Mass-balance and dynamic measurements carried out on glacier de Saint Sorlin since 1957 provide a good opportunity to study the dynamics of this glacier. Ice-flow analysis shows that dynamic changes have been important over the last 40 years and that these changes are not consistent with the concepts usually used in glacier modelling. Present velocities are larger than the 1960 velocities, although the thickness decreased everywhere (10^30 m in the ablation zone). A simple numerical ice-flow model which does not include longitudinal stress gradients has been used to investigate these phenomena. This model allows us to infer the sliding velocity from observed surface and calculated deformation velocities. We conclude that: (1) the sliding velocity cannot be described by Weertman analysis or empirical relations which link the sliding to the thickness and surface slope; (2) the inferred sliding velocity is uniform over at least half of the glacier; and (3) there is no clear link between the sliding process and the quantity of water coming from surface ablation. Furthermore, it may not be reasonable to calibrate model flow parameters from geometry changes because the surface geometry is relatively insensitive to velocity changes over some decades.

The Laurichard active rock glacier is the permafrost‐related landform with the longest record of monitoring in France, including an annual geodetic survey, repeated geoelectrical campaigns from 1979 onwards and continuous recording of ground temperature since 2003. These data were used to examine changes in creep rates and internal structure from 1986 to 2006. The control that climatic variables exert on rock glacier kinematics was investigated over three time scales. Between the 1980s and the early 2000s, the main observed changes were a general increase in surface velocity and a decrease in internal resistivity. At a multi‐year scale, the high correlation between surface movement and snow thickness in the preceding December appears to confirm the importance of snow cover conditions in early winter through their influence on the ground thermal regime. A comparison of surface velocities, regional climatic datasets and ground sub‐surface temperatures over six years suggests a strong relation between rock glacier deformation and ground temperature, as well as a role for liquid water due to melt of thick snow cover. Finally, unusual surface lowering that accompanied peak velocities in 2004 may be due to a general thaw of the top of the permafrost, probably caused both by two successive snowy winters and by high energy inputs during the warm summer of 2003. Copyright © 2009 John Wiley & Sons, Ltd.

ABSTRACT. Glaciological exp eriments have b een carried out at D ome du GOLlter (4300 m a.s. !.), Mont Bl a nc, in order to understand the fl ow of Gm/ice in this high-altitude Alpin e glac ierized a rea. Acc umulatio n m easurements from stakes show a ve ry strong spati a l va ri ability a nd a n unusual feature of mass-bala nce fluctuations for th e Alps, i. e. th e snow acc umul a ti on d oes not show a ny seasona l p a ttern s. IVleas ured verti cal velocities w hich should m atch with long-term m ean mass bala nce a re consistent with observed a cc umul ation s. Th er efore, the meas urem ent of ve rti cal ve loc iti es seenl.S a good way of quickl y obtaining r elia bl e mea n acc umul ation values for seve ral decad es in such a region.A simple flo w model can be used to determine the m a in fl owlines o f the glacier and to propose snow/ice age of co re sampl es from th e two boreholes drill ed d o wn to the bedrock inJune 199+. Th ese res ults coincide with radioactivity m easurements m a de to identify th e well-know n radioac tive snow laye rs of 1963 and 1986. \Ve can hope to o btain ice samples 55-60 yea rs old a b o ut 20 or 30 m a b ove the bedrock (110 m dee p). Below, the deform ation o f the ice laye rs is too g reat to be dated acc urately.

ABSTRACT. Along the 1040 km extending from Cape Prud'homme (lat.66°4I'S., long.139°55'E.), near Dumont d'Urville station, to Dome C (lat. 74 °39 , S., long. 124 ° 10' E.), the variations in annual accumulation can be analysed by a division of the entire data set into three sub-sets depending on the types of measurements and the character of the spatial distribution. Along the first 33 km, from the coast to stake E40, annual measurements show considerable inter-annual variability, 52% of which can be explained by the spatio-temporal homogeneity of the balance distribution. However, we obtain a better result (64%) for the fluctuation homogeneity standardized using the standard deviation. This means that there is a strong space-time distribution structure, characterized by an equal variation of the balance around the mean value specific to each location. This is so in spite of the existence of considerable surface roughness (sastrugi), the influence of which should be reduced by averaging values around each stake. From stake E40 to stake R60, a distance of 170 km, the almost periodic oscillations in the accumulation with a wavelength close to 40 km can be explained by the formation of a gravityinertia wave, disturbing the geostrophic equilibrium, occurring at the break in slope 200 km from the coast. The very low values of accumulation for stakes D55 and D58S show that the oscillations were almost stationary during the study period (about 25 years). Finally, along the 840 km from stake R60 to Dome C we can observe a decrease in accumulation resulting from the decrease in mean temperature.