Radar Backscatter Characteristics Using Numerical Simulation of the Medium and Scattering Processes

Northwest Research Associates, Incorporated, Seattle WA

Investigators

Abstract

State-of-the-art numerical techniques will be used in this project to simulate the radar backscatter from the middle atmosphere thereby providing a direct coupling between the dynamics in the radar volume and parameters computed from the radar signal (e.g. velocities, momentum fluxes, and energy dissipation rates). For the first time a direct numerical simulation (DNS) of evolving turbulence structures with sufficient resolution to resolve the Bragg scale features and a DNS of the Maxwell equations are integrated to study this problem. A fluid simulation will provide volumes containing turbulent structures formed during the evolution of a Kelvin-Helmholtz instability or breaking gravity waves. This numerical tool is a high resolution simulation capable of resolving the full turbulence spectrum, allowing the radar Bragg scale to be specified within the inertial range of turbulence thereby permitting the computation of all turbulence and radar backscatter quantities. These structures will be integrated into a Finite-Difference Time-Domain (FDTD) implementation of the Maxwell equations which provides an accurate calculation of the scattering from the complex structures generated by the fluid code. The integration of these two simulations creates a unique capability to aid in the investigation of the scattering mechanism for different types of radar systems and how these processes affect the results derived from the radar signals with few underlying assumptions.