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Short-term variations in ice-flow velocity were obtained at intervals of a few hours and a few days in the ablation area of Glaciar Soler, Patagonia, Chile, in November 1985. A maximum flow rate was measured at about four times the minimum value. A good correlation, with a time lag of 7.5 h, was found between the ice-flow velocity in the lower reaches and the amount of water discharge from the glacier terminus. It was concluded, therefore, that the velocity variations should have resulted from the variations in basal sliding velocity which is strongly controlled by the subglacial water pressure.

The effect of the El Niño Southern Oscillation (ENSO) on rainfall characteristics in the tropical peatland areas of Central Kalimantan, Indonesia, is demonstrated. This research used rainfall data collected between 1978 and 2008. The results suggest a relationship between ENSO events and the trend in rainfall observed in the study area. Further analyses show that El Niño events have a stronger effect on the rainfall compared to La Niña events. El Niño events were also correlated to the increase in the number of days with less than 1 mm of rainfall in the dry season. The analysis reveals that the impact of El Niño events on rainfall in dry seasons is intensifying annually. Furthermore, ENSO events are not the only factors affecting rainfall trends in the observed area. Other factors, such as deforestation, may also affect the trend.Key words ENSO; rainfall characteristics; tropical peatland areas L'effet du phénomène ENSO sur les caractéristiques des précipitations dans les zones de tourbières tropicales du Kalimantan central (Indonésie) Résumé L'effet de l'oscillation australe El Niño (ENSO) sur les caractéristiques des précipitations dans les zones de tourbières tropicales du Kalimantan central, en Indonésie, est mis en évidence. Nous avons utilisé pour cette recherche des données pluviométriques recueillies entre 1978 et 2008. Les résultats suggèrent une relation entre les événements El Niño et la tendance des précipitations observées dans la zone d'étude. D'autres analyses montrent que le phénomène El Niño a un effet plus fort sur les précipitations qu'un évènement La Niña. Les événements El Niño ont également été corrélés avec l'augmentation du nombre de jours de moins de 1 mm de pluie pendant la saison sèche. L'analyse révèle que l'impact du phénomène El Niño sur les précipitations en saison sèche s'intensifie chaque année. En outre, les événements El Niño ne sont pas les seuls facteurs qui affectent les tendances pluviométriques dans la zone observée. D'autres facteurs, tels la déforestation, peuvent également influencer la tendance.

A device capable of measuring the extinction coefficient of solar radiation within the snow cover was developed, using small silicone photocells as sensors. Extinction coefficient measured for natural snow covers in the field was 37-97 m-1 for dry snow of density 90-470 kg m-3. It decreased in the process of metamorphism from new snow to slightly compacted snow, and increased in the process of settlement from slightly compacted to compacted snow. It was 23-58 m-1 for wet snow of density 430-530 kg m-3 and in water content from 5-15%, being smaller than that for dry snow of the same density. The authors also determined local temperature increase of snow cover related to absorption of solar radiation. The temperature profile within the snow cover was calculated by solving the equation of heat conduction including the term of absorption of radiative energy. Measured and calculated snow temperatures agreed well, indicating the accuracy of the extinction measurements.

This research aims to analyze the effect of canal damming on surface water level stability in the drainage canals in the peatland area of Central Kalimantan, Indonesia. The focus of this research is the investigation of surface water level in Kalampangan Canal and Taruna Canal, the two biggest canals on the peatland lying between Sebangau River and Kahayan River. Surface water levels in this research were measured using automatic gauges and loggers for 11 stations.Research results indicate that the surface water level in the dammed area (Lg2) has the most stable water level compared to the ones of other stations. Statistical analysis using box plot method stated that Lg2 has the lowest range of normal water level compared to other stations. The research results also showed that the water level of Lg2 in the canal has specific water system, which did not depend on the flow regime in the vicinity. Based on the analysis, the dams in the canal were able to retain water in the canal for a long period of time. The dams were able to maintain the water level in Lg2 at an elevation of about + 18.0 m in the condition without water supply or water loss to other areas.

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Short-term variations in ice-flow velocity were obtained at intervals of a few hours and a few days in the ablation area of Glaciar Soler, Patagonia, Chile, in November 1985. A maximum flow rate was measured at about four times the minimum value. A good correlation, with a time lag of 7.5 h, was found between the ice-flow velocity in the lower reaches and the amount of water discharge from the glacier terminus. It was concluded, therefore, that the velocity variations should have resulted from the variations in basal sliding velocity which is strongly controlled by the subglacial water pressure.