Resolution of freshwater and saline water aquifers by composite geophysical data analysis methods     

G. K. Hodlur  Ratnakar Dhakate  T. Sirisha  D. B. Panaskar 《水文科学杂志》2013,58(3):414-434

Abstract

The resolution of the freshwater and saline water aquifers in a coastal terrain (Mahanadi Basin, India) is updated. We analysed electrical borehole log data at four sites and compared the water resistivity regime of the freshwater and saline water zones obtained from electrical borehole logging, with the resistivity regime obtained by interpreting vertical electrical sounding (VES) data. The multilayer VES data interpretation is modified to a simple model, containing only the freshwater zone and the saline water zone. The composite geophysical parameters of the freshwater and saline water zones, in particular the resistivity and longitudinal unit conductance regime, are identified. The resolution obtained from the composite geophysical data analyses is very clear and convincing. The composite longitudinal unit conductance regime of the saline water zones is very high compared to that of the freshwater zones. This makes the identification of the two aquifers easy and increases its reliability. A technique which enables analysis of composite geophysical data of freshwater and saline water zones at VES sites in the vicinity of the borehole log sites is proposed. The significance of longitudinal unit conductance in resolving the freshwater and saline water aquifers is illustrated graphically. The proposed technique is validated by correlating the longitudinal unit conductance and resistivity with the total dissolved solids. The efficiency of the technique is validated by carrying out discriminant function analysis.

Citation Hodlur, G. K., Dhakate, R., Sirisha, T. & Panaskar, D. B. (2010) Resolution of freshwater and saline water aquifers by composite geophysical data analysis methods. Hydrol. Sci. J. 55(3), 414–434.  相似文献   

Growth and survival of Halimione portulacoides stem cuttings in heavy metal contaminated soils     

《Marine pollution bulletin》2013,76(1-2):28-32

The halophytic shrub Halimione portulacoides demonstrates a high tolerance to heavy metal contamination and a capacity for accumulating metals within its tissues. On the Iberian Peninsula, this species has colonized habitats with high levels of metal pollution. The aim of this study is to analyze the response of H. portulacoides stem cuttings to this pollution. Growth, photosynthesis and metal uptake were examined in H. portulacoides through an experiment in which stem cuttings were replanted in metal-contaminated soil. This condition decreased growth and lowered both photosynthetic rate and stomatal conductance. Reduced photosynthetic performance was largely due to the reduced concentration of photosynthetic pigments. Despite these responses, there was some important evidence suggesting the phytoremediatory potential of Halimione stem cuttings. The results of our study indicate that this salt-marsh shrub may represent a biotool of value in the restoration of polluted areas.  相似文献   

Winter Leaf Conductance Rates of Pinus Strobus L. (Eastern White Pine)     

《自然地理学》2013,34(5):474-482

Our knowledge of winter leaf conductance and transpiration rates during the winter and early spring is especially weak for Pinus strobus L. (eastern white pine). Hence, the present study was conducted to: (1) measure and examine the winter leaf conductance and transpiration rates among 10 P. strobus trees to supply preliminary data for an understudied tree species; and (2) investigate whether observed leaf conductance and transpiration rates are large enough to merit incorporation into existing water balance models. The fieldwork was conducted at the Fair Hill Natural Resources Management Area in northeastern Maryland (39°42'N, 75°50'W) using a Li-Cor 1600M Steady State Porometer. Meteorological data were acquired from a continuously recording meteorological station on-site. Meteorological data were recorded at five-minute intervals to ensure that weather conditions could be temporally sequenced with porometer readings. The 10 co-occurring P. strobus sample trees were of similar age and health on uniform soils in an open field. Winter and early spring leaf conductance values of the selected trees reached 20 mmol m^-2 s^-1, whereas transpiration reached 0.13 mmol m^-2 s^-1. Results of the study indicate that there is statistically significant differences in leaf conductance rates among co-occurring P. strobus trees (H = 16.74, p = .05). Since the upper winter leaf conductance and transpiration rates measured in this study overlap with growing season leaf conductance and transpiration values reported by others, it is suggested that winter leaf conductance of and transpiration from P. strobus trees are significant enough to incorporate into water balance calculations.  相似文献   

Tree root systems competing for soil moisture in a 3D soil–plant model     

《Advances in water resources》2014

Competition for water among multiple tree rooting systems is investigated using a soil–plant model that accounts for soil moisture dynamics and root water uptake (RWU), whole plant transpiration, and leaf-level photosynthesis. The model is based on a numerical solution to the 3D Richards equation modified to account for a 3D RWU, trunk xylem, and stomatal conductances. The stomatal conductance is determined by combining a conventional biochemical demand formulation for photosynthesis with an optimization hypothesis that selects stomatal aperture so as to maximize carbon gain for a given water loss. Model results compare well with measurements of soil moisture throughout the rooting zone, of total sap flow in the trunk xylem, as well as of leaf water potential collected in a Loblolly pine forest. The model is then used to diagnose plant responses to water stress in the presence of competing rooting systems. Unsurprisingly, the overlap between rooting zones is shown to enhance soil drying. However, the 3D spatial model yielded transpiration-bulk root-zone soil moisture relations that do not deviate appreciably from their proto-typical form commonly assumed in lumped eco-hydrological models. The increased overlap among rooting systems primarily alters the timing at which the point of incipient soil moisture stress is reached by the entire soil–plant system.  相似文献   

棉花阴、阳叶的气孔导度和光合作用观测对比及模型应用   总被引：1，自引：0，他引：1  

申双和  陶寅  张方敏 《南京气象学院学报》2008,31(4):468-472

以实验观测数据为基础,对棉花阳叶和阴叶光合速率、气孔导度的变化进行比较,通过双叶模型和大叶模型对冠层光合作用进行对比分析,结果表明,大叶模型的计算结果普遍高于双叶模型,总体高出13％。由此可见,过去在研究植被一大气碳交换中使用大叶模型估算植物光合作用会夸大碳汇的作用。  相似文献   

Physical characteristics of Acidic Mining Lake 111     

G?kay?KarakasEmail author  Iris?Brookland  Bertram?Boehrer 《Aquatic Sciences - Research Across Boundaries》2003,65(3):297-307

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Lake Lucerne, Switzerland, a long term study of 1961-1992   总被引：1，自引：0，他引：1  

Heinrich Bührer  Heinz Ambühl 《Aquatic Sciences - Research Across Boundaries》2001,63(4):432-456

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Species differences in stomatal control of water loss at the canopy scale in a mature bottomland deciduous forest   总被引：2，自引：0，他引：2  

D. E. Pataki  R. Oren   《Advances in water resources》2003,26(12):1267

In order to evaluate factors controlling transpiration of six common eastern deciduous species in North America, a model describing responses of canopy stomatal conductance (G_S) to net radiation (R_N), vapor pressure deficit (D) and relative extractable soil water (REW) was parameterized from sap flux data. Sap flux was measured in 24 mature trees consisting of the species Carya tomentosa, Quercus alba, Q. rubra, Fraxinus americana, Liriodendron tulipifera, and Liquidambar styraciflua in a bottomland oak-hickory forest in the Duke Forest, NC. Species differences in model coefficients were found during the 1997 growing season. All species showed a reduction in G_S with increasing D. R_N influenced G_S in the overstory shade intolerant L. styraciflua to a larger extent than the other species measured. In addition, despite a severe drought during the study period, only L. tulipifera showed a decline in G_S with decreasing REW. The primary effect of the drought for the other species appeared to be early autumn leaf senescence and abscission. As a result, despite the drought in this bottomland forest accustomed to ample water supply, maximum daily transpiration (1.6 mm) and growing season transpiration (264 mm) were similar to a nearby upland forest measured during a year of above average precipitation. These results may aid in assessing differences in water use and the ability of bottomland deciduous species to tolerate alterations in the frequency or amount of precipitation. Results also suggest little variation in water use among forests of similar composition and structure growing in different positions in the landscape and subjected to large interannual variation in water supply.  相似文献   

Estimation of tree transpiration and response of tree conductance to meteorological variables in desert-oasis system of Northwest China     

CHEN Rensheng  KANG Ersi  ZHANG Zhihui  Zhao Wenzhi  SONG Kechao  Zhang Jishi  LAN Yongchao 《中国科学D辑(英文版)》2004,47(Z1)

Transpirations of three dominated tree species, namely Mongol Scotch Pine (Pinus sylvestris var. mongolica Litvin), White elm (Ulmus pumila) and Gansu Poplar (Populus gansuensis Wang et Yang) in oasis shelter forest (Linze site) and of two dominated tree species,namely Euphrates Poplar (Populus euphratica Oliv.) and Russia olive (Elaeagnus angustifolia Linn.) in lowland desert (Erjinaqi site) have been estimated using measured sapflow in summer,autumn and winter, 2002 and in spring, 2003. An ENVIS System was used for each site to measure microclimate variables, soil moisture and sapflow every half an hour, and the study time scale is one day. In the 104 days of observation during the growing season at the Linze site, the average daily sapflow of Gansu Poplar is 9.93L·d-1,and the average transpiration per unit leaf area is 1.99mm·d-1.For White elm tree,the daily average sapflow is 4.08L·d-1,while the daily average transpiration per unit leaf area is 0.49mm·d-1.The values for Mongol Scotch Pine are 3.91L·d-1 and 0.25mm·d-1,respectively.In the total 73 days of observation during the growing season at the Erjinaqi site, the daily average sapflows of Russia olive and Euphrates Poplar are 12.1 and 20.97L·d-1,respectively,and the average transpirations per unit leaf area are 0.22 amd 0.31mm·d-1,respectively.In the observation period of the growing season,tree conductances of Mongol Scotch Pine, White elm, Gansu Poplar or Russia olive show an exponential relationship with the daily average air temperature or vapour pressure deficit, but the relationship is not so obvious between tree conductance and global radiation. The transpiration process of each tree species is affected by all the observed four environmental variables. The response of tree conductance to different climatic factors changes with tree species. The effect of the same factor to the same tree species is also variable in different growing stages. The sapflow of every tree species is relatively large in later spring to early summer, and low in summer, and then reaches its largest value in later September. In the mid-November, the sapflow is relatively large, especially the deciduous tree species. This may be characteristic of the tree species in Arid Regions of Northwest China.  相似文献   

Computing energy budget within a crop canopy from Penmann’s formulae     

Mahendra Mohan  K. K. Srivastava 《Journal of Earth System Science》2001,110(2):179-184

The Lhomme’s model (1988a), that extended Penmann's formulae to a multi-layer model, is redefined as a function of micrometeorological and physiological profiles of crop canopy. The sources and sinks of sensible and latent heat fluxes are assumed to lie on a fictitious plane called zero-displacement plane. Algorithms are given to compute sensible and latent heat flux densities. Performance of the algorithms is compared with that of earlier algorithms.  相似文献