Finite difference method Numerical methods 15 Nonlinear equations 7 Partial differential equations 7 Iterative methods 5 Approximation equations 4 Discrete elements method 4 Implicit finite-difference schemes 4 Numerical experiments 4 Remote sensing 4 Backscattering 3 Boundary conditions 3 Boundary layer flow 3 Continuous wave radar 3 Doppler effect 3 Doppler frequency 3 Drying 3 FMCW radar 3 Finite difference approximations 3 Finite element method 3 Frequency modulation 3 Frequency-modulated-continuous-wave radars 3 Friction 3 Heat convection 3 Heat transfer 3 Magnetohydrodynamics 3 Mass transfer 3 Mean square error 3 Measurement function 3 Meteorological instruments 3