected by human disturbance and water conditions. In addition, the total amount of mineralized C(in 49 d) was positively related to C_0, C_0 k and electrical conductivity of soils. These findings indicated that anthropogenic disturbance suppressed the organic C mineralization potential in subtropical coastal wetland soils, and changes of water pattern as affected by human activities in the future would have a strong influence on C cycling in the subtropical estuarine wetlands.  相似文献   

Leak-off mechanism and pressure prediction for shallow sediments in deepwater drilling     

Qiang Tan  Jingen Deng  Jin Sun  Wei Liu  Baohua Yu 《中国海洋大学学报(英文版)》2018,17(1):65-71

Deepwater sediments are prone to loss circulation in drilling due to a low overburden gradient. How to predict the magnitude of leak-off pressure more accurately is an important issue in the protection of drilling safety and the reduction of drilling cost in deep water. Starting from the mechanical properties of a shallow formation and based on the basic theory of rock-soil mechanics, the stress distribution around a borehole was analyzed. It was found that the rock or soil on a borehole is in the plastic yield state before the effective tensile stress is generated, and the effective tangential and vertical stresses increase as the drilling fluid density increases; thus, tensile failure will not occur on the borehole wall. Based on the results of stress calculation, two mechanisms and leak-off pressure prediction models for shallow sediments in deepwater drilling were put forward, and the calculated values of these models were compared with the measured value of shallow leak-off pressure in actual drilling. The results show that the MHPS (minimum horizontal principle stress) model and the FIF (fracturing in formation) model can predict the lower and upper limits of leak-off pressure. The PLC (permeable lost circulation) model can comprehensively analyze the factors influencing permeable leakage and provide a theoretical basis for leak-off prevention and plugging in deepwater drilling.  相似文献   

重力数据约束的二维地震层析成像在台湾海峡南部的应用     

王笋  闫培  刘善虎 《大地测量与地球动力学》2019,39(3):302-306

地震-重力联合反演可以降低多解性，针对大勘探范围内岩石波速-密度关系存在较大散布的问题，引入交叉梯度结构约束构建统一的目标函数是一种有效的解决方案。利用台湾海峡南部HX-13测线进行验证：由于火成岩侵入体的存在，部分区域难以拾取可靠的地震初至，常规的走时反演无法准确恢复基底面的形态。搜集研究区的船测重力资料，根据地震地质条件和数据特点设置合适的反演参数，实现基于物性和结构双重约束的重力-地震联合反演。由对反演结果的分析和解释可以看出，该方法可在很大程度上弥补地震数据不完备的缺陷，使反演过程稳定，并提高模型的可靠性。  相似文献   

桑沟湾沉积碳库年汇入速率的长期变化及其区域性差异   总被引：1，自引：1，他引：0  

刘赛  杨庶  杨茜  孙耀 《海洋学报》2018,40(1):47-56

对取自桑沟湾北西南三根柱样近200 a碳来源及埋藏通量的解析，分析了湾内不同站位各形态碳的差异性，进而对全湾碳埋藏进行了估算。湾内环流、贝藻养殖等造成湾内不同区域碳埋藏的差异；桑沟湾总碳（TC）平均量1.79%，有机碳（TOC）平均量0.54%，无机碳（TIC）平均量1.25%，TOC含量相对较小，为海陆混合来源，以陆源有机碳（C_t）为主，大规模人工养殖后，海源有机碳（C_a）有明显增加的趋势。桑沟湾碳埋藏通量平均为228.9 g/（m2·a），以无机碳为主要埋藏形式（约占70%），高的沉积速率及生物残骸沉降使桑沟湾养殖区碳的来源及埋藏区别于其他陆架海域。  相似文献   

Geophysical Signature of the Shallow Water Flow in the Deepwater Basin of the Northern South China Sea     

Xiaohua Zhang  Yunbao Sun  Shiguo Wu 《中国海洋大学学报(英文版)》2018,17(4):791-798

Shallow water flow (SWF), a disastrous geohazard in the continental margin, has threatened deepwater drilling operations. Under overpressure conditions, continual flow delivering unconsolidated sands upward in the shallow layer below the seafloor may cause large and long-lasting uncontrolled flows; these flows may lead to control problems and cause well damage and foundation failure. Eruptions from over-pressured sands may result in seafloor craters, mounds, and cracks. Detailed studies of 2D/3D seismic data from a slope basin of the South China Sea (SCS) indicated the potential presence of SWF. It is commonly characterized by lower elastic impedance, a higher Vp/Vs ratio, and a higher Poisson’s ratio than that for the surrounding sediments. Analysis of geological data indicated the SWF zone originated from a deepwater channel system with gas bearing over-pressured fluid flow and a high sedimentation rate. We proposed a fluid flow model for SWF that clearly identifies its stress and pressure changes. The rupture of previous SWF zones caused the fluid flow that occurred in the Baiyun Sag of the northern SCS.  相似文献   

Analysis of nonstationarity in low flow in the Loess Plateau of China          下载免费PDF全文

Kun‐xia Yu  Lars Gottschalk  Xiang Zhang  Peng Li  Zhanbin Li  Lihua Xiong  Qian Sun 《水文研究》2018,32(12):1844-1857

An approach for nonstationary low‐flow frequency analysis is developed and demonstrated on a dataset from the rivers on the Loess Plateau of China. Nonstationary low‐flow frequency analysis has drawn significant attention in recent years by establishing relationships between low‐flow series and explanatory variables series, but few studies have tested whether the time‐varying moments of low flow can be fully described by the time‐varying moments of the explanatory variables. In this research, the low‐flow distributions are analytically derived from the 2 basic explanatory variables—the recession duration and the recession coefficient—with the assumption that the recession duration and recession coefficient variables follow exponential and gamma distributions, respectively; the derived low‐flow distributions are applied to test whether the time‐varying moments of explanatory variables can explain the nonstationarities found in the low‐flow variable. The effects of ecosystem construction measures, that is, check dam, terrace, forest, and grassland, on the recession duration and recession coefficient are further discussed. Daily flow series from 11 hydrological stations from the Loess Plateau are used and processed with a moving average technique. Low‐flow data are extracted following the pit under threshold approach. Six of the 11 low‐flow series show significant nonstationarities at the 5% significance level, and the trend curves of the moments of low flow are in close agreement with the curves estimated from the derived distribution with time‐dependent moments of the recession duration and time‐constant moments of the recession coefficient. It is indicated that the nonstationarity in the low‐flow distribution results from the nonstationarity in the recession duration in all 6 cases, and the increase in the recession duration is resulted from large‐scale ecosystem constructions rather than climate change. The large‐scale ecosystem constructions are found to have more influence on the decrease in streamflow than on the increase in watershed storage, thus resulting in the reduction of low flow. A high return period for the initial fixed design value decreases dramatically with an increasing recession duration.  相似文献   

Understanding coastal wetland hydrology with a new regional‐scale,process‐based hydrological model          下载免费PDF全文

Yu Zhang  Wenhong Li  Ge Sun  Guofang Miao  Asko Noormets  Ryan Emanuel  John S. King 《水文研究》2018,32(20):3158-3173

Coastal wetlands represent an ecotone between ocean and terrestrial ecosystems, providing important services, including flood mitigation, fresh water supply, erosion control, carbon sequestration, and wildlife habitat. The environmental setting of a wetland and the hydrological connectivity between a wetland and adjacent terrestrial and aquatic systems together determine wetland hydrology. Yet little is known about regional‐scale hydrological interactions among uplands, coastal wetlands, and coastal processes, such as tides, sea level rise, and saltwater intrusion, which together control the dynamics of wetland hydrology. This study presents a new regional‐scale, physically based, distributed wetland hydrological model, PIHM‐Wetland, which integrates the surface and subsurface hydrology with coastal processes and accounts for the influence of wetland inundation on energy budgets and evapotranspiration (ET). The model was validated using in situ hydro‐meteorological measurements and Moderate Resolution Imaging Spectroradiometer (MODIS) ET data for a forested and herbaceous wetland in North Carolina, USA, which confirmed that the model accurately represents the major wetland hydrological behaviours. Modelling results indicate that topographic gradient is a primary control of groundwater flow direction in adjacent uplands. However, seasonal climate patterns become the dominant control of groundwater flow at lower coastal plain and land–ocean interface. We found that coastal processes largely influence groundwater table (GWT) dynamics in the coastal zone, 300 to 800 m from the coastline in our study area. Among all the coastal processes, tides are the dominant control on GWT variation. Because of inundation, forested and herbaceous wetlands absorb an additional 6% and 10%, respectively, of shortwave radiation annually, resulting in a significant increase in ET. Inundation alters ET partitioning through canopy evaporation, transpiration, and soil evaporation, the effect of which is stronger in cool seasons than in warm seasons. The PIHM‐Wetland model provides a new tool that improves the understanding of wetland hydrological processes on a regional scale. Insights from this modelling study provide benchmarks for future research on the effects of sea level rise and climate change on coastal wetland functions and services.  相似文献   

Immunohistochemical identification of dynorphin A and Kappa opioid receptor-1 in the digestive system of scallop Chlamys farreri     

Sun  Hushan  Wang  Yiyan  Liu  Xiaoli  Liu  Dongwu 《中国海洋湖沼学报》2018,36(6):2288-2296

Journal of Oceanology and Limnology - Little is known about the roles of dynorphin and Kappa opioid receptor (KOR) in mollusks. In this study, we aim to determine the distribution of dynorphin A...  相似文献   

中国区域水资源系统韧性与效率的发展协调关系评价   总被引：1，自引：0，他引：1  

孙才志  孟程程 《地理科学》2020,40(12):2094-2104

在界定水资源系统韧性概念的基础上，综合应用赋权法、SBM-DEA模型及发展协调度模型对2000—2016年全国31个省区的区域水资源系统的效率、韧性以及两者之间的发展协调关系进行评价。结果如下：① 中国区域水资源系统效率整体上处于非有效区，在研究期间呈现出在波动中上升的趋势。② 中国区域水资源系统韧性的平均值为0.39，总体水平较低，研究期间整体上呈波动上升趋势。③ 中国区域水资源系统效率与韧性的发展度总体呈现平稳上升—较快上升—急剧下降—上升的趋势，呈倒“U”型发展；协调度在研究期间呈现波动中上升趋势，大部分省区的发展度较好，而协调度较弱。④ 2000—2016年，水资源效率与韧性的发展协调度一直维持着“东?中?西”阶梯式递减格局，失调省区的数量降低，初级协调、中级协调、良好协调省区的数量逐渐提升，整体向协调趋势发展；空间格局上呈现由2000年倒“E”型对称式分布格局向如今北部围绕天津、中部围绕上海、南部围绕广东的三级格局演变，格局分布与中国三大经济区基本吻合，可知中国水资源系统效率与韧性的发展协调水平与经济发展水平之间有明显的关系。  相似文献