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781.
李建春  高玉婷  曲衍波  关梅  张勇  王森 《地理科学》2022,42(7):1155-1165
充分识别陆海空间冲突并制定科学规划是实现陆海统筹的关键。基于陆海空间利用现状与规划,构建陆海空间冲突的理论分析框架,采用冲突识别矩阵、邻域冲突测度模型和社会网络分析等方法,以山东省莱州市为案例区,1 km格网为研究单元,分别从陆地对海洋、海洋对陆地2个方向定量识别陆海空间的现状冲突和规划冲突,并结合四象限模型对冲突进行分区。主要研究结果如下:① 从冲突范围与强度来看,莱州市陆地利用与规划越过海岸线的范围更大,陆海交互冲突范围将持续增加,陆海统筹应重视空间复合利用与跨系统交互影响。② 从冲突的类型来看,现状冲突中陆地的水域与湿地以及海洋的渔业用海等利用方式对海陆系统产生的影响较大;而在规划冲突中,陆地的一般农地区和其他用地区,海洋的农渔业区和港口航运区4类功能分区跨系统产生的影响较大。③ 现状与规划的耦合分区结果显示,相对独立的陆海空间规划对于控制和缓解空间冲突具有一定效果,然而陆海空间统筹利用与管理迫在眉睫,应结合系统观点根据不同分区特点进行优化。  相似文献   
782.
Nowadays, numerical modeling is a common tool used in the study of sedimentary basins, since it allows to quantify the processes simulated and to determine interactions among them. One of such programs is SIMSAFADIM-CLASTIC, a 3D forward-model process-based code to simulate the sedimentation in a marine basin at a geological time scale. It models the fluid flow, siliciclastic transport and sedimentation, and carbonate production. In this article, we present the last improvements in the carbonate production model, in particular about the usage of Generalized Lotka-Volterra equations that include logistic growth and interaction among species. Logistic growth is constrained by environmental parameters such as water depth, energy of the medium, and depositional profile. The environmental parameters are converted to factors and combined into one single environmental value to model the evolution of species. The interaction among species is quantified using the community matrix that captures the beneficial or detrimental effects of the presence of each species on the other. A theoretical example of a carbonate ramp is computed to show the interaction among carbonate and siliciclastic sediment, the effect of environmental parameters to the modeled species associations, and the interaction among these species associations. The distribution of the modeled species associations in the theoretical example presented is compared with the carbonate Oligocene-Miocene Asmari Formation in Iran and the Miocene Ragusa Platform in Italy.  相似文献   
783.
Spatial and Temporal Variations of Sound Speed at the PN Section   总被引:3,自引:0,他引:3  
Gridded sound speed data were calculated using Del Grosso's formulation from the temperature and salinity data at the PN section in the East China Sea covering 92 cruises between February 1978 and October 2000. The vertical gradients of sound speed are mainly related to the seasonal variations, and the strong horizontal gradients are mainly related to the Kuroshio and the upwelling. The standard deviations show that great variations of sound speed exist in the upper layer and in the slope zone. Empirical orthogonal function analysis shows that contributions of surface heating and the Kuroshio to sound speed variance are almost equivalent. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
784.
The production of organic matter and calcium carbonate by a dense population of the brittle star Acrocnida brachiata (Echinodermata) was calculated using demographic structure, population density, and relations between the size (disk diameter) and the ash-free dry weight (AFDW) or the calcimass. During a 2-year survey in the Bay of Seine (Eastern English Channel, France), organic production varied from 29 to 50 gAFDW m−2 year−1 and CaCO3 production from 69 to 104 gCaCO3 m−2 year−1. Respiration was estimated between 1.7 and 2.0 molCO2 m−2 year−1. Using the molar ratio (ψ) of CO2 released: CaCO3 precipitated, this biogenic precipitation of calcium carbonate would result in an additional release between 0.5 and 0.7 molCO2 m−2 year−1 that represented 23% and 26% of total CO2 fluxes (sum of calcification and respiration). The results of the present study suggest that calcification in temperate shallow environments should be considered as a significant source of CO2 to seawater and thus a potential source of CO2 to the atmosphere, emphasizing the important role of the biomineralization (estimated here) and dissolution (endoskeletons of dead individuals) in the carbon budget of temperate coastal ecosystems.  相似文献   
785.
The paper deals with the processes of ethnic consolidation, ethnic and linguistic assimilation and inter-ethnic integration taking place in the USSR. The author shows the influence of consolidation and assimilation processes over the trends in the numerical strength of individual peoples and the resulting change in the country's ethnic composition as this is reflected in the Soviet population censuses of 1926, 1959, 1970, and 1979.  相似文献   
786.
The possibility of filling empty underground spaces, which exist owing to the extraction of mineral raw materials, with fly ash and cement fly ash mixes has been studied for the purpose of reducing the impact of deep mining on the surface. The method of physical modelling was used to study the behaviour of fly ash mixes deposited in extracted mine spaces. The models were constructed for two different geometries of underground extracted mine spaces: into cavities of the type of large slits created in the course of mining in steeply lode deposits without subsequently filling the empty space and in vertical shafts of rectangular or circular cross-section with horizontal side headings that have partly caved in due to mine shocks or other seismic events.  相似文献   
787.
The urban heat island (UHI), together with summertime heat waves, foster’s biophysical hazards such as heat stress, air pollution, and associated public health problems. Mitigation strategies such as increased vegetative cover and higher albedo surface materials have been proposed. Atlanta, Georgia, is often affected by extreme heat, and has recently been investigated to better understand its heat island and related weather modifications. The objectives of this research were to (1) characterize temporal variations in the magnitude of UHI around Metro Atlanta area, (2) identify climatological attributes of the UHI under extremely high temperature conditions during Atlanta’s summer (June, July, and August) period, and (3) conduct theoretical numerical simulations to quantify the first-order effects of proposed mitigation strategies. Over the period 1984–2007, the climatological mean UHI magnitude for Atlanta-Athens and Athens-Monticello was 1.31 and 1.71°C, respectively. There were statistically significant minimum temperature trends of 0.70°C per decade at Athens and −1.79°C per decade at Monticello while Atlanta’s minimum temperature remained unchanged. The largest (smallest) UHI magnitudes were in spring (summer) and may be coupled to cloud-radiative cycles. Heat waves in Atlanta occurred during 50% of the years spanning 1984–2007 and were exclusively summertime phenomena. The mean number of heat wave events in Atlanta during a given heat wave year was 1.83. On average, Atlanta heat waves lasted 14.18 days, although there was quite a bit of variability (standard deviation of 9.89). The mean maximum temperature during Atlanta’s heat waves was 35.85°C. The Atlanta-Athens UHI was not statistically larger during a heat wave although the Atlanta-Monticello UHI was. Model simulations captured daytime and nocturnal UHIs under heat wave conditions. Sensitivity results suggested that a 100% increase in Atlanta’s surface vegetation or a tripling of its albedo effectively reduced UHI surface temperature. However, from a mitigation and technological standpoint, there is low feasibility of tripling albedo in the foreseeable future. Increased vegetation seems to be a more likely choice for mitigating surface temperature.  相似文献   
788.
Diatoms were identified and enumerated from a surface sediment calibration set of 50 lakes in northwestern Québec. The relationship between species composition and environmental variables was examined using canonical correspondence analysis (CCA). Forward selection and Monte Carlo permutation tests in CCA indicated that diatom species distributions in the data set are most strongly correlated to lakewater pH. A strong (r 2 boot = 0.83) weighted averaging calibration model, that includes bootstrapped error estimates, was developed for inferring past lakewater pH. Using this model, temporal changes in pH were reconstructed for two kettle lakes, Lac de la Pépinière and Lac Perron. Based on limnological data, both the study lakes were expected to have recently acidified due to increased acidic precipitation and increases in anthropogenic metal loading. However, our long-term pH inference data indicate that these lakes were naturally acidic during pre-industrial times. Nonetheless, the rate of acidification, particularly in Lac de la Pépinière, has accelerated in the last ∼75 years. These long-term pH records developed for the dilute lakes in northwestern Québec suggest that the region has received increased atmospheric pollutants from the nearby Horne smelter in Rouyn-Noranda. The pH inference profiles are markedly different from many other paleolimnological studies in acid-sensitive regions of Canada that have become acidic primarily as a result of industrial activities. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.  相似文献   
789.
通过对华北地区13次Ms5级以上地震在震前不同时间的贝尼奥夫应变释放曲线的特征进行分析,得出大部分中强地震前存在地震矩释放加速现象,同时从空间上分析了应变释放特性与地震的关系,发现很多地震在震前1~2年震中附近区域会出现大范围类椭圆形的低m值区域,这个区域与未来主震的位置有着很好的对应,这为华北地区未来中强地震的危险性判定提供了参考。  相似文献   
790.
The paper presents the testing of the possibility of determining the heights of GPS points in the homogeneous field in the new Croatian Height Reference System (HVRS71) by using the method of height transformation. The testing was made in the area of Zagreb. As part of the field works, normal orthometric heights of 27 GPS points were determined according to the new height system, by transferring the benchmark heights using the geometric levelling method, thus obtaining GPS/levelling points of known ellipsoidal and normal orthometric heights. The GPS/levelling points served as the basis for determining the transformation models that enabled the computation of normal orthometric heights from ellipsoidal heights of any GPS point in the observed area. The empirical data used for modelling were reduced undulation dN values of GPS/levelling points. As part of the dN modelling with parametric functions, the approximation surfaces were obtained on the basis of three polynomials: FN310, FN312 and FN318. The transformation models were also tested using non-parametric Watson and Loess algorithms. The FN318 and Loess models yielded the best results.  相似文献   
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