Régionalisation des précipitations sur les massifs montagneux français à l’aide de régressions locales et par types de temps

Gottardi, Frédéric; Obled, Charles; Gailhard, Joël; Paquet, Emmanuel

doi:10.4267/climatologie.647

Cited by 15 publications

(17 citation statements)

References 8 publications

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“…In addition, we used the same multiplication factor for winter and summer precipitation, ignoring the phase of the precipitation. The correction factor could be different and closer to that for liquid precipitation (Gottardi, 2009). Nonetheless, the rain heat flux is known to be of minor importance for the total SEB on glaciers in the Alps (Hock, 2005).…”

Section: Discussionmentioning

confidence: 91%

“…The mean multiplication factor is found to be 1.64 over the whole glacier. For comparison, Gerbaux and others (2005) found a factor of 1.5 for the whole glacier and Gottardi (2009) found a value of 1.6 for solid precipitation in this massif. The precipitation correction factor takes into account the difference of scale (glacier vs massif) and the high-altitude effects on the precipitation field estimates.…”

Section: Study Site and Datamentioning

confidence: 84%

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Variational assimilation of albedo in a snowpack model and reconstruction of the spatial mass-balance distribution of an alpine glacier

et al. 2012

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ABSTRACT. Accurate knowledge of the spatial distribution of the mass balance of temperate glaciers is essential for a better understanding of the physical processes controlling the mass balance and for the monitoring of water resources. In relation to albedo variations, the shortwave radiation budget is a controlling variable of the surface energy balance of glaciers. Remotely sensed albedo observations are here assimilated in a snowpack model to improve the modeling of the spatial distribution of the glacier mass balance. The albedo observations are integrated in the snowpack simulation using a variational data assimilation scheme that modifies the surface grain conditions. The study shows that mesoscale meteorological variables and MODIS-derived albedo maps can be used to obtain a good reconstruction of the annual mass balance on Glacier de Saint-Sorlin, French Alps, on a 100 m × ×100 m grid. Five hydrological years within the 2000-10 decade are tested. The accuracy of the method is estimated from comparison with field measurements. Sensitivity to roughness lengths and winter precipitation fields is investigated. Results demonstrate the potential contribution of remote-sensing data and variational data assimilation to further improve the understanding and monitoring of the mass balance of snowpacks and temperate glaciers.

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Section: Discussionmentioning

confidence: 91%

Section: Study Site and Datamentioning

confidence: 84%

Variational assimilation of albedo in a snowpack model and reconstruction of the spatial mass-balance distribution of an alpine glacier

et al. 2012

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“…The Euclidean distance is applied using a weight Ω for elevation:

\sqrt{\sum Δ x_{1}^{2} + Δ x_{2}^{2} + {(Ω . Δ x_{3})}^{2}}

. For instance, a weight Ω = 20 is used for precipitation in Gottardi et al [, ].…”

Section: Methodsmentioning

confidence: 99%

Decreasing spatial dependence in extreme snowfall in the French Alps since 1958 under climate change

et al. 2016

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Whereas changes in magnitude of geophysical extremes under climate change have received significant attention, potential concomitant changes in spatial dependence structures have remained unexplored so far. Here we provide first evidence of such an effect, highlighting a significant trend in the spatial dependence structure of snowfall extremes in the French Alps at decadal time scale. Specifically, we process a comprehensive data set of winter maximum snowfall from all over the French Alps collected in 90 stations from 1958 to 2012. We estimate extremal dependence over 20 year moving estimation windows taking into account possible anisotropy potentially related to orographic effects and/or patterns in atmospheric flows. For each window, we derive a range representing the distance above which extremes are almost independent. We show that snowfall extremes tended to become less spatially dependent over time, with the dependence range reduced roughly by half during the study period. We demonstrate the connection between this trend and local and synoptic climatic variables associated with the current climate change context. In details, the decreasing pattern in extremal dependence is concomitant with a trend toward less harsh winter conditions. It is attributable at first to the increase in temperature and its major control on the snow/rain partitioning. Yet a magnitude effect, with less dependent extremes due to a decrease in intensity of precipitation, also exists. Finally, we show that our results are largely insensitive to the minimal modeling assumptions necessary to our data‐based approach. This robustness makes it potentially suitable for various other studies in the field of geophysical extremes.

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“…On average, the multiplication factors used for the SAFRAN precipitation adjustment are 1.3 for Arveyron d'Argentière and 1.4 for Arveyron de la Mer de Glace. For comparison, these values are slightly lower than those quantified by Gerbaux and others (2005) (1.5) for the Argentière and Saint-Sorlin glaciers, Gottardi (2009) (1.6) for solid precipitation on the French Alps and Dumont and others (2012) (1.64) for the Saint-Sorlin glacier. It should be noted that the values for this factor depend on the calibration period and the site considered.…”

Section: Resultsmentioning

confidence: 50%

Glacier-wide summer surface mass-balance calculation: hydrological balance applied to the Argentière and Mer de Glace drainage basins (Mont Blanc)

et al. 2018

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We present the glacier-wide summer surface mass balances determined by a detailed hydrological balance (sSMBhydro) and the quantification of the uncertainties of the calculations on the Argentière and Mer de Glace-Leschaux drainage basins, located in the upper Arve watershed (French Alps), over the period 1996–2004. The spatial distribution of precipitation within the study area was adjusted using in situ winter mass-balance measurements. The sSMBhydro performance was assessed via a comparison with the summer surface mass balances based on in situ glaciological observations (sSMBglacio). Our results show that the sSMBhydro has an uncertainty of ± 0.67 m w.e. a−1 at Argentière and ± 0.66 m w.e. a−1 at Mer de Glace-Leschaux. Estimates of the Argentière sSMBhydro values are in good agreement with the sSMBglacio values. These time series show almost the same interannual variability. From the marked difference between the sSMBhydro and sSMBglacio values for the Mer de Glace-Leschaux glacier, we suspect a significant role of groundwater fluxes in the hydrological balance. This study underlines the importance of taking into account the groundwater transfers to represent and predict the hydro-glaciological behaviour of a catchment.

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Régionalisation des précipitations sur les massifs montagneux français à l’aide de régressions locales et par types de temps

Cited by 15 publications

References 8 publications

Variational assimilation of albedo in a snowpack model and reconstruction of the spatial mass-balance distribution of an alpine glacier

Variational assimilation of albedo in a snowpack model and reconstruction of the spatial mass-balance distribution of an alpine glacier

Decreasing spatial dependence in extreme snowfall in the French Alps since 1958 under climate change

Glacier-wide summer surface mass-balance calculation: hydrological balance applied to the Argentière and Mer de Glace drainage basins (Mont Blanc)

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