滇池水域双酚A的环境多介质迁移和归趋模拟

以双酚A为研究对象,利用四级多介质逸度模型模拟非稳态非平衡条件下1991-2011年间双酚A在滇池水域水相、表层沉积物相和中层沉积物相中的浓度分布、相间的迁移通量,确定主要迁移过程;结合实测数据,对模型进行可靠性验证;并对常数之外的12个模型参数进行灵敏度分析.结果表明:入滇总量98%的双酚A主要通过水体降解去除,滇池出水去除量和水体残留量共约占1%,余下部分进入沉积物相;沉积物相是残留双酚A最主要的汇,其中,表层沉积物相中双酚A浓度最高,3相中浓度变化趋势受外界输入影响较大;水相→表层沉积物相的迁移为双酚A在滇池的主要迁移过程,其次为表层沉积物相→中层沉积物相;双酚A在水中的降解速率、有机碳分配系数,各环境相中有机碳含量、固相体积比等参数灵敏度较高,对模型的影响较为显著;模型计算浓度与实测浓度吻合较好,表明建立的四级多介质逸度模型适用于滇池水域双酚A环境多介质迁移和归趋模拟.     

逸度模型在湖泊流域农药多介质归趋研究中的应用与展望

农药的施用在促进农业经济发展的同时,也带来了诸多环境问题.农药由农业活动排放进入到环境后会通过不同的途径在各介质之间进行迁移和转化,最后由径流作用汇聚于湖泊中,破坏生态环境,影响人类健康.因此,研究湖泊流域生态系统中农药的多介质归趋具有重要意义.使用基于逸度的多介质模型模拟农药在环境中的行为是一个十分有效的方法.逸度模型利用"逸度"的概念描述污染物在各个环境介质之间的迁移和转化过程趋势,其结果建立在化学物质自身物化性质和环境系统性质之上,不仅适用于预测农药在环境各介质中的残留水平,还可以揭示区域内污染的空间分布特征,是湖泊流域生态系统管理中一个重要的工具.本文综述了逸度模型的理论基础,对近年来国内外逸度模型的发展现状、相关环境模型及其在农药归趋研究和湖泊流域生态系统管理中的运用进行了总结,并展望了逸度模型在农药多介质研究中的应用前景,以期对我国农药的管理、合理施用方面提供科学与技术支持.     

近50年来内蒙古查干淖尔湖水量变化及其成因分析

内蒙古查干淖尔湖是位于季风边缘区干旱与半干旱过渡带的封闭湖泊,对气候变化响应极为敏感.利用1958-2010年的查干淖尔湖21期遥感影像以及湖泊流域1955-2010年的3个气象站点和1个水文站点的气温、降水、蒸发和径流等数据,分析查干淖尔湖近50余年的湖泊水量、面积/水位波动及其原因.结果表明,近50年来在区域气候暖干化的背景下,查干淖尔湖不断萎缩,流域生态环境退化.1958-2010年湖泊容积以2×106m3/a的速度锐减66.9%(从124.1×106m3降到41.1×106m3),湖泊面积缩小73.3%(从105.3 km2降到28.1 km2),平均缩减速度为1.8 km2/a;流域年均气温上升了2.5℃,年降水量下降了36.6 mm.湖泊水量与流域气温和蒸发量显著负相关.查干淖尔湖分为东西两部分,中间由天然堤坝相连,东湖在水闸的人为控制下水位波动范围不超过1 m.西湖水位波动则相对剧烈,湖面下降7.6 m,于2002年彻底干涸,湖盆裸露,已成为盐尘暴、沙尘暴源地.     

近50年中国东南地区地面太阳辐射变化对气温变化的影响

太阳是地球表层的最终能量来源,地面太阳辐射的变化会深刻影响地球的气候变化.本文利用中国东南地区14个气象台站1961～2008年总辐射和气温的同步观测资料,分析了近50年该地区地面太阳辐射的变化对气温变化的可能影响.结果表明,1961～1989年期间,该地区的地面太阳辐射显著减弱,所引起的气温下降超过了其他因素的增温效...     

Analysis of long-term variations of fog and haze in China in recent 50 years and their relations with atmospheric humidity

Our analysis of fog and haze observations from the surface weather stations in China in recent 50 years(from 1961 to 2011)shows that the number of fog days has experienced two-stage variations,with an increasing trend before 1980 and a decreasing trend after 1990.Especially,an obvious decreasing trend after 1990 can be clearly seen,which is consistent with the decreasing trend of the surface relative humidity.However,the number of haze days has demonstrated an increasing trend.As such,the role of reduction of atmospheric relative humidity in the transition process from fog into haze has been further investigated.It is estimated that the mean relative humidity of haze days is about 69%,lower than previously estimated,which implies that it is more difficult for the haze particles to transform into fog drops.This is possibly one of the major environmental factors leading to the reduction of number of fog days.The threshold of the relative humidity for transition from fog into haze is about82%,also lower than previously estimated.Thus,the reduction of the surface relative humidity in China mainly due to the increase of the surface temperature and the saturation specific humidity may exert an obvious impact on the environmental conditions for the formations of fog and haze.In addition,our investigation of the relationship between haze and visibility reveals that with the increase of haze days,the visibility has declined markedly.Since 1961,the mean visibility has dropped from 4–10to 2–4 km,about a half of the previous horizontal distance of visibility.     

Flood changes during the past 50 years in Wujiang River,South China

Changing trends of peak flood and flood duration in the Wujiang River Basin are detected with the help of the Mann–Kendall test and the Pettitt analysis during the past 50 years. Results indicate that the peak flood and the flood duration at Lishi Station have different changing features. The peak flood showed only marginally increasing trend, whereas the flood duration exhibited decreasing trend at the significance level of 90%. The result shows a weak positive correlation between the peak flood and the flood duration. The changes of flood duration are influenced by the total rainfall duration, which is in downward trend at significance level 90%. In addition, the changing trends of peak flood are similar to the total rainfall amount. In the change‐point analysis, it was found that the change points for the peak flood and flood duration series were in the years 1993 and 1966, respectively. Human activities such as the construction of reservoirs were the main driving forces causing the change of flood duration. The periodicity of the peak flood during the period 1955–2007 at Lishi Station is detected by using the wavelet analysis. The result indicates that the peak flood at Lishi Station displayed alternation between big floods and small floods on the 25‐ to 26‐year period. At the same timescale, the peak flood of Wujiang River showed an evidence of change between big floods and small floods. It was essential to be prepared and aware of the consequences of climate changes and human influences affecting the water resources in the Wujiang River Basin. This result is expected to draw more attention from the local governments in its decision making and water resource management. Copyright © 2012 John Wiley & Sons, Ltd.     

The source and fate of sediment and mercury in Hunza River basin,Northern Areas,Pakistan

This article presents results of mercury in surface waters from Hunza River basin, Northern Areas, Pakistan. Small‐scale gold mining activities along the Hunza and Gilgit rivers are long known to be discharging mercury in the amalgamation and roasting processes. Previous studies reported high mercury concentrations in soils close to mining operations as well as serious health problems for miners. However, none of the studies have focused on the level of contamination in aqueous environments. This is the first study on the investigation of source and fate of sediment and river‐borne mercury in the Hunza River. The samples collected near gold panning sites showed higher mercury concentrations than critical levels established by the U.S. Environmental Protection Agency. The observed dissolved mercury concentrations ranged from 5.10 to 25.25 ng/l, whereas particulate‐bound mercury ranged from 4.85 to 154.62 ng/l. Particulate‐phase mercury corresponded to more than 75% of the total observed mercury concentrations for all of the sampled rivers. Thus, suspended sediments represented the major pathway of the riverine mercury transport. A mass balance calculation suggested an annual mercury flux of 48.6 g/km² into the Hunza River basin. The samples collected from the most affected river, the Shimsal River, averaged to have 108 ng/l total mercury. This amount was close to the average soil mercury data of 151 ng/l as reported by the Pakistan Mineral Development Corporation in 2001. The dominant source of contamination was shown to be the leaching of large quantities of mercury from the mercury‐rich sediment and flood plain soil into the rivers, rather than the direct release from mining activities. Significant decrease in both dissolved and particulate‐bound mercury concentration downstream of Attabad Lake suggested that mercury is being accumulated or consumed in the lake. Although minimization or elimination of mercury loses from the mining process seems important for the well‐being of the miners, preventing the remobilization of accumulated mercury is equally important in mercury control in this region. Copyright © 2014 John Wiley & Sons, Ltd.     

Application of Brownian model in the northwestern Beijing, China

The mathematic theory of Brownian passage-time model and its difference from other recurrence models such as Poisson, lognormal, gamma and Weibull, were introduced. We assessed and analyzed the earthquake probabilities of the major faults with the elapsed time much greater than the recurrence interval in the northwest region of Beijing (China) in 100-year by using both Brownian passage-time model and Poisson model, and concluded that the calculated results obtained from Brownian passage-time model is more reasonable. Foundation item: Joint Seismological Science Foundation of China (103034) and Key Project “Assessment of Seismic Safety” from China Earthquake Administration during the tenth Five-year Plan.     

Application of Brownian model in the north- western Beijing, China

Introduction Since the tens years, the research on active fault has been stepped from qualitative phase toquantitative phase. With the developing of research on fault activity, fault segmentation, interac-tion among the adjacent or near fault segments, geodetic and paleoearthquake, scientists have re-alized that strong earthquake recurrence along active fault has different properties and multiplepatterns (Working Group on California Earthquake Probabilities, 1988, 1990, 1995, 1999, 2003…     

上海近50年气温变化与城市化发展的关系

根据上海地区2个气象站近50年的年均气温数据,采用回归分析、滑动平均和Mann\|Kendall检验法研究上海地区气温的年代际变化与跃变,城郊温差的年际变化;采用趋势拟合与相关分析,研究城郊温差与城市人口、GDP、能源消耗量、建成区面积和住宅竣工面积等各项城市发展指标的关系.结果表明：（1）近50年来,上海地区年均气温缓慢上升,20世纪90年代后城郊温差呈锯齿状上升趋势,若以徐家汇代表城区,奉贤代表郊区,则近50年来,城郊温差增温率为0.23℃/10a.（2）1989~1990年为上海城区气温的跃变年份,而郊区的气温跃变出现在20世纪90年代中期.（3）各项城市发展指标均与上海城郊温差有着显著的相关性,表明它们与上海城市热岛的发展关系密切,其中,住宅建设是上海城市热岛最主要的驱动因素,城市人口和经济发展也具有重要影响.     

Integrated modelling of Polycyclic Aromatic Hydrocarbons in the marine environment: Coupling of hydrodynamic, fate and transport, bioaccumulation and planktonic food-web models

Spatio-temporal variability of pollutants in the environment is a complex phenomenon that requires a combined approach for its analysis. Whereas data on measured levels of contaminants in various environmental compartments is essential, it is not always possible to monitor at the necessary frequency and with the adequate spatial sampling distribution to capture this variability. Therefore a modelling approach able to complement experimental data and close the gaps in the monitoring programs is useful for assessing the contaminant dynamics occurring at different time scales. In this work a 1D water column fate model has been developed and tested for Polycyclic Aromatic Hydrocarbons (PAHs). The model has been coupled with a simple ecological model that includes a bioaccumulation module. Afterwards, the model has been used to study the temporal variability of contaminant concentrations as well as the fluxes between compartments. The results evidence the complex coupling between spatio-temporal scales and its influence on environmental concentration levels.     

A 3-D numerical study of salinity variations in the Bohai Sea during the recent years

Salinity is an important component of the marine system. Previous studies indicated that the mean salinity in the Bohai Sea had increased by 2.0 psu in the second half of the 20th century, mainly due to a sharp decrease in the Yellow River runoff, and also the effects of large-scale climatic variations and the intrusions of the North Yellow Sea Water (NYSW). Since 2002, the Yellow River Conservancy Commission has carried out the flow regulation at the beginning of every flood season, resulting in more discharge of the Yellow River freshwater into the Bohai Sea. In this study, the variations of salinity in the Bohai Sea during the recent years are investigated using a well-established three-dimensional baroclinic model, HAMburg Shelf Ocean Model (HAMSOM). The simulation results show that the Yellow River diluted water was mainly discharged into the Laizhou Bay, so the remarkable increase in the Yellow River runoff after 2002 led to a regime shift of salinity in the Laizhou Bay. However, in other parts of the Bohai Sea, salinity variation was influenced by the surrounding rivers or the intrusions of NYSW, and has little relation with the Yellow River runoff. As a whole, advection is more important than diffusion in the salinity distribution, and seasonal oscillation is the main feature of salinity variation. Via several case studies, evaporation and precipitation rates are found to be important in the long-term simulation of salinity.     

近50a淮河流域汛期降水日数和强度的分布与变化特征

选用1961-2010年淮河流域145个地面气象站的观测资料,分析淮河流域汛期(5-9月)降水的时空变化规律.结果表明:淮河流域汛期降水的空间分布不仅受到地理位置和地形的影响,而且与湿度和风速的空间分布具有较好的相关性;在时间变化上,雨日出现频率有下降的趋势,但暴雨日比重和暴雨日平均降水量均有升高的趋势.淮河流域汛期暴雨日出现频率以及各类型雨日的平均降水量均有上升的趋势,强降水时空变化呈现局地性和频发性.     

Two conceptual models of displacement transfer and examples

The concept of displacement transfer[1] was initially utilized by Dahlstrom (1970) to explain the relation- ships of overlapping thrusts in the Canadian Rockies wherein the displacement on one thrust is transferred to another, but the total displacement is still held con- stant along trend. Displacement transfer, which may exist in compressional[2] as well as tensile environ-ments[3], is a familiar kinematic mechanism that keeps the magnitude of deformation steady along trend in the linear str…     

Carbon budgets of three temperate forest ecosystems in Dongling Mt.,Beijing,China

There is a general agreement that forest ecosystems in the Northern Hemisphere function as signifi-cant sinks for atmospheric CO2; however, their magnitude and distribution remain large uncertainties. In this paper, we report the carbon (C) stock and its change of vegetation, forest floor detritus, and mineral soil, annual net biomass increment and litterfall production, and respiration of vegetation and soils between 1992 to 1994, for three temperate forest ecosystems, birch (Betula platyphylla) forest, oak (Quercus liaotungensis) forest and pine (Pinus tabulaeformis) plantation in Mt. Dongling, Beijing, China. We then evaluate the C budgets of these forest ecosystems. Our results indicated that total C density (organic C per hectare) of these forests ranged from 250 to 300 t C ha-1, of which 35―54 t C ha-1 from vegetation biomass C and 209―244 t C ha-1 from soil organic C (1 m depth, including forest floor detritus). Biomass C of all three forests showed a net increase, with 1.33―3.55 t C ha-1 a-1 during the study period. Litterfall production, vegetation autotrophic respiration, and soil heterotrophic respira-tion were estimated at 1.63―2.34, 2.19―6.93, and 1.81―3.49 t C ha-1 a-1, respectively. Ecosystem gross primary production fluctuated between 5.39 and 12.82 t C ha-1 a-1, about half of which (46%―59%, 3.20―5.89 t C ha-1 a-1) was converted to net primary production. Our results suggested that pine forest fixed C of 4.08 t ha-1 a-1, whereas secondary forests (birch and oak forest) were nearly in balance in CO2 exchange between the atmosphere and ecosystems.     

Potential and visible evaporation and its variations in European Russia over the recent 50 years by experimental data

Variations in pan evaporation in European Russia from 1951 to 2010 have been studied, and regions with specific variations of potential evaporation have been identified. It is shown that evaporation decseases all over the territory under consideration, and intensity of its decreasing up to the late 1970s was far in excess of that in the decades that followed. The decrease in the variations in evaporation may be regarded as an indicator of reduction of intensity of heat and moisture exchange between the underlying surface and the atmosphere. A new characteristic of the moisture regime of the territory, i.e., visible evaporation, was introduced to characterize, in this case, the amount of free moisture in the atmosphere that can be involved in the terrestrial water cycle. The humidity of the territory in the European Russia has shown to have increased since 1966. Regions where changes in the moisture regime show common patterns have been identified and the specific features of humidity distribution in different natural zones of European Russia have been assessed.     

近10年来北京夏季城市热岛的变化及环境效应的分析研究

根据1993～2003年北京地区气象台站7、8月的温度资料,分析研究了近10年来北京夏季城市热岛的变化及其环境效应.结果表明：北京夏季城市热岛的水平范围扩大到近郊区和远郊区的通州,分布特征也由“单中心”转变为“多中心”;平均热岛强度呈逐渐增强趋势,在夏季出现了强热岛;北京夏季出现热岛和强热岛的天数激增,7月最大热岛强度也呈逐年上升趋势;热岛的强度和水平分布都有明显的日变化;由于热岛效应使城区增温显著,北京夏季的高温日（Tmax≥35℃）也逐年增多. 本文还指出朝阳区气象观测站由于周围高大植被的影响,观测资料已不具备城区代表性.同时也证明绿化对降低城市热岛效应是极为有效的.本文的研究成果对北京城市发展和规划有一定的科学参考价值.     

Water, heat fluxes and water use efficiency measurement and modeling above a farmland in the North China Plain

Net radiation (Rn), water vapor flux (LE), sensible heat flux (Hs) and soil heat flux (G)were measured above a summer maize field with the eddy-covariance technique, simulation and analysis of water, heat fluxes and crop water use efficiency were made with the RZ-SHAW model at the same time in this study. The results revealed significant diurnal and seasonal variability of water vapor flux for summer maize. Most part of Rn was consumed by the evapotranspiration of the summer maize. The proportion of water vapor flux to net radiation ((LE/Rn) increased with the crop development and peaked around milk-filling stage with a value of 60%, a slightly lower than that obtained by the RZ-SHAW model. Daily evapotranspiration estimated by the model agreed with the results measured with the eddy-covariance technique, indices of agreement (IA) for hourly water vapor fluxes simulated and measured were above 0.75, root mean square errors (RMSE) were no more than 1.0. Diurnal patterns of Hs showed the shape of inverted "U" shifted to the forenoon with a maximum value around 11:30 (Beijing time), while LE exhibited an inverted "V" with a maximum value at around 13:00, about an hour later than Hs. Diurnal change of CO2showed an asymmetrical "V" curve and its maximal rates occurred at about 11:30. Variations of water use efficiency during the phonological stages of the summer maize showed a rapid increase with the photosynthetic photon flux density (PPFD) after sunrise, a state of equilibrium around 10:00 followed a decrease. Maximum values of water use efficiency were 24.3, and its average value ranged from 7.6 to 10.3 g kg-1.     

Main models and distribution patterns of gas reservoirs in large-medium gas fields of China

Based on characteristics and trap types of gas reservoirs in large and medium gas fields in China, 4 gas reservoir models have been established:(i) structural trap gas reservoir model I, formed earlier than or simutaneously with generating of gases; (ii) structural trap gas reservoir model II, formed later than generating of gases; (iii) fossil weathered residuum gas reservoir model; and (iV) mud diapir abnormal temperature and pressure gas reservoir model. Distribution patterns of large-medium gas fields are described with the concept of “sealed compartment”. It is concluded that the inner-compartment area, marginal area of the compartment and the areas between two overlapped sealed compartments are the most favourable areas for discovering large-medium gas fields. Project supported by the “85–102” Chinese National Key Science and Technology Project.     

Influencing domain of peripheral sources in the urban heavy pollution process of Beijing

Multiple cities in a diveloped economic area may consist of a city cluster,and the difusion and mixing of its pollutants result in the effect of pollutants plume between cities and the large-scale regional pollution diffusion phenomenon.The distant transfer and diffusion of pollutants occurs when massive aerosols are affected by the dynamic porcess of large-scale circulations.Research suggesten that the life span of aerosol particles whose diameters are about 1 um is the longest.The longevity …