Climatic Aggressiveness and Precipitation Concentration in a Peruvian Amazon Basin: Alto Huallaga Interbasin

Precipitation in the central Peruvian Amazon is characterized by being seasonal and with strong intensities during the first months of the year, leading to flooding and the subsequent collapse of the local infrastructure in provinces of San Martin, Huanuco, Pasco and La Libertad Regions of Peru, which are located within the delimitation of the Alto Huallaga Interbasin. Therefore, the objective of this research was to evaluate the climatic aggressiveness and concentration precipitation in the Amazon basin, applying three indices of aggressiveness and a precipitation concentration index (ICP), estimated from the precipitation record of the climatic stations in the study area. The results show a very high correlation between mean precipitation and altitude (R2 = 0.72) and with respect to the aggressiveness, the modified Fournier-Maule index (IFMM) was the one with the best correspondence with respect to altitude (R2 = 0.72) and mean precipitation (R2 = 0.98), however, the ICP shows moderate correlations with altitude (R2 = 0.21) and mean precipitation (R2 = 0.16). Likewise, the extreme values of the different indices were estimated for different return periods and a multiple linear regression model was developed to relate climatic aggressiveness and the ICP to estimate the mean precipitation (R2 = 0.99). Finally, it is concluded that, the Alto Huallaga Interbasin presents a very low climatic aggressiveness and the concentration of rain is moderately seasonal.