Surveying at the limits of local RTK networks: Test results from the perspective of high accuracy users

Precise GNSS-based differential positioning in real time is usually known as the real-time kinematics (RTK) technique. RTK reduces the effects of orbit errors and ionospheric and tropospheric refraction by forming differences between the observables (e.g. double-differences). These effects, however, grow with increasing baseline length, although the use of corrections generated in real-time from an active GNSS network allows these distance-dependent errors to be reduced. This technology increases the reliability of the system and thereby the accuracy of real-time positioning. In this study, the test results of RTK positioning at different test points located in the border area between the Autonomous Communities of the Region of Murcia and the Community of Valencia, in SE Spain, are presented. The analysis is based on three GNSS local active networks present in this border area, namely MERISTEMUM, REGAM and ERVA networks. Test measurements with RTK rover were performed in this region in order to analyze the real-time services offered by these three networks. Moreover, precise coordinates for each test point were determined using Bernese 5.0. The results confirm that it is possible to achieve centimetre-scale accuracy with RTK positioning based on the networks studied, even in border regions.     

On the Stochasticity of the Asteroid Belt

The study of the stochasticity of the asteroid belt requires the analysis of a large number of orbits. We detect the dynamical character of a set of 5 400 asteroids using the Fast Lyapunov Indicator, a method of analysis closely related to the computation of the Lyapunov Characteristic Exponents, but cheaper in computational time. For both regular and chaotic orbits we try to associate the motion to the underlying resonances network. For it we consider different methods of classification of rational numbers proposed by number theory, and we choose the one which seems to be strictly related to the dynamical behaviour of a system. This revised version was published online in July 2006 with corrections to the Cover Date.     

on the relationship between fast lyapunov indicator and periodic orbits for symplectic mappings

The computation on a relatively short time of a quantity, related to the largest Lyapunov Characteristic Exponent, called Fast Lyapunov Indicator allows to discriminate between ordered and weak chaotic motion and also, under certain conditions, between resonant and non resonant regular orbits. The aim of this paper is to study numerically the relationship between the Fast Lyapunov Indicator values and the order of periodic orbits. Using the two-dimensional standard map as a model problem we have found that the Fast Lyapunov Indicator increases as the logarithm of the order of periodic orbits up to a given order. For higher order the Fast Lyapunov Indicator grows linearly with the order of the periodic orbits. We provide a simple model to explain the relationship that we have found between the values of the Fast Lyapunov Indicator, the order of the periodic orbits and also the minimum number of iterations needed to obtain the Fast Lyapunov Indicator values.     

Two-dimensional Non-linear Alfvén Wings Generated by the Electrodynamic Interaction between Callisto and the Jovian Magnetosphere

When a highly conducting magnetized plasma passes an object with lower conductivity, or a body with inhomogeneous conductivity, 2-D structures are formed, the so-called `Alfvén wings'. These structures may arise, for example, at a Jovian moon without an intrinsic magnetic field (Callisto). In this case, Alfvén wings could be generated in the magnetized Jovian magnetospheric plasma flow owing to the in homogeneity of the moon's ionosphere/atmosphere conductivity. Such Alfvén wings may be considered as a satellite magnetosphere; the satellite magnetospheric magnetic field is a disturbed field of the Jovian magnetospheric plasma flow. An analytical solution is obtained in a simple proposed model. This revised version was published online in July 2006 with corrections to the Cover Date.     

Resting Stages of Crustaceans in the Crimean Hypersaline Lakes(Ukraine) and Their Ecological Role

正1 Introduction A presence of resting stages in various aquatic organisms is a long-known phenomenon as a mechanism of species adaptation to exist in unstable aquatic habitats,surviving adverse conditions in the"sleeping"state(Radzikowski,2013).Bank of resting stages of planktonic organisms is an important component of the plankton community,without which we cannot understand community dynamics(Brendonck and De Meester,2003).     

Pollen Viability for Air Pollution Bio-Monitoring

Biological characterization of Corylus avellana L. and Pinus nigra L. pollen samples was carried out to determine the actual value of pollen as a bio-indicator of the effects of atmospheric pollution, using samples from plants naturally developed in sites controlled for air pollution. In Trentino (North Italy), we selected six stations at three different levels of air pollution, which are constantly monitored with automatic gauges by the Environmental Protection Agency of Trento.First results showed that pollen viability of both species, germinability and pollen tube length of P. nigra, were higher in areas with no road traffic compared to heavy traffic ones. Pollen viability of P. nigra was positively correlated to ozone (O₃) concentrations and altitude but negatively to sulphur dioxide (SO₂), particulate matter with a diameter less than 10 m (PM₁₀), nitrogen oxides (NO_x) and nitrogen dioxide (NO₂) concentrations.     

An Experimental Study of the Statistics of Temperature Fluctuations in the Atmospheric Boundary Layer

A statistical characterization for two-point temperature fluctuations in the planetary boundary layer (PBL) is analyzed and its implications on the long-standing closure problem discussed. Despite the non-triviality of the dynamics of temperature fluctuations, our analysis supports the idea that the most relevant statistical properties can be captured solely in terms of two scaling exponents. They turned out to be weakly dependent on the stability properties of the PBL. Its statistics have been investigated by collecting data from a field experiment carried out in the urban area of Turin (Italy) from January 2007 to March 2008. Our results confirm those from a large-eddy simulation (LES) analysis carried out for the convective PBL with different level of convection. We extend the scenario to the stable PBL, a regime much more difficult to simulate when exploiting LES.     

An Excel Macro to Plot the HFE‐Diagram to Identify Sea Water Intrusion Phases

A hydrochemical facies evolution diagram (HFE‐D) is a multirectangular diagram, which is a useful tool in the interpretation of sea water intrusion processes. This method note describes a simple method for generating an HFE‐D plot using the spreadsheet software package, Microsoft Excel. The code was applied to groundwater from the alluvial coastal plain of Grosseto (Tuscany, Italy), which is characterized by a complex salinization process in which sea water mixes with sulfate or bicarbonate recharge water.