Evaluation of historical CMIP6 model simulations and future projections of temperature and precipitation in Paraguay

LOVINO, MIGUEL A.; PIERRESTEGUI, MARÍA JOSEFINA; MÜLLER, OMAR V.; BERBERY, ERNESTO H.; MÜLLER, GABRIELA V.; PASTEN, MAX

CLIMATIC CHANGE

SPRINGER

Año: 2021 vol. 164

0165-0009

This study evaluates the ability of 19 models of CMIP phase 6 (CMIP6) to simulate Paraguay's climate features. Historical multi-member simulations of single models and their multi-model ensembles are bias-corrected and evaluated with statistical metrics. Future projections of precipitation and temperature are generated with the ensembles for three integrated sce-narios of socio-economic development and greenhouse gas emissions (SSP1-2.6, SSP2-4.5, and SSP5-8.5). The 19 models simulate well the observed mean temperature. The bias-corrected multi-model ensemble reaches the highest skill scores and accurately reproduces the mean spatial field and annual cycle. The bias-corrected multi-model ensemble of precipitation represents the annual cycle weakly, missing the sharp onset and decay of the South American Monsoon. Some individual models and the multi-model ensemble correctly reproduce the west-east gradient, although they underestimate its pronounced spatial variability.Ensembles of future simulations project that by 2100 the annual mean temperature may in-crease for the three scenarios. On average, the increases are almost 1.7 °C in the sustainable development and low emissions scenario (SSP1-2.6), 3 °C in the middle-of-the-road devel-opment and medium emissions scenario (SSP2-4.5), and 5.5 °C in the fossil-fueled develop-ment and high emissions scenario (SSP5-8.5). Models project a slight decrease in annual precipitation towards the northwest (less than 50 mm) and an increase towards the southeast (more than 200 mm). Paraguay's humid eastern part is projected to have a small growth in temperature and an increase in precipitation. In contrast, the western arid Chaco region would experience a substantial increase in temperature, while rainfall would slightly decrease.