The climate version of the Eta regional forecast model. 1. Evaluation of consistency between the Eta model and HadAM3P global model

TL;DR

This study evaluates the consistency between a regional climate model based on Eta and a global model HadAM3P over South America, demonstrating they produce similar large-scale climate structures.

Contribution

It provides a detailed comparison of the Eta regional model and HadAM3P global model, validating the regional model's ability to replicate large-scale climate features.

Findings

Models show no significant differences in large-scale structures.

Regional model maintains consistency over the integration period.

Both models effectively capture key climate features.

Abstract

The regional climate model prepared from Eta WS forecast model has been integrated over South America with the horizontal resolution of 40 km for the period of 1960-1990. The model was forced at its lateral boundaries by the outputs of HadAM3P. The data of HadAM3P represent simulation of modern climate with the resolution about 150 km. In order to prepare climate regional model from the Eta forecast model multiple modifications and corrections were made in the original model. The run of climate Eta model was made on the supercomputer SX-6. The detailed analysis of the results of dynamical downscaling experiment includes an investigation of a consistency between the regional and AGCM models as well as of ability of the regional model to resolve important features of climate fields on the finer scale than that resolved by AGCM. In this work the results of the investigation of a consistency between the output fields of the Eta model and HadAM3P are presented. The geopotential, temperature and wind fields of both models were analysed. For the evaluation of the likeness of these two models outputs,there were used Fourier analysis of time series, consistency index, constituted from linear regression coefficients, time mean and space mean models' arithmetic difference and root mean square difference, dispersion analysis,and some others characteristics. This investigation demonstrates that there are not significant differences in behaviour and spatial arragement of large-scale structures of the two models. Also, the regional model characteristics do not have considerable positive or negative trend during integration time in relation to the global model characteristics. From the total analysis we can affirm that in the description of large-scale climate structures these two models are in consistency.