Evaluating near-surface wind speeds simulated by the CRCM6-GEM5 model using AmeriFlux data over North America

TL;DR

This study assesses the accuracy of the CRCM6-GEM5 regional climate model in simulating near-surface wind speeds across North America, highlighting the influence of model parameters and schemes on simulation quality.

Contribution

It provides a comprehensive evaluation of the model's wind speed simulations using AmeriFlux data, identifying key factors affecting performance and proposing improvements.

Findings

Roughness length (z0) significantly impacts wind speed simulation.

Using a lower limit for Obhukov length worsens stable condition simulations.

Turbulent orographic form drag scheme improves accuracy.

Abstract

We evaluate the performance of various configurations of the Canadian Regional Climate Model (CRCM6-GEM5) in simulating 10-meter wind speeds using data from 27 AmeriFlux stations across North America. The assessment employs a hierarchy of error metrics, ranging from simple mean bias to advanced metrics that account for the dependence of wind speeds on variables such as friction velocity and stability. The results reveal that (i) the value of roughness length (z0) has a large effect on the simulation of wind speeds, (ii) using a lower limit for the Obhukov length instead of a lower limit for the lowest level wind speed seems to deteriorate the simulation of wind speeds under very stable conditions, (iii) the choice of stability function has a small but noticeable impact on the wind speeds, (iv) the turbulent orographic form drag scheme shows improvement over effective roughness length approach.