Networks analysis of Brazilian climate data based on the DCCA cross-correlation coefficient

state capitals and the Brazilian capital, for a total of 108 time series. In this preliminary phase of the analysis, the objective was to evaluate the self-correlation of the variables in the Brazilian state capitals. The locations of the Brazilian states and regions can be seen in the S1 File, S1 Fig in S1 File, and the names of the state capitals with their location in Table 1. This results corrob- orates with studies of [24, 38–41]. Fig 1 shows the behavior of the fluctuation function FDFA(n) for global radiation in all state capitals per region. A characteristic pattern is observed for all time scales regardless of the region, with three clearly defined behaviors: (i) n ⩽ 13 (1 day and 6 scale observations: boxes with length 4, 5, 7, 9, 11, 13); (ii) 13 < n ⩽ 5625 (1—430 days, with 48 scale observations: boxes with the length between 16 and 5625); and (iii) n > 5625 (430 days and 8 scale observa- tions: boxes with length 6242, 6925, 7680, 8514, 943, 10457, 11585, 12831, 4327). We can also compute the αDFA(medium) ffi 1.21(±0.04) for up to 1 day of observations, the αDFA(medium) ffi 0.87(±0.02) for intervals between 1 and 430 days, and the αDFA(average) ffi 0.06(±0.01) for intervals greater than 430 days. αDFA(medium) ffi 1.21 represents a non-stationary persistent behavior, αDFA(medium) ffi 0.87 represents a long-range persistence, and αDFA(medium) ffi 0.06 represents an anti-persistent behavior. With a behavior very similar to the global radiation, temperature (see S2 Fig in S1 File) also

presents a specific pattern for n � 13, 13 < n � 5.625, and n > 5.625. Only the state capitals in the Southeast and South regions showed a less intense transition in the trend associated with observations with n � 13, (1 day). Humidity (see S3 Fig in S1 File) in the state capitals for the Southeast and South regions and wind speed (S4 Fig in S1 File) in the state capitals for the Central-West, Southeast, and South regions, did not show the transition to n � and 13, show- ing different characteristics for the state capitals in the North and Northeast regions. Fig 1. Detrended fluctuation analysis for global radiation. The plots show, respectively the curves for all capitals in the regions North, Northeast, Central-West, Southeast, and South, respectively. The vertical axis gives the FDFA, and the horizontal axis shows the box size. https://doi.org/10.1371/journal.pone.0290838.g001 PLOS ONE Networks analysis of Brazilian climate data based on the DCCA cross-correlation coefficient PLOS ONE | https://doi.org/10.1371/journal.pone.0290838 September 15, 2023 7 / 18