Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Desai, A. R.*; Wohlfahrt, G.*; Zeeman, M. J.*; Katata, Genki; Eugster, W.*; Montagnani, L.*; Gianelle, D.*; Mauder, M.*; Schmid, H. P.*
Environmental Research Letters, 11(2), p.024013_1 - 024013_9, 2016/02
Times Cited Count：21 Percentile：58.47(Environmental Sciences)Regional ecosystem productivity is highly sensitive to inter-annual climate variability, both within and outside the primary carbon uptake period. However, Earth system models lack sufficient spatial scales and ecosystem processes to resolve how these processes may change in a warming climate. Here, we show, how for the European Alps, mid-latitude Atlantic ocean winter circulation anomalies drive high-altitude summer forest and grassland productivity, through feedbacks among orographic wind circulation patterns, snowfall, winter and spring temperatures, and vegetation activity. Therefore, to understand future global climate change influence to regional ecosystem productivity, Earth systems models need to focus on improvements towards topographic downscaling of changes in regional atmospheric circulation patterns and to lagged responses in vegetation dynamics to non-growing season climate anomalies.
Cs transport and accumulation in the Ogaki Dam of eastern FukushimaYamada, Susumu; Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masaaki; Malins, A.; Machida, Masahiko
Environmental Research Letters, 10(1), p.014013_1 - 014013_9, 2015/01
Times Cited Count：24 Percentile：59.22(Environmental Sciences)The Ogaki Dam Reservoir is one of the principal irrigation dam reservoirs in the Fukushima Prefecture and its upstream river basin was heavily contaminated by radioactivity from the Fukushima Daiichi Nuclear Power Plant accident. For the purpose of environmental assessment, it is important to determine the present condition of the water in the reservoir and to understand the behavior of sediment-sorbed radioactive cesium under different modes of operation of the dam. This paper addresses this issue with numerical simulations of fluvial processes in the reservoir using the 2D simulation code Nays2D. We present results for sediment deposition on the reservoir bed and the discharge via the dam under typical yearly flood conditions. The simulations show that almost all the sand and silt that enter into the reservoir deposit onto the reservoir bed. However, the locations where they tend to deposit differ, with sand tending to deposit close to the entrance of the reservoir, whereas silt deposits throughout the reservoir. Both sand and silt settle within a few hours of entering the reservoir. In contrast, clay remains suspended in the reservoir water for a period as long as several days, thus increasing the amount that is discharged downstream from the reservoir. Under the current operating mode of the dam, about three-quarters of clay that enters the reservoir during the flood is discharged downstream. By raising the height of the dam exit, the amount of clay exiting the reservoir can be reduced by a factor of three. The results indicate that the dam can be operated to buffer radioactive cesium and limit the contamination spreading into lowland areas of the Ukedo River basin. These results should be a factor in considerations for the future operation of the Ogaki Dam, and will be of interest for other operators of dam reservoirs in areas contaminated by radioactive fallout.
