期刊文献+
共找到27篇文章
< 1 2 >
每页显示 20 50 100
南京市居民个人节水意识认知与行为调研分析
1
作者 张帆 吴艾婧 范云柱 《水利发展研究》 2023年第1期65-68,共4页
近年来,江苏省全面推进节约用水管理工作,全省单位地区生产总值用水量、单位工业增加值用水量的降幅每年均超额完成国家和省政府规定的目标任务,用水效率明显提升。文章通过了解南京市居民个人节水意识、节水行为、节水关注度、节水宣... 近年来,江苏省全面推进节约用水管理工作,全省单位地区生产总值用水量、单位工业增加值用水量的降幅每年均超额完成国家和省政府规定的目标任务,用水效率明显提升。文章通过了解南京市居民个人节水意识、节水行为、节水关注度、节水宣传等情况,发现存在的问题,为南京市节约用水管理工作提供数据支撑。 展开更多
关键词 节水管理 节水意识 节水关注 认知行为分析 江苏省南京市
下载PDF
水资源紧缺条件下系统节水价值的矩阵模型研究
2
作者 刘纯义 陈诚 《灌溉排水学报》 CSCD 北大核心 2006年第3期79-81,共3页
影响系统节水价值的因素很多,如系统的结构型式、产业结构型式、节水成本、节水技术水平、节水量、水资源价值量等,合理地量化分析计算各要素在价值形成中的贡献大小,把这些因素的复杂关系概括成矩阵形式,形成3个矩阵,从而构建了系统节... 影响系统节水价值的因素很多,如系统的结构型式、产业结构型式、节水成本、节水技术水平、节水量、水资源价值量等,合理地量化分析计算各要素在价值形成中的贡献大小,把这些因素的复杂关系概括成矩阵形式,形成3个矩阵,从而构建了系统节水价值的矩阵模型。 展开更多
关键词 系统节水 节水度 价值 矩阵
下载PDF
水资源紧缺条件下系统节水价值的矩阵模型研究
3
作者 陈诚 刘纯义 《水利经济》 2006年第5期9-10,34,共3页
介绍系统节水概念、节水的劳动价值和系统节水价值的影响因素,合理地量化分析计算各要素在价值形成中的贡献大小,把这些因素的复杂关系概括成矩阵形式,形成三个矩阵,从而构建了系统节水价值的矩阵模型。
关键词 系统节水 节水度 价值 矩阵
下载PDF
Dwarfing effects of plant growth regulators on narcissi 被引量:3
4
作者 任旭琴 梁宏伟 +1 位作者 陈伯清 季美云 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第4期339-341,共3页
The effects of four kinds of plant growth regulators with different concentrations on narcissi were studied in 2001. The results showed that the regulators could inhibit the growths of height and leaves of narcissi. O... The effects of four kinds of plant growth regulators with different concentrations on narcissi were studied in 2001. The results showed that the regulators could inhibit the growths of height and leaves of narcissi. Of the four regulators, the dwarfing effects of paclobatrazol (PP333) and uniconazole (S3307) on narcissi were better than those of chlorocholine (CCC) and dimethyl amino-sussinamic acid (B9). All of the regulators did not have significant effect on the root length. Moreover, the time of flowering was later for the narcissi treated with regulators than that of the control to a certain extent, and the range delayed was from 2 days to 19 days. The correlation analysis results showed that there was a significant correlation between the time of flowering and the concentrations of regulators. The ornament value of narcissi was obviously improved by using the regulators. 展开更多
关键词 Narcissus tuzetta var. chinesis Roem Plant growth regulators PP333 S3307 B9 CCC
下载PDF
Seasonal changes of soil respiration in Betula platyphylla forest in Changbai Mountain, China 被引量:2
5
作者 刘颖 韩士杰 林鹿 《Journal of Forestry Research》 SCIE CAS CSCD 2009年第4期367-371,I0007,共6页
A stdudy was conducted to determine the seasonal changes of soil respiration and the contribution of root respiration to soil respiration in Betula plaophylla forest in Changbai Mountain from May to September in 2004.... A stdudy was conducted to determine the seasonal changes of soil respiration and the contribution of root respiration to soil respiration in Betula plaophylla forest in Changbai Mountain from May to September in 2004. Results indicated that the total soil respiration, root-severed soil respiration and the root respiration followed a similar seasonal trend, with a high rate in summer due to wet and high temperature and a low rate in spring and autumn due to lower temperature. The mean rates of total soil respiration, root-severed soil respiration and root respiration were 4.44, 2.30 and 2.14 μmol.m^-2.s^-1, respectively during the growing season, and they were all exponentially correlated with temperature. Soil respiration rate had a linear correlation with soil volumetric moisture. The Q10 values for total soil respiration, root-severed soil respiration and root respiration were 2,82, 2.59 and 3. 16, respectively. The contribution rate of root respiration to the total soil respiration was between 29.3% and 58.7% during the growing season, indicating that root is a major component of soil respiration. The annual mean rates of total soil respiration, root-severed soil respiration and root respiration were 1.96, 1.08, and 0.87 μmol.m^-2.s^-1, or 741.73 408.71, and 329.24 g.m^-2.a^-1, respectively. Root respiration contributed 44.4% to the annual total soil respiration. The relationship proposed for soil respiration with soil lemperature was useful for understanding and predicting potential changes in Changbai Mountain B. platyphylla forest ecosystem in response to forest management and climate change. 展开更多
关键词 root respiration seasonal variations soil respiration soil temperature soil water content
下载PDF
A Seasonal Prediction Model for the Summer Rainfall in Northeast China Using the Year-To-Year Increment Approach 被引量:9
6
作者 ZHU Ya-Li 《Atmospheric and Oceanic Science Letters》 2011年第3期146-150,共5页
Using the year-to-year increment approach,this study investigated the relationship of selected climatic elements with the increment time series of the summer rainfall between successive years in Northeast China,includ... Using the year-to-year increment approach,this study investigated the relationship of selected climatic elements with the increment time series of the summer rainfall between successive years in Northeast China,including the soil moisture content,sea surface temperature,500 hPa geopotential height,and sea level pressure in the preceding spring for the period 1981-2008.Two spring predictors were used to construct the seasonal prediction model:the area mean soil moisture content in Northwest Eurasia and the 500 hPa geopotential height over Northeast China.Both the cross-validation and comparison with previous studies showed that the above two predictors have good predicting ability for the summer rainfall in Northeast China. 展开更多
关键词 Northeast China summer rainfall seasonalprediction year-to-year increment
下载PDF
The inter-annual variability of the Yellow Sea Warm Current surface axis and its influencing factors 被引量:8
7
作者 宋德海 鲍献文 +3 位作者 王小华 徐玲玲 林霄沛 吴德星 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第3期607-613,共7页
Based on the Pathfinder sea surface temperature(PFSST),the surface axis and its pattern of the Yellow Sea Warm Current(YSWC) are discussed.A structure of double-warm-tongue is found in February and it varies in differ... Based on the Pathfinder sea surface temperature(PFSST),the surface axis and its pattern of the Yellow Sea Warm Current(YSWC) are discussed.A structure of double-warm-tongue is found in February and it varies in different years.Two indexes are calculated to represent the westward shift(WSI) and northward extension(NEI) of the warm water in the Yellow Sea(YS).Wavelet analysis illustrates that the WSI and NEI have prominent periods of 3-6 years and 3-4 years,respectively.The Empirical Orthogonal Function(EOF) decomposition is applied to the winter wind stress curl and the Kuroshio Current(KC) transport,which are believed to play important roles in forcing the variability of the YSWC surface axis.Statistics shows that the WSI is significantly related with the second EOF mode of the wind stress curl in February,which may force the YSWC surface axis moving westward and maintaining the double warm tongues because of its opposite curl in the YSWC domain.The first EOF mode of wind stress curl in January is propitious for inducing the warm tongue in the YS to advance more northward.Hence,the wind stress curls both in January and in February could force variations of the YSWC surface axis;however,the effect of the January wind stress curl is relatively weaker than that of the February.The relationship between the NEI and the KC transport is remarkable,and it seems that the stronger KC supplies more power to push the YSWC northward against the southward wind. 展开更多
关键词 Yellow Sea Yellow Sea Warm Current (YSWC) surface axis inter-annual variability sea surface temperature (SST)
下载PDF
Estimate of CH_4 Emissions from Year-Round Flooded Rice Fields During Rice Growing Season in China 被引量:99
8
作者 CAIZu-Cong KANGGuo-Ding +1 位作者 H.TSURUTA A.MOSIER 《Pedosphere》 SCIE CAS CSCD 2005年第1期66-71,共6页
A special kind of rice field exists in China that is flooded year-round. These rice fields have substantially large CH4 emissions during the rice-growing season and emit CH4 continuously in the non-rice growing season... A special kind of rice field exists in China that is flooded year-round. These rice fields have substantially large CH4 emissions during the rice-growing season and emit CH4 continuously in the non-rice growing season. CH4 emission factors were used to estimate the CH4 emissions from year-round flooded rice fields during the rice-growing season in China. The CH4 emissions for the year-round flooded rice fields in China for the rice growing season over a total area of 2.66 Mha were estimated to be 2.44 Tg CH… 展开更多
关键词 IPCC methodology methane emission rice fields year-round flooded
下载PDF
Influence of atmospheric circulation on precipitation in Altai Mountains 被引量:4
9
作者 MALYGINA Natalia PAPINA Tatiana +1 位作者 KONONOVA Nina BARLYAEVA Tatiana 《Journal of Mountain Science》 SCIE CSCD 2017年第1期46-59,共14页
We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in t... We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in the precipitation regime had a positive trend for the warm seasons(April-October),but weakly positive or negative trends for the cold seasons(November-March). It was found that these changes correspond to the decreasing contribution of "Northern meridional and Stationary anticyclone(Nm-Sa)" and "Northern meridional and East zonal(Nm-Ez)" circulation groups and to the increasing contribution of "West zonal and Southern meridional(Wz-Sm)" circulation groups,accordingly to the Dzerdzeevskii classification. In addition,it was found that the variation of precipitation has a step change point in 1980. For the warm seasons,the precipitation change at this point is associated with the reduced influence of "West zonal(Wz)","Northern meridional and Stationary anticyclone(Nm-Sa)" and "Northern meridional and Southern meridional(Nm-Sm)" circulation groups. For the cold seasons,a substantialincrease of "Wz-Sm" and a decrease of "Nm-Sa","Nm-Ez" circulation groups are responsible for the precipitation change in the two time periods(1959-1980 and 1981-2014). 展开更多
关键词 Altai Mountains Precipitation Atmospheric circulation
下载PDF
Effects of Water-table Depth and Soil Moisture on Plant Biomass, Diversity, and Distribution at a Seasonally Flooded Wetland of Poyang Lake, China 被引量:24
10
作者 XU Xiuli ZHANG Qi +2 位作者 TAN Zhiqiang LI Yunliang WANG Xiaolong 《Chinese Geographical Science》 SCIE CSCD 2015年第6期739-756,共18页
Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dra... Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis (CCA), spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community (ranging from q).5 m above ground to +10.3 m below ground), intermediate in P. australis community (-2.6 m to +7.8 m) and shallow- est in C. cinerascens community (-4.5 m to +6.1 m). Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass present Gaussian models along the gradient of average water-table depth in growing season, while species diversity indices show bimodal patterns. The optimal average water-table depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively, and are 2.2 m and 2.4 m for species richness and Shannon-Wiener indices, respectively. Outcomes of this work improved the under- standings of the relationship between hydrology and vegetation. 展开更多
关键词 water-table depth soil moisture species diversity BIOMASS Gaussian model Poyang Lake wetland
下载PDF
Optimum Scheduling for the Chilled Water System of an Intelligent Building 被引量:2
11
作者 郭巧 范新建 《Journal of Beijing Institute of Technology》 EI CAS 2001年第4期383-388,共6页
The energy saving issue of chilled water system in an intelligent building is analyzed from the systematic point of view, and an optimum scheduling scheme which can save energy of the system facilities and satisfy the... The energy saving issue of chilled water system in an intelligent building is analyzed from the systematic point of view, and an optimum scheduling scheme which can save energy of the system facilities and satisfy the constraints of the real time cold loads and system running is also proposed. It can make the minimum cost of the system by optimizing the number of running chillers, running parameters and the distribution of real time loads of running chillers. The improved genetic algorithm is used in the optimum scheduling scheme. The computation results show that the building energy consumption can be decreased by about 10%. 展开更多
关键词 genetic algorithm intelligent building systematic energy saving chilled water system optimal scheduling
下载PDF
Temporal and Spatial Variability of Dissolved Organic Carbon Concentration in the Xijiang River, South China 被引量:4
12
作者 TAO Zhen GAO Quanzhou +5 位作者 GUO Wenping WANG Zhengang ZHANG Yongling XIE Chenji HUANG Xiakun ZHONG Hongwei 《Journal of Mountain Science》 SCIE CSCD 2011年第5期694-703,共10页
A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than ... A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological seasons. The DOC level during the flood season (1.18 mg L-1) was less than that during the non-flood season (1.40 mg L-1). Owing to the concomitance of the flushing and dilution effects of the runoff during the high-water period, the variation of riverine DOC concentration with discharge in the XJR differed from that reported in many other major rivers. The DOC export flux above the city of Wuzhou was about 0.62× 106 g C km-2 yr-1. The DOC transported during the "056" Massive Flood period comprised 30.35% of the annual total, while the discharge accounted for 36.32% of the total annual flow. The characteristics in riverine DOC concentration in the XJR were attributed to the combined effect of the geomorphologic, monsoon climatic and hydrological processes as well as land-use within the drainage basin. 展开更多
关键词 Export flux Hydrological processes Massive flood Riverine dissolved organic carbon The Xijiang River
下载PDF
Seasonal variability of salinity budget and water exchange in the northern Indian Ocean from HYCOM assimilation 被引量:10
13
作者 张玉红 杜岩 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第6期1082-1092,共11页
Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BO... Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BOB), as well as water exchange between the two basins. Results show that fresh water flux cannot explain salinity changes in salinity budget of both regions. Oceanic advection decreases salinity in the southeastern AS during the winter monsoon season and increases salinity in the southern BOB during the summer monsoon season. In winter, the Northeast Monsoon Current (NMC) carries fresher water from the BOB westward into the southern AS; this westward advection is confined to 4°-6°N and the upper 180 m south of the Indian peninsula. Part of the less saline water then turns northward, decreasing salinity in the southeastern AS. In summer, the Southwest Monsoon Current (SMC) advects high-salinity water from the AS eastward into the BOB, increasing salinity along its path. This eastward advection of high-salinity water south of the India Peninsula extends southward to 2°N, and the layer becomes shallower than in winter. In addition to the monsoon current, the salinity difference between the two basins is important for salinity advection. 展开更多
关键词 seasonal variability salinity budget Arabian Sea Bay of Bengal zonal water exchange HYbridCoordinate Ocean Model (HYCOM) assimilation
下载PDF
ON STRONG SIGNALS OF MONTHLY PRECIPITATION ANOMALIES IN EARLY RAINING SEASON OF GUANGDONG AND CONCEPTUAL MODELS OF PREDICTION
14
作者 林爱兰 《Journal of Tropical Meteorology》 SCIE 2002年第2期150-157,共8页
Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential heigh... Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential height field, outgoing longwave radiation (OLR) field, sea surface temperature (SST) and fourteen indexes of general circulation depicting atmosphere activity at high, middle and low latitutes. Being multiple tools of information, a number of conceptual models are formulated that are useful for prediction of the magnitude of monthly precipitation (drought, flood and normal conditionss). 展开更多
关键词 early raining season of the year precipitation anomalies strong signals conceptual models
下载PDF
A research on the relationship between ejaculation and serum testosterone level in men 被引量:1
15
作者 蒋鸣 蒋新 +1 位作者 邹强 沈进稳 《Journal of Zhejiang University Science》 CSCD 2003年第2期236-240,共5页
The purpose of this study is to gain understanding of the relationshi p between ejaculation and serum testosterone level in men. The serum testosteron e concentrations of 28 volunteers were investigated daily during a... The purpose of this study is to gain understanding of the relationshi p between ejaculation and serum testosterone level in men. The serum testosteron e concentrations of 28 volunteers were investigated daily during abstinence peri ods after ejaculation for two phases. The authors found that the fluctuations o f testosterone levels from the 2nd to 5th day of abstinence were minimal. On the 7th day of abstinence, however, a clear peak of serum testosterone appeared, re aching 145.7% of the baseline (P<0.01). No regular fluctuation was observed foll owing continuous abstinence after the peak. Ejaculation is the precondition and beginning of the special periodic serum testosterone level variations, which wou ld not occur without ejaculation. The results showed that ejaculation-caused va r iations were characterized by a peak on the 7th day of abstinence; and that the effective time of an ejaculation is 7 days minimum. These data are the first to document the phenomenon of the periodic change in serum testosterone level; the correlation between ejaculation and periodic change in the serum testosterone le vel, and the pattern and characteristics of the periodic change. 展开更多
关键词 EJACULATION Periodic change TESTOSTERONE
下载PDF
Hydrodynamic characteristics of Wujiangdu Reservoir during the dry season-a case study of a canyon reservoir 被引量:1
16
作者 Haitao Zhang Baoli Wang +3 位作者 Qiong Han Jie Shi Xiaolong Qiu Tiejun Wang 《Acta Geochimica》 EI CAS CSCD 2017年第3期506-510,共5页
With the development of hydropower in the karst area of Southwest China, a series of cascade canyon reservoirs have been formed through the construction of dams. Given that hydrodynamic conditions in canyon reservoirs... With the development of hydropower in the karst area of Southwest China, a series of cascade canyon reservoirs have been formed through the construction of dams. Given that hydrodynamic conditions in canyon reservoirs play a pivotal role in controlling the spatiotemporal distribution of physical and chemical properties of the stored water, hydrodynamic characteristics are of great importance in understanding biogeochemical cycles in those reservoirs. To further this understanding, a field campaign was conducted in the Wujiangdu Reservoir of Guizhou Province. It was found that from the reservoir inlet to the front of the dam, velocity(v) was negativelycorrelated and had a logarithmic relationship with distance along the ship track(s) under dry-season flow conditions[v =-0.104 ln(s) + 0.4756]. Analysis showed that dryseason flow velocity had no significant correlation with water temperature, p H, or dissolved oxygen(DO). However, when velocity decreased to 0.061 m/s, water depth increased abruptly. In addition, DO displayed a sudden drop and the trend in p H changed from increasing to decreasing, while water temperature showed an opposite trend, indicating the existence of a transition zone from the river to the reservoir. 展开更多
关键词 Canyon reservoir Hydrodynamic characteristics A transition zone Wujiang River
下载PDF
Subdaily to Seasonal Change of Surface Energy and Water Flux of the Haihe River Basin in China: Noah and Noah-MP Assessment 被引量:1
17
作者 Fuqiang YANG Li DAN +3 位作者 Jing PENG Xiujing YANG Yueyue LI Dongdong GAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第1期79-92,共14页
The land surface processes of the Noah-MP and Noah models are evaluated over four typical landscapes in the Haihe River Basin(HRB) using in-situ observations. The simulated soil temperature and moisture in the two lan... The land surface processes of the Noah-MP and Noah models are evaluated over four typical landscapes in the Haihe River Basin(HRB) using in-situ observations. The simulated soil temperature and moisture in the two land surface models(LSMs) is consistent with the observation, especially in the rainy season. The models reproduce the mean values and seasonality of the energy fluxes of the croplands, despite the obvious underestimated total evaporation. Noah shows the lower deep soil temperature. The net radiation is well simulated for the diurnal time scale. The daytime latent heat fluxes are always underestimated, while the sensible heat fluxes are overestimated to some degree. Compared with Noah, Noah-MP has improved daily average soil heat flux with diurnal variations. Generally, Noah-MP performs fairly well for different landscapes of the HRB. The simulated cold bias in soil temperature is possibly linked with the parameterized partition of the energy into surface fluxes. Thus, further improvement of these LSMs remains a major challenge. 展开更多
关键词 land surface model Haihe River Basin soil temperature soil moisture surface energy flux seasonal cycle
下载PDF
Seasonal Dynamics of Turbidity Maximum in the Muthupet Estuary, India
18
作者 PRIYA K.L. JEGATHAMBAL P. JAMES E.J. 《Journal of Ocean University of China》 SCIE CAS 2015年第5期765-777,共13页
Results are presented of the longitudinal and vertical profiling of salinity and suspended particulate matter(SPM) at the Muthupet estuary, India, during a one year period under widely varying freshwater flow conditio... Results are presented of the longitudinal and vertical profiling of salinity and suspended particulate matter(SPM) at the Muthupet estuary, India, during a one year period under widely varying freshwater flow conditions. Freshwater flow was available during post-monsoon and monsoon. An up-estuary shift in the location of estuarine turbidity maxima(ETM) was observed during the transition from post-monsoon to pre-monsoon and further it shifted downstream during the transition from pre-monsoon to monsoon, thereby exhibiting a pronounced seasonal cycle. The salinity intrusion was dependent on the freshwater discharge and was expressed as a power function of freshwater flow, explaining 97% of the variance. The formation of a salt plug in Muthupet estuary and its seasonal dynamics were observed, which is not an identified feature of any of the Indian estuaries studied so far. The geographical positions of salt plug and ETM core were more or less the same during their formation. The occurrence of two ETM during the LW of post-monsoon and the absence of ETM during monsoon explains the strong seasonal variation in the formation of ETM. The primary factor affecting the formation of ETM was identified as the freshwater flow over an annual cycle; the resuspension of sediments by tidal current affecting the formation on a flood/ebb cycle was secondary. The extent of shift of ETM was found to be an inverse logarithmic function of the freshwater discharge. The separation between ETM intrusion and salinity intrusion increased two fold with the increase in ETM intrusion. 展开更多
关键词 estuarine turbidity maximum salinity intrusion suspended particulate matter salt plug Muthupet estuary India
下载PDF
Responses of Halophyte Salicornia bigelovii to Different Forms of Nitrogen Source 被引量:4
19
作者 N. KUDO H. FUJIYAMA 《Pedosphere》 SCIE CAS CSCD 2010年第3期311-317,共7页
Salt-affected soils are agricultural and environmental problems on a global scale. Plants suffer from saline stresses in these soils and show nitrogen (N) deficiency symptoms. However, halophytes grow soundly under ... Salt-affected soils are agricultural and environmental problems on a global scale. Plants suffer from saline stresses in these soils and show nitrogen (N) deficiency symptoms. However, halophytes grow soundly under saline conditions. In order to clarify the N nutrition of the halophyte Salicornia bigelovii, it was grown at several N levels (1, 2, 3, and 4 mmol L-1), supplied in the form of NO3 or ammonium (NH4+), under high NaCl conditions (200 mmol L-l). NH4^+- fed plants showed better growth than NO3-fed plants at 1-3 mmol L-1N, and plants in both treatments showed the same growth at 4 mmol L-1 N. Nitrogen contents in NO3-fed plants increased with the N concentrations in solution; competitive inhibition of NO3- absorption by Cl- was observed under lower N conditions. In addition, shoot dry weight was significantly correlated only with shoot N content. Therefore, growth of NO3-fed plants was regulated by N absorption. In contrast, N contents of shoots in NH4+-fed plants did not change with N concentration. Shoot Na content decreased with increasing N concentration, while K content increased. Dry weight was highly correlated only with K content in NH4+-fed plants. These observations indicated that growth of NH4+-fed plants was mainly regulated by K absorption. 展开更多
关键词 cation absorption nitrogen nutrition plant growth saline stress
下载PDF
Seasonal Variation of Tritium and Major Elements in Snow and Precipitation in Niigata, Japan
20
作者 Yurong Jiao Hiroshi Imaizumi 《Journal of Environmental Science and Engineering(A)》 2012年第10期1218-1225,共8页
In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions... In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions (Na+, K+, Ca2+, Mg2+, NH4+, SO4^2-, NO3- and Cl-) were combined with tritium (^3H or T) concentration (T specific activity) in both precipitation and snow, and transformation patterns of polluted air mass in Niigata region were revealed. The low level tritium in precipitation was measured by a distillation process and an electrolytic enrichment process. Each tritium concentration in the precipitation sample thus obtained was measured by liquid scintillation counter. On the basis of the above measurement and analysis, it was found that the tritium and nss (non-sea-salt) calcium concentrations showed a seasonal variation with a highest value in spring over one year. 展开更多
关键词 Precipitation chemistry tritium tracer backward trajectory analysis Fukusima accident Niigata City.
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部