ALBERT

Description: Snow is an important component of the Earth's climate system and is particularly vulnerable to global warming. It has been suggested that warmer temperatures may cause significant declines in snow water content and snow cover duration. In this study, snowfall and snowmelt were projected by means of a regional climate model that was coupled to a physically based snow model over Shasta Dam watershed (SDW) to assess changes in snow water content and snow cover duration during the 21 st century. This physically based snow model requires both physical data and future climate projections. These physical data include topography, soils, vegetation, and land use/land cover which were collected from associated organizations. The future climate projections were dynamically-downscaled by means of the regional climate model under four emission scenarios simulated by two general circulation models (GCMs) (ECHAM5 and CCSM3). The downscaled future projections were bias-corrected before projecting snowfall and snowmelt processes over SDW during 2010-2099. This study's results agree with those of previous studies, that projected snow water equivalent (SWE) is decreasing by 50 - 80% while the fraction of precipitation falling as snowfall is decreasing by 15 % to 20 %. The obtained projection results show that future snow water content will change both in time and space. Furthermore, the results confirm that physical data such as topography, land cover and atmospheric-hydrologic data, are instrumental in the studies on the impact of climate change on the water resources of a region.

Description: A methodology based on long-term dynamical downscaling to analyse climate change effects on watershed-scale precipitation during a historical period is proposed in this study. The reliability and applicability of the methodology were investigated based on the long-term dynamical downscaling results. For an application of the proposed methodology, two study watersheds in Northern California were selected: the Upper Feather River watershed and the Yuba River watershed. Then, precipitation was reconstructed at 3-km spatial resolution and hourly intervals over the study watersheds for 141 water years from 1 October 1871 to 30 September 2012 by dynamically downscaling a long-term atmospheric reanalysis dataset, 20th century global reanalysis version 2 by means of a regional climate model. The reconstructed precipitation was compared against observed precipitation, in order to assess the applicability of the proposed methodology for the reconstruction of watershed-scale precipitation and to validate this methodology. The validation shows that the reconstructed precipitation is in good agreement with observation data. Moreover, the differences between the reconstructed precipitation and the corresponding observations do not significantly change through the historical period. After the validation, climate change analysis was conducted based on the reconstructed precipitation. Through this analysis, it was found that basin-average precipitation has increased significantly over both of the study watersheds during the historical period. An upward trend in monthly basin-average precipitation is not significant in wet months except February while it is significant in dry months of the year. Furthermore, peak values of basin-average precipitation are also on an upward trend over the study watersheds. The upward trend in peak basin-average precipitation is more significant during a shorter duration. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Description: We present the results of the quasi-static cyclic tensile tests of Cu-Al-Mn shape memory alloy (SMA) bars of 4 and 8 mm diameters to examine their superelasticity and other mechanical properties closely related to seismic applications. The present Cu-Al-Mn SMA bars have achieved the recovery strains of over 8% and the fracture strains of over 17%. Low-cycle fatigue was observed in neither of the bars. The mechanical properties obtained from the test, along with the lower material cost and higher machinability than Ni-Ti SMAs, demonstrate the high potential of the present Cu-Al-Mn SMA bars to be used in seismic applications. © 2010 John Wiley & Sons, Ltd.