Development of a measuring set-up for high-sensitivity analysis of hydrogen by the 15N nuclear reaction technique

1993 ◽  
Vol 346 (1-3) ◽  
pp. 205-207
Author(s):  
D. Endisch ◽  
H. Sturm ◽  
F. Rauch
2021 ◽  
Author(s):  
Christian Voigt ◽  
Karsten Schulz ◽  
Franziska Koch ◽  
Karl-Friedrich Wetzel ◽  
Ludger Timmen ◽  
...  

Abstract. The Zugspitze Geodynamic Observatory Germany has been set up with a worldwide unique installation of a superconducting gravimeter at the summit of Mount Zugspitze. With regard to hydrology, this karstic high-alpine site is largely dominated by high precipitation amounts and a long seasonal snow cover period with significant importance for water supply to its forelands, while it shows a high sensitivity to climate change. However, regarding the majority of alpine regions worldwide there is only weak knowledge on temporal water storage variations due to only sparsely distributed hydrological and meteorological point sensors and the large variability and complexity of alpine signals. This underlines the importance of well-equipped areas such as Mount Zugspitze serving as natural test laboratories for an improved monitoring, understanding and prediction of alpine hydrological processes. The observatory superconducting gravimeter OSG 052 supplements the existing sensor network as a novel hydrological sensor system for the direct observation of the integral gravity effect of total water storage variations in the alpine research catchment Zugspitze. Besides the experimental setup and the available datasets, the required gravimetric prerequisites are presented such as calibration, tidal analysis and signal separation of the superconducting gravimeter observations from the first 2 years. The snowpack is identified as primary contributor to seasonal water storage variations and thus to the gravity residuals with a signal range of up to 750 nm/s2 corresponding to 1957 mm snow water equivalent measured at a representative station at the end of May 2019. First hydro-gravimetric sensitivity analysis are based on simplified assumptions of the snowpack distribution within the area around Mount Zugspitze. These reveal a snow-gravimetric footprint of up to 4 km distance around the gravimeter with a dominant gravity contribution from the snowpack in the Partnach spring catchment. This study already shows that the hydro-gravimetric approach can deliver important and representative integral insights into this high-alpine site. This work is regarded as a concept study showing preliminary gravimetric results and sensitivity analysis for upcoming long-term hydro-gravimetric research projects.


2021 ◽  
Vol 13 (2) ◽  
pp. 188
Author(s):  
Tingting Li ◽  
Irena Hajnsek ◽  
Kun-Shan Chen

Soil moisture is one of the vital environmental variables in the land–atmosphere cycle. A study of the sensitivity analysis of bistatic scattering coefficients from bare soil at the Ku-band is presented, with the aim of deepening our understanding of the bistatic scattering features and exploring its potential in soil moisture retrieval. First, a well-established advanced integral method was adopted for simulating the bistatic scattering response of bare soil. Secondly, a sensitivity index and a normalized weight quality index were proposed to evaluate the effect of soil moisture on the bistatic scattering coefficient in terms of polarization and angular diversity, and the combinations thereof. The results of single-polarized VV data show that the regions with the maximum sensitivity and high quality index, simultaneously, to soil moisture are in the forward off-specular direction. However, due to the effect of surface roughness and surface autocorrelation function (ACF), the single-polarized data have some limitations for soil moisture inversion. By contrast, the results of two different polarization combinations, as well as a dual-angular simulation of one transmitter and two receivers, show significant estimation benefits. It can be seen that they all provide better ACF suppression capabilities, larger high-sensitivity area, and higher quality indices compared to single-polarized estimation. In addition, dual polarization or dual angular combined measurement provides the possibility of retrieving soil moisture in backward regions. These results are expected to contribute to the design of future bistatic observation systems.


Bioanalysis ◽  
2018 ◽  
Vol 10 (24) ◽  
pp. 2047-2067 ◽  
Author(s):  
Weiwei Han ◽  
Yajun Zheng ◽  
Theoneste Muyizere ◽  
Zhiping Zhang

2009 ◽  
Author(s):  
Daniel Keith Marble ◽  
Ben Urban ◽  
Jose Pacheco ◽  
Floyd D. McDaniel ◽  
Barney L. Doyle

2013 ◽  
Vol 17 (2) ◽  
pp. 461-478 ◽  
Author(s):  
L. Loosvelt ◽  
H. Vernieuwe ◽  
V. R. N. Pauwels ◽  
B. De Baets ◽  
N. E. C. Verhoest

Abstract. Compositional data, such as soil texture, are hard to deal with in the geosciences as standard statistical methods are often inappropriate to analyse this type of data. Especially in sensitivity analysis, the closed character of the data is often ignored. To that end, we developed a method to assess the local sensitivity of a model output with resect to a compositional model input. We adapted the finite difference technique such that the different parts of the input are perturbed simultaneously while the closed character of the data is preserved. This method was applied to a hydrologic model and the sensitivity of the simulated soil moisture content to local changes in soil texture was assessed. Based on a high number of model runs, in which the soil texture was varied across the entire texture triangle, we identified zones of high sensitivity in the texture triangle. In such zones, the model output uncertainty induced by the discrepancy between the scale of measurement and the scale of model application, is advised to be reduced through additional data collection. Furthermore, the sensitivity analysis provided more insight into the hydrologic model behaviour as it revealed how the model sensitivity is related to the shape of the soil moistureretention curve.


2020 ◽  
Vol 12 (17) ◽  
pp. 7187
Author(s):  
Dariusz Młyński

This work aimed to quantify how the different parameters of the Snyder model influence the errors in design flows. The study was conducted for the Kamienica Nowojowska catchment (Poland). The analysis was carried out according to the following stages: determination of design precipitation, determination of design hyetograph, sensitivity analysis of the Snyder model, and quality assessment of the Snyder model. Based on the conducted research, it was found that the Snyder model did not show high sensitivity to the assumed precipitation distribution. The parameters depending on the retention capacity of the catchment had much greater impact on the obtained flow values. The verification of the model quality showed a significant disproportion in the calculated maximum flow values with the assumed return period.


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