Evaluation of regional climate models ALARO-0 and REMO2015 at 0.22° resolution over the CORDEX Central Asia domain

Sara Top,Steven Caluwaerts,Armelle Reca Remedio,Viesturs Zandersons,Lesley De Cruz,Lola Kotova,Svetlana Aniskevich,Arne Kriegsmann,Rozemien De Troch,Piet Termonia,Bert Van Schaeybroeck,Abdulla Sakalli,Leonid Bobylev,Rafiq Hamdi,Hans Van De Vyver,Philippe De Maeyer,Natalia Gnatiuk,Anne Gobin

doi:10.5194/gmd-14-1267-2021

Abstract

Abstract. To allow for climate impact studies on human and natural systems, high-resolution climate information is needed. Over some parts of the world plenty of regional climate simulations have been carried out, while in other regions hardly any high-resolution climate information is available. The CORDEX Central Asia domain is one of these regions, and this article describes the evaluation for two regional climate models (RCMs), REMO and ALARO-0, that were run for the first time at a horizontal resolution of 0.22∘ (25 km) over this region. The output of the ERA-Interim-driven RCMs is compared with different observational datasets over the 1980–2017 period. REMO scores better for temperature, whereas the ALARO-0 model prevails for precipitation. Studying specific subregions provides deeper insight into the strengths and weaknesses of both RCMs over the CAS-CORDEX domain. For example, ALARO-0 has difficulties in simulating the temperature over the northern part of the domain, particularly when snow cover is present, while REMO poorly simulates the annual cycle of precipitation over the Tibetan Plateau. The evaluation of minimum and maximum temperature demonstrates that both models underestimate the daily temperature range. This study aims to evaluate whether REMO and ALARO-0 provide reliable climate information over the CAS-CORDEX domain for impact modeling and environmental assessment applications. Depending on the evaluated season and variable, it is demonstrated that the produced climate data can be used in several subregions, e.g., temperature and precipitation over western Central Asia in autumn. At the same time, a bias adjustment is required for regions where significant biases have been identified.

Highlights

There is a strong need for climate information at the regional to local scale that is useful and usable for impact studies on human and natural systems (Giorgi et al, 2009)
In this study we aim to address the scarcity of reliable climate information over the CAS-CORDEX domain by evaluating two different regional climate models (RCMs) based on multiple scores for temperature and precipitation over the longer period of 38 years
Annual biases generally vary between −3 and 3 ◦C for both RCMs, with the exception of orographically complex regions and some areas in northern and eastern Siberia for ALARO-0

Summary

Introduction

There is a strong need for climate information at the regional to local scale that is useful and usable for impact studies on human and natural systems (Giorgi et al, 2009). Within CORDEX there are large ensembles of model simulations available at different resolutions for the Africa (Nikulin et al, 2012, 2018), Europe (Jacob et al, 2014; Kotlarski et al, 2014), Mediterranean (Ruti et al, 2016), and North America (Diaconescu et al, 2016; Whan and Zwiers, 2017; Gibson et al, 2019) CORDEX regions (Gutowski et al, 2016). These large ensembles consist of more than 10 different global–regional climate model (GCM–RCM) combinations. A number of highresolution global simulations at climatic timescales, with resolutions of at least 50 km in the atmosphere and 28 km in the ocean, have been performed within the Coupled Model Intercomparison Project 6 (CMIP6) (Haarsma et al, 2016)

Objectives

Methods

Results

Discussion

Conclusion