Search

Gravity satellite GRACE-derived terrestrial water storage change would be seriously affected by glacial isostatic adjustment(GIA) in Scandinavia. To solve this problem, it is calculated that the measured linear ratio of GIA gravity rates and vertical displacement rates according to the data from collocation stations for absolute gravity and GPS. Using the linear ratio and uplift field derived from GPS observation network, the gravity signal of GIA is got. Gravity change rates from GRACE RL05 data can be corrected for GIA using independent gravity rates derived from GPS vertical velocities, and then it is calculated that corresponding equivalent water thickness in Scandinavia and the uncertainties are evaluated by considering the uncertainties from data. The proposed method utilizes observational data only and can avoid the enormous uncertainty from GIA models.The results are compared with that of two hydrological models. The ratio of gravity versus uplift obtained by ground-based measurements in Scandinavia is 0.148±0.020 μGal/mm(1 Gal=10-2 m/s2), which validates Wahr's approximate theoretical ratio and is very close to the result from North America. From January 2003 to March 2011, terrestrial water storage shows obvious increase in Scandinavia. The main signal locates at the Vänern lake which is in the southern tip of the peninsula. The rate of total water storage is 4.6±2.1 km3/a and the corresponding cumulative quantity is 38±17 km3 for the period 2003 to 2011. Results from hydrological models are consistent with the result very well. The correlation coefficient between GRACE and WGHM hydrological model can reach 0.69, while for GLDAS model the correlation coefficient is slightly smaller.

Traditional data envelopment analysis (DEA) models in the performance evaluation are based on black box thought, so that inputs in the boxes (decision making units) are converted into outputs. One of the drawbacks of these models is the neglect of internal structure, intermediate products or linking activities; also the actual transforming process generally isn’t modeled explicitly. According to the multi-stage structure of the banking industry; in this research, after pointing out black box (aggregation) and separation approaches, needs for inclusion of internal process of the decision making unit (DMU) expressed and a slacks-based network data envelopment analysis model is introduced and used in performance evaluation of the banking industry. The major merit of slacks-based measure is its ability to provide suitable efficiency measures, especially for weakly efficient units. Among the findings of this research is that in the structures with linking and networking effects, using the black box and separation approaches, don’t produce actual assessment of performance and should be used network models.

As global warming continues, the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management. In North America as elsewhere in the world, changes in water resources strongly impact agriculture and animal husbandry. From a combination of Gravity Recovery and Climate Experiment (GRACE) gravity and Global Positioning System (GPS) data, it is recently found that water storage from August, 2002 to March, 2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005. In this paper, we use GRACE monthly gravity data of Release 5 to track the water storage change from August, 2002 to June, 2014. In Canadian Prairies and the Great Lakes areas, the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a, which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error. We also find a long term decrease of water storage at a rate of −12.0 ± 4.2 Gt/a in Ungava Peninsula, possibly due to permafrost degradation and less snow accumulation during the winter in the region. In addition, the effect of total mass gain in the surveyed area, on present-day sea level, amounts to −0.18 mm/a, and thus should be taken into account in studies of global sea level change. Keywords: Canadian Prairies, Great Lakes, Ungava Peninsula, Water storage changes, Gravity Recovery and Climate Experiment (GRACE) data, Global Positioning System (GPS) data, Glacial isostatic adjustment, Separation approach

This work reports on the fabrication of a mini column packed with controlled pore glass and glass wool, and its application for the on-line preconcentration of lead with the aid of an anionic surfactant ( sodium dodecyl sulphate, SDS) and AAS detection. Lead reacts with SDS in a highionic-strength environment, and the product is retained and preconcentrated on a high-surface area substrate like glass wool. The intervention of controlled pore glass increases the active surface of glasswool and prevents its accumulation into a sticky mass after wetting. Washing the mini column with a methanolic solution of HNO3, causes the retained micellar face to be eluted, and consequently the lead content can be determined with AAS. A preconcentration factor of 50 along with a signal enhancement due to the combined presence of SDS and methanol yields a detection limit of 1.5 mu g L-1. The correlation coefficient of the calibration curve is 0.999, and the linear range 5-500 mu g L-1. The method was used for the determination of lead in water and wastewater with good results. International Journal of Environmental Analytical Chemistry

The on-line incorporation of cloud point extraction (CPE) to flow injection analysis (FIA) is modified to extract and preconcentrate metal species rapidly, avoiding the formation of hydrophobic complexes, using a mixed micellar medium. Coupling the procedure with chemiluminescence (CL) detection based on the catalytic activity of metal species on the luminol-hydrogen peroxide reaction and enhancing the signal with the presence of a micellar carrier containing bromide ions produces a powerful tool for the preconcentration and determination of metal species at ng l(-1) levels. As an analytical demonstration ultratrace concentrations of chromium were conveniently detected and quantified in samples with a complex matrix such as seawater and wastewater. The figures of merit for the determination of chromium were: 0.9-1.6% R.S.D. (n = 5) with detection and quantification limits 0.5 and 2.0 ng l(-1), respectively. The calibration graph was rectilinear from 2 to 200 ng l(-1) (r = 0.9996, n = 6). Several other metal ions were determined in ideal situations, with analogous results. (C) 2002 Elsevier Science B.V. All rights reserved. Analytica Chimica Acta