Search results for "Fall"
showing 10 items of 964 documents
Intraseasonal descriptors and rainfall extremes in austral summer over South Africa : Observations and Meso-scale modelling
2022
Rainfall extremes are of major and increasing importance in semi-arid countries and their variability has strong implications for water resource and climate impacts on the local societies and environment. Here, we examine intraseasonal descriptors (ISDs) and wet extremes in austral summer rainfall (November−February) over South Africa (SA). Using daily observations from 225 rain gauges and ERA5 reanalysis between 1979 and 2015, we propose a novel typology of wet extreme events based on their spatial fraction, thus differentiating large- and small-scale extremes. Long-term variability of both types of extreme rainfall events is then extensively discussed in the context of ISDs. Following the…
Past and future spatio-temporal variability of rainfall of the Bani catchment in West Africa.
2011
6 pages; International audience; Since 1970, on the Bani, main tributary of the upper Niger, annual discharges have decreased by 69% while annual rainfall has decreased only by 15% to 25% over the catchment. Among the possible causes for this very strong discharge decrease changes of precipitation patterns must be explored. Four different methods of spatial interpolation of rainfall fields were compared on intra-seasonal indices (number of dry days, the dry spells, EDI, SPI, etc.) for the period 1950-2006. This study was also conducted on simulated pluviometric data generated by a regional climatic model (WRF) for the 2032-2041 period. The pluviometric deficit is explained by a conjunction …
Climats tropicaux d'aujourd'hui à demain : variabilité et changements
2008
Present and future tropical climates : their climate variability and their climate changes The oriffttality of tropical climates is re-examined under the light of climate variability and climate change, both present and future . The interannual variability of rainfall is on average larger in the tropics than in the extra-tropics, but it is also spatially more contrasted. Human communities have often responded to this constraint through efficient coping strategies. The regions showing the most variable climate do not necessarily have lower population densities, an indication that in the long run variability is not decisive. However, the recent demographic growth of these regions is often low…
Types de configurations pluviométriques sur le bassin méditerranéen, forçages atmosphériques et évènements intenses (1979-2013).
2015
Sixrecurrent and redundant daily rainfall patterns have been extracted over the Mediterranean area from 1979 to 2013: five areassociated to regionals rainfall excess (South-West Mediterranean, Mid-North Mediterranean, East Mediterranean, WestMediterranean and north-west Mediterranean) and one to generalized deficit. Each rainfall pattern is associated with atypical barometric spatial configuration leading to local wind bringing moisture to the coast leading to specific local rainfallsurplus. Rainfall patterns also explain a large part of the spatial characteristics and the probability of occurrence of intenseevents. For example, more than 20% of days of “West-Mediterranean” rainfall pattern…
Conditions atmosphériques associées aux chutes de grêles en Bourgogne.
2020
A network of 96 hail pads is installed in Burgundy since 2014. Hailfalls in this part of France are mainly recorded from Avril to September and usually at the end of the afternoon when the surface air has been warmed enough to trigger an upward lift. Atmospherically speaking, hailfalls in Burgundy are associated with southward winds blowing from the Mediterranean Sea (Gulf of Lions) according to a strong negative barometric anomaly centered over Germany and extended southwestward until the south of Spain. A weak northwestward wind is at the same time also blowing until the northern part of Burgundy creating a thermal air-mass conflict and therefore a convective available potential energy wh…
Étude climatique de la mousson vietnamienne et applications à la prévision saisonnière
2008
This thesis aims at documenting the physical and dynamic processes associated with the monsoon circulation of Vietnamese regional and synoptic scales, to explore the predictability of its key components and develop statistical and dynamical methods for forecasting the monsoon onset and seasonal. It is divided into two parts. The first part is, in fact, a climate study based on analysis of diagnostic data: - first, the monthly rainfall and temperature data station over the period 1960-2000 are used to analyze the cycle and the variability of these fields on the seven traditional climatic regions of Vietnam using the observed precipitation in various stations. Classifications and correlations…
Temporal evolution of heavy rainfall in the southern West Africa coastline belt.
2018
The Southern Coastalbelt of West Africa (SCWA) is exposed to recurrent flooding. The two objectives of the study are to show thespecificity of SCWA to heavy rainfall occurrence and to determine the trends of the latter. Daily rainfall data of41 stations in the southern parts of Côte d’Ivoire, Ghana, Togo and Benin for the period 1951–2015 and ClimateHazards Group InfraRed Precipitation data were used. The approach is based on the determination (for eachstation and grid point) of the 95th centile (P95) of precipitations greater than or equal to 1 mm. Results indicatethat rainfall is heavier on the coastal belt than inland (average P95 is 65,4 and 45,5 m/day for coastal and inlandstations res…
Psychomotor disadaptation syndrome
2020
Psychomotor disadaptation syndrome (PDS) was first described by the Geriatrics School of Dijon (France), three decades ago, under the name «psychomotor regression syndrome». Over time, the original clinical features remained unchanged. However, progress has been made in its pathophysiology understanding and care, hence the new name, PDS, appeared in the 1990s. The PDS is also called sub-cortico-frontal dysfunction syndrome since the 2000s. It corresponds to a decompensation of posture, gait and psychomotor automatisms, related to an alteration of the postural and motor programming, which is a consequence of sub-cortico-frontal lesions. The clinical features of PDS associate backward disequi…