Numerical Differentiation by Spline Functions and Its Application to Analyzing a Lake Temperature Observation

摘要

Numerical differentiation by use of classical interpolation formulas yields a diversity of results. Consistent numerical differentiation can be performed by using a spline function as an interpolating function. As an application, temperature observed in a lake is numerically differentiated as a function of time and of depth by use of cubic splines. The deviation of the actual heat transfer mechanism from vertical heat conduction can thus be detected. The reliability of numerical differentiation by spline functions is manifest in this example. (Author)