A workshop was held at the University of the West Indies, Jamaica, in May 2012 to build capacity in climate data rescue and to enhance knowledge about climate change in the Caribbean region. Scientists brought their daily observational surface temperature and precipitation data from weather stations for an assessment of quality and homogeneity and for the calculation of climate indices helpful for studying climate change in their region. This study presents the trends in daily and extreme temperature and precipitation indices in the Caribbean region for records spanning the 1961-2010 and 1986-2010 intervals. Overall, the results show a warming of the surface air temperature at land stations. In general, the indices based on minimum temperature show stronger warming trends than indices calculated from maximum temperature. The frequency of warm days, warm nights and extreme high temperatures has increased while fewer cool days, cool nights and extreme low temperatures were found for both periods. Changes in precipitation indices are less consistent and the trends are generally weak. Small positive trends were found in annual total precipitation, daily intensity, maximum number of consecutive dry days and heavy rainfall events particularly during the period 1986-2010. Correlations between indices and the Atlantic multidecadal oscillation (AMO) index suggest that temperature variability and, to a lesser extent, precipitation extremes are related to the AMO signal of the North Atlantic surface sea temperatures: stronger associations are found in August and September for the temperature indices and in June and October for some of the precipitation indices.

The snow avalanche is one of the major processes that shapes the landscape of high mountains. A significant manifestation of its activity is changing the course of the timberline, whose course and growth disturbances constitute a good source of information about the history of avalanche activity. The aim of this study was to: i) detail the temporal and spatial reconstruction of snow avalanche events within the three surveyed couloirs in the Rybi Potok Valley, in the High Tatras, ii) analyse of the relationship between the relief of the runout zone and the course of the avalanches. Dendrogeomorphological, geomorphological and cartographic methods were employed here. Detailed geomorphological maps comprising the runout zone were prepared and use to divide the runout zone into subzones of similar relief. The dendrogeomorphological reconstructions of avalanche events were carried out on two scales, i.e. for the entire runout zone and for the determined subzones. The courses of major avalanche events in the studied couloirs over the past 100 years were reconstructed. A detailed dendrogeomorphological analysis in the subzones allowed the identification of additional local avalanche events whose extent had not covered the entire avalanche path.

No abstract

Principal component analysis was used to define patterns in water table hydrographs at four small, lake‐watershed research sites in the United States. The analysis provided insights into (1) characteristics of ground water recharge in different parts of the watersheds; (2) the effect of seepage from lakes on water table fluctuations; and (3) the effect of differences in geologic properties on water table fluctuations. At two sites where all of the water table wells were completed in permeable deposits, glacial out‐wash in Minnesota and dune sand in Nebraska, the patterns of water table fluctuation primarily reflected timing and magnitude of recharge. The water table had more frequent and wider ranges in fluctuations where it was shallow compared with where it was deep. At two sites where the water table wells were completed in sand or till, a glaciated mountain valley in New Hampshire and stagnation moraine in North Dakota, the patterns of water table fluctuations were strongly related to the type of geologic unit in which the wells are completed. Furthermore, at the New Hampshire site, the patterns of water table fluctuations were clearly different for wells completed in sand downgradient of a lake compared with those completed in sandy terraces on a mountain‐side. The study indicates that principal component analysis would be particularly useful for summarizing large data sets for the purpose of selecting index wells for long‐term monitoring, which would greatly reduce the cost of monitoring programs.