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J. C. Morales J.-P. Beaulieu V. Coudé du Foresto M. Ollivier I. Ortega Castello R. Clédassou J. Jaubert P. Van-Troostenberghe R. Varley I. P. Waldmann E. Pascale M. Tessenyi 《Experimental Astronomy》2015,40(2-3):655-670
The Exoplanet Characterization Observatory (EChO) is a concept of a dedicated space telescope optimized for low-resolution transit and occultation spectroscopy to study the exoplanet diversity through the composition of their atmospheres. The scope of this paper is to answer the following question: Can we schedule a nominal EChO mission, with targets known today (in mid 2013), given the science requirements, realistic performances and operational constraints? We examine this issue from the point of view of duration of the mission and the scheduling restrictions with a sample of exoplanet systems known nowadays. We choose different scheduling algorithms taking into account the science and operational constraints and we verified that it is fairly straightforward to schedule a mission scenario over the lifetime of EChO compliant with the science requirements. We identified agility as a critical constraint that reduces significantly the efficiency of the survey. We conclude that even with known targets today the EChO science objectives can be reached in the 4.5 years duration of the mission. We also show that it is possible to use gaps between exoplanet observations, to fit the required calibration observations, data downlinks and station keeping operations or even to observe more exoplanet targets to be discovered in the coming years. 相似文献
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Nonmodal growth (NG) and unstable normal mode growth are considered in spherical geometry. Two groups of initial conditions (IC) are studied: "connected" IC (common in Cartesian studies) and "separated" IC (based on observed conditions prior to cyclogenesis). Time series of growth rates are emphasized in conjunction with eigenmode projections. Projections show that early on normal mode growth was much stronger for connected IC and that NG caused negative growth early on of some variables for separated IC. Projections explain why amplitude, kinetic energy (KE), and potential vorticity have more NG than available potential energy (APE). Though varying between ICs and with initial phase shift, NG increases with wavenumber. For middle wavelengths, NG is significant and positive using connected IC but negative or small using separated IC. Total energy and KE growth rates of short waves are very similar during the first 2 days for both ICs. Amplitude time series closely follow KE in all cases studied. APE has less overlap than does KE between the main modes present, so less NG occurs for APE than for KE. In separated IC cases, APE growth rates evolve consistent with emergence of an unstable normal mode and little NG. 相似文献
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A. Deschamps F. Courboulex S. Gaffet A. Lomax J. Virieux A. Amato A. Azzara B. Castello C. Chiarabba G.B. Cimini M. Cocco M. Di Bona L. Margheriti F. Mele G. Selvaggi L. Chiaraluce D. Piccinini M. Ripepe 《Journal of Seismology》2000,4(4):377-386
We present the spatio-temporal distribution of more than 2000 earthquakesthat occurred during the Umbria-Marche seismic crisis, between September 26and November 3, 1997. This distribution was obtained from recordings of atemporary network that was installed after the occurrence of the first two largest shocks (Mw =, 5.7, Mw = 6.0) of September 26. This network wascomposed of 27 digital 3-components stations densely distributed in theepicentral area. The aftershock distribution covers a region of about 40 km long and about2 km wide along the NW-SE central Apennines chain. The activity is shallow,mostly located at less than 9 km depth. We distinguished three main zonesof different seismic activity from NW to SE. The central zone, that containsthe hypocenter of four earthquakes of magnitude larger than 5, was the moreactive and the more complex one. Sections at depth identify 40–50°dipping structures that agree well with the moment tensor focalmechanisms results. The clustering and the migration of seismicity from NW to SE and the generalfeatures are imaged by aftershock distribution both horizontally and at depth. 相似文献
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Stacy Supak Huan Luo Laura Tateosian Kunsheng Fang Julia Harrell Cris Harrelson Andrew D. Bailey Hugh Devine 《Transactions in GIS》2012,16(2):89-104
By responding to potentially life‐threatening emergencies such as foodborne illnesses and water contamination, U.S. public health agencies play a vital role in promoting human health and protecting the environment. Local, state, and federal partners must collaborate to strategically plan initiatives, allocate resources, and evaluate emergency response activities. These collaborative decision‐making processes can be improved by using web‐based mapping applications for visualization and analysis. We developed a web‐based GIS framework which is applied to public health data for North Carolina's (NC) Department of Health and Human Services. The application visualizes all state‐regulated food service facilities and supports query and analysis tools crucial for food recalls or radiation contamination tracking. Built with PostgreSQL/PostGIS, GeoServer, and a customized GeoExplorer map viewer, the framework delivers a web‐based mapping tool that is flexible and Open Source. The flexibility of the framework is an important dimension of its scalability, allowing it to be customizable, modular, and portable so that it is easily configurable to support additional research and education initiatives. This approach reverses a trend toward application‐specific web mapping development in Open Source GIS. To demonstrate flexibility, we configured an additional website for forest landowner management to be used by another state agency, the NC Forest Service. 相似文献
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Jorge P. Castello Luis Poersch Marcelo C. Vasconcellos Ronaldo Cavalli Wilson Wasielesky 《Estuaries and Coasts》2008,31(1):215-222
A predictive model for impact assessment of shrimp (Farfantepenaeus paulensis) culture in pen enclosures was developed. Experiments were carried out at Saco da Mangueira, a small embayment at the Patos
Lagoon estuarine area (southern Brazil). Nitrogen budget was assessed considering inputs and outputs from the culture system.
The measured parameters were water flow, shrimp density, pen mesh size and clogging effect, artificial diet quality, and food
conversion rates. Shrimp excretion was estimated from literature available. A N-NT concentration of 0.07 mg L−1 of was assumed as a conservative critical reference value to assess environmental impact and water deterioration. Trials
showed that for Saco da Mangueira conditions, a total number of 70 pen enclosures of 0.3 ha (i.e., a total production of 32.2 ton)
is recommended as a maximal number. This model is a useful tool for impact assessment and coastal management and may be applied
to other estuarine areas. 相似文献
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Lucia Luzi Fabio Sabetta Francesco Mele Barbara Castello 《Bulletin of Earthquake Engineering》2010,8(5):1159-1174
The Italian Accelerometic Archive (ITACA) was created in 2007 during a joint project between the Italian Institute for Geophysics
and Vulcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV) and the Italian Civil Protection (Dipartimento della Protezione Civile, DPC). The project, started in 2006, had the aim of filling the data gap of existing strong motion databases and facilitating
strong motion data users in obtaining good quality waveforms, through the collection, homogenization and distribution of strong
motion data acquired during the period 1972–2004 in Italy by different institutions (Ente Nazionale per l’Energia Elettrica, ENEL, Italian electricity company; Ente per le Nuove tecnologie, l’Energia e l’Ambiente, ENEA, Italian energy and environment organization DPC). The compiled database contains 2,182 three-component waveforms generated
by 1,008 earthquakes with a maximum moment magnitude of 6.9 (1980 Irpinia earthquake) and can be accessed on-line at the portal
denominated ITACA at the site , where a wide range of search tools enables the user to interactively retrieve events, recording stations and waveforms with
particular characteristics, whose parameters can be specified, as needed, through user friendly interfaces. A range of display
options allows users to view data in different contexts, extract and download time series and spectral data. This article
describes the state of the art up to 2006 and the activities which led to the completion of the project. 相似文献
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The Patos Lagoon estuary is an important environment for the life cycle of many species, including the pink shrimp Farfantepenaeus paulensis. This area acts as a nursery ground for the shrimp larvae, which are spawned in a coastal area and transported into the lagoon during spring and early summer (September to December). Harvesting of shrimp occurs from January to May, and yields have varied from around 1,000 to 8,000 tons year?1. This study is based on analysis of river discharge, pink shrimp catches, and wind velocity time series from 1964 to 2004. Negative correlation between pink shrimp catches and river runoff reflects the influence of discharge on the lagoon circulation and, consequently, on the intrusion of salt water and larvae. When river discharge is below average, landward currents forced by SW winds can enhance larval transport into the estuarine area, leading to an increase in pink shrimp captures. Above average river input would force a seaward flow that works as a barrier to ingress of larvae. This is unusual when compared to many other estuarine systems, and the main factor that accounts for this behavior is the morphology (choking) of Patos Lagoon. Interannual variability related to El Niño/Southern Oscillation events also influence pink shrimp production in this area. Low/high shrimp catches are related to El Niño (flood)/La Niña (drought) events. Wind can also impact production through its effect on the southward displacement of larvae from the spawning area. Long-term trends indicate an increase in river discharge around 20 m3 s?1year?1 and a decrease in shrimp catches on the order of 57 tons year?1. 相似文献
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