## 2 Materials and Methods  
### Study Area  
Brazil has a large territory with various meteorological systems, which substantially affect the rainfall regimes in the country. To investigate these meteorological systems, we divided the country into five regions based on rainfall regime [28; 29]: southern Brazil (R1), central region (R2), northeastern (R3), northeast Coast (R4), and north Brazil (R5). Regions have heterogeneous seasonal rainfall characteristics (Figure 1). Based on climatological averages [30], the expected rainfall during the austral summer (December, January, February) by region is 80 to 220 mm/month in R1, 100 to 420 mm/month in R2, 20 to 420 mm/month in R3, 30 to 140 mm/month in R4, and 10 to 420 mm/month in R5. In the austral winter (June, July, August), rainfall varies between 40 to 140 mm/month in R1, 10 to 80 mm/month in R2, 10 to 180 mm/month in R3, 10 to 180 mm/month in R4, and 50 to 380 mm/month in R5.  
Frontal systems, cyclones, and mesoscale convective systems (MCS) are the main rain-producing systems in R1 [5; 6], and these events can occur together and also independently [31; 32]. El Nino-Southern Oscillation (ENSO) also plays a fundamental role in rainfall variability in R1 [33; 34; 35]. During autumn and winter, rains are caused by the frontal systems at mid-latitudes. In addition, during this period, the latitudinal temperature gradient generates baroclinic waves in the upper-level westerly winds in upper air [6], and the low-level jets stream moves to the southeast through the Andes (acting as an orographic barrier) causing cyclogenesis [36]. During spring and summer, the MCS predominates.  
One of the most common meteorological systems in R2 is the SACZ, where the flow from the northwest of the low-level-jet converges with the circulation of the South Atlantic subtropical high and with the northeast trade winds, resulting in a band of cloudiness and intensification of precipitation [37; 38]. R2 is characterized by six months of rain during the austral summer followed by six months of scanty rainfall in austral winter, the main characteristic of a monsoon region [39; 40].  
The main meteorological systems acting in R3 are the intertropical convergence zone and the upper level cyclonic vortex [41]. The mean annual rainfall is registered primarily from January through May. According to [PERSON] and [PERSON] [42], the rainfall in this region is modulated by stratiform and deep convective precipitating clouds.  
In R4, the main meteorological systems acting are intertropical convergence cone, tropical mesoscale convective systems, the trade winds, upper level cyclonic vortex, easterly waves, and sea breeze circulation [9; 10]. The annual cumulative rainfall is around 1000 mm along the coast [40; 43], mostly concentrated in March through July (70%) and modulated by shallow convective precipitating clouds [42].  
Finally, the main meteorological systems acting in R5 are the intertropical convergence zone [7], the tropical squall lines [8], and the Trade Winds. The period from November to April constitutes the rainy season, and the total annual rainfall ranges from 2000 to 3000 millimeters [40]. This region exhibits large rainfall variability, and is generally associated with El Nino or La Nina. During the years of La Nina, rainfall tends to increase [33; 35].