On the singular values decoupling in the Singular Spectrum Analysis of volcanic tremor at Stromboli

The well known strombolian activity at Stromboli volcano is occasionally interrupted by rarer episodes of paroxysmal activity which can lead to considerable hazard for Stromboli inhabitants and tourists. On 5 April 2003 a powerful explosion, which can be compared in size with the latest one of 1930, covered with bombs a good part of the normally tourist-accessible summit area. This explosion was not forecasted, although the island was by then effectively monitored by a dense deployment of instruments. After having tackled in a previous paper the problem of highlighting the timescale of preparation of this event, we investigate here the possibility of highlighting precursors in the volcanic tremor continuously recorded by a short period summit seismic station. We show that a promising candidate is found by examining the degree of coupling between successive singular values that result from the Singular Spectrum Analysis of the raw seismic data. We suggest therefore that possible anomalies in the time evolution of this parameter could be indicators of volcano instability to be taken into account e.g. in a bayesian eruptive scenario evaluator. Obviously, further (and possibly forward) testing on other cases is needed to confirm the usefulness of this parameter

Indicadores para avaliação dos impactos ambientais e sociais das nano-cápsulas e nanopartículas na agricultura.

Resumo: A Nanotecnologia oferece a perspectiva de grandes avanços que permitirão melhorar a qualidade de vida e preservar o meio ambiente e os nano-produtos agrícolas ganham espaço com as descobertas de novas aplicações, muitas das quais já disponíveis no mercado. Este projeto visa desenvolver indicadores para avaliação dos impactos ambientais e sociais das nano-cápsulas e nano-partículas utilizadas na agricultura. Estes serão futuramente validados através de consultas a especialistas de áreas correlatas à Nanotecnologia na Agricultura e utilizados no software Impactos NanoAgri

Emprego da técnica Delphi para validação de indicadores de impacto de nanotecnologias agrícolas.

Para estudar os impactos das nanotecnologias agrícolas é essencial avaliar quais fatores definem o sistema estudado com base na literatura especializada, embasando estes indicadores com dados científicos relevantes e de consenso na comunidade científica. Após o levantamento, os indicadores devem passar por um processo de validação para que tenha relevância técnica e credibilidade científica. Existem várias modalidades de validação, a escolhida pela equipe consistiu em submeter os indicadores em formato de questionários a um painel de convidados, empregando a Técnica Delphi. Através da análise das respostas foi possível elaborar um perfil dos especialistas envolvidos com pesquisas na área de Nanotecnologia no Brasil, além de informações que podem contribuir para melhorar a eficiência de futuras consultas

On the predictability of volcano-tectonic events by low frequency seismic noise analysis at Teide-Pico Viejo volcanic complex, Canary Islands

The island of Tenerife (Canary Islands, Spain), is showing possible signs of reawakening after its last basaltic strombolian eruption, dated 1909 at Chinyero. The main concern relates to the central active volcanic complex Teide - Pico Viejo, which poses serious hazards to the properties and population of the island of Tenerife (Canary Islands, Spain), and which has erupted several times during the last 5000 years, including a subplinian phonolitic eruption (Montaña Blanca) about 2000 years ago. In this paper we show the presence of low frequency seismic noise which possibly includes tremor of volcanic origin and we investigate the feasibility of using it to forecast, via the material failure forecast method, the time of occurrence of discrete events that could be called Volcano-Tectonic or simply Tectonic (i.e. non volcanic) on the basis of their relationship to volcanic activity. In order to avoid subjectivity in the forecast procedure, an automatic program has been developed to generate forecasts, validated by Bayes theorem. A parameter called 'forecast gain' measures (and for the first time quantitatively) what is gained in probabilistic terms by applying the (automatic) failure forecast method. The clear correlation between the obtained forecasts and the occurrence of (Volcano-)Tectonic seismic events - a clear indication of a relationship between the continuous seismic noise and the discrete seismic events - is the explanation for the high value of this 'forecast gain' in both 2004 and 2005 and an indication that the events are Volcano-Tectonic rather than purely Tectonic

The Ross Shelf cavity water exchange variability during 1995-1998

This work aims at presenting an analysis of the evolution of the physical properties of a water column at the southern limit of the Ross Sea, Antarctica. Data has been collected over a four year period (from January 1995 to July 1998) by means of an oceanographic mooring (named mooring “F”) berthed a few miles north of theRoss IceShe lf at a depth of 600 m on thecon tinental shelf. The velocity and temperature measurements have been investigated seeking for ISW (Ice Shelf Water) outflow footprints. These outflows are irregular massive injections of cold water from below the Ice Shelf, flowing mainly across the cavity floor into the Ross Sea bottom layers. The study evidenced a large number of DISW outflow events (Deep Ice Shelf Water, the coldest and densest fraction of the ISW, the actual main object of the present study), characterized by an interannual variability that could turn out to bean important co-factor in thev ariations of theplane tary heat balance and climate instability. Differences in DISW outflow timings from biennium 1995-1996, during which a jet-like behaviour was dominating (each events was only a few days long), and 1997-1998 (with a few long and rather continous cold water outflows) have been detected. Moreover, in 1996 measurements evidenced a relatively long and warm period (about 110 days from March to July) characterized by thetotal absenceof DISW outflow, this interval being morethan twice longer with respect to any other similar ones registered during 1995, 1997 and 1998, and longer that any other warm period observed in the area during the early ’80s. The estimates of cold water exchanged during the four years return a more complicated framework: 1996 behaviour seems to be closer to the 1997 than to the 1995 one, with high fluxes and high volumes. 1995 can probably be considered as the ignition of an interannual anomaly, which climax is the long warm period of spring 1996

Coupled wave-2D hydrodynamics modeling at the Reno River mouth (Italy) under climate change scenarios

This work presents the results of the numerical study implemented for the natural area of Lido di Spina, a touristic site along the Italian coast of the North Adriatic Sea, close to the mouth of River Reno. High-resolution simulations of nearshore dynamics are carried out under climate change conditions estimated for the site. The adopted modeling chain is based on the implementation of multiple-nested, open-source numerical models. More specifically, the coupled wave-2D hydrodynamics runs, using the open-source TELEMAC suite, are forced at the offshore boundary by waves resulting from the wave model (SWAN) simulations for the Adriatic Sea, and sea levels computed following a joint probability analysis approach. The system simulates presentday scenarios, as well as conditions reflecting the high IPCC greenhouse concentration trajectory named RCP8.5 under predicted climate changes. Selection of sea storms directed from SE (Sirocco events) and E-NE (Bora events) is performed together with Gumbel analysis, in order to define ordinary and extreme sea conditions. The numerical results are here presented in terms of local parameters such as wave breaking position, alongshore currents intensity and direction and flooded area, aiming to provide insights on how climate changes may impact hydrodynamics at a site scale. Although the wave energy intensity predicted for Sirocco events is expected to increase only slightly, modifications of the wave dynamics, current patterns, and inland flooding induced by climate changes are expected to be significant for extreme conditions, especially during Sirocco winds, with an increase in the maximum alongshore currents and in the inundated area compared to past conditions. \ua9 2018 by the authors

The response of the Ligurian and Tyrrhenian Seas to a summer Mistral event: A coupled atmosphere–ocean approach

In this paper the effect of a summer Mistral event on the Ligurian and Tyrrhenian Seas in the northwestern Mediterranean is discussed, using a coupled numerical model and satellite and in situ observations. The focus is on the spatial and temporal distribution of the ocean mixed layer response to the strong winds, and on how this is affected by atmosphere–ocean coupling. The model used is the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS®1), developed at the Naval Research Laboratory. This system includes an atmospheric sigma coordinate, non-hydrostatic model, coupled to a hydrostatic sigma-z level ocean model (Naval Coastal Ocean Model), using the Earth System Modeling Framework (ESMF). The model is run at high (km scale) resolution to capture the fine structure of wind jets and surface cooling. Two non-assimilating numerical experiments, coupled and uncoupled, are run for a 3-day period of a Mistral event, to examine more closely the impact of coupling on the surface flux and sea surface temperature (SST) fields. The cooling of SST up to 3 °C over 72 h in the coupled run significantly reduced the surface momentum and heat fluxes, relative to the uncoupled simulation, where the SST was kept fixed at the initial value. Mixed layer depths increase by as much as 30 m during the event. A heat budget analysis for the ocean is carried out to further explain and investigate the SST evolution. Shear-induced mixing in inertial waves is found to be important to the surface cooling. Effects of coupling on the atmospheric boundary layer are found to be significant, but overall the effect of coupling on the synoptic low pressure system is small

Synthetic Modeling for an Acoustic Exploration System for Physical Oceanography

10 pages, 6 figures, 1 tableMarine multichannel seismic (MCS) data, used to obtain structural reflection images of the earth¿s subsurface, can also be used in physical oceanography exploration. This method provides vertical and lateral resolutions of O(10¿100) m, covering the existing observational gap in oceanic exploration. All MCS data used so far in physical oceanography studies have been acquired using conventional seismic instrumentation originally designed for geological exploration. This work presents the proof of concept of an alternative MCS system that is better adapted to physical oceanography and has two goals: 1) to have an environmentally low-impact acoustic source to minimize any potential disturbance to marine life and 2) to be light and portable, thus being installed on midsize oceanographic vessels. The synthetic experiments simulate the main variables of the source, shooting, and streamer involved in the MCS technique. The proposed system utilizes a 5-s-long exponential chirp source of 208 dB relative to 1 ¿Pa at 1 m with a frequency content of 20¿100 Hz and a relatively short 500-m-long streamer with 100 channels. This study exemplifies through numerical simulations that the 5-s-long chirp source can reduce the peak of the pressure signal by 26 dB with respect to equivalent air gun¿based sources by spreading the energy in time, greatly reducing the impact to marine life. Additionally, the proposed system could be transported and installed in midsize oceanographic vessels, opening new horizons in acoustic oceanography researchThe first author’s work has been supported by the European Commission through Marie Curie Actions FP7-PEOPLE-2010-IOF-271936 and FP7-PEOPLE-2012-COFUND-600407. This work has been done in the framework of the Spanish project POSEIDON (CTM2010-25169) and the Italian National Flagship Programme RITMARE (Programma Nazionale della Ricerca 2011-2013 MIUR). We want to acknowledge the team of GO project funded by the EU (015603-GO-STREP)Peer Reviewe

Identification of Seismo-Volcanic Regimes at Whakaari/White Island (New Zealand) Via Systematic Tuning of an Unsupervised Classifier

We present an algorithm based on Self-Organizing Maps (SOM) and k-means clustering to recognize patterns in a continuous 12.5-year tremor time series recorded at Whakaari/White Island volcano, New Zealand (hereafter referred to as Whakaari). The approach is extendable to a variety of volcanic settings through systematic tuning of the classifier. Hyperparameters are evaluated by statistical means, yielding a combination of “ideal” SOM parameters for the given data set. Extending from this, we applied a Kernel Density Estimation approach to automatically detect changes within the observed seismicity. We categorize the Whakaari seismic time series into regimes representing distinct volcano-seismic states during recent unrest episodes at Whakaari (2012/2013, 2016, and 2019). There is a clear separation in classification results between background regimes and those representing elevated levels of unrest. Onset of unrest is detected by the classifier 6 weeks before the August 2012 eruption, and ca. 3.5 months before the December 2019 eruption, respectively. Regime changes are corroborated by changes in commonly monitored tremor proxies as well as with reported volcanic activity. The regimes are hypothesized to represent diverse mechanisms including: system pressurization and depressurization, degassing, and elevated surface activity. Labeling these regimes improves visualization of the 2012/2013 and 2019 unrest and eruptive episodes. The pre-eruptive 2016 unrest showed a contrasting shape and nature of seismic regimes, suggesting differing onset and driving processes. The 2016 episode is proposed to result from rapid destabilization of the shallow hydrothermal system, while rising magmatic gases from new injections of magma better explain the 2012/2013 and 2019 episodes

Use of whole-genus genome sequence data to develop a multilocus sequence typing tool that accurately identifies Yersinia isolates to the species and subspecies levels

The genus Yersinia is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus. Here we report the mining of this enormous data set to create a multilocus sequence typing-based scheme that can identify Yersinia strains to the species level to a level of resolution equal to that for whole-genome sequencing. Our assay is designed to be able to accurately subtype the important human-pathogenic species Yersinia enterocolitica to whole-genome resolution levels. We also report the validation of the scheme on 386 strains from reference laboratory collections across Europe. We propose that the scheme is an important molecular typing system to allow accurate and reproducible identification of Yersinia isolates to the species level, a process often inconsistent in nonspecialist laboratories. Additionally, our assay is the most phylogenetically informative typing scheme available for Y. enterocolitica