Avaliação dos tipos de ZCIT sobre o oceano Pacífico Tropical em um modelo de canal tropical

Abstract

Simulations of the Intertropical Convergence Zone (ITCZ) using a Tropical Channel Model (TCM) were evaluated from a climatological perspective. The main focus of the analysis is on the model's ability to reproduce the position and the distinct spatial patterns of the ITCZ over the Tropical Pacific Ocean. TCM is based on the Weather Research and Forecasting (WRF) model, combining the main advantages of global and regional models. These TCMs are global in the zonal direction, but with boundary conditions in the meridional Direction (0°-360°, 34°S34°N). In this way, TCM simulations can have higher resolution than normally in a global climate model (GCM). Thus, we investigated how the TCM-WRF model represents the climate variability patterns of the tropical region, in particular the ITCZ over the tropical Pacific, and discussed its average frequency of occurrence for each type (e.g., Dual, Equator, North, South, Weak, and Full). In addition, the same evaluation was performed with 16 atmospheric general circulation models (AGCMs) from the 6th phase of the Climate Model Intercomparison Project (CMIP6), which generally perform poorly in the tropics. The horizontal resolution of the TCM is ~100 km, with 41 vertical levels and the 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-ensemble models was performed against precipitation data from the Global Precipitation Climatology Project (GPCP). The TCM model showed a positive BIAS, indicating an overestimation of the model. In the pattern analyses, the three predominant ones were North, South and Weak for the GPCP, only the AMIP-ensemble models represented these patterns as observed. While the TCM showed the predominance of the Equator and Full patterns, while there were almost no cases of Weak. In addition, the North, South and Double patterns in the TCM model showed an equal spatial representation, different from the standard GPCP, which has a well-defined spatial representation. The AMIP-ensemble models better represented the patterns and frequency of the ITCZ patterns. The high volume of daily precipitation simulated by the TCM model was crucial in the difference between the cases compared to what was observed.