High accuracy measurements of water storage change in Mining Lake 111, Germany     

Bertram Boehrer  Stephanie Kastner  Gregor Ollesch 《Limnologica》2010,40(2):156-160

Several pressure sensors were deployed in a small lake to determine its storage change. It could be shown that a deep enough deployment and an averaging over a time interval of 1 hour and 5 measuring points allowed for a measurement of 1 or 2 kg/m² (i.e. 2 mm of water column) of changes in the storage on the scale of the lake size. This accuracy for the lake storage could not be achieved by other methods, especially if conditions were difficult, e.g. snowfall, or in cases when precipitation was small. Finally, the pressure measurement - originally intended to roughly determine the water level - turned out to be a direct measurement of water mass in the lake, which was the proper magnitude for exchanges between atmosphere and lake. Hence the measurement of lake storage could become an interesting approach even for meteorological measurements, such as precipitation and evaporation on a water surface.  相似文献   

1957—2009年南澳蒸发量变化特征及影响因子     

林苗青  杜勤博  翁武坤 《辽宁气象》2011,(1):40-44

利用1957—2009年南澳县小型蒸发皿蒸发量资料,分析了南澳蒸发量的气候变化趋势。结果表明：南澳10月蒸发量最大,2月蒸发量最少;秋季蒸发量最大,夏季次之,冬季最少。1957—2009年蒸发量呈明显下降趋势,20世纪60—90年代基本上是锐减,21世纪的第1个10 a反而上升,平均以7.2 mm/a的趋势下降;11月减幅最大,7月减幅最小;冬季减幅最大,秋季次之,夏季最小。对蒸发量下降的原因分析表明,日照时数和平均风速的减少与蒸发量的减少呈显著相关,是蒸发量减少的主要影响因子;低云量的增多导致日照时数减少;低云量、总云量、相对湿度、降水量、水汽压与蒸发量呈负相关关系,其中低云量、总云量与蒸发量负相关显著。  相似文献   

Accumulation and speciation of selenium in evaporation basins in California,USA   总被引：1，自引：0，他引：1  

Ji-Hun Ryu  Suduan Gao  Kenneth K. Tanji 《Journal of Geochemical Exploration》2011

The accumulation of selenium in evaporation basins (or ponds) in the San Joaquin Valley, California is of a great concern due to its potential hazards to environments. In this study, the accumulation, speciation and concentrations of Se were examined in waters as well as sediments in a system of the evaporation ponds. A significant decrease in the total dissolved Se concentration in Cell 1 in which drainage water with higher Se concentration was pumped from Inlet Channels indicated that the immobilization of Se was active in the Cell 1 and resulted in the higher Se concentration in sediments compared to the terminal cell such as Cell 9. The percentage of reduced Se species such as selenite [Se(IV)] and org-Se of total Se in drainage waters was also found increased in Cell 1 compared to Inlet Channels. The total dissolved Se concentrations in water along flow paths from Cell 1 were relatively constant except for terminal cells such as Cells 9 and 10, which showed higher total dissolved Se concentrations due to evapoconcentration. The percentage of reduced Se forms of total Se was inversely proportional to the percentage of Se(VI) depending on the redox condition of evaporation ponds along the flow paths. Sequential extractions of Se species in sediments indicated that organic associated Se and elemental Se were prevalent forms in sediments in the ponds system. The higher concentrations of elemental Se and organic associated Se in sediments in Cell 1 indicated that the immobilization of Se was active in the sediments compared to Cell 9, while the percentage of both fractions of total Se in sediments in Cells 1 and 9 was relatively constant. The organic materials from algae might provide carbon sources for Se reduction and Se sink in sediments in its elemental and organic associated forms.  相似文献   

Reply to comments on “Evaporation estimation using artificial neural networks and adaptive neurofuzzy inference system techniques” by A. Moghaddamnia,M. Ghafari Gousheh,J. Piri,S. Amin and D. Han [Adv. Water Resour. 32 (2009) 88–97]     

D. Han 《Advances in water resources》2009

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滨州沿海蒸发量与海盐产量的关系研究   总被引：1，自引：0，他引：1       下载免费PDF全文

刘昭武  王凤娇  牛丽玲  王立静 《气象与环境学报》2009,25(1):31-34

海盐生产主要依靠自然蒸发,蒸发量预报对海盐生产有重要的指导作用。通过对1993—2007年滨州沿海蒸发量和海盐产量的分析,海盐产量的时间分布特征与净蒸发量基本一致,净蒸发量是影响海盐生产的决定性因素。分析蒸发量与气象要素之间的关系,分月建立了逐步回归方程,经检验可作为蒸发量的一种客观预报方法。  相似文献   

Tufa Accumulations in Ephemeral Streams: Observations from The Kimberley,north-west Australia     

Janet S. Wright 《The Australian geographer》2000,31(3):333-347

Four types of tufa occur along creeks draining the Oscar Range in the Kimberley region of Western Australia; stream-bed tufa, tufa dams, stream-bed tufa waterfalls, and rimstone pools. Well-developed tufa dam and waterfall formations occur at significant breaks of slope within the channel long profile. This suggests that disruption of the hydraulic flow regime and increased turbulence at these points has an important role to play in determining the location of tufa deposits. However, the best-developed stream-bed tufa deposits are located immediately upstream of dam and waterfall formations, which indicates that the evaporation of water ponded behind these flow obstructions may lead to calcium carbonate precipitation during the dry season. The presence of plant and cyanobacterial communities on, and the incorporation of organic material into, the best-developed tufa formations indicates that biological activity may have an important role to play in determining both the rate of tufa deposition and the internal structure of the resulting accumulations.  相似文献   

Study of evaporation and recharge in desert soil using environmental tracers, New Mexico, USA   总被引：4，自引：0，他引：4  

A.-R. Shurbaji  A. R. Campbell 《Environmental Geology》1997,29(3-4):147-151

 The purpose of this study is to investigate the rates and mechanisms of recharge and evaporation in soils of a desert environment using two environmental tracers (chloride and oxygen-18). The profiles of chloride concentration and oxygen-18 enrichment in soil-water, together with the depth distribution of water content in soil, reveal information about long-term recharge and instantaneous evaporation processes without needing to know the physical properties of the soil. Three holes were hand-augured, in different desert settings in southeastern New Mexico. The chloride concentration profiles were used, with the chloride mass balance method, to estimate long-term recharge rates in these three holes as 0.5, 0.8, and 2.4 mm yr^–1. Analysis using a bimodal flow and transport model shows that possibly 85% of the recharge occurs via movement of water through preferred pathways in the root zone. Preferential flow was evident in all three sampling sites. Clay layers have a noticeable effect on the development of water content distribution and thus on oxygen-18 enrichment and chloride concentration profiles. The spatial variation in clay layering partly explains the variation in recharge rate estimates. Received: 13 October 1995 · Accepted: 15 November 1995  相似文献   

浅海原油净化过程的模拟实验──分散油的挥发降解过程   总被引：2，自引：0，他引：2  

王永辰  祝陈坚  孙秉一  史致丽  于圣睿  郝恩良  李铁  石晓勇 《海洋与湖沼》1995,26(4):389-396

于1989年3－7月在青岛海洋大学进行“河口”原油和“东营”原油实验室模拟实验，以了解海上溢油进入海水中的分散（溶解和乳化）油的挥发降解过程。结果表明，分散油的蒸发速率除与原油本身性质有关外，还与环境温度、水体盐度和水面风速有关。水体中油含量随时间变化可表示为：，温度、盐度和风速增大时，均有助于分散油的挥发，其中风速变化对Kv的影响最大，而盐度变化的影响最小。  相似文献   

多种水面类型蒸发的研究   总被引：1，自引：0，他引：1  

毛锐  高俊峰 《海洋与湖沼》1996,27(4):445-450

分析有水草水面、污水面、受热水面、盐水（盐水）面等特定水面类型的蒸发量，并与清水、淡水对照，求出蒸发比，还计算了太湖地区有水草水面和受热水面的蒸发模型，为确定湖泊的蒸发量提供一新途径，最后建议用水生植物的蒸腾规律来控制水面蒸发，调节水面温度。  相似文献   

Boron isotopic fractionation during seawater evaporation   总被引：6，自引：0，他引：6  

Y.K. Xiao  S.Z. Li  H.Z. Wei  A.D. Sun  W.G. Liu  W.J. Zhou  Z.Q. Zhao  C.Q. Liu  G.H. Swihart 《Marine Chemistry》2007,103(3-4):382-392

Laboratory experiments were undertaken to investigate the behaviour of boron at the seawater–air interface during seawater evaporation. Seawaters adjusted to different pH values were heated to 27, 33 and 40 °C inside a quartz evaporator. The vapor was collected with a quartz condenser using a cold trap. A natural seawater–vapor process in quiet air conditions and excluding the sea-spray component was realized using this arrangement. The results indicate an enrichment of ¹¹B in the condensate. This implies that in the natural environment, rainfall with δ¹¹B values lower than that of seawater has been affected either by continental boron sources or by the boron extracted from seawater under airflow conditions. While the net flux of boron carried away from the ocean by air masses due to seawater evaporation is significant compared to other fractionation-associated processes removing boron from the ocean, the effect of isotopic fractionation as boron enters the vapor phase on the isotopic composition of boron in the ocean over time is small.  相似文献