Multi-scale analysis and interpretation of multi-method geophysical data sets

Redundant wavelet transform is proposed to analyze multi-method databases. Multi-scale analyses are used to separate target features from noise and background. As a main result, we generate composite images optimized for complemen- tary information

Testing of multi-coil FDEM sensors on a field model with magnetic susceptibility contrast

Introduction The main advantage of frequency domain electromagnetic induction (FDEM) sensors is the simultaneous measurement of both electrical conductivity and magnetic susceptibility. Nevertheless, this sensor type is still not routinely used in geoarchaeological prospection (English Heritage, 2008). Although both the electrical conductivity and the magnetic susceptibility measurement has been related to electrical resistivity and magnetometer measurements respectively (Kvamme, 2006), these..

Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times $10^{-22}$.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200

Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers

We study frequency dependent (FD) input-output schemes for signal-recycling interferometers, the baseline design of Advanced LIGO and the current configuration of GEO 600. Complementary to a recent proposal by Harms et al. to use FD input squeezing and ordinary homodyne detection, we explore a scheme which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are sub-optimal among all possible input-output schemes, provide a global noise suppression by the power squeeze factor, while being realizable by using detuned Fabry-Perot cavities as input/output filters. At high frequencies, the two schemes are shown to be equivalent, while at low frequencies our scheme gives better performance than that of Harms et al., and is nearly fully optimal. We then study the sensitivity improvement achievable by these schemes in Advanced LIGO era (with 30-m filter cavities and current estimates of filter-mirror losses and thermal noise), for neutron star binary inspirals, and for narrowband GW sources such as low-mass X-ray binaries and known radio pulsars. Optical losses are shown to be a major obstacle for the actual implementation of these techniques in Advanced LIGO. On time scales of third-generation interferometers, like EURO/LIGO-III (~2012), with kilometer-scale filter cavities, a signal-recycling interferometer with the FD readout scheme explored in this paper can have performances comparable to existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi

Search for gravitational wave bursts in LIGO's third science run

We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

1D sequential inversion of portable multi‐configuration electromagnetic induction data

International audienc

Potentials and constraints of different type of soil moisture observations for flood simulations in headwater catchments

Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall and by the state of the catchment prior to the rainfall, e.g. by the spatial pattern of the soil moisture, groundwater conditions, and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods and in different scales and their potential use for flood simulation. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly thermogravimetric method, Frequency Domain Reflectometry (FDR) sensors, Spatial-Time Domain Reflectometry (STDR) cluster, Ground Penetrating Radar (GPR), airborne polarimetric synthetic aperture radar (polarimetric-SAR) and Advanced Synthetic Aperture Radar (ASAR) based on the satellite Envisat. We present exemplary soil measurement results, with spatial scales ranging from point scale, via hillslope and field scale to the catchment scale. Only the Spatial- TDR cluster was able to record continuous data. The other methods are limited to the date of over flights (airplane and satellite) or measurement campaigns on the ground. For possible use in flood simulation, the observation of soil moisture at multiple scales has to be combined with suitable hydrological modelling, using the hydrological model WaSiM-ETH. Therefore, several simulation experiments have been conducted in order to test both the usability of the recorded soil moisture data and the suitability of a distributed hydrological model to make use of this information. The measurement results show that airborne-based and satellite-based systems in particular provide information on the near surface spatial distribution. However, there are still a variety of limitations, such as the need for parallel ground measurements (Envisat-ASAR), uncertainties in polarimetric decomposition techniques (Polarimetric-SAR), very limited information from remote sensing methods about vegetated surfaces, and the non-availability of continuous measurements. The model experiments showed the importance of soil moisture as an initial condition for physically based flood modelling. However, the observed moisture data reflect the surface or near-surface soil moisture only. Hence, only saturated overland flow might be related to these data. Other flood generation processes influenced by catchment wetness in the subsurface, such as subsurface storm flow or quick groundwater drainage cannot be assessed by these data. One has to acknowledge that, in spite of innovative measuring techniques on all spatial scales, soil moisture data for entire vegetated catchments are still today not operationally available. Therefore, observations of soil moisture should primarily be used to improve the quality of continuous, distributed hydrological catchment models that simulate the spatial distribution of moisture internally. Thus, when and where soil moisture data are available, they should be compared to their simulated equivalents in order to improve the parameter estimates and possibly the structure of the hydrological model

Chapter I/2: INNOVATIONS AND KNOWLEDGE TRANSFER FOR ACHIEVINGLANDSCAPE SUSTAINABILITYГлава I/2: Инновации и передача знаний для достижения устойчивости ландшафтов

The need for soil tillage and its appropriate depth and procedures has been key questions of plant cropping and design of agricultural landscapes worldwide. We re-evaluated the largest series of international soil tillage trials, ever conducted. They were carried out on 50 locations in 8 countries of Eastern and Central Europe from 1955 to 1967. Framework conditions were Late-Holocene: Mechanized tillage and cropping technologies and organo-mineral fertilisers were available, whilst fungicides, herbicides, pesticides and hybrid seeds were little applied or not available during that time. Rotations were wide and balanced. These conditions come close to current organic farming systems. We analysed a multivariate set of more than 4,000 crop yield meta-data. Results revealed strong effects of soil fertility (as evaluated based on the Muencheberg Soil Quality Rating) and of organo-mineral fertilisation on crop yields, whilst soil tillage depth had lower and site-specific effects. Ploughing led to higher crop yields due to better suppression of weeds and mineralisation of plant nutrients. On humid sites in Europe without erosion risks, in a well structured agricultural landscape, the moldboard plough should be an inevitable part of productive and sustainable cropping systems.Необходимость обработки почвы, ее оптимальная глубина и приемы были ключевыми вопросами растениеводства и создания сельскохозяйственных ландшафтов во всем мире. Мы выполнили переоценку международной серии опытов по обработке почвы, крупнейшей из когда-либо проводившихся. Опыты были проведены в 50 географических точках в 8 странах Восточной и Центральной Европы с 1955 по 1967 гг. Рамочные условия – позднеголоценовые: использовались механизированные технологии обработки почвы и возделывания сельскохозяйственных культур, органические и минеральные удобрения, тогда как фунгициды, гербициды, пестициды и гибридные семена в то время применялись мало или отсутствовали. Севообороты включали широкий набор культур и были сбалансированными. Эти условия близки к современным системам органического сельского хозяйства. Мы проанализировали многомерный массив из более чем 4 тысяч метаданных, относящихся к урожайности сельскохозяйственных культур. Результаты выявили выраженные эффекты плодородия почвы (оцененного на основе Мюнхебергской системы рейтинга качества почвы), органических и минеральных удобрений на урожайность. Эффект глубины обработки почвы был ниже и зависел от местоположения. Вспашка повышала урожайность культур благодаря лучшему подавлению сорняков и минерализации питательных веществ в почве. В условиях влажного климата в Европе и отсутствия рисков эрозии, в хорошо структурированном сельскохозяйственном ландшафте, отвальный плуг должен быть необходимой частью продуктивных и устойчивых систем земледелия