影响中国的台风频数年代际变化趋势:1951-2004年

Interdecadal variations in the frequency of typhoon affecting China (TAC) during 1951-2004 were investigated in this study. The yearly frequency of TACs showed a slightly increasing trend from the 1950s to the early 1970s and a significant decreasing trend afterwards. There were more TACs during the 1960s while the most inactive period was observed in recent 10 years. A decreasing trend was observed in the monthly frequency of TACs in June, August and September throughout the 54 years. Large interannual variabilities were apparent in yearly and monthly frequencies of TACs.     

中国城市固体废弃物甲烷排放研究

The greenhouse effect of methane (CH4) is only inferior to that of carbon dioxide (CO2). As an important anthropogenic emission source, the calculation of the emission amount of CH4 from waste treatment in landfills plays an important role in compiling greenhouse gases inventory and in estimating the climate change effects caused by increasing of greenhouse gases. Based on the previous work, and according to the sampling and analysis on municipal solid waste (MSW) in typical cities, the degradable organic carbon (DOC) percentile was identified in typical cities in recent years. According to the IPCC greenhouse gases inventory guideline and default method of CH4 emission from MSW landfills, and in light of MSW managing situation in different regions, the amount of CH4 emission was calculated. The results show that the amount of CH4 emission decreases geographically from east to west and it increases temporally from 1994 to 2004 in China.     

Laser Scanning的基本原理及其应用前景

首先介绍了激光测距仪的发展历程,针对应用领域的不同,分别对3维激光成像仪和机载/星载激光测高仪的测量原理进行了阐述,并分别介绍了两种激光测距仪的工作流程以及数据处理流程,最后对两种激光测距仪的应用范围进行了阐述,并把两种激光测距技术和普通摄影测量进行了比较,指出了激光测距技术相对于普通摄影测量的优点,即高精度性、穿透性、实时性。     

Self-calibration Applied in Converting Simulation Surveying

In the field of converting simulation surveying and traditional close range photogrammetry, it has been developed so far to survey objects by commercial digital camera and this technique is applied widely in every part of production. In order to get three-dimensional information of objects, commercial digital camera must be examined. For a long time, digital camera has been examined by DLT. Then there must be a high-precision control field. For realizing surveying without control points, a method for self-calibration is proposed.     

Bioenergy potentials from forestry in 2050

The purpose of this study was to evaluate the global energy production potential of woody biomass from forestry for the year 2050 using a bottom-up analysis of key factors. Woody biomass from forestry was defined as all of the aboveground woody biomass of trees, including all products made from woody biomass. This includes the harvesting, processing and use of woody biomass. The projection was performed by comparing the future demand with the future supply of wood, based on existing databases, scenarios, and outlook studies. Specific attention was paid to the impact of the underlying factors that determine this potential and to the gaps and uncertainties in our current knowledge. Key variables included the demand for industrial roundwood and woodfuel, the plantation establishment rates, and the various theoretical, technical, economical, and ecological limitations related to the supply of wood from forests. Forests, as defined in this study, exclude forest plantations. Key uncertainties were the supply of wood from trees outside forests, the future rates of deforestation, the consumption of woodfuel, and the theoretical, technical, economical, or ecological wood production potentials of the forests. Based on a medium demand and medium plantation scenario, the global theoretical potential of the surplus wood supply (i.e., after the demand for woodfuel and industrial roundwood is met) in 2050 was calculated to be 6.1 Gm³ (71 EJ) and the technical potential to be 5.5 Gm³ (64 EJ). In practice, economical considerations further reduced the surplus wood supply from forests to 1.3 Gm³ year⁻¹ (15 EJ year⁻¹). When ecological criteria were also included, the demand for woodfuel and industrial roundwood exceeded the supply by 0.7 Gm³ year⁻¹ (8 EJ year⁻¹). The bioenergy potential from logging and processing residues and waste was estimated to be equivalent to 2.4 Gm³ year⁻¹ (28 EJ year⁻¹) wood, based on a medium demand scenario. These results indicate that forests can, in theory, become a major source of bioenergy, and that the use of this bioenergy can, in theory, be realized without endangering the supply of industrial roundwood and woodfuel and without further deforestation. Regional shortages in the supply of industrial roundwood and woodfuel can, however, occur in some regions, e.g., South Asia and the Middle East and North Africa.     

Large-eddy simulation of plant canopy flows using plant-scale representation

Turbulent flow in a corn canopy is simulated using large-eddy simulation (LES) with a Lagrangian dynamic Smagorinsky model. A new numerical representation of plant canopies is presented that resolves approximately the local structure of plants and takes into account their spatial arrangement. As a validation, computational results are compared with experimental data from recent field particle image velocimetry (PIV) measurements and two previous experimental campaigns. Numerical simulation using the traditional modelling method to represent the canopy (field-scale approach) is also conducted as a comparison to the plant-scale approach. The combination of temporal PIV data, LES and spatial PIV data allows us to couple a wide range of relevant turbulence scales. There is good agreement between experimental data and numerical predictions using the plant-scale approach in terms of various turbulence statistics. Within the canopy, the plant-scale approach also allows the capture of more details than the field-scale approach, including instantaneous gusts that penetrate deep inside the canopy.     

Time mean and variability of the scale-decomposed atmospheric water budget in a 25-year simulation of the Canadian Regional Climate Model over North America

The scaled-decomposed atmospheric water budget over North America is investigated through the analysis of 25 years of simulation by the Canadian Regional Climate Model (CRCM) driven by the NCEP–NCAR reanalyses for the period 1975–1999. The time average and time variability of the atmospheric water budget for the winter and summer seasons are decomposed into their large-scale and small-scale components to identify the added value of the regional model. For the winter season, the intra-seasonal transient-eddy variance is the main temporal variability. The large- and small-scale terms are of the same order of magnitude, and are large over both coasts and weak over the continent. For the summer season, the time–mean atmospheric water budget is rather different to that of winter, with maximum values over the south-eastern part of the continent. The summer intra-seasonal variance is about twice stronger than in winter and also dominates the variability, but the inter-monthly variance is non-negligible and can be in part associated to North American Monsoon System. Over the continent, the intra-seasonal climatological variance is dominated by the variability of the small scales. The small scales, that is those scales that are only resolved in the regional model but not in the reanalyses, contribute to the added value in a regional climate simulation. In the winter season, the added value of the CRCM is large and dominated by oceanic forcing, while in summer, it is dominant (larger than the large scales) and controlled mainly by convective processes.     

Occurrence and Resistance of Pathogenic Bacteria Along the Tietê River Downstream of São Paulo in Brazil

The load of pathogenic bacteria, their fate and their dangerousness in the Tietê River were assessed along 100 km starting from the city of São Paulo, Brazil. The data were compared with those from two German rivers. High loads of pathogens were found in the Tietê River near the city of São Paulo (Escherichia coli O157:H7, Shigella flexneri, and Shigella boydii), which were absent 30 km downstream of São Paulo. The antibiotic resistances observed in the Tietê river were rather low and decreased after the major input in São Paulo to significantly lower levels about 30 km downstream. While the Brazilian isolates were more susceptible for ampicillin than the German ones, the reverse was observed for gentamycin. For optimal control of infections in humans critical areas where these bacteria survived longer and their elimination mechanisms should be identified as well as the extent and the origin of antibiotic resistance should be determined.     

1994年9月16日台湾浅滩7.3级地震发震构造的讨论

从台湾海峡与台湾浅滩的地貌特征、区域构造格局、海峡盆地形成历史、深部构造与断裂构造、震源机制解以及地震活动等方面论述了台湾浅滩７．３级地震的发震构造,认为北东东向澎湖—北港隆起南侧断裂（义竹断裂）是该地震的发震构造。     

数字电子水准仪DiNi10性能实测分析

对蔡司公司的ＤｉＮｉ１０数字电子水准仪,通过主要指标测试、条件试验和６６ｋｍ的实际外业测量,特别是与精密自平水准仪Ｎｉ００２的４０ｋｍ同桩平行测量试验,论述了此种仪器的性能及其作业规律和特点。结果表明该仪器可用于一等水准测量和精密地形变监测。指出了该仪器的不足之处。