Thermal ion measurements from the French Detection of Electro‐Magnetic Emissions Transmitted from Earthquake Regions micro‐satellite have been used to study the climatology of nighttime Medium‐scale traveling ionospheric disturbances (MSTIDs) in the topside ionosphere at 650 km altitude during the 6 years of the satellite operation, from 2005 to 2010. This period encompasses the declining phase of solar cycle 23, the deep solar minimum of 2008–2009 and the early rise of solar cycle 24. MSTIDs were detected from the quasi‐periodic variations of the density of the dominant ionospheric O + ions. Mostly present between ∼15° and ∼40° invariant latitudes with a small number of events in equatorial regions, the MSTIDs exhibit, on the average, larger occurrence rates in the Southern hemisphere with a peak in the Eastern Pacific‐South America longitude sector. The dependence of MSTID activity on solar activity appears more complex than the previously reported simple anti‐correlation. In addition to year‐to‐year variations, our study has, in particular, put in evidence a noticeable hemispheric asymmetry in the seasonal variations during the deep solar minimum of 2008–2009. These statistical observations provide a remarkable observational support to the key role of sporadic Es layers and the conjugate mapping of the associated electric fields. Yet, improved theoretical and numerical models, taking into account the actual inter‐hemispheric differences of the seasonal and solar activity variations of thermospheric and ionospheric processes, are needed for a better understanding of the highly complex MSTID phenomena.

Using plasma measurements from the CNES DEMETER micro-satellite, we have performed a global survey of ionospheric disturbances observed at middle and low latitudes on the nightime part of the DEMETER orbit in the local time sector 21.30-22.30 LT. This study encompasses the 6 years of the satellite operations, from 2005 to 2010, including years of moderate magnetic activity of solar cycles 23 and 24 and the deep solar minimum in 2009-2010. We report in this poster a statistical analysis of MSTID events characterized by quasi-periodic variations of the O+ density observed below ~ 40° geomagnetic latitudes with wavelengths ranging from 350 to 700 km. Although detected in both hemispheres they occur predominantly at southern latitudes with a rather strong peak over the Pacific ocean. A detailed analysis has shown that these events may be sorted in 4 categories according to their latitudinal extent. Most of them are restricted to a latitude band between ~ 15° and 40° geomagnetic in North or South but some of them extend from mid latitudes in one hemisphere to low latitude in the other hemisphere, thus spanning equatorial regions up to 5-10°. The apparent negative correlation with magnetic activity seems to indicate that most of these events are driven by AGW originating from low altitude atmospheric levels and not triggered by auroral phenomena. We shall present the seasonal and inter-annual variations showing significant changes associated with solar activity. Our results will be compared to other ground-based or satellite observations and our investigation pointed out a strong effect of these MSTID and their parent AGW on the electrodynamics of the low latitude ionosphere.

Recent numerical studies in stratospheric dynamics and its variability as well as climate, have highlighted the need of more observational analyses to improve simulation of the West African monsoon (WAM). In this paper, activity and spectral characteristics of short-scale vertical waves (wavelengths <4 km) are analysed in equatorial coastal and tropical lower stratosphere during the WAM. A first detailed description of such waves over West Africa is derived from high-resolution vertical profiles of temperature and horizontal wind obtained during Intensive Observation Period of the African Monsoon Multidisciplinary Analyses (AMMA) Campaign 2006. Monthly variation of wave energy density is revealed to trace the progression of the inter-tropical convergence zone (ITCZ) over West Africa. Mesoscale inertia gravity-waves structures with vertical and horizontal wavelengths of 1.5–2.5 and 400–1100 km respectively and intrinsic frequencies of 1.1–2.2 f or periods <2 days are observed in the tropical LS with intense activity during July and August when the WAM is installed over the tropical West Africa. Over equatorial region, gravity waves with intrinsic frequencies of 1.4–4 f or periods <5.2 days, vertical wavelength of 2.1 km and long horizontal wavelengths of 1300 km are intense during the WAM coastal phase. From July to October, gravity waves with intrinsic frequencies of 1.2–3.8 f or periods <6 days, vertical wavelength of 2.1 km and horizontal wavelengths of 1650 km are less intense during the WAM Sahelian phase of the WAM, March–June. Unlike potential energy density, kinetic energy density is observed to be a good proxy for the activity of short-scale vertical waves during the WAM because quasi-inertial waves are dominant. Long-term wave activity variation from January 2001 to December 2009, highlights strong year-to-year variation superimposed on convective activity and quasi-biennial oscillation-like variations especially above tropical stations.

Using local (rainfall data) and global satellite observations (atmospheric fields reanalysis, OLR data, satellite- observed brightness temperature data and cloud cluster data), the activity of convective equatorial waves revealed to be strongly coupled with the West african Monsoon (WaM) variability. a previous study of wave activity in the West african area (Kafando et al., 2008), revealed that the signature of the monsoon is clearly observed on total energy density in the lower stratosphere (19-23km). the annual cycle and the climatology of wave total energy density showed that peaks of activity match the period of intense convection. in the present study, wave activity in relation with monsoon proxies (convection and precipitations) has been used to analyze the WaM interannual variability using nine years radiosonde observations, tropical rainfall Measuring Mission (trMM) data and Outgoing longwave radiation (Olr) data over several West african meteorological stations located in the latitudinal belt 4°n–20°n.

Developpement et deploiement d'une application desktop et mobile sur une mini grille de calcul a l'Universite de Kinshasa pour le traitement des donnees GPS

The most general definition of climate change is a change in the statistical properties of the climate system when considered over periods of decades or longer, regardless of cause. However this change could be very different from one region to another. Glaciers are considered among the most sensitive indicators of climate change, advancing when climate cools and retreating when climate warms.

Advances in e-Infrastructure promise to revolutionize sensing systems and the way in which data are collected and assimilated, and complex water systems are simulated and visualized. According to the EU Infrastructure 2010 work-programme, data and compute infrastructures and their underlying technologies, either oriented to tackle scientific challenges or complex problem solving in engineering, are expected to converge together into the so-called knowledge infrastructures, leading to a more effective research, education and innovation in the next decade and beyond. Grid technology is recognized as a fundamental component of e-Infrastructures. Nevertheless, this emerging paradigm highlights several topics, including data management, algorithm optimization, security, performance (speed, throughput, bandwidth, etc.), and scientific cooperation and collaboration issues that require further examination to fully exploit it and to better inform future research policies. The paper illustrates the results of six different surface and subsurface hydrology applications that have been deployed on the Grid. All the applications aim to answer to strong requirements from the Civil Society at large, relatively to natural and anthropogenic risks. Grid technology has been successfully tested to improve flood prediction, ground-water resources management and Black Sea hydrological survey, by providing large computing resources. It is also shown that Grid technology facilitates e-cooperation among partners by means of services for authentication and authorization, seamless access to distributed data sources, data protection and access right, and standardization. (C) 2011 Elsevier B.V. All rights reserved.

The term Grid emerged in the nineties, when the rapid increase of network speeds facilitated the time-efficient integration of distributed computers and storage resources [Foster and Kesselmann, 1998]. In the meantime, the resources shared through Grids have been extended to personal computers, servers, compute clusters, supercomputers, storage systems and services like databases and so forth. In 2000 the first European project, DataGrid, to deploy a Grid over Europe was launched, followed up to now by other European projects, called EGEEI, EGEEII and EGEEIII. Since the beginning, 2000, the Earth Science community has started using the Grid. The experience acquired via academic and R&D applications has demonstrated that Grid infrastructure could respond to the ES requirements. However, the interface between the ES software environment and Grid middleware is not simple for many applications. After nearly a decade of European Grid projects like EGEE, that have developed the infrastructure and put it in production for various scientific communities, the next challenge is to find a sustainable model for a continued operational phase. For this purpose, an organizational structure with a central office, called EGI (European Grid Initiative), was founded. In this structure, the provisioning of infrastructure and related services is based on the National Grid Initiatives (NGI) of the participating countries. The user communities are organized according to their scientific domain in so called Grid Virtual Research Communities.

This study is the first which gives the climatology of West African equatorial ionosphere by using Ouagadougou station through three solar cycles. It has permitted to show the complete morphology of ionosphere parameters by analyzing yearly variation, solar cycle and geomagnetic activity, seasonal evolution and diurnal development. This work shows that almost all ionospheric parameters have 11-year solar cycle evolution. Seasonal variation shows that only foF2 exhibits annual, winter and semiannual anomaly. foF2 seasonal variation has permitted us to identify and characterize solar events effects on F2 layer in this area. In fact (1) during quiet geomagnetic condition foF2 presents winter and semiannual anomalies asymmetric peaks in March/April and October. (2) The absence of winter anomaly and the presence of equinoctial peaks are the most visible effects of fluctuating activity in foF2 seasonal time profiles. (3) Solar wind shock activity does not modify the profile of foF2 but increases ionization. (4) The absence of asymmetry peaks, the location of the peaks in March and October and the increase of ionization characterize recurrent storm activity. F1 layers shows increasing trend from cycle 20 to cycle 21. Moreover, E layer parameters seasonal variations exhibit complex structure. It seems impossible to detect fluctuating activity effect in E layer parameters seasonal variations but shock activity and wind stream activity act to decrease E layer ionization. It can be seen from Es layer parameters seasonal variations that wind stream activity effect is fairly in-dependent of solar cycle. E and Es layers critical frequencies and virtual heights diurnal variations let us see the effects of the greenhouse gases in these layers.

The Earth Science (ES) community has three major IT related concerns: Modeling (computing intensive), exploitation of datasets, and production of large shared datasets. All could be accomplishable using Grid. Different Grid middleware solutions exist and are being developed. In DEGREE (Dissemination and Exploitation of Grids in Earth sciencE) the aim was to disseminate and promote uptake of Grid in ES and to create a bridge between ES and Grid communities. DEGREE identified key ES requirements and has disseminated these to Grid projects, evaluated Grid middleware tools and standards regarding ES requirements and provided feedback to Grid developers. In order to convey requirements to the Grid community, test suite specifications were developed. Test suites provide real applications for testing functional and non-functional aspects of Grid, contrary to typical whiteboard tests or use cases. In this paper the GOMEVAL test suite is explained in detail and the results obtained are discussed.

Adoption of information and communication technologies and access to the Internet is expanding in Africa, but because of the rapid growth elsewhere, a Digital Divide between Africa and the rest of the world exists, and the gap is growing. In many sub-Saharan African countries, education and research sector suffer some of the worst deficiencies in access to the Internet, despite progress in development of NRENs National Research and Education (cyber) Networks. By contrast, it is widely acknowledged in policy statements from the African Union, the UN, and others that strength in this very sector provides the key to meeting and sustaining Millennium Development Goals. Developed countries with effective cyber-capabilities proclaim the benefits to rich and poor alike arising from the Information Revolution. This is but a dream for many scientists in African institutions. As the world of science becomes increasingly Internet-dependent, so they become increasingly isolated. eGY-Africa is a bottom-up initiative by African scientists and their collaborators to try to reduce this Digital Divide by a campaign of advocacy for better institutional facilities. Four approaches are being taken. The present status of Internet services, problems, and plans are being mapped via a combination of direct measurement of Internet performance (the PingER Project) and a questionnaire-based survey. Information is being gathered on policy statements and initiatives aimed at reducing the Digital Divide, which can be used for arguing the case for better Internet facilities. Groups of concerned scientists are being formed at the national, regional levels in Africa, building on existing networks as much as possible. Opinion in the international science community is being mobilized. Finally, and perhaps most important of all, eGY-Africa is seeking to engage with the many other programs, initiatives, and bodies that share the goal of reducing the Digital Divide either as a direct policy objective, or indirectly as a means to an end, such as the development of an indigenous capability in science and technology for national development. The expectation is that informed opinion from the scientific community at the institutional, national, and international levels can be used to influence the decision makers and donors who are in a position to deliver better Internet capabilities.

The Earth Sciences (ES) community, with its mosaic of disciplines and players such as academia, industry, national surveys, international organizations, has specific requirements described next. In particular, any observation depends on four coordinates (three spatial dimensions and time) and then needs geospatial tools for its use. The data policy is very complex and strict, as many real-time data may be strategic for the country and/or have an economic impact. In addition, the ES community provides short-term and medium-term predictions of weather and natural hazards in real-time and requires for those tasks immediate availability of resources by advance reservation or pre-emption. Model simulations of a host of phenomena relating to the Earth and its space environment need access to various large sets of data distributed geographically in different data centres. The various sources of data, among others, include satellite missions, observational networks, large instruments and simulations.

(1) Euro-Mediterranean Centre for Climate Change and University of Salento, Lecce, Italy (giovanni.aloisio@unile.it), (2) Euro-Mediterranean Centre for Climate Change and University of Salento, Lecce, Italy (sandro.fiore@unile.it), (3) Institut Pierre-Simon Laplace, Paris, France (sebastien.denvil@ipsl.jussieu.fr), (4) Institut Pierre-Simon Laplace, Paris, France (monique.petitdidier@cetp.ipsl.fr), (5) High Altitude Observatory at the National Center for Atmospheric Research,USA (pfox@cs.rpi.edu), (6) Fraunhofer Institut fur Algorithmen und Wissenschaftliches Rechnen (SCAI), S. Augustin, Germany (horst.schwichtenberg@scai.fraunhofer.de), (7) University of Reading, UK (jdb@mail.nerc-essc.ac.uk), (8) University of Catania, Catania, Italy (roberto.barbera@ct.infn.it)

Gravity wave activity is studied with six years radio sounding data from some of the African meteorological stations located in the 18° N and 05° S latitude domains. This study focuses on gravity wave parameters (e.g., total energy, kinetic and potential energies, fraction of upward propagating energy) above Bamako, Mali (12°53’ N, 07°95’ W). Climatology and seasonal variation are analyzed in the lower stratosphere and upper troposphere. Sources and variability are also examined in relation to convection indices and monsoons.

We study equatorial night-time F layer behaviour from quarter-hourly ionograms at Korhogo/Ivory Coast (9.2° N, 5° W, dip lat. −2.4°) during local Spring March–April 1995, declining solar flux period, according to the magnetic activity. The height and thickness of the F-layer are found to vary intensely with time and from one day to the next. At time of the equinox transition, by the end of March, a net change of the nightly height-time variation is observed. The regime of a single height peak phase before 22 March changes to up to three main F-layer height phases after 30 March, each associated to a dominant mechanism. The first phase is identified to the post-sunset E×B pulse, the second phase associated to a change in the wind circulation phenomenon and the third one attributed to pre-sunrise phenomena. The influence of the magnetic activity is identified by the increase in the second peak amplitude. After the 21 April magnetic-equinox period, the height-time morphology becomes more irregular suggesting meridional wind abatement. The initiation, the growth and the maintenance of ESF are explored in relation to these nightly variations. The Rayleigh-Taylor instability is clearly identified as main precursor phenomenon. This is followed by the P-type (F-layer peak spread) structures, the whole with no specific dependence on the magnetic activity and on the F-layer phases, in contrast to further I and F-type (Inside and Frequency spread) ESFs. We discuss our results in the light of recent advanced experiments in Peru and the pacific.