11,612 research outputs found
Bias correction methods for regional climate model simulations considering the distributional parametric uncertainty underlying the observations
Hydrological modelling under climate change considering nonstationarity and seasonal effects
Traditional hydrological modelling assumes that the catchment does not change with time. However, due to changes of climate and catchment conditions, this stationarity assumption may not be valid in the future. It is a challenge to make the hydrological model adaptive to the future climate and catchment conditions. In this study IHACRES, a conceptual rainfall–runoff model, is applied to a catchment in southwest England. Long observation data (1961–2008) are used and seasonal calibration (only the summer) has been done since there are significant seasonal rainfall patterns. Initially, the calibration is based on changing the model parameters with time by adapting the parameters using the step forward and backward selection schemes. However, in the validation, both models do not work well. The problem is that the regression with time is not reliable since the trend may not be in a monotonic linear relationship with time. Therefore, a new scheme is explored. Only one parameter is selected for adjustment while the other parameters are set as the fixed and the regression of one optimised parameter is made not only against time but climate condition. The result shows that this nonstationary model works well both in the calibration and validation periods.</jats:p
Internal Space-time Symmetries of Massive and Massless Particles and their Unification
It is noted that the internal space-time symmetries of relativistic particles
are dictated by Wigner's little groups. The symmetry of massive particles is
like the three-dimensional rotation group, while the symmetry of massless
particles is locally isomorphic to the two-dimensional Euclidean group. It is
noted also that, while the rotational degree of freedom for a massless particle
leads to its helicity, the two translational degrees of freedom correspond to
its gauge degrees of freedom. It is shown that the E(2)-like symmetry of of
massless particles can be obtained as an infinite-momentum and/or zero-mass
limit of the O(3)-like symmetry of massive particles. This mechanism is
illustrated in terms of a sphere elongating into a cylinder. In this way, the
helicity degree of freedom remains invariant under the Lorentz boost, but the
transverse rotational degrees of freedom become contracted into the gauge
degree of freedom.Comment: LaTex 14 pages, presented at the International Conference on
Supersymmetry and Quantum Field Theory, in commemoration of Dmitri Volkov's
75th Birthday, Kharkov, Ukraine, 2000; to be published in the proceeding
Intercomparison of joint bias correction methods for precipitation and flow from a hydrological perspective
Bias correction of daily precipitation over South Korea from the Long-Term Reanalysis using a Composite Gamma-Pareto Distribution Approach
Exploration of Daily Rainfall Intensity Change in South Korea 1900–2010 Using Bias-Corrected ERA-20C
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