Comparison of Regional Climate Model Simulations to Observational Data for Georgia

Abstract

<p>The global climate change resulting from natural and growing anthropogenic factors of particular importance for the territory of Georgia as the frequency and intensity of extreme weather events (extreme high temperatures, heavy precipitation levels, and agricultural and ecological droughts) are increasing in the territory. Georgia’s complex orography and proximity to the Black and Caspian Seas necessitates the use of high-resolution models, such as regional climate models, to assess future climate change hazards. In this study, we analyse the output from high-resolution simulation of mean and extreme precipitation and temperature using the Abdus Salam International Centre for Theoretical Physics Regional Climate Model version 4.7.1 for the period of 2010–1014 as an initial assessment of model performance for the territory. The simulation is performed at a 12 km horizontal grid spacing using<strong> </strong>ERA5 data as boundary conditions. Comparison with observed station data shows that the model performs better in simulating the monthly mean and extreme values of temperature than precipitation. In some mountain stations, the biases between observation and simulated precipitation are high, partly due to the mountainous terrain, when the horizontal resolution of the model (12 km) can lead to a significant discrepancy between the model's points and the locations of weather stations.  </p> <p>This study represents the first step of Georgia’s first high resolution assessment to better understand how climate change will impact the territory required to climate change policy and decision-making.</p> <p>This work was supported by Shota Rustaveli National Science Foundation of Georgia (SRNSFG) № FR-19-8110.</p>

Comparison of RegCM4.7.1 Simulation with the Station Observation Data of Georgia, 1985–2008

“…The study is based on the assumption that the RegCM4.7.1 model with selected parameterization schemes is a suitable tool for regional climate modeling in Georgia. Despite some previous sensitivity analyses [41][42][43][44][45], it is important to acknowledge that more sensitivity analysis and comparison with other modeling approaches could further validate the suitability of the RegCM4.7.1 model for climate studies in Georgia.…”

“…Figure 1 illustrates the RegCM domain, topography, and Georgia's location in the region. These parameterizations were chosen in previous studies [41][42][43][44][45]. We carried out several short-term simulations of RegCM for the territory of Georgia with different parameterizations, and we also compared the outcomes of these simulations with the observational data of weather stations in Georgia [41][42][43][44][45].…”

“…These parameterizations were chosen in previous studies [41][42][43][44][45]. We carried out several short-term simulations of RegCM for the territory of Georgia with different parameterizations, and we also compared the outcomes of these simulations with the observational data of weather stations in Georgia [41][42][43][44][45]. As a result, we selected the most optimal parameterization and domain size both from the point of view of computer resources and the best outcome.…”

The Performance of RegCM4.7.1 over Georgia’s Territory Using Two Different Configurations

“…The discrepancy between the model data and the observational data is particularly obvious when it comes to precipitation. This can be explained by the complex terrain of Georgia and the resolution of the model, which leads to a significant difference between the model points and the actual locations of the meteorological stations [6]. Usually, the observational data from the meteorological stations are compared to the data in the nearest grid of the model simulation.…”

“…The regional climate model (RegCM) was developed by the Abdus Salam International Centre for Theoretical Physics (ICTP) and has been widely used for climate simulations for different regions of the world [3][4][5][6][7][8][9].…”