Spatial spin-up of fine scales in a regional climate model simulation driven by low-resolution boundary conditionsReport as inadecuate




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Climate Dynamics

, Volume 49, Issue 1–2, pp 563–574

First Online: 21 September 2016Received: 29 April 2016Accepted: 07 September 2016DOI: 10.1007-s00382-016-3358-2

Cite this article as: Matte, D., Laprise, R., Thériault, J.M. et al. Clim Dyn 2017 49: 563. doi:10.1007-s00382-016-3358-2

Abstract

In regional climate modelling, it is well known that domains should be neither too large to avoid a large departure from the driving data, nor too small to provide a sufficient distance from the lateral inflow boundary to allow the full development of the small-scale SS features permitted by the finer resolution. Although most practitioners of dynamical downscaling are well aware that the jump of resolution between the lateral boundary condition LBC driving data and the nested regional climate model affects the simulated climate, this issue has not been fully investigated. In principle, as the jump of resolution becomes larger, the region of interest in the limited-area domain should be located further away from the lateral inflow boundary to allow the full development of the SS features. A careless choice of domain might result in a suboptimal use of the full finer resolution potential to develop fine-scale features. To address this issue, regional climate model RCM simulations using various resolution driving data are compared following the perfect-prognostic Big-Brother protocol. Several experiments were carried out to evaluate the width of the spin-up region i.e. the distance between the lateral inflow boundary and the domain of interest required for the full development of SS transient eddies as a function of the RCM and LBC resolutions, as well as the resolution jump. The spin-up distance turns out to be a function of the LBC resolution only, independent of the RCM resolution. When varying the RCM resolution for a given resolution jump, it is found that the spin-up distance corresponds to a fixed number of RCM grid points that is a function of resolution jump only. These findings can serve a useful purpose to guide the choice of domain and RCM configuration for an optimal development of the small scales allowed by the increased resolution of the nested model.

KeywordsRegional climate modelling Nested model Jump of resolution Spatial spin-up Big-Brother experiment 



Author: Dominic Matte - René Laprise - Julie M. Thériault - Philippe Lucas-Picher

Source: https://link.springer.com/



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