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141.
信息时代地图技术美的研究与实践 总被引:3,自引:1,他引:3
通过分析现代地图表现形式及存在的问题,探讨了信息时代地图制图技术美的含义和地图技术美的表现形式。并在技术美创新理念指导下,对利用计算机技术和图形图像处理技术来改进地图符号设计,提高地图表现力进行了一些理论探讨和技术尝试.同时也得到了一些有益的启示。 相似文献
142.
在信息传播媒体的竞争日益严酷的时代,面对天气预报节目只依靠简单的画面加解说,拉洋片式传统方法这样一种一成不变的局面,策划创意制作出《天气资讯》节目,打破天气预报节目以往的节目形式和播出形式,以极少的投入获得最大的社会效益和经济效益。 相似文献
143.
1. IntroductionThe basic role of urban-rural boundary layer re-search is to study all kinds of physical process changesin the atmosphere boundary layer over urban and itssurrounding areas. Urban heat island (UHI) is a well-known feature of urban-rural climate. Attempts toincrease the understanding of the causes of the UHIand other urban-rural boundary layer phenomena haveused observational, theoretical and modelling methodssince long before. Seaman (1989) used a hydrostaticmodel, with real … 相似文献
144.
A new efficient method is developed for the analysis of pile-group effects on the seismic stiffness and strength design of buildings with pile foundations. An efficient continuum model consisting of a dynamic Winkler-type soil element and a pile is used to express the dynamic behavior of the structure-pile-soil system with only a small numerical error. The pile-group effect is taken into account through the influence coefficients among piles which are defined for interstory drifts and pile-head bending moments. It is shown that, while the pile-group effect reduces the interstory drift of buildings in general, it may increase the bending moment of piles at the head. This means that the treatment without the pile-group effect results in the conservative design for super-structures and requires a revised member design for piles. 相似文献
145.
A high resolution (3–8 km grid), 3D numerical ocean model of the West Caribbean Sea (WCS) is used to investigate the variability
and the forcing of flows near the Meso-American Barrier Reef System (MBRS) which runs along the coasts of Mexico, Belize,
Guatemala and Honduras. Mesoscale variations in velocity and temperature along the reef were found in seasonal model simulations
and in observations; these variations are associated with meandering of the Caribbean current (CC) and the propagation of
Caribbean eddies. Diagnostic calculations and a simple assimilation technique are combined to infer the dynamically adjusted
flow associated with particular eddies. The results demonstrate that when a cyclonic eddy (negative sea surface height anomaly
(SSHA)) is found near the MBRS the CC shifts offshore, the cyclonic circulation in the Gulf of Honduras (GOH) intensifies,
and a strong southward flow results along the reef. However, when an anticyclonic eddy (positive SSHA) is found near the reef,
the CC moves onshore and the flow is predominantly westward across the reef. The model results help to explain how drifters
are able to propagate in a direction opposite to the mean circulation when eddies cause a reversal of the coastal circulation.
The effect of including the Meso-American Lagoon west of the Belize Reef in the model topography was also investigated, to
show the importance of having accurate coastal topography in determining the variations of transports across the MBRS. The
variations found in transports across the MBRS (on seasonal and mesoscale time scales) may have important consequences for
biological activities along the reef such as spawning aggregations; better understanding the nature of these variations will
help ongoing efforts in coral reef conservation and maintaining the health of the ecosystem in the region. 相似文献
146.
The seasonal and interannual variations of Beijing urban heat island (UHI) are investigated in this paper using the temperature data from 1960 to 2000 at 20 meteorological stations in the Beijing region, and then the relationship between the intensity and spatial scale of UHI and Beijing urbanization indices is analyzed and discussed. Main conclusions are the followings. First, Beijing UHI shows obvious seasonal variations, and it is strongest in winter, next in spring and autumn, and least in summer. The seasonal variation of the UHI mainly occurs in the urban area. The UHI intensity at the center of Beijing is more than 0.8℃ in winter, and only 0.5℃ in summer. Second, the intensity of Beijing HUI exhibits a clear interannual warming trend with its mean growth rate (MGR) being 0.3088℃/10 a. The MGR of HUI is largest in winter, next in spring and autumn, and least in summer, and the urban temperature increase makes a major contribution to the growth of HUI intensity. Third, since the Reform and Opening, the urbanization indices have grown several ten times or even one hundred times, the intensity of HUI has increased dramatically, and its spatial scale also expanded distinctively along with the expansion of urban architectural complexes. Fourth, the interannual variation of urbanization indices is very similar with that of HUI intensity, and their linear correlation coefficients are significant at a more than 0.001 confidence level. 相似文献
147.
Ji-Hoon Kim Jeongho Lee Tae-Jin Cheong Rak-Hyeon Kim Dong-Chan Koh Jong-Sik Ryu Ho-Wan Chang 《Journal of Hydrology》2005,300(1-4):188-198
The purpose of this study is to apply time series analysis to investigate whether the groundwater quality in the coastal area is affected by the tide. Continuous and regular in situ monitoring data of electrical conductivity (EC) and groundwater level, and tidal level data measured by the National Oceanographic Research Institute were used for the time series analysis. Through the time series analysis, it is known that EC and groundwater level conspicuously fluctuate with two periodicities (15.4 and 0.52-day), which is very similar to those of the tide. Also the behaviors of their fluctuations vary in accordance with the tidal period. These indicate that the groundwater quality has been mainly controlled by the tidal level, and the strength of tidal effect on the groundwater quality is different according to the tidal period. 相似文献
148.
Temporal variability in the maternal environment and its effect on seed size and seed quality in Flourensia cernua DC. (Asteraceae). 总被引:1,自引:0,他引:1
The biological phenomenon commonly referred to as maternal effect occurs whenever the environment exerts an influence upon the mother that is later expressed in characteristics of her offsprings. For example, the environmental conditions experienced by a mother plant during flowering and fruiting can modify the quality of her descendants (seeds), and even interrupt their development. Between-year variation in minimum temperature and the classic, between-year variation in precipitation represent an unpredictable environment for winter blooming plants in arid zones. In this study, we investigated the effect of maternal environment (temperature and precipitation) on seed size and seed quality in F. cernua, over a 5-year period. Results indicated that the proportion of filled seeds, as well as their size, increased with higher absolute minimum temperatures during seed formation, and that, to a lesser extent, both the precipitation occurred during the same period and the annual precipitation also have a positive influence on seed size. In this way, environmental conditions prevailing during seed formation exerted a strong maternal effect on the size and quality of seeds produced and, probably also, in the developmental possibilities of F. cernua seedlings. This effect was subject to important, between-year variation. 相似文献
149.
D. Shankar S. S. C. Shenoi R. K. Nayak P. N. Vinayachandran G. Nampoothiri A. M. Almeida G. S. Michael M. R. Ramesh Kumar D. Sundar O. P. Sreejith 《Journal of Earth System Science》2005,114(5):459-474
Hydrographic observations in the eastern Arabian Sea (EAS) during summer monsoon 2002 (during the first phase of the Arabian
Sea Monsoon Experiment (ARMEX)) include two approximately fortnight-long CTD time series. A barrier layer was observed occasionally
during the two time series. These ephemeral barrier layers were caused byin situ rainfall, and by advection of low-salinity (high-salinity) waters at the surface (below the surface mixed layer). These barrier
layers were advected away from the source region by the West India Coastal Current and had no discernible effect on the sea
surface temperature. The three high-salinity water masses, the Arabian Sea High Salinity Water (ASHSW), Persian Gulf Water
(PGW), and Red Sea Water (RSW), and the Arabian Sea Salinity Minimum also exhibited intermittency: they appeared and disappeared
during the time series. The concentration of the ASHSW, PGW, and RSW decreased equatorward, and that of the RSW also decreased
offshore. The observations suggest that the RSW is advected equatorward along the continental slope off the Indian west coast. 相似文献
150.
Correcting the Smoothing Effect of Ordinary Kriging Estimates 总被引:2,自引:0,他引:2
Jorge Kazuo Yamamoto 《Mathematical Geology》2005,37(1):69-94
The smoothing effect of ordinary kriging is a well-known dangerous effect associated with this estimation technique. Consequently kriging estimates do not reproduce both histogram and semivariogram model of sample data. A four-step procedure for correcting the smoothing effect of ordinary kriging estimates is shown to be efficient for the reproduction of histogram and semivariogram without loss of local accuracy. Furthermore, this procedure provides a unique map sharing both local and global accuracies. Ordinary kriging with a proper correction for smoothing effect can be revitalized as a reliable estimation method that allows a better use of the available information. 相似文献