南水北调东线水源核心区浮游植物多样性状况与评价研究

分别于2013年4月、8月、10月和2014年1月对南水北调东线水源核心区河流浮游植物群落结构、浮游植物密度进行调查,并利用多样性指数进行水质评价.区域共检出浮游植物5门34科67属118种,春秋两季物种数较多,夏冬两季物种数较少.优势种为蓝藻门小席藻( Phormidium.tenue)、绿藻门小球藻( Chlorella.pyrenoidosa)、硅藻门变异直链藻( Melosira.varians).区域浮游植物密度为3.5 ×105 cells/L,Shannon-wiener指数为2.32,Margalef指数为1.06,Pielou均匀度指数为0.54,水质为寡污-中污水平.     

晋江河口柱状沉积物中重金属的赋存形态及生态风险评价

采用改进的BCR连续提取法对晋江河口柱状沉积物中的重金属(Fe、Zn、Ni、Pb、Cu和Cr)进行形态分析。结果表明,在垂向分布上重金属的形态分布基本一致。其中,Fe主要存在于残渣态,Pb、Cu和Ni主要存在于可还原态,Zn主要存在于弱酸溶态,Cr主要存在于可氧化态。各金属总可提取态占总量的比值(即生物有效性)排序为:CuCrPb=Zn=NiFe,Cu、Cr、Pb、Zn和Ni的迁移性和生物有效性均较高,对环境存在较大的潜在危害。运用次生相与原生相比值法对重金属潜在生态风险进行评价,结果表明:Fe处于无污染水平,Zn、Pb、Ni、Cu和Cr均处于中到重度污染水平。     

中远船务构筑特色安全文化的探索与实践

本文主要阐述了在企业核心价值理念孵化牵引下生发的安全文化理念,总结和提炼了具有企业特色的“严、细、真、实、慎”的安全文化,并从制度建设、行为规范以及体现执行力的十大主要措施上,进行了比较系统的论述,对进一步促进企业安全文化建设提出了4个方面的对策。     

SNOW AND ICE ALBEDO MEASURED WITH TWO TYPES OF PYRANOMETERS1

ABSTRACT: In order to obtain total short-wave albedos of snow and ice, both incident and reflected solar radiation were measured over a frozen lake surface using two different types of radiation measurement devices: a Kipp and Zonen thermopile pyranometer with a spectral sensitivity of 300 to 2800 nm and a LI-COR photovoltaic pyranometer with a spectral sensitivity of 400 to 1100 am. The spectral response of the LI-COR pyranometers limits its use as a short-wave radiation measurement device. Therefore, two equations were developed to adjust both the daily incident radiation data and the daily reflected radiation data measured by the LI-COR instrument to total short-wave radiation values, i.e., to the waveband of 300 to 2800 nm (visible to near-infrared spectrum). The LI-COR data were then adjusted, and a total short-wave adjusted albedo was calculated with a modeling efficiency of 0.97.     

EFFECT OF SIMULATED CLIMATE CHANGE ON SNOWMELT RUNOFF MODELING IN SELECTED BASINS1

ABSTRACT: The projected increase in the concentration of CO₂ and other greenhouse gases in the atmosphere is likely to result in a global temperature increase. This paper reports on the probable effects of a temperature increase and changes in transpiration on basin discharge in two different mountain snowmelt regions of the western United States. The hydrological effects of the climate changes are modeled with a relatively simple conceptual, semi-distributed snowmelt runoff model. Based on the model results, it may be concluded that increased air temperatures will result in a shift of snowmelt runoff to earlier in the snowmelt season. Furthermore, it is shown that it is very important to include the expected change in climate-related basin conditions resulting from the modeled temperature increase in the runoff simulation. The effect of adapting the model parameters to reflect the changed basin conditions resulted in a further shift of streamflow to April and an even more significant decrease of snowmelt runoff in June and July. If the air temperatures increase by approximately 5°C and precipitation and accumulated snow amounts remain about the same, runoff in April and May, averaged for the two basins, is expected to increase by 185 percent and 26 percent, respectively. The runoff in June and July will decrease by about 60 percent each month. Overall, the total seasonal runoff decreases by about 6 percent. If increased CO₂ concentrations further change basin conditions by reducing transpiration by the maximum amounts reported in the literature, then, combined with the 5°C temperature increase, the April, May, June, and July changes would average +230 percent, +40 percent, ?55 percent, and ?45 percent, respectively. The total seasonal runoff change would be +11 percent.     

边缘型旅游地的理论与实证研究

阐述了边缘型旅游地的概念和类型,从旅游资源、旅游交通、旅游感知、社会经济等方面透视了边缘型旅游地的特性,并系统探讨了边缘型旅游地的动态演替模式.在此基础上,提出了边缘型旅游地的开发应走产品特色化、形象驱动化、区域联动化、政府主导化的综合发展战略.     

APPLICATION OF THE SNOWMELT RUNOFF MODEL USING MULTIPLE-PARAMETER LANDSCAPE ZONES ON THE TOWANDA CREEK BASIN,PENNSYLVANIA1

ABSTRACT: The Snowmelt Runoff Model (SRM) is designed to compute daily stream discharge using satellite snow cover data for a basin divided into elevation zones. For the Towanda Creek basin, a Pennsylvania watershed with relatively little relief, analysis of snow cover images revealed that both elevation and land use affected snow accumulation and melt on the landscape. The distribution of slope and aspect on the watershed was also considered; however, these landscape features were not well correlated with the available snow cover data. SRM streamflow predictions for 1990, 1993 and 1994 snowmelt seasons for the Towanda Creek basin using a combination of elevation and land use zones yielded more precise streamflow estimates than the use of standard elevation zones alone. The use of multiple-parameter zones worked best in non-rain-on-snow conditions such as in 1990 and 1994 seasons where melt was primarily driven by differences in solar radiation. For seasons with major rain-on-snow events such as 1993, only modest improvements were shown since melt was dominated by rainfall energy inputs, condensation and sensible heat convection. Availability of GIS coverages containing satellite snow cover data and other landscape attributes should permit similar reformulation of multiple-parameter watershed zones and improved SRM streamflow predictions on other basins.     

MODEL ACCURACY IN SNOWMELT-RUNOFF FORECASTS EXTENDING FROM 1 TO 20 DAYS1

ABSTRACT: This paper examines the performance of snowmelt-runoff models in conditions approximating real-time forecast situations. These tests are one part of an intercomparison of models recently conducted by the World Meteorological Organization (WMO). Daily runoff from the Canadian snowmelt basin Illecille. waet (1155 km², 509–3150 m a.s.l.) was forecast for 1 to 20 days ahead. The performance of models was better than in a previous WMO project, which dealt with runoff simulations from historical data, for the following reasons: (1) conditions for models were more favorable than a real-time forecast situation because measured input data and not meteorological forecast inputs were distributed to the modelers; (2) the selected test basin was relatively easy to handle and familiar from the previous WMO project; and (3) all kinds of updating were allowed so that some models even improved their accuracy towards longer forecast times. Based on this experience, a more realistic follow-up project can be imagined which would include temperature forecasts and quantitative precipitation forecasts instead of measured data.     

导线覆冰大跨越输电塔-线体系动力特性分析

大跨越输电塔-线体系对导线覆冰等环境荷载反应敏感,容易发生动态倒塌破坏。目前对线路覆冰下输电塔的振动问题虽然取得了一定的研究成果,但是线路覆冰下输电塔的动力特性规律尚需进一步研究。本文以实际工程为例,建立了大跨越输电塔-线体系数值分析模型,分析了导线划分精度对输电塔-线体系动力特性的影响,并在此基础上分析了导线覆冰对输电塔-线体系动力特性的影响。研究结果表明:导线划分精度对输电塔振动影响较大;导线覆冰不仅影响输电塔振动频率,而且对输电塔振型也有较大影响,尤其是对输电塔横担的振动影响更大。