Influence of Hydro-climatic Factors on Streamflow Patterns in Chilean Catchments

Abstract. Chile's extreme latitudinal gradient (18°–56° S) and diverse climatic regimes make it a natural laboratory for understanding hydro-climatic controls on streamflow evolution under climate change. This study quantifies maximum streamflow trends and their relationships with precipitation, temperature, and soil moisture across 38 catchments representing nine distinct Chilean climate zones over 2000–2021. We integrated field streamflow observations, gridded climate datasets (CR2MET), and satellite soil moisture data (SMAP/SMOS), applying Mann-Kendall trend analysis, Theil-Sen slope estimation, and Spearman correlation tests Results reveal significant declining streamflow trends in 67 % of winter-rainfall catchments (median slope: -1.12 mm/year, p<0.1), while summer-rainfall and tundra regions show the most substantial temperature increases (+0.06 °C/year). Mediterranean and temperate climates exhibit the strongest precipitation-streamflow correlations (ρ = 0.20–0.79), with soil moisture acting as an intermediate control mechanism. Our findings indicate that accumulated precipitation is the dominant driver in 53 % of analysed catchments, with soil moisture modulate the precipitation-runoff relationship, particularly in water-limited environments. These results provide critical insights for water resource management in Chile's diverse climatic regions and contribute to understanding hydro-climatic linkages in transitional climate zones globally.