Mayara Lins, Maria Cristina Silva, Pallav Ray, Xin Zhou, Fabrício Silva, Helber Gomes, Federal University of Alagoas, Brazil

This work attempts to explore the Weather Research and Forecasting (WRF) model-based Tropical Channel Model (TCM) that combines the main advantages of global and regional models. In other words, these TCMs use a global zone, but with boundary conditions only in the northern and southern directions (0°-360°, 34°S-34°N). In this way, TCM simulations can have higher resolution than normally in a global climate model (GCM). Thus, we investigate how the TCM-WRF model represents the climate variability patterns of the tropical region, in particular the Intertropical Convergence Zone (ITCZ) over the west-central Pacific, and discuss their average frequency of occurrence for each type (e.g., Double, Equator, North, South, Weak and Full). Also, we do the same assessment with 17 atmospheric general circulation models (AGCMs) from the 6th phase of Climate Model Intercomparison Project (CMIP6), which generally show poor performance in the tropics. The horizontal grid-spacing of the TCM is 36 km, with 41 vertical levels and top of the model at 50 hPa. The TCM was integrated from December 1, 2009 to December 31, 2014. The evaluation of the TCM-WRF simulation and AMIP models were performed against the Climate Prediction Center Morphing Technique (CMORPH) precipitation data. Preliminary results show that TCM-WRF was able to represent the spatial pattern of the ITCZ, but with a more northerly shift from the south ITCZ. Moreover, the TCM was unable to predict the weak ITCZ. The possible reasons behind such performance of the TCM and whether or not these biases were rectified in the AMIP6 models are discussed.