Figure 1: Climatogram of Yangambi region, monthly decadal means of rainfall (mm), PET (mm), sunshine (hours) and average temperatures (°C) from 1931 to 2018

Figure 2: Chronological monthly rainfall means (mm) and lineary trend from 1931 to 2017 for Yangambi region

Figure 3: Yearly rainfall and rainfall-days from 1931 to 2017 in Yangambi in red et fitted lines in blue

Figure 4: Monthly rainfall seasonal (blue-white), cyclical (green) and irregular (yellowish) indexes (%) for 87 years from 1931 to 2017 in Yangambi (red : number of months since 1931)

Figure 5: Monthly rainfall polynomial seasonal indexes (%) from 1931 to 2018 and red numbers are season zones

Figure 6: Agroclimatic events projected on abscissa from intersection of probabilities of consecutive 2-humid decades with PET et PET/2 (average from 1950 to 2017)

Figure 7: Water balance on soil residual water (RS), runoff and drainage (RDR), soil usable water reserve (RU), evapotranspiration deficit (MET-RET) and dry matter (RET/PET)

Figure 8: Significant yearly average temperatures trend rupture after 26 years, in 1977, of observations from 1951 to 2017 in Yangambi region

Column 1

Column 2

Column 3

column 4 = column3/ number 24

Column 5 = column2/ column4

Column 6

 

Years and months

Original data
............................. T X S X C X I

13-month moving total weighted (7th month centered)

Centered 12-month moving average (7th month centered)

Percent of centered 12-moving average

 

Seasonal Index (S)

Column 7 = column2/ column6

Column 8

Column 9 = column7/column8

Column 10 = 1,2,1 of 9

Column 11 = column10/ number 4

Column 12= column 8/ column 11

Deseasonalized data
.........................................
T X C X I

 

Trend values (T)

Cyclical-Irregular Percentages
.......................................................
C X I

Three-month moving total weighted

Cyclical average Percentage

 

Irregular percents

Table 1: Columns of proccessing serial monthly rainfall original data in seasonal, cyclical and irregular movements