Estimation of probable maximum flood (PMF) is a crucial process in water resources management and in the design of large hydraulic structures. However, there are uncertainties in the estimation of ...hydrologic conditions that contribute to extreme floods. In particular, this is the case in snow‐dominated regions, as surface air temperature and wind speed are understood to have a substantial effect on the magnitude of a flood during a storm event. Motivated by the development of a new approach to investigate and estimate reliable PMF values and in an attempt to resolve the uncertainty issues, this study introduces a physically based modeling approach. For the case study, seven watersheds located in the Sierra‐Nevada mountain range of California, including Cosumnes, Mokelumne, Stanislaus, Tuolumne, Merced, Upper San Joaquin, and Upper Kings were selected. The hydroclimate model was first implemented over the physical boundaries of the study region, and then utilized to simulate possible maximum flood conditions with input from 10 extreme precipitation scenarios. The study results provide evidence of a nonlinear atmospheric–hydrologic system; the extreme 72‐h basin‐averaged precipitation depth was found not to be linearly proportional to 72‐h flow volume equivalent depth. It can also be concluded that a large precipitation depth may not be the sole reason for a large flood event. Temperature and other atmospheric variables also contribute significantly to the production of snowfall and liquid water available for runoff, and to the resulting hydrologic response, such as the flood peak discharge and volume.
It is now widely recognized that climate change affects multiple sectors in virtually every part of the world. Impacts on one sector may influence other sectors, including seemingly remote ones, ...which we call “interconnections of climate risks.” While a substantial number of climate risks are identified in the Intergovernmental Panel on Climate Change Fifth Assessment Report, there have been few attempts to explore the interconnections between them in a comprehensive way. To fill this gap, we developed a methodology for visualizing climate risks and their interconnections based on a literature survey. Our visualizations highlight the need to address climate risk interconnections in impact and vulnerability studies. Our risk maps and flowcharts show how changes in climate impact natural and socioeconomic systems, ultimately affecting human security, health, and well‐being. We tested our visualization approach with potential users and identified likely benefits and issues. Our methodology can be used as a communication tool to inform decision makers, stakeholders, and the general public of the cascading risks that can be triggered by climate change.
Plain Language Summary
The paper demonstrates in a most holistic manner how climate change can generate various risks and how they are actually interconnected. Based on a literature survey using the Intergovernmental Panel on Climate Change Fifth Assessment Report, we identified 91 climate risks and 253 causal relationships among them and graphically drew such interconnected risks. We found that changes in the climate system impact the natural and socioeconomic system, influencing ultimately human security, health, and well‐being. This indicates that climate change can trigger a cascade of impacts across sectors. Our findings point to the need to address the climate risk interconnections in impact and vulnerability studies. We tested our visualization approach with potential users and identified likely benefits and issues. The implications of our study go beyond science. Our study is useful to inform stakeholders of a broad yet fresh perspective of climate risks that have not been presented before.
Key Points
The paper developed a methodology for visualizing how climate change can generate various risks and how they can be interconnected
We identified 91 climate risks and 253 causal relationships among them based on a literature survey and graphically presented the interconnected risks
We found that changes in the climate system impact natural and socioeconomic systems, ultimately influencing human security, health, and well‐being
Field observations were conducted with respect to the vertical migration of the dinoflagellate Peridinium bipes and its influence on vertical nutrient transport in a stratified reservoir. P. bipes ...migrated vertically with circadian rhythms; that is, P. bipes migrated downward and accumulated in the top layer of the hypolimnion from evening to night and then migrated upward and accumulated in the epilimnion in the early morning. In the top layer of the hypolimnion, a rapid decrease in nutrient concentration was observed in the evening, presumably due to uptake by P. bipes. Active migration from the epilimnion to the top of the hypolimnion was also suggested by estimation of the descent velocity of P. bipes, which was advantageous for the uptake of nutrients. Moreover, based on the equilibrium of forces during migration, the energy cost of vertical migration could be inferred to be negligible. The results suggest that active vertical migration of P. bipes played an important role in nutrient transport between the hypolimnion and the epilimnion in a stratified reservoir.
A Ge/SiGe coupled quantum well (CQW) for optical modulators based on phase modulation has been proposed and studied theoretically. First we analyze quantized energies and wavefunctions of electrons ...and holes, and valence band dispersions for holes by solving the Schrödinger equation using the propagation matrix method and the
k
·
p
perturbation theory with the 4×4 Luttinger–Kohn Hamiltonian. The Ge/SiGe CQW is expected to exhibit unique quantum-confined Stark effect (QCSE) and polarization-independent large electrorefractive index change in transparent wavelength range. In addition, we calculated the driving voltage of a phase modulator with the multiple Ge/SiGe CQW. The product of a half-wave voltage and a phase shifter length
V
π
L
p is estimated to be about 0.31
V
cm. The proposed CQW structure is a promising candidate for Si-based optoelectronic devices such as the Mach–Zehnder interferometer optical modulators and switches.
► We propose a novel Ge/SiGe coupled quantum well for optical modulators and switches. ► Its electrorefractive index change is analyzed using the
k
·
p
perturbation theory. ► It will exhibit a large refractive index change in 1.55
μm wavelength region. ► The structure is promising for low-voltage optical devices based on phase modulation.
The storage-discharge relations have been widely used for water resource management and have led to reliable estimation of the impact of climate change on water resources. In a previous study, we ...carried out a sensitivity analysis of the parameters in a discharge-storage relation in the form of a power function and found that the optimum parameters can be characterized by an exponential function (Fujimura et al., 2014). The aim of this study is to extend the previous study to clarify the properties of the parameters in the storage–discharge relations by carrying out a sensitivity analysis of efficiency using a hydrological model. The study basins are four mountainous basins in Japan with different climates and geologies. The results confirm that the two parameters in the storage–discharge relations can be expressed in an inversely proportional relationship. In addition, we can conveniently assume a practical function for the storage–discharge relations where only one parameter is used on the basis of the new relationship between the two parameters.
Accurate estimation of the low-flow discharge is very important in evaluating the impact of climate change on water resources. This study focuses on the storage–discharge equation and the optimal ...parameters of the low flow. In order to investigate the sensitivity of the two parameters in the process of the calculation of low flow, we prepared 19 900 sets of the two parameters in the storage–discharge equation and carried out hydrological analysis using the hourly hydrological model presented by Fujimura et al. (2012). The study basins are the Sameura Dam basin (SAME basin) located in western Japan which has variability of rainfall, and the Shirakawa Dam basin (SIRA basin) located in a region of heavy snowfall in eastern Japan. The period of available hydrological data is 20 years for the SAME basin and 10 years for the SIRA basin. The results suggest that the optimal combination of two parameters can be identified by exponential equations. This study also estimates the annual water balance for the two basins based on hydrological analysis using the optimal parameters in the storage–discharge equation of low flow.
Status of breakup reaction theory Ogata, K; Matsumoto, T; Hashimoto, S ...
Journal of physics. Conference series,
09/2011, Letnik:
312, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Recent studies on breakup reactions with the continuum-discretized coupled-channels method are reviewed. The topics covered are: four-body breakup processes for 6He induced reaction, dynamical ...relativistic effects on Coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple-α reaction rate) and new approach to inclusive breakup processes.
The vector analyzing power has been measured for the elastic scattering of neutron-rich
6
He from polarized protons at 71 MeV/nucleon. Two approaches based on local one-body potentials were applied ...to investigate the spin-orbit interaction between a proton and a
6
He nucleus. An optical model analysis revealed that the spin-orbit potential for
6
He is characterized by a shallow and long-ranged shape compared with the global systematics of stable nuclei. A semi-microscopic analysis with a α +
n
+
n
cluster folding model suggests that the inclusion of realistic interaction between a proton and the α core is important in describing the
p
-
6
He elastic scattering.
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