Future supernovae data and quintessence models     

Elisa Di Pietro  Jean-François Claeskens 《Monthly notices of the Royal Astronomical Society》2003,341(4):1299-1310

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Comparison of neural network and McNish and Lincoln methods for the prediction of the smoothed sunspot index     

Françoise Fessant  Catherine Pierret  Pierre Lantos 《Solar physics》1996,168(2):423-433

In this paper we propose a comparison between two methods for the problem of long-term prediction of the smoothed sunspot index. These two methods are first the classical method of McNish and Lincoln (as improved by Stewart and Ostrow), and second a neural network method. The results of these two methods are compared in two periods, during the ascending and the declining phases of the current cycle 22 (1986–1996). The predictions with neural networks are much better than with the McNish and Lincoln method for the atypical ascending phase of cycle 22. During the second period the predictions are very similar, and in agreement with observations, when the McNish and Lincoln method is based on the data of declining phases of the cycles.  相似文献   

Evaporation estimation on Lake Titicaca: a synthesis review and modelling     

François Delclaux  Anne Coudrain  Thomas Condom 《水文研究》2007,21(13):1664-1677

The aim of this study was to validate evaporation models that can be used for palaeo‐reconstructions of large lake water levels. Lake Titicaca, located in a high‐altitude semi‐arid tropical area in the northern Andean Altiplano, was the object of this case study. As annual evaporation is about 90% of lake output, the lake water balance depends heavily on the yearly and monthly evaporation flux. At the interannual scale, evaporation estimation presents great variability, ranging from 1350 to 1900 mm year^?1. It has been found that evaporation is closely related to lake rainfall by a decreasing relationship integrating the implicit effect of nebulosity and humidity. At the seasonal scale, two monthly evaporation data sets were used: pan observations and estimations derived from the lake energy budget. Comparison between these data sets shows that (i) there is one maximum per year for pan evaporation and two maxima per year for lake evaporation, and (ii) pan evaporation is greater than lake evaporation by about 100 mm year^?1. These differences, mainly due to a water depth scale factor, have been simulated with a simple thermal model θ_w(h, t) of a free‐surface water column. This shows that pan evaporation (h = 0·20 m) is strongly correlated with direct solar radiation, whereas the additional maximum of lake evaporation (h = 40 m) is related to the heat restitution towards the atmosphere from the water body at the end of summer. Finally, five monthly evaporation models were tested in order to obtain the optimal efficiency/complexity ratio. When the forcing variables are limited to those that are most readily available in the past, i.e. air temperature and solar radiation, the best results are obtained with the radiative Abtew model (r = 0·70) and with the Makkink radiative/air temperature model (r = 0·67). Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

On the (anticipated) diversity of terrestrial planet atmospheres     

Jérémy Leconte  François Forget  Helmut Lammer 《Experimental Astronomy》2015,40(2-3):449-467

On our way toward the characterization of smaller and more temperate planets, missions dedicated to the spectroscopic observation of exoplanets will teach us about the wide diversity of classes of planetary atmospheres, many of them probably having no equivalent in the Solar System. But what kind of atmospheres can we expect? To start answering this question, many theoretical studies have tried to understand and model the various processes controlling the formation and evolution of planetary atmospheres, with some success in the Solar System. Here, we shortly review these processes and we try to give an idea of the various type of atmospheres that these processes can create. As will be made clear, current atmosphere evolution models have many shortcomings yet, and need heavy calibrations. With that in mind, we will thus discuss how observations with a mission similar to EChO would help us unravel the link between a planet’s environment and its atmosphere.  相似文献   

Use of a flood-routing model to assess lateral flows in a karstic stream: implications to the hydrogeological functioning of the Grands Causses area (Tarn River,Southern France)     

Jean-Baptiste Charlier  Roger Moussa  Vincent Bailly-Comte  Laurent Danneville  Jean-François Desprats  Bernard Ladouche  Arthur Marchandise 《Environmental Earth Sciences》2015,74(12):7605-7616

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Local and indigenous knowledge on climate-related hazards of coastal and small island communities in Southeast Asia     

Lisa Hiwasaki  Emmanuel Luna  Syamsidik  José Adriano Marçal 《Climatic change》2015,128(1-2):35-56

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Assessing climate change impacts on European wind energy from ENSEMBLES high-resolution climate projections     

Isabelle Tobin  Robert Vautard  Irena Balog  François-Marie Bréon  Sonia Jerez  Paolo Michele Ruti  Françoise Thais  Mathieu Vrac  Pascal Yiou 《Climatic change》2015,128(1-2):99-112

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Use of SARAL/AltiKa over Mountainous Lakes,Intercomparison with Envisat Mission     

Adalbert Arsen  Jean-François Crétaux  Rodrigo Abarca del Rio 《Marine Geodesy》2015,38(3):534-548

The SARAL/AltiKa project is based on a single Ka band altimeter (35.75 GHz), which is the first oceanography altimeter to operate at such a high frequency. Ka band offers reduced radar footprint in comparison to traditional Ku band altimeters and negligible ionospheric effects. In this paper we present and evaluate benefits of AltiKa altimeter applied in the study of lakes in Andean chain in South America. Water levels time series obtained with Envisat/RA-2 and SARAL/AltiKa altimeters over 17 lakes of various sizes are calculated and compared to in situ observations. SARAL/AltiKa measurements tend to be extremely well correlated with in situ measurements and offer significant improvements compared to the Envisat mission.  相似文献   

Shatter cones and planar deformation features confirm Santa Marta in Piauí State,Brazil, as an impact structure     

Grace Juliana Gonçalves de Oliveira  Marcos Alberto Rodrigues Vasconcelos  Alvaro Penteado Crósta  Wolf Uwe Reimold  Ana Maria Góes  Astrid Kowitz 《Meteoritics & planetary science》2014,49(10):1915-1928

A total of 184 confirmed impact structures are known on Earth to date, as registered by the Earth Impact Database . The discovery of new impact structures has progressed in recent years at a rather low rate of about two structures per year. Here, we introduce the discovery of the approximately 10 km diameter Santa Marta impact structure in Piauí State in northeastern Brazil. Santa Marta is a moderately sized complex crater structure, with a raised rim and an off‐center, approximately 3.2 km wide central elevated area interpreted to coincide with the central uplift of the impact structure. The Santa Marta structure was first recognized in remote sensing imagery and, later, by distinct gravity and magnetic anomalies. Here, we provide results obtained during the first detailed ground survey. The Bouguer anomaly map shows a transition from a positive to a negative anomaly within the structure along a NE–SW trend, which may be associated with the basement signature and in parts with the signature developed after the crater was formed. Macroscopic evidence for impact in the form of shatter cones has been found in situ at the base around the central elevated plateau, and also in the interior of fractured conglomerate boulders occurring on the floor of the surrounding annular basin. Planar deformation features (PDFs) are abundant in sandstones of the central elevated plateau and at scattered locations in the inner part of the ring syncline. Together, shatter cones and PDFs provide definitive shock evidence that confirms the impact origin of Santa Marta. Crystallographic orientations of PDFs occurring in multiple sets in quartz grains are indicative of peak shock pressures of 20–25 GPa in the rocks exposed at present in the interior of the crater. In contrast to recent studies that have used additional, and sometimes highly controversial, alleged shock recognition features, Santa Marta was identified based on well‐understood, traditional shock evidence.  相似文献   

10Be exposure age constraints on the Late Weichselian ice‐sheet geometry and dynamics in inter‐ice‐stream areas,western Svalbard     

Jon Y. Landvik  Edward J. Brook  Lyn Gualtieri  Henriette Linge  Grant Raisbeck  Otto Salvigsen  Françoise Yiou 《Boreas: An International Journal of Quaternary Research》2013,42(1):43-56

The Late Weichselian ice sheet of western Svalbard was characterized by ice streams and inter‐ice‐stream areas. To reconstruct its geometry and dynamics we investigated the glacial geology of two areas on the island of Prins Karls Forland and the Mitrahalvøya peninsula. Cosmogenic ¹⁰Be surface exposure dating of glacial erratics and bedrock was used to constrain past ice thickness, providing minimum estimates in both areas. Contrary to previous studies, we found that Prins Karls Forland experienced a westward ice flux from Spitsbergen. Ice thickness reached >470 m a.s.l., and warm‐based conditions occurred periodically. Local deglaciation took place between 16 and 13 ka. At Mitrahalvøya, glacier ice draining the Krossfjorden basin reached >300 m a.s.l., and local deglaciation occurred at c. 13 ka. We propose the following succession of events for the last deglaciation. After the maximum glacier extent, ice streams in the cross‐shelf troughs and fjords retreated, tributary ice streams formed in Forlandsundet and Krossfjorden, and, finally, local ice caps were isolated over both Prins Karls Forland and Mitrahalvøya and their adjacent shelves.  相似文献