Abstract

A series of numerical experiments were conducted to investigate the sensitivity of the WRF Model to the advection scheme. The differences in the simulated results between third- and fifth-order schemes are not large, however the vertical velocity field of the former is somewhat smoother. On the o... Show moreA series of numerical experiments were conducted to investigate the sensitivity of the WRF Model to the advection scheme. The differences in the simulated results between third- and fifth-order schemes are not large, however the vertical velocity field of the former is somewhat smoother. On the other hand, fourth- and sixth-order schemes easily produce grid-scale computational noise, although the time step is set to be smaller than the recommended one. Artificial second-order diffusion damps the noise, however it negates the advantage of the high-order advection scheme. Explicit fourth-order diffusion damps the noise, however it smoothes the field more than the inherent, implicit diffusion in the third-order scheme. Contrary to this, explicit sixth-order diffusion damps noise, but maintains detailed structure and high energy spectral density of the vertical velocity. We recommend the fifth-order upwind scheme for use in the WRF Model. Show less