221 research outputs found
Comparación de métodos para estimar el balance de masa del glaciar de Zongo, Bolivia (16º S, 68º O)
No full textThe longest and most continuous series of measurements of mass balance in the Intertropical Zone correspond to Zongo glacier, Bolivia. Measurements, which were initiated in 1991, were taken using both the hydrological and glaciological methods. Comparison of these results show discrepancies in the mass balances obtained. In order to verify the mass balances derived from both methods, a new mass balance was performed using the photogrammetric method, results of which were compared with the existing glaciological and hydrological methods. This comparison showed that the hydrological and photogrammetric methods are equivalent. However, these results disagree with the glaciological method. This difference is attributed to a lack of measurements using the glaciological method in areas of difficult access on Zongo glacier. In these areas, the glaciological method simply used interpolation to estimate the specific net mass balance. The final results of this three-method comparison show that the Zongo glacier maintained very close to a steady state of mass balance between 1956 and 1963 and then gained significant mass between 1963 and 1975 (3.86 m eq. aqua). After 1975, mass balances have been almost negative. Moreover, this research extended the range of mass balance observations on Zongo glacier to cover the past 50 years (1956-2006).La serie más larga y continua de mediciones de balance de masa en la Zona Intertropical de Sud América corresponden al glaciar de Zongo, Bolivia. Las mediciones fueron iniciadas en 1991, empleando tanto el método glaciológico como el hidrológico. Los resultados muestran discrepancias en los balances de masa obtenidos por ambos métodos. Con el objetivo de verificar estos balances de masa, se realizó un nuevo balance de masa mediante el método fotogramétrico, que fue comparado con los métodos glaciológico e hidrológico ya existentes. Los resultados de esta comparación entre balances de masa obtenidos con el método hidrológico y fotogramétrico son equivalentes, mientras que la comparación de los resultados obtenidos entre estos y el método glaciológico, están en desacuerdo. Esta diferencia, se atribuye a la imposibilidad de realizar mediciones adecuadas con el método glaciológico en las zonas de difícil acceso del glaciar de Zongo, las cuales son simplemente interpoladas en la estimación del balance de masa neto específico. Los resultados muestran, en general, que el glaciar Zongo ha estado muy cercano a un estadio de equilibrio entre 1956 y 1963; ganó masa entre 1963 y 1975 de manera significativa (3.86 m eq. agua) y a partir de 1975, los balances de masa son negativos. Por otra parte, se han extendido las observaciones del balance de masa del glaciar de Zongo para los últimos 50 años (1956-2006)
Vivre dans les zones rurales et urbaines de Nouvelle-Calédonie : impact sur la consommation alimentaire, la durée du sommeil et les paramètres anthropométriques chez les adolescents mélanésiens
No full textInfographie résumant l'article scientifique suivant :Galy O., Paufique E., Nedjar-Guerre A., Wacalie F., Wattelez G., Le Roux P.-Y., Ponidja S., Zongo P., Serra-Mallol C., Allman-Farinelli M., Frayon S. Living in Rural and Urban Areas of New Caledonia: Impact on Food Consumption, Sleep Duration and Anthropometric Parameters Among Melanesian Adolescents. Nutrients. 2020; 12(7):2047. doi: 10.3390/nu12072047Infography related to the following scientific paper: Galy O., Paufique E., Nedjar-Guerre A., Wacalie F., Wattelez G., Le Roux P.-Y., Ponidja S., Zongo P., Serra-Mallol C., Allman-Farinelli M., Frayon S. Living in Rural and Urban Areas of New Caledonia: Impact on Food Consumption, Sleep Duration and Anthropometric Parameters Among Melanesian Adolescents. Nutrients. 2020; 12(7):2047. doi: 10.3390/nu12072047Infographie résumant l'article scientifique suivant :Galy O., Paufique E., Nedjar-Guerre A., Wacalie F., Wattelez G., Le Roux P.-Y., Ponidja S., Zongo P., Serra-Mallol C., Allman-Farinelli M., Frayon S. Living in Rural and Urban Areas of New Caledonia: Impact on Food Consumption, Sleep Duration and Anthropometric Parameters Among Melanesian Adolescents. Nutrients. 2020; 12(7):2047. doi: 10.3390/nu1207204
Contribuição das queimadas na América do Sul para o derretimento das geleiras andinas : estudo de caso sobre o impacto do aerossol "black carbon" na geleira Zongo-Bolívia
No full textO período de maior ocorrência das queimadas na América do Sul, de agosto à outubro, coincide com mudanças sazonais na circulação atmosférica que tornam favoráveis o transporte e a deposição de black carbon sobre as geleiras Andinas. Com o intuito de avaliar o potencial impacto do black carbon emitido pelas queimadas na bacia Amazônica sobre a massa de gelo dessas geleiras, foram modeladas a emissão de BC, o seu transporte e deposição sobre a geleira Zongo, as mudanças no albedo e a perda de massa de gelo/neve em 2 anos críticos, 2007 e 2010. Os valores de emissão para estes anos na bacia Amazônica foram de 34 e 26 Gg para os picos em setembro, e 51 e 76 Gg anuais. Estes valores foram utilizados para a modelagem da emissão, transporte, deposição e perda de massa de gelo devido ao black carbon. A redução no albedo devido as queimadas foi de 2,5-5%, o que resultou em uma perda de massa de gelo/neve de 3,0-6,5 kg/m² ao ano, equivalente a um incremento de 2-4,5% na perda de massa de gelo/neve anual. Esta perda de massa de gelo devido as queimadas pode ser observada na descarga da geleira nos meses de agosto e setembro. O recuo da frente da geleira apresentou uma relação direta com o desmatamento e o número de queimadas na América do sul. Períodos com maiores taxas de recuo coincidiram com os anos de maiores eventos de queimada e desmatamento.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe period of greatest occurrence of fires in South America, from August to October, coincides with seasonal changes in atmospheric circulation that favor the transportation and deposition of black carbon on the Andean glaciers. In order to evaluate the potential impact of the black carbon emitted by the fires in the Amazon over these glaciers, we modeled the emission of BC, its transport and deposition on the Zongo glacier, the change in glacier albedo and the resulting Ice / snow mass loss, during 2 critical years, 2007 and 2010. The emission values for these years in the Amazon basin were 34 and 26 Gg for the peaks in September, and 51 and 76 Gg annual. These values were used for modeling the emission, transport, deposition and loss of ice/snow due to black carbon. The estimated albedo reduction were 2.5-5%, which resulted in a loss of ice / snow mass of 3.0-6.5 kg / m² per year, equivalent to an increase of 2-4,5% annual ice / snow mass loss. The estimated ice/snow loss due to Amazon fire emission can be observed in the Zongo's discharge during august and september. The retreat of the front of the glacier presented a direct relation with the deforestation and the number of fires events in South America. Periods with the highest retreat rates coincided with the years of major events of burning and deforestation
Glaciers et évolution climatique dans les Andes boliviennes - Glacier de Zongo et glacier de Chacaltaya, Cordillère Royale, 16°S
No full textGlaciers and climatic evolution in the Andes of Bolivia Zongo and Chacaltaya glaciers -real cordillera, 16°S
Abstract
The high sensibility and the short lag time response of glaciers to climatic changing make it possible to use them for analyzing the variability and the evolution of climate in the Tropics. Measurements of mass balance and hydrological balance were performed every month on the two glaciers. Methods are presented. Results obtained during the three hydrological years 1991-1994 have shown great variability. This variability is controlled mainly by the extension of the precipitation period in the warm season which extends over six months. ENSO (El Niño Southern Oscillation) events are associated with quite negative mass balance, as shown both by the response of glaciers to the last 1991-1992 event and by the mass balance reconstruction from hydrological data for the two last decades. The glacier retreat is increasing dramatically since the 1980's in the Central Andes due to a succession of ENSO events and the forces of global warming.Résumé
Par sa sensibilité et son délai de réponse bref, le glacier est d'un grand intérêt pour analyser l'évolution et la variabilité actuelles du climat entre les tropiques. Les méthodes de détermination des bilans de masse et des bilans hydrologiques, avec un pas de mesure mensuel, sont présentées. Les résultats obtenus sur trois années hydrologiques (1991-1994) montrent une grande variabilité. Celle-ci est contrôlée surtout par l'extension de la période des précipitations au sein de la saison chaude qui dure environ six mois. Les événements ENSO (El Niño Southern Oscillation ) sont associés à des bilans nettement négatifs, ce qui est démontré par la réponse du glacier à l'épisode ENSO de 1991-1992 et dans la reconstruction des bilans effectuée sur la base de données hydrologiques pour les deux dernières décennies. Le recul accéléré des glaciers tropicaux depuis les années 1980 est lié à la fois à une succession d'événements ENSO et au réchauffement atmosphérique.Glaciares y evolución climática en los Andes bolivianos. Glaciar de Zongo y Glaciar de Chacaltaya, Cordillera Real, 16°S.
Resumen
Por su sensibilidad y su plazo de respuesta breve, el glaciar es de un gran interés para analizar la evolución y la variabilidad actuales del clima entre los trópicos. Se presentan los métodos de determinación del balance de masas y del balance hidrológico, con una frecuencia de mediciones mensual. Los resultados recogidos durante tres años (1991-1994) muestran una gran variabilidad. Esta es controlada sobre todo por la extensión del periodo de precipitaciones en medio de la temporada cálida que dura más o menos seis meses. Los eventos ENSO (El Niño Southern Oscillation ) son asociados a balances netamente negativos, lo que es demostrado por la respuesta del glaciar al episodio de 1991-1992 y por la reconstrucción de los balances efectuada con base en los datos hidrológicos durante los dos últimos decenios. El retroceso acelerado de los glaciares tropicales desde los años 1980 es vincunlado a la vez a una succesión de eventos ENSO y al recalentamiento atmosférico.Francou Bernard, Ribstein P. Glaciers et évolution climatique dans les Andes boliviennes - Glacier de Zongo et glacier de Chacaltaya, Cordillère Royale, 16°S. In: Bulletin de l'Institut Français d'Études Andines, tome 24, N°1, 1995. pp. 23-36
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Predicting glacio-hydrologic change in the headwaters of the Zongo River, Cordillera Real, Bolivia
No full textIn many partially glacierized watersheds glacier recession driven by a warming climate could lead to complex patterns of streamflow response over time, often marked with rapid increases followed by sharp declines, depending on initial glacier ice cover and rate of climate change. Capturing such “phases” of hydrologic response is critical in regions where communities rely on glacier meltwater, particularly during low flows. In this paper, we investigate glacio-hydrologic response in the headwaters of the Zongo River, Bolivia, under climate change using a distributed glacio-hydrological model over the period of 1987–2100. Model predictions are evaluated through comparisons with satellite-derived glacier extent estimates, glacier surface velocity, in situ glacier mass balance, surface energy flux, and stream discharge measurements. Historically (1987–2010) modeled glacier melt accounts for 27% of annual runoff, and 61% of dry season (JJA) runoff on average. During this period the relative glacier cover was observed to decline from 35 to 21% of the watershed. In the future, annual and dry season discharge is projected to decrease by 4% and 27% by midcentury and 25% and 57% by the end of the century, respectively, following the loss of 81% of the ice in the watershed. Modeled runoff patterns evolve through the interplay of positive and negative trends in glacier melt and increased evapotranspiration as the climate warms. Sensitivity analyses demonstrate that the selection of model surface energy balance parameters greatly influences the trajectory of hydrological change projected during the first half of the 21st century. These model results underscore the importance of coupled glacio-hydrology modeling.This is the publisher’s final pdf. The article is copyrighted by American Geophysical Union and published by John Wiley & Sons, Inc. It can be found at: http://sites.agu.org/The Modern Era Retrospective-analysis for Research and Applications (MERRA) reanalysis meteorological data can be downloaded from the Goddard Earth Sciences Data and Information Services Center (GES-DISC, http://disc.sci.gsfc.nasa.gov). Most of the glaciological and meteorological data measured in the watershed that were utilized in this study can be downloaded from the Glacioclim database (http://www-lgge.ujfgrenoble.fr/ServiceObs/). Nonpublic glaciological and meteorological data can be obtained with agreement from the Institute of Research for Development (IRD). The CMIP5 general circulation model output can be downloaded from the World Climate Research Program (WCRP, http://cmippcmdi.llnl.gov/cmip5/). The Landsat Thematic Mapper scenes can be downloaded from the United States Geological Survey (USGS, http://earthexplorer.usgs.gov/). All glacio-hydrological model data presented in this manuscript are available by request through the corresponding author ([email protected]). Surface energy balance observations were provided by Jean Emmanuel Sicart ([email protected])
A change project to promote conflict resolution in order to ensure sustainable development in Africa
No full textThe article describes the idea of a change project (a new course) in higher education. The aim of the change project is to promote traditional conflict resolution mechanisms and strategies in order to ensure sustainable development in Africa. The new program will combine the Sustainable Development Goals (SDGs) and various conflict resolution scenarios by applying the technique of design thinking. The program will involve discussions about types of conflicts in Africa, the real causes of these conflicts, mechanisms for peaceful conflict resolution (with special emphasis on the rakiré and the palaver tree) and design thinking. The author intends to implement the program at the Faculty of International Relations of the Ivan Franco National University in Lviv
Evolution récente des paramètres cryo-climatiques et des teneurs isotopiques des précipitations dans les Andes boliviennes : La Paz et Glacier du Zongo
No full textInternational audienceA proximité de La Paz, les indicateurs marquants de la tendance climatique sont a) une augmentation de la température de ré-analyse à 500 hPa de 0,017°C.an-1 entre 1973 et 2004, b) à la station météorologique Laïca Cota, entre 1995 et 2004, une élévation de la température de 0,03°C.an-1 , une diminution de l'humidité relative de 0,6 %.an-1 , c) une augmentation du δ 18 O des précipitations de 0,26 ‰.an-1 et de leur excès en deutérium de 0,1‰.an-1. Une des principales conséquences de cette tendance est un recul du front du glacier Zongo de 12 m.an-1 entre 1991 et 2004 (réduction de 2% par an des surfaces glaciaires de 1997 à 2004 :1,84 km 2 en 2004). L'analyse temporelle concomitante des données montre que la variabilité des conditions ENSO a des conséquences en phase à l'échelle infra-annuelle pour la température, l'humidité relative, la précipitation, le bilan glaciaire, et des conséquences en déphasage, sur des périodes dépassant l'année, pour le rapport isotopique des précipitations andines
Review of "Landlords and Lodgers: socio-spatial organisation in an Accra community" by D. Pellow
No full textDeborah Pellow has conducted fieldwork in the Ghanaian capital ofAccra since 1970. Landlords and Lodgers is the culmination of this research, focussing on the dominantly Muslim quarter of Sabon Zongo where the author commenced a long-term project in the early 1980s. The book contains previously published material, but Pellow’s synthesis of the data provides a more comprehensive analysis of the history, social politics and evolution of Sabon Zango’s vibrant urban space. In closely considering the genealogical foundations of the community, the book’s central aim is to describe the spatialisation of changing social relations over the past century and the ways in which cultural values and practices become manifest in the built environment
Analysis of Plasmodium falciparum diversity in natural infections by deep sequencing.
No full textMalaria elimination strategies require surveillance of the parasite population for genetic changes that demand a public health response, such as new forms of drug resistance. Here we describe methods for the large-scale analysis of genetic variation in Plasmodium falciparum by deep sequencing of parasite DNA obtained from the blood of patients with malaria, either directly or after short-term culture. Analysis of 86,158 exonic single nucleotide polymorphisms that passed genotyping quality control in 227 samples from Africa, Asia and Oceania provides genome-wide estimates of allele frequency distribution, population structure and linkage disequilibrium. By comparing the genetic diversity of individual infections with that of the local parasite population, we derive a metric of within-host diversity that is related to the level of inbreeding in the population. An open-access web application has been established for the exploration of regional differences in allele frequency and of highly differentiated loci in the P. falciparum genome
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