Search results for "Geodesy"

Smaguma spēks Latvijas rietumu, ziemeļu un dienvidu apvidos

1936

Atsevišķs nospiedums no žurnāla "Mērniecības un kultūrtechnikas vēstnesis": 1935., Nr. 1.-3., 4.-6., 7.-9. ; 1936., Nr. 1.-2., 3.-4., 5.-6. un 7.-8.

Windowed Etas Models With Application To The Chilean Seismic Catalogs

2015

Abstract The seismicity in Chile is estimated using an ETAS (Epidemic Type Aftershock sequences) space–time point process through a semi-parametric technique to account for the estimation of parametric and nonparametric components simultaneously. The two components account for triggered and background seismicity respectively, and are estimated by alternating a ML estimation for the parametric part and a forward predictive likelihood technique for the nonparametric one. Given the geographic and seismological characteristics of Chile, the sensitivity of the technique with respect to different geographical areas is examined in overlapping successive windows with varying latitude. A different b…

Deriving Seismic Surface Rotations for Engineering Purposes

2006

Direct Inversion of S ‐ P Differential Arrival Times for Ratio in SE Asia

2020

An evaluation of the microscopical counting methods of the tape in hirst-burkard pollen and spore trap

1981

Abstract Three different sampling units in current use and different sampling strategies were tested. Randomly placed microscope fields are good in estimating the daily mean concentration, but very big sample size is needed. Traverses across the slide in systematic order are best to estimate the shortterm concentrations and diurnal variation. A formula for the estimation of the error in one transverse traverse is given. Twelve transverse traverses in systematic order is also enough to estimate the daily mean concentration. One or two traverses along the length of the slide give often unreliable estimates because of the irregularities in the transverse variation of the particle concentration…

The southern Tyrrhenian Sea margin an example of lithospheric scale strike-slip duplex

2010

The southern Tyrrhenian Sea margin is dominated by deformations whose kinematics are relatively poorly constrained, and different models have been proposed to account for its recent evolution. Analysis of new structural and space geodesy data, combined with available geophysical information, reveal a deformation field characterised by subhorizontal NW-SE directed shortening and SW-NE directed extension. The main recognised regional-scale structure comprises E-W trending fault zones, namely the Ustica-Eolie Line and the Mt. Kumeta-Alcantara Line, connected by the NW-SE trending Marettimo, Trapani, San Vito, Palermo, Gratteri-Mt. Mufara and Eolie faults. This fault network displays a remarkab…

Continuous Discharge Monitoring Using Non-contact Methods for Velocity Measurements: Uncertainty Analysis

2014

At gauged site, water stage and discharge hydrographs can be related also during unsteady flow conditions, using the one-dimensional diffusive hydraulic model, DORA, and exploiting sporadic surface velocity measurements carried out with a radar sensor, during the rising limb of the flood. Indeed, starting from the measured surface velocity, the application of a simplified entropic velocity distribution model allows obtaining the benchmark discharge for the Manning’s roughness calibration. The aim of this work is twofold. First, to address the uncertainty of the approach. Second, to detect the minimum water level along the rising limb in which the occasional surface velocity measurement shou…

Geodetic data analysis of VGOS experiments

2021

Very Long Baseline Interferometry (VLBI) serves as one of the common geodetic methods to define the global reference frames and monitor Earth's orientation variations. The technical upgrade of the VLBI method known as the VLBI Global Observing System (VGOS) includes a critical re-design of the observed frequencies from the dual band mode (S and X band, i.e. 2 GHz and 8 GHz) to observations in a broadband (2 – 14 GHz). Since 2019 the first VGOS experiments are available for the geodetic analysis in free access at the International VLBI service for Geodesy and Astrometry (IVS). Also regional-only subnetworks such as European VLBI stations have succeeded already in VGOS mode. Based on these br…

UV Index experimental values on vertical surfaces

2011

UV erythemal irradiance (UVER) has been studied on a horizontal plane and on vertical surfaces with different orientations in Valencia, Spain. The evolution of the solar noon value and the maximum daily value over a year has been analysed from the instantaneous UVER taken every five minutes on the horizontal plane and on vertical surfaces with north, south, east and west orientations. The annual evolution of these values shows a sinusoidal form for all planes except for the vertical south plane with maxima in spring and autumn. The UV Index (UVI) on these planes was also determined. The percentage of coincidence of the UVI at solar noon and of the maximum daily UVER values, considering diff…

Evaluation of models for estimating solar irradiation on vertical surfaces at Valencia, Spain

1991

Abstract Hourly irradiation data recorded on vertical surfaces at north, east, south, and west orientations during the winter period going from December 1989 to March 1990 in Valencia, Spain, have been compared with estimated solar irradiation from several tilted-surface models. The isotropic-, Temps' and Coulson's-, Klucher's-, Hay's-, Skartveit's and Olseth's-, Gueymard's- and Perez' (simplified) models have been considered for this comparison. Root-mean-square-difference (RMSD), mean-bias-difference (MBD) and mean-absolute-difference (MAD) estimators have been used to measure the departure of models from experimental data. Modeled values are evaluated with the original coefficients propo…