Phenomenology of the Lense-Thirring effect in the Solar System

Recent years have seen increasing efforts to directly measure some aspects of the general relativistic gravitomagnetic interaction in several astronomical scenarios in the solar system. After briefly overviewing the concept of gravitomagnetism from a theoretical point of view, we review the performed or proposed attempts to detect the Lense-Thirring effect affecting the orbital motions of natural and artificial bodies in the gravitational fields of the Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of the impact of several sources of systematic uncertainties of dynamical origin to realistically elucidate the present and future perspectives in directly measuring such an elusive relativistic effect.Comment: LaTex, 51 pages, 14 figures, 22 tables. Invited review, to appear in Astrophysics and Space Science (ApSS). Some uncited references in the text now correctly quoted. One reference added. A footnote adde

The Pioneer Anomaly

Radio-metric Doppler tracking data received from the Pioneer 10 and 11 spacecraft from heliocentric distances of 20-70 AU has consistently indicated the presence of a small, anomalous, blue-shifted frequency drift uniformly changing with a rate of ~6 x 10^{-9} Hz/s. Ultimately, the drift was interpreted as a constant sunward deceleration of each particular spacecraft at the level of a_P = (8.74 +/- 1.33) x 10^{-10} m/s^2. This apparent violation of the Newton's gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. In this review, we summarize the current knowledge of the physical properties of the anomaly and the conditions that led to its detection and characterization. We review various mechanisms proposed to explain the anomaly and discuss the current state of efforts to determine its nature. A comprehensive new investigation of the anomalous behavior of the two Pioneers has begun recently. The new efforts rely on the much-extended set of radio-metric Doppler data for both spacecraft in conjunction with the newly available complete record of their telemetry files and a large archive of original project documentation. As the new study is yet to report its findings, this review provides the necessary background for the new results to appear in the near future. In particular, we provide a significant amount of information on the design, operations and behavior of the two Pioneers during their entire missions, including descriptions of various data formats and techniques used for their navigation and radio-science data analysis. As most of this information was recovered relatively recently, it was not used in the previous studies of the Pioneer anomaly, but it is critical for the new investigation.Comment: 165 pages, 40 figures, 16 tables; accepted for publication in Living Reviews in Relativit

Controls on explosive-effusive volcanic eruption styles

One of the biggest challenges in volcanic hazard assessment is to understand how and why eruptive style changes within the same eruptive period or even from one eruption to the next at a given volcano. This review evaluates the competing processes that lead to explosive and effusive eruptions of silicic magmas. Eruptive style depends on a set of feedbacks involving interrelated magmatic properties and processes. Foremost of these are magma viscosity, gas loss, and external properties such as conduit geometry. Ultimately, these parameters control the speed at which magmas ascend, decompress and outgas en route to the surface, and thus determine eruptive style and evolution

Environmental Impact Assessment of Explosive Volcanoes: A Case Study

Although there are some parameters identified in the literature to quantify environmental impact of volcanic eruptions, e.g., Dust Veil Index (DVI), Volcanic Explosivity Index (VEI), and Volcanic Aerosol Index (VAI), no parametric studies have been undertaken to assess the environmental impact of explosive volcanoes. In this regard, this study deals with a parametric investigation of the environmental impact of the explosive volcanoes through some key parameters, such as (1) lateral blast effect, (2) debris avalanche effect, (3) lahars effect, (4) pyroclastic flow effect, (5) earthquake effect, (6) pyroclastic surge effect, (7) health effect, (8) tsunami effect, and (9) atmospheric effect. Considering these and their impact levels, a new parameter for explosive volcanic eruptions, so-called the “Environmental Impact Factor (EIF),” ranging from 0 to 1, is proposed as a function of the VEI which ranges between 1 and 8. We also conduct a quantitative evaluation of the environmental effects of the Mount St. Helens volcano (erupted on May 18, 1980) in USA. For this purpose, a case study for the St Helens eruption is conducted by taking into account the Volcanic Explosivity Index as 5, Environmental Correction Factor as 1.6, and the actual influence distances of the products and earthquake effect from the St Helens eruption. Of the above parameters, the first five parameter and also ash effect that can be commonly observed after the St. Helens eruption is considered. As a result of the analysis, the EIF will provide a quantitative record of environmental impact of the explosive volcanic products in terms of the influence distance and the VEI. Moreover, it is estimated that, in the case study, the environmental impact factors corresponding to the actual influence distances of the explosive products and earthquake effect become 0.568 in 12.8 km for lateral blast, 0.635 in 14 km for debris avalanche, 0.525 in 100 km for lahar, 0.875 in 8 km for pyroclastic flow, 0.978 in 16 km for ash (with an ash depth of 25 cm), and 0.921 in 1.6 km for earthquake effects. © Springer Science+Business Media New York 2013. All rights reserved

An experimental 392-year documentary-based multi-proxy (vine and grain) reconstruction of May-July temperatures for KAszeg, West-Hungary

In this paper, we present a 392-year-long preliminary temperature reconstruction for western Hungary. The reconstructed series is based on five vine- and grain-related historical phenological series from the town of KAszeg. We apply dendrochronological methods for both signal assessment of the phenological series and the resultant temperature reconstruction. As a proof of concept, the present reconstruction explains 57% of the temperature variance of May-July Budapest mean temperatures and is well verified with coefficient of efficiency values in excess of 0.45. The developed temperature reconstruction portrays warm conditions during the late seventeenth and early eighteenth centuries with a period of cooling until the coldest reconstructed period centred around 1815, which was followed by a period of warming until the 1860s. The phenological evidence analysed here represent an important data source from which non-biased estimates of past climate can be derived that may provide information at all possible time-scales.</p