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Jean-Denis Taupin Gaëlle Gaultier Guillaume Favreau Christian Leduc Christelle Marlin 《Comptes Rendus Geoscience》2002,334(1):43-50
The isotopic content of rainfall was measured in Niamey (Niger) over a period of eight years (1992–1999). Seasonal distribution of rainy events depends on the monsoon movement over the region. At the beginning and at the end of the rainy season, low rainfall, high temperatures and low relative humidity favour isotopic enrichment. In the middle of the rainy season, heavy rainfall, low temperatures and relative humidity close to saturation lead to isotopically depleted contents because of the mass effect; moreover, in the case of low rainfall, marked vertical convective development favours high altitude condensation. How far the Intertropical Front moves north, determines the quality of the rainy season and influences the isotopic contents. Thus the isotopic contents of rainfall are good climatic indicators. To cite this article: J.-D. Taupin et al., C. R. Geoscience 334 (2002) 43–50 相似文献
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Jean-Denis Taupin 《Comptes Rendus Geoscience》2003,335(2):215-225
Many earlier studies have shown the very large spatial variability of rainfall in the Sahel at all time steps, from the event to the season. Often, the meteorological network in these countries is sparse, with one to five rain gauges per 10 000 km2. It is thus difficult to calculate accurate estimates of the mean rainfall over such a large area. To improve the knowledge of Sahelian systems and the spatial distribution of rainfall, a dense network was set up in an area of 16 000 km2 in southwestern Niger between 1991 and 1996. The aim was to calculate accurate rainfall spatial means over an area of 12 000 km2 at different time steps (from the season to the ten-day period). With the spatialisation method used (kriging), it was possible to calculate curves of estimation errors of mean rainfall versus the rain-gauge network density. Operational abacuses of the standard estimation error as a function of the spatial mean of rainfall and the network density are proposed. 相似文献
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Résumé A proximité de La Paz, Bolivie, 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 et une diminution de l'humidité relative de 0.6 % an-1; et (c) une augmentation du δ18O 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 km2 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. 相似文献
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Carla Manciati Marcos Villacís Jean-Denis Taupin Eric Cadier Remigio Galárraga-Sánchez Bolívar Cáceres 《水文科学杂志》2013,58(8):1519-1535
AbstractMost Latin American glaciers are located in the tropical Andes. The melting processes of Glacier “15” on Antisana volcano were studied to understand the relationship between glacier retreat and natural climate variability and global climate change. Glaciers on the Antisana volcano are crucial sources of water as they feed the headwater rivers that supply Quito with potable water. The aim of this study was to build empirical models based on multiple correlations to reconstruct the mass loss of glaciers over a period of 10 years at three scales: local (data recorded by meteorological stations located around the volcano), regional (data from stations located around the country) and global (re-analysis data). Data quality was checked using graphical and statistical methods. Several empirical models based on multiple correlations were created to generate longer time series (42 and 115 years) of the mass balance for the glacier ablation zone. The long mass balance series were compared with the temperature variation series of the Earth’s surface in the Southern Hemisphere to estimate the relation between the mass balance and global warming. Our results suggest that the meteorological factors that best correlate with mass balance are temperature and wind.
Editor D. Koutsoyiannis 相似文献
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Estimate of recharge of a rising water table in semiarid Niger from 3H and 14C modeling 总被引：1，自引：0，他引：1
Favreau G Leduc C Marlin C Dray M Taupin JD Massault M Le G Babic M 《Ground water》2002,40(2):144-151
A hydrodynamic survey carried out in semiarid southwest Niger revealed an increase in the unconfined ground water reserves of approximately 10% over the last 50 years due to the clearing of native vegetation. Isotopic samplings (3H, 18O, 2H for water and 14C, 13C for the dissolved inorganic carbon) were performed on about 3500 km2 of this silty aquifer to characterize recharge. Stable isotope analyses confirmed the indirect recharge process that had already been shown by hydrodynamic surveys and suggested the tracers are exclusively of atmospheric origin. An analytical model that takes into account the long-term rise in the water table was used to interpret 3H and 14C contents in ground water. The natural, preclearing median annual renewal rate (i.e., recharge as a fraction of the saturated aquifer volume) lies between 0.04% and 0.06%. For representative characteristics of the aquifer (30 m of saturated thickness, porosity between 10% and 25%), this implies a recharge of between 1 and 5 mm/year, which is much lower than the estimates of 20 to 50 mm/year for recent years, obtained using hydrological and hydrodynamic methods and the same aquifer parameters. Our study, therefore, reveals that land clearing in semiarid Niger increased ground water recharge by about one order of magnitude. 相似文献
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