孢粉指标在我国海岸带古气候、古海面变化中的应用现状     

蔡庆芳  刘冬雁  贾培蒙 《江苏地质》2015,39(4):621-626

对海岸带沉积记录孢粉指标在古气候、古海平面变化研究中的应用现状进行了简述。孢粉研究工作随着科学技术的发展取得了很大的进步,近年来,许多学者结合高密度采样和精确AMS14C测年等技术来恢复古环境演变过程。我国近海孢粉学研究在渤海、黄海、东海和南海均取得了大量研究成果  相似文献   

Detecting understory plant invasion in urban forests using LiDAR     

《International Journal of Applied Earth Observation and Geoinformation》2015

Light detection and ranging (LiDAR) data are increasingly used to measure structural characteristics of urban forests but are rarely used to detect the growing problem of exotic understory plant invaders. We explored the merits of using LiDAR-derived metrics alone and through integration with spectral data to detect the spatial distribution of the exotic understory plant Ligustrum sinense, a rapidly spreading invader in the urbanizing region of Charlotte, North Carolina, USA. We analyzed regional-scale L. sinense occurrence data collected over the course of three years with LiDAR-derived metrics of forest structure that were categorized into the following groups: overstory, understory, topography, and overall vegetation characteristics, and IKONOS spectral features – optical. Using random forest (RF) and logistic regression (LR) classifiers, we assessed the relative contributions of LiDAR and IKONOS derived variables to the detection of L. sinense. We compared the top performing models developed for a smaller, nested experimental extent using RF and LR classifiers, and used the best overall model to produce a predictive map of the spatial distribution of L. sinense across our country-wide study extent. RF classification of LiDAR-derived topography metrics produced the highest mapping accuracy estimates, outperforming IKONOS data by 17.5% and the integration of LiDAR and IKONOS data by 5.3%. The top performing model from the RF classifier produced the highest kappa of 64.8%, improving on the parsimonious LR model kappa by 31.1% with a moderate gain of 6.2% over the county extent model. Our results demonstrate the superiority of LiDAR-derived metrics over spectral data and fusion of LiDAR and spectral data for accurately mapping the spatial distribution of the forest understory invader L. sinense.  相似文献   

1991-2012年大陆台资不同类型制造业的时空格局演化     

高月华  韦素琼  陈松林 《地域研究与开发》2015,(1)

台商投资可促进大陆产业升级和两岸关系稳定。基于1991—2012年台商对大陆制造业直接投资数据,将大陆台资制造业细分成劳动密集型产业、资金密集型产业、技术密集型产业,分析其时空扩散特征,并用灰色关联方法探讨台资制造业时空格局演化的影响要素。结果表明:1大陆台资制造业行业结构有明显的阶段变化,与岛内产业结构调整密切相关;2大陆台资制造业空间分布表现出集聚与扩散并存,在集聚主导下呈现由南向北、由东向西的扩散态势,并由南部沿海地区的单集聚格局发展为南部与东部沿海地区的双集聚中心,最后演化为东部沿海地区的单集聚中心;3东部沿海地区承接南部沿海地区的三类产业(尤其是技术密集型产业)转移成为高度集聚区,中西部则主要吸引资源型和劳动密集型产业;4不同阶段影响台商对大陆不同类型制造业投资的主导因子不同。  相似文献   

中国科学院气候系统模式模拟的ENSO循环   总被引：1，自引：1，他引：0  

苏同华  薛峰  孙泓川  周广庆 《海洋学报(英文版)》2015,34(1):55-65

On the basis of more than 200-year control run, the performance of the climate system model of Chinese Academy of Sciences(CAS-ESM-C) in simulating the El Ni?o-Southern Oscillation(ENSO) cycle is evaluated, including the onset, development and decay of the ENSO. It is shown that, the model can reasonably simulate the annual cycle and interannual variability of sea surface temperature(SST) in the tropical Pacific, as well as the seasonal phase-locking of the ENSO. The model also captures two prerequisites for the El Ni?o onset, i.e., a westerly anomaly and a warm SST anomaly in the equatorial western Pacific. Owing to too strong forcing from an extratropical meridional wind, however, the westerly anomaly in this region is largely overestimated. Moreover, the simulated thermocline is much shallower with a weaker slope. As a result, the warm SST anomaly from the western Pacific propagates eastward more quickly, leading to a faster development of an El Ni?o. During the decay stage, owing to a stronger El Ni?o in the model, the secondary Gill-type response of the tropical atmosphere to the eastern Pacific warming is much stronger, thereby resulting in a persistent easterly anomaly in the western Pacific. Meanwhile, a cold anomaly in the warm pool appears as a result of a lifted thermocline via Ekman pumping. Finally, an El Ni?o decays into a La Ni?a through their interactions. In addition, the shorter period and larger amplitude of the ENSO in the model can be attributed to a shallower thermocline in the equatorial Pacific, which speeds up the zonal redistribution of a heat content in the upper ocean.  相似文献   

Engaging a temporal–spatial stretch: An inquiry into the role of the state in cultivating and claiming the Chinese knowledge diaspora     

《Geoforum》2015

This paper examines the role of the state in cultivating and claiming the Chinese knowledge diaspora for development, focusing on the Chinese–German academic space. It calls for a temporal–spatial stretch in conceptualising the state in this policy arena. The spatial stretch broadens the usual analysis of the state to go beyond the sending nation-state framework. It illustrates that the state, rather than functioning as a unitary body, comprises different agencies and exists in a multiplicity of forms. Examples demonstrate that the Chinese state at various geographical levels and localities as well as states in other countries engage with one another in making and tapping the Chinese knowledge diaspora. The temporal stretch necessitates an extension of our analytical optic from the conventional focus on how the state claims the diaspora ‘out there’ towards recognising its important role in the strategic and selective production of the diaspora. Furthermore, this paper calls for a higher sensitivity to other temporal characteristics in state policies and practices. Moving away from an expectation of a permanent return of its talents overseas, the Chinese state has turned to the ‘diaspora option’, which refers to regulating and tapping the potential of the Chinese knowledge network that contributes from afar and/or circulates transnationally. Other mechanisms to control the temporality of knowledge diaspora engagement will also be illustrated. Finally, the paper provides an analysis of the complex, sometimes collaborative while other times competitive relationship, between the Chinese and German states in producing and regulating the Chinese knowledge diaspora.  相似文献   

Hydrogen isotope characteristics of thermogenic methane in Chinese sedimentary basins     

《Organic Geochemistry》2015

  相似文献   

Cognition and construction of the theoretical connotations of new urbanization with Chinese characteristics     

Chen  Mingxing  Ye  Chao  Lu  Dadao  Sui  Yuwen  Guo  Shasha 《地理学报(英文版)》2019,29(10):1681-1698

Journal of Geographical Sciences - Since the reform and opening up in China, rapid urbanization has boosted the development of economy and society, but it has also been confronted by tremendous...  相似文献   

Response of phytoplankton to multispecies mariculture: a case study on the carrying capacity of shellfish in the Sanggou Bay in China   总被引：3，自引：0，他引：3  

GE Changzi  FANG Jianguang  SONG Xief  MAO Yuze  YE Naihao 《海洋学报(英文版)》2008,27(1):102-112

A multispecies model for shellfish polyculture in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamys farreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen(DIN) in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the large-scale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m³, the expandable multiple of scallop culture k and that of oyster culture y are determined as k=-0.276 5y+4.690 5 and 0.133 3k+0.006 6y ≤ 0.667 5, where, k (or y) is equal to 1, the culture scale of scallop (or oyster) is 8.8×10⁹ individuals (or 66 ha, with a density of 59 ind./m²), and the kelp culture scale is 3 300 ha with a density of 12 ind./m².  相似文献   

我国月球激光测距研究与进展   总被引：2，自引：0，他引：2  

郑向明  郭锐  李语强  李祝莲  伏红林  熊耀恒 《天文研究与技术》2007,4(3):231-237

月球激光测距是国内外所瞩目的宏伟目标,代表着单光子探测技术的高峰。文中概述了全球月球激光测距的现状以及21世纪初月球激光测距的发展趋势;分析了我国开展月球激光测距的意义。最后介绍了云南天文台1.2m望远镜进行月球激光测距的发展战略和科学目标。  相似文献   

复方中药及其与抗生素联用对斜带石斑鱼变形假单胞菌病的防治效果          下载免费PDF全文

徐晓津  李秀华  马一帆  李慧耀  祁欣  吕海龙  鄢庆枇 《应用海洋学学报》2020,39(4):574-580

通过药物体外抑菌效果及其对斜带石斑鱼(Epinephelus coioides)抗病力影响的研究，筛选出有效治疗斜带石斑鱼变形假单胞菌(Pseudomonas plecoglossicida)病的复方中药与中西药联用配方。在不同复方中药实验组投喂饲料中添加不同比例黄连、黄芪与黄柏，设定三联复方中药实验组Ⅰ、Ⅱ、Ⅲ（黄连、黄芪、黄柏质量比分别为0.9∶〖KG-*2〗1.3∶〖KG-*2〗0.9、1.2∶〖KG-*2〗0.9∶〖KG-*2〗1.0、1.0∶〖KG-*2〗1.0∶〖KG-*2〗1.0）；复方中药与抗生素联用组中， 将不同质量比的中药黄连、黄芪、黄柏与抗生素恩诺沙星添加入饲料，分别设定为中西药联用实验组Ⅳ、V、VI。各三联中药与中西药联用实验组均添加占饲料2.2%质量分数的药物。研究结果为：三联复方中药浓度为60 mg/mL，黄连、黄芪、黄柏质量比为1.2∶〖KG-*2〗0.9∶〖KG-*2〗1.0时，抑制变形假单胞菌的效果最好，为复方中药组中最佳配方。养殖实验进行至40 d时，鱼死亡率由高到低分别为：对照组Ⅱ>对照组Ⅳ>对照组Ⅲ>实验组Ⅰ>实验组Ⅲ>实验组Ⅱ>实验组V>实验组VI >实验组Ⅳ>对照组Ⅰ。实验组Ⅱ（饲料中添加质量比为1.2∶〖KG-*2〗0.9∶〖KG-*2〗1.0的黄连∶〖KG-*2〗黄芪∶〖KG-*2〗黄柏）为药效最好的复方中药配方，实验组Ⅳ（黄连∶〖KG-*2〗黄芪∶〖KG-*2〗黄柏∶〖KG-*2〗恩诺沙星比为 0.9∶〖KG-*2〗1.3∶〖KG-*2〗0.9∶〖KG-*2〗1.3）为治疗鱼病效果最好的中西药联用配方。中西药联用相比复方中药治疗斜带石斑鱼变形假单胞菌病效果好，对于患变形假单胞菌病的斜带石斑鱼有较好的疗效。  相似文献