Historical Seismology: Interdisciplinary Studies of Past and Recent Earthquakes, eds. J. Fréchet, M. Meghraoui, and M. Stucchi     

Pawel Wiejacz 《Pure and Applied Geophysics》2009,166(12):2097-2098

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Application of predictive regional ionosphere model to medium range RTK positioning   总被引：1，自引：0，他引：1  

Pawel Wielgosz  Andrzej Krankowski  Rafal Sieradzki  Dorota A. Grejner-Brzezinska 《Acta Geophysica》2008,56(4):1147-1161

Real Time Kinematic (RTK) GPS positioning over longer distances requires a support of atmospheric (ionospheric and tropospheric) corrections, since the atmospheric errors decorrelate with the growing distances and cannot be completely eliminated by double differencing of the satellite observations. Currently, the most commonly used approach is to derive the atmospheric corrections at the reference station network and provide them in real time to the roving receiver. Another solution, proposed here, is to use predictive atmospheric models in order to derive the atmospheric corrections. This paper presents the test results of the performance assessment of the predictive ionosphere model (UWM-IPM) application to medium-range RTK positioning. The rover data collected within 25 to 67 km from the closest reference station were processed in the kinematic mode with the support of the ionospheric corrections derived from the UWM-IPM model. The RTK solution was derived in both single-and multi-baseline modes, and compared to the two reference solutions obtained without the ionospheric corrections. All numerical tests were carried out using the MPGPS software developed in cooperation with The Ohio State University; a recent extension to the software, developed at the University of Warmia and Mazury in Olsztyn, introduces the predictive ionosphere model to the RTK solution. The test results are very promising, and indicate that predicted ionosphere corrections can effectively support medium-range RTK positioning, and allow for fast ambiguity resolution over distances of several tens of kilometers under moderate ionospheric conditions.  相似文献   

Palaeoecological analysis of a Late Quaternary sediment profile in northern Oman     

B. Urban  A. Buerkert 《Journal of Arid Environments》2009,73(3):296-305

High resolution palaeoecological studies of the Arabian Peninsula for the late Quaternary period are scarce. Consequently, little is known about time-dependent relationships between vegetation, environment and the development of human settlements in this area. To help fill this gap for the arid Hajar mountains of northern Oman, a 20 m deep profile in a sediment-filled depression near an oasis settlement was analysed for its physico-chemical properties, pollen and spores and other palynomorphs. Charcoal frequencies in combination with geochemical data provided evidence of an Early Holocene increase of rainfall. The onset of dryer conditions at about 8 ka was indicated by charcoal frequencies and geochemical data as were previously unrecognised short humid periods dated to 5.7, 5 and 4.4 ka. The upper 4 m of sediments contained a 4300 year-old pollen profile reaching into the archaeologically important Umm al-Nar period characterized by increased settlement activities throughout Oman. Variation in mollusc shell frequency and periodic peaks of NH₄-N suggested only minor local variations of rainfall throughout the last 2000 years. The sudden appearance of Olea spec., Ziziphus and Fabaceae pollen since about 500 years ago points to a late onset of oasis agriculture nearby.  相似文献   

Application of Dempster-Shafer theory in mineral resource potential mapping     

CHEN Yong-liang  WU Wei  LI Xue-bin Mineral Resource Prediction Institute of Comprehensive Information  Jilin University  Changchun  Jilin  China Northeastern Geography  Agricultural Ecology Institute of Chinese Academy of Sciences  Changchun  Jilin  China Design  Research Institute of Urban  Rural Planning of Changchun  Changchun  Jilin  China 《东北亚地学研究》2005,(Z1)

The Dempster-Shafer theory has been successfully applied to mineral resource potential mapping in G1S environmental. In this applied form, basic probability assignment and combined basic probability assignment are applied to measuring map pattern and map pattern combination, respectively; and the environment composed of the only two singleton sets (deposit set and non-deposit set), is used for expressing the entire map area. For a subarea in which the certain map pattern combination exists, the combined basic probability assignment corresponding to the map pattern combination existing in this subarea, expresses the belief of inferring the subarea belonging to the deposit set from the evidence that the corresponding map pattern combination existing in the subarea. Thus, it may be served as a statistical index measuring the relative mineral resource potentials of the subarea. And it may be determined like 1) dividing the map area into a series of small equal-sized grid cells and then select the training sample set composed of the well-known grid cells or the entire grid cells; 2) estimating the basic probability assignments corresponding to each map pattern from the training sample set; 3) determining the map pattern combination existing in each cell, and then appling the Dempster's Rule of Combination to integrating the all basic probability assignments corresponding to the map patterns existing in the cell into the combined basic probability assignment. Mineral resource potential mapping with the Dempster-Shafer theory is demonstrated on a case study to select mineral resource targets. The experimental results manifest that the model can be compared with the weights of evidence model in the effectiveness of mineral resource target selection.  相似文献   

Effect of a simple mountain range on underground seismic motion     

Ji&#;í Zahradník  Ludvík Urban 《Geophysical Journal International》1984,79(1):167-183

Summary. The influence of a simple mountain range on seismic ground motion is studied. A two-dimensional model of the medium and vertically incident plane SH -waves are considered. Attention is devoted not only to the wavefield along the Earth's surface, but also within the medium. The wavefield is computed in two steps: (1) the computation of the impulse response by the finite-difference method, (2) the computation of the response to a time variation of the incident wave. approximately corresponding to a 'hundred-year' local earthquake at the site. Numerical results (the impulse response, the transfer function, the accelerograms, and their spectra) indicate strong spatial variability of the wavefield due to the topographical anomaly. The differences as large as 100 per cent in the peak amplitudes of the accelerograms, and of the order of 5 Hz in their predominant frequencies, at closely (∼ 200 m) spaced internal points of the medium have been found. Attention is focused also on the effect of causal absorption. Even unrealistically strong absorption seems to be unable to reduce significantly the spatial variability of the ground motion, caused by the topography. A variability like this. implying the occurrence of underground differential strains, might be of engineering importance in the antiseismic design of underground structures (tunnels, for example) in mountainous seismic regions. The ground-motion variability along the surface of the mountain is considerably smaller than within the medium.  相似文献   

Sunshine duration and its variability in the main ridge of the Karkonosze Mountains in relation to with atmospheric circulation     

Urban  Grzegorz  Migała  Krzysztof  Pawliczek  Piotr 《Theoretical and Applied Climatology》2018,131(3-4):1173-1189

Theoretical and Applied Climatology - Sunshine duration analysis was based on a series of measurements spanning the period from 1901 to 2014 for Śnieżka (1603 m a.s.l.)...  相似文献   

Modular development of an inline monitoring system for waterborne pathogens in raw and drinking water     

Daniel Karthe  Ole Behrmann  Verena Blättel  Dennis Elsässer  Christian Heese  Matthias Hügle  Frank Hufert  Andreas Kunze  Reinhard Niessner  Johannes Ho  Buren Scharaw  Matthias Spoo  Andreas Tiehm  Gerald Urban  Silvia Vosseler  Thomas Westerhoff  Gregory Dame  Michael Seidel 《Environmental Earth Sciences》2016,75(23):1481

The state-of-the-art monitoring of drinking water hygiene is based on the cultivation and enumeration of indicator bacteria. Despite its proven reliability, this approach has the disadvantages of being (a) relatively slow and (b) limited to a small number of indicator bacteria. Ideally, alternative methods would be less time-consuming while providing information about a larger set of hygienically relevant microorganisms including viruses. In this paper, we present insights into the design of a modular concentration and detection system for bacteria, bacteriophages and viruses. Following further validation, this or similar techniques have the potential to extend and speed up the monitoring of raw and drinking water hygiene in the future. The system consists of different modules for the concentration of microorganisms, an amplification and detection unit that includes a module for the differentiation between live and dead microorganisms, and an automated system for decision support and self-diagnosis. The ongoing testing under controlled laboratory conditions and real-life conditions in the water supply industry yields further system improvements. Moreover, the increased sensitivity and broader range of microbiological parameters emphasize the need for a reconsideration of the currently used criteria for the assessment of (drinking) water hygiene.  相似文献   

Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation     

Krzysztof Migała  Grzegorz Urban  Karol Tomczyński 《Theoretical and Applied Climatology》2016,125(1-2):337-351

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Submodels of a Brackish Water Environment   总被引：2，自引：0，他引：2  

Manfred  Bölter  Gerd  Liebezeit  Karin  Wolter Urban  Palm-Gren 《Marine Ecology》1982,3(3):243-253

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Calibration and Verification of Jason-1 Using Global Along-Track Residuals with TOPEX     

D. P. Chambers  J. C. Ries  T. J. Urban 《Marine Geodesy》2003,26(3):305-317

It is demonstrated that the Jason-1 measurements of sea surface height (SSH), wet path delay, and ionosphere path delay are within required accuracies, via a global cross-calibration with similar measurements made by TOPEX/Poseidon (T/P) over a 6-month period. Since the two satellites were on the same groundtrack separated in time by only 70 s, measurements were recorded at approximately the same location and time. The variations in the wet path delay measured by Jason-1 compared to T/P are only 5 mm RMS, well within the required performance of 1.2 cm RMS. The RMS of the ionosphere differences is also well within the expected values, with a mean RMS of 1.2 cm. The largest difference is that the Jason-1 SSH is biased high relative to T/P SSH by 144 mm after the T/P and Jason-1 data are both corrected with improved sea state bias (SSB) models. However, the bias will change if a different SSB model is used, so the user should be cautious that the bias used matches the SSB models. The bias is generally constant within ± 10 mm in the open ocean, but appears to be higher or lower in some regions. Additionally, the SSH has been verified by comparison with 36 island tide gauges over the same period. After removing the global relative bias, the Jason-1 SSH data agree with tide gauges within 3.7 cm RMS and with T/P data within about 3.5 cm RMS on average for 1-s measurements, meeting the required accuracy of 4.2 cm RMS.  相似文献