Les techniques paradoxales ou l’inefficacité technique voulue

RésuméL’étude de la monte en amazone et de la marche en chaussures à talons hauts a mis au jour des techniques singulières : les techniques paradoxales. Ces dernières, réservées à certaines catégories de personnes (femmes presque toujours, lettrés, groupes ethniques…), se caractérisent par une inefficacité connue de la société concernée alors que, pour le même but, coexiste une technique à l’efficacité éprouvée. Ces techniques présentent en outre la particularité de posséder des fonctions latentes qui contrarient à divers degrés leurs fonctions manifestes. Monstrueuses à plus d’un titre, les techniques paradoxales, plus encore que par leur inefficacité pratique, se signalent par une efficacité sociale qui s’appuie précisément sur leur caractère limitant : ce caractère est valorisé et accentué aux limites du possible, jusqu’à ce qu’une modification des mentalités et/ou de la structure sociale vienne parfois bouleverser leur reproduction.AbstractThe study of sidesaddle-riding in Amazonia and walking in high heels sheds light on a special category : paradoxical techniques. Reserved for certain categories (nearly always women, men of letters, ethnic groups), these techniques are characterized by their ineffectiveness, which the society widely recognizes since other techniques exist with a proven effectiveness for the same purpose. Paradoxical techniques also have latent functions that, to various degrees, hamper the obvious ones. Monstrous in more than one regard, these techniques, beyond their practical ineffectiveness, stand out owing to a social effectiveness based on the limitations inherent in them. This characteristic is valued and stressed up to the limits of what is possible, until a shift in mentalities and/or in the social structure affects the reproduction of these techniques

On North Pacific Multidecadal Cllimate Variability

The multidecadal climate variability in the North Pacific region is investigated by using a 2000-yr-long integration with a coupled ocean–atmosphere general circulation model. It is shown that the multidecadal variability evolves largely independent of the variations in the tropical Pacific, so that this kind of multidecadal variability may be regarded as internal to the North Pacific. The coupled model results suggest that the multidecadal variability can be explained by the dynamical ocean response to stochastic wind stress forcing. Superimposed on the red background variability, a multidecadal mode with a period of about 40 yr is simulated by the coupled model. This mode can be understood through the concept of spatial resonance between the ocean and the atmosphere

Low-frequency climate variability in the Atlantic basin during the 20th century

From joint sea surface temperature/sea level pressure (SST/SLP) EOF analyses, lowfrequency variability modes are compared. The multi-decadal oscillation (MDO) changed phases twice during the 20th century, with its north Atlantic SST patterns resembling the Atlantic multi-decadal oscillation (AMO). The quasi-decadal oscillation (QDO) SST patterns displayed a double tripole configuration over the entire Atlantic basin, leading to tropical inter-hemispheric out-of-phase relationship. From the mid-1960s onward, while ST anomalies were negative to the north (negative phases of MDO/AMO), the Sahelian drought persisted with a weaker hurricane power dissipation index (PDI). During that period, the QDO modulated the intensity of the Sahelian drought

Rainfall variability at decadal and longer time scales: signal or noise?

Rainfall variability occurs over a wide range of temporal scales. Knowledge and understanding of such variability can lead to improved risk management practices in agricultural and other industries. Analyses of temporal patterns in 100 yr of observed monthly global sea surface temperature and sea level pressure data show that the single most important cause of explainable, terrestrial rainfall variability resides within the El Nino-Southern Oscillation (ENSO) frequency domain (2.5-8.0 yr), followed by a slightly weaker but highly significant decadal signal (9-13 yr), with some evidence of lesser but significant rainfall variability at interclecadal time scales (15-18 yr). Most of the rainfall variability significantly linked to frequencies tower than ENSO occurs in the Australasian region, with smaller effects in North and South America, central and southern Africa, and western Europe. While low-frequency (LF) signals at a decadal frequency are dominant, the variability evident was ENSO-like in all the frequency domains considered. The extent to which such LF variability is (i) predictable and (ii) either part of the overall ENSO variability or caused by independent processes remains an as yet unanswered question. Further progress can only be made through mechanistic studies using a variety of models

Interannual variability of the Tropical Atlantic independent of and associated with ENSO: Part II. The South Tropical Atlantic

Two dominant ocean-atmosphere modes of variability on interannual timescales were defined in Part I of this work, namely, the North Tropical Atlantic (NTA) and South Tropical Atlantic (STA) modes. In this paper we focus on the STA mode that covers the equatorial and sub-tropical South Atlantic. We show that STA events occurring in conjunction with ENSO have a preference for the southern summer season and seem to be forced by an atmospheric wave train emanating from the central tropical Pacific and travelling via South America, in addition to the more direct ENSO-induced change in the Walker circulation. They are lagged by one season from the peak of ENSO. These events show little evidence for other-than-localised coupled ocean-atmosphere interaction. In contrast, STA events occurring in the absence of ENSO favour the southern winter season. They appear to be triggered by a Southern Hemisphere wave train emanating from the Pacific sector, and then exhibit features of a self-sustaining climate mode in the tropical Atlantic. The southward shift of the inter tropical convergence zone that occurs during the warm phase of such an event triggers an extra tropical wave train that propagates downstream in the Southern Hemisphere. We present a unified view of the NTA and STA modes through our observational analysis of the interannnual tropical Atlantic variability