海洋自然资本评估中生物能值转换率的研究          下载免费PDF全文

丁洁琼  魏方懿  叶观琼  曾江宁  林颖  韩宇 《应用海洋学学报》2020,39(2):253-260

自然资本评估是研究生态系统服务与社会经济发展的重要方式。由于海洋具有特殊性和复杂性、开放性、流动性和多层次耦合性等特点,海洋自然资本评估方法的研究进展缓慢。能值分析理论通过能值转换率将生态系统内流动和储存的各种不同类别的能量和物质转换为同一标准的能值,可衡量和比较不同等级的能量价值,系统完整地反映自然资本价值,这一特点是其他评估方法所缺乏的。为精确量化海洋生物资本价值,本研究引入海洋食物网信息能流图和生态系统能量传递规律,提出了生物能值转换率的经验公式,即Tn=T1·E^1-nL(T1为初级生产者的太阳能值转换率,n为营养级,EL为林德曼效率)。为验证经验公式的可行性,选用相关案例进行了研究,得到海洋食物网中不同食性生物所处营养级及其相应的能值转换率。经验公式有一定误差,具体应用时应通过调研文献和相关数据,确定关键参数的取值范围以提高准确性。本研究得出的经验公式简化了海洋生物能值转换率的计算方法,促进了能值分析理论在海洋自然资本评估中的进一步应用。  相似文献   

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马开锋  彭碧波  洪樱 《大地测量与地球动力学》2007,27(1):85-90

???????????????仯????????????????GPS??????????????????????????????????????????????????????????????????????λ?ü????????????????????????????????????GPS??????15????????????25????????????????????????????????????25??????????????????????????????  相似文献   

GPS/DR原始观测值组合导航定位研究   总被引：1，自引：0，他引：1  

于兴旺  张小红  刘经南  赵莹 《武汉大学学报(信息科学版)》2009,34(2)

根据GPS/DR组合系统的导航定位原理,推导了利用GPS原始观测值与DR航位推算信息进行组合的Kalman滤波模型,并利用该滤波模型对GPS/DR原始观测数据进行航位解算.数据处理结果表明,即使在只有两颗GPS观测卫星的情况下,该滤波模型也可以充分利用GPS现测信息提高DR航位推算精度.  相似文献   

The cooperative and conflictual interactions between the United States,Russia, and China: A quantitative analysis of event data   总被引：1，自引：0，他引：1  

YUAN Lihua  SONG Changqing  CHENG Changxiu  SHEN Shi  CHEN Xiaoqiang  WANG Yuanhui 《地理学报(英文版)》2020,30(10):1702-1720

The United States, Russia and China are militarily and economically among the most powerful countries in the post-Cold War period, and the interactions between the three powers heavily influence the international system. However, different conclusions about this question are generally made by researchers through qualitative analysis, and it is necessary to objectively and quantitatively investigate their interactions. Monthly-aggregated event data from the Global Data on Events, Location and Tone(GDELT) to measure cooperative and conflictual interactions between the three powers, and the complementary cumulative distribution function(CCDF) and the vector autoregression(VAR) method are utilized to investigate their interactions in two periods: January, 1991 to September, 2001, and October, 2001 to December, 2016. The results of frequencies and strengths analysis showed that: the frequencies and strengths of USA-China interactions slightly exceeded those of USA-Russia interactions and became the dominant interactions in the second period. Although that cooperation prevailed in the three dyads in two periods, the conflictual interactions between the USA and Russia tended to be more intense in the second period, mainly related to the strategic contradiction between the USA and Russia, especially in Georgia, Ukraine and Syria. The results of CCDF indicated that similar probabilities in the cooperative behaviors between the three dyads, but the differences in the probabilities of conflictual behaviors in the USA-Russia dyad showed complicated characteristic, and those between Russia and China indicated that Russia had been consistently giving China a hard time in both periods when dealing with conflict. The USA was always an essential factor in affecting the interactions between Russia and China in both periods, but China's behavior only played a limited role in influencing the interactions between the USA-Russia dyad. Our study provides quantitative insight into the direct cooperative and conflictual interactions between the three dyads since the end of the Cold War and helps to understand their interactions better.  相似文献   

国际工程承包中的成本控制          下载免费PDF全文

宋世明 《山东国土资源》2004,20(4):21-23

承包商在实施国际承包工程中，主要目的是为了追求利润。为达此目的，必须对成本进行控制。要实现成本控制目标，必须对影响成本的主要因素、成本控制的基础、成本控制的主要环节基本清楚。下面就笔者在国际承包工程中的经验教训谈些粗浅认识，或许对读者有所裨益。  相似文献   

山东省滨州市城镇体系的分形研究   总被引：1，自引：0，他引：1  

董立峰  苑惠丽  宋芙蓉  陈淑清 《测绘科学》2009,34(6)

运用分形理论从等级规模和空间结构两方面分析了滨州市城镇体系结构特征。从城镇体系规模结构方面,计算了滨州市城市规模分形分布的分维数和城镇体系的首位指数,并讨论了滨州市城镇体系的等级规模结构及其特点;从城镇体系空间结构角度,计算滨州市空间结构的关联维数,分析其分形特征。最后,提出滨州市城市发展的方向:扩大首位城市规模,培育次级中心城市,积极发展县域小城镇。  相似文献   

电子地图多尺度显示中“放大镜”效果的实现     

贾奋励  游雄  宋国民  刘颖真 《测绘学院学报》2009,(1)

"放大镜"效果是电子地图多尺度表达的形式之一,能够以更多的细节显示某个或某几个重点,而其他区域则以较少的细节表示。"放大镜"效果的实现需要从数学基础、数据组织、显示调度等多方面进行改造,针对上述几方面讨论了"放大镜"效果的实现方式,并进行了实验论证。  相似文献   

基于统一基础网格的空间数据权限管理模型研究     

俞晖  杨盈  陈学业 《测绘与空间地理信息》2009,32(4):67-69

从空间数据应用权限管理的角度,对空间数据权限进行了必要的需求分析,提出空间数据应用权限需进一步细化,并指出基于基础城市统一进出网格实现权限管理的可行性和管理模型.  相似文献   

Model Test Study on Ice-Induced Vibrations of Compliant Multi-Cone Structures     

黄焱  史庆增  宋安 《中国海洋工程》2009,23(2):317-328

For the study on the ice-induced vibration of a compliant mono-cone structure,a series of model tests were performed from 2004 to 2006.In these tests,the ice sheet before the compliant conical structure was found to be failed in two-time breaking.Based on this important finding,model tests study of the ice force on a compliant multi-cone structure were performed from 2006 to 2007.in these tests,the ice sheet broke before each single cone non-simultaneously.The exciting energy of the total ice force was found to be in a wide range of frequencies,and the structure can be easily excited with nonlinear resonance.  相似文献   

A study of SAR remote sensing of internal solitary waves in the north of the South China Sea:I.Simulation of internal tide transformation   总被引：2，自引：1，他引：1  

FAN Zhisong  ZHANG Yuanling  SONG Mei 《海洋学报(英文版)》2008,27(4)

For settlement of the well-known problem of contemporary radar imaging models,i.e.,the pmblem of a general underestimation of radar signatures of hydrodynamic features over oceanic internal waves and underwater bottom topography in tidal watels at at high radar frequency bands(X-band and C-band),the impact of the ocean surface mixed layer turbulence and the significance of strat-ified oceanic model on SAR remote sensing of internal solitary waves are proposed.In the north of the South China Sea by utilizing seme observed data of background field the nonlinearity coefficient,the dispersion coefficient,the horizontal variability coefficient and the phase speed in the generalized K-dV equation are determined approximately.Through simulations of internal tide transfor-mation the temporal evolution and spatial distribution of the vertical displacement and horizontal velocity of intereal wave field are obtained.The simulation results indicate that the maximum amplitudes of internal solitary waves occur at depth 35 m,but the maximum current speeds take place at depth 20 m in this area of the sea(about 20°30'N,114°E)in August.It was noticed that considering the effects of flood current and ebb current respectively is appropriate to investigate influence of the background shear flow on coefficients of the K-dV equation.The obtained results provide the possibility for the simulation of SAR signatures of inter-nal solitary waves under considering the impact of ocean surface mixed layer turbulence in the companion paper.  相似文献