Peter Vajda, Pavol Zahorec Pavol, Juraj Papčo and Anna Kubová
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., Gorobets A. V., Levi Y., Erpul, G., Birkel C., Hoyos N., Naipal V., Oliveira P. T. S., Bonilla C. A., Meddi M., Nel W., Al Dashti H., Boni M., Diodato N., Van Oost K., Nearing M., Ballabio C., 2017: Global rainfall erosivity assessment based on high-temporal resolution rainfall records. Sci. Rep., 7 , 4175, doi: 10.1038/s41598-017-04282-8.
Prokoph A., Adamowski J., Adamowski K., 2012: Influence of the 11 year solar cycle on annual streamflow maxima in Southern Canada. J. Hydrol, 442-443 , 55–62, doi: 10.1016/j.jhydrol.2012.03.038.
Ramachandra Rao A., Hamed
In Hungary, at the foot of the Eastern Alps, in the Sopronbánfalva Geodynamic Observatory (SGO), a quartz-tube extensometer has been used for recording the Earth’s tides and local tectonic deformations since 1991. The 27-year long strain record (1991–2017) shows a continuous compression of the rock with changing rate. The relations between the measured local deformation and present-day tectonics in the region of the observatory were investigated. The local strain rate variations were also compared with the temporal and spatial distribution as well as with the magnitudes of earthquakes occurred within 200 km from the observatory in two sectors around the azimuth of the extensometer (116°): 116°±15° and 296°±15°. Our investigations show that earthquakes can also influence the strain rate. Earthquakes to the west of SGO generally increase the compressive strain rate, while earthquakes in the Pannonian Basin, with some exceptions, have no significant effect on the local strain rate variations measured in the SGO. It has been found that the recorded compressive strain is in good accordance with the recent tectonic processes in the region of the SGO determined by Global Navigation Satellite System (GNSS) technology and geophysical measurements. From the results it can be concluded that the uplift of the Alps, tectonic processes in the East Alpine region and in the Pannonian Basin play the most important role in the changing local compressive strain rate.
Vladimír Pohánka, Peter Vajda and Jaroslava Pánisová
Here we investigate the applicability of the harmonic inversion method to time-lapse gravity changes observed in volcanic areas. We carry out our study on gravity changes occured over the period of 2004–2005 during the unrest of the Central Volcanic Complex on Tenerife, Canary Islands. The harmonic inversion method is unique in that it calculates the solution of the form of compact homogeneous source bodies via the mediating 3-harmonic function called quasigravitation. The latter is defined in the whole subsurface domain and it is a linear integral transformation of the surface gravity field. At the beginning the seeds of the future source bodies are introduced: these are quasi-spherical bodies located at the extrema of the quasigravitation (calculated from the input gravity data) and their differential densities are free parameters preselected by the interpreter. In the following automatic iterative process the source bodies change their size and shape according to the local values of quasigravitation (calculated in each iterative step from the residual surface gravity field); the process stops when the residual surface gravity field is sufficiently small. In the case of inverting temporal gravity changes, the source bodies represent the volumetric domains of temporal mass-density changes. The focus of the presented work is to investigate the dependence of the size and shape of the found source bodies on their differential densities. We do not aim here (yet) at interpreting the found solutions in terms of volcanic processes associated with intruding or rejuvenating magma and/or migrating volatiles.
The article deals with a method of acquiring the temporal and spatial distribution of local precipitation from measurement of performance characteristics of local sources of high frequency electromagnetic radiation in the 1-3GHz frequency range in the lower layers of the troposphere up to 100 m. The method was experimentally proven by monitoring the GSM G2 base stations of cell phone providers in the frequency range of 920-960MHz using methods of frequential and spatial diversity reception. Modification of the SART method for localization of precipitation was also proposed. The achieved results allow us to obtain the timeframe of the intensity of local precipitation in the observed area with a temporal resolution of 10 sec. A spatial accuracy of 100m in localization of precipitation is expected, after a network of receivers is built. The acquired data can be used as one of the inputs for meteorological forecasting models, in agriculture, hydrology as a supplementary method to ombrograph stations and measurements for the weather radar network, in transportation as part of a warning system and in many other areas.
Global atmospheric effects on the gravity field quantities
We compile the global maps of atmospheric effects on the gravity field quantities using the spherical harmonic representation of the gravitational field. A simple atmospheric density distribution is assumed within a lower atmosphere (< 6 km). Disregarding temporal and lateral atmospheric density variations, the radial atmospheric density model is defined as a function of the nominal atmospheric density at the sea level and the height. For elevations above 6 km, the atmospheric density distribution from the United States Standard Atmosphere 1976 is adopted. The 5 × 5 arc-min global elevation data from the ETOPO5 are used to generate the global elevation model coefficients. These coefficients (which represent the geometry of the lower bound of atmospheric masses) are utilized to compute the atmospheric effects with a spectral resolution complete to degree and order 180. The atmospheric effects on gravity disturbances, gravity anomalies and geoid undulations are evaluated globally on a 1 × 1 arc-deg grid.
Hana Středová, Josef Krása, Petr Štěpánek and Ivan Novotný
Number of erosive rains, kinetic energy of erosive rains and factor of erosive efficiency of rains according to the USLE methodology were assessed by two methods of erosive rains determination. The first method (VAR1) defined erosive rains by intensity ≥ 0.4 mm· min-1; total ≥ 12.5 mm and the second method (VAR2) by intensity ≥ 6 mm· 15 min-1; total ≥ 12.5 mm. Database contained one minute precipitation data from four automatic stations in the Czech Republic for the period of 2000-2005. Two-way analysis of variance (ANOVA) showed a statistically highly significant difference between the annual number of erosive rains determined by the two methods. The rains simultaneously complying with two following criteria (30 min intensity lower than 15 mm·h−1 and sum of 40 mm) were not generally classified as erosive rains according to VAR2. The number of erosive rains determined by VAR2 most often reached 40 to 50% of VAR1 results. Two-way ANOVA proved highly significant differences between the kinetic energy values for the erosive rains determined by VAR1 a VAR2. According to VAR2 the rains with kinetic energy lower than 3 MJ·ha −1 are generally not considered as erosive rains. The results of kinetic energy of the erosive rains determined by VAR2 most often reached 60 to 70% of VAR1 results. Two-way ANOVA has not proved a statistical difference between annual values of R factor of erosive rains determined by the two methods. According to VAR2 the rains with R factor lower than 5 are in general not included into annual R factor value. The results of annual R factor values of erosive rains determined by VAR2 are about 25% lower than the results of VAR1. Correlation between number of erosive rains, kinetic energy of erosive rains and annual R factor value assessed by both methods showed a statistically significant relationship. The conversion formulas between results of the two methods (VAR1 and VAR2) were derived by linear regression. As conclusion we can state that when using present automatic stations in R factor analyses, we have to be aware of overestimating the erosivities compared to historical data based on ombrograms, where only low temporal resolution data were available.
Pavol Zahorec, Peter Vajda, Juraj Papčo, Sergio Sainz-Maza Aparicio and Jorge Pereda De Pablo
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