A Regional Approach for Investigation of Temporal Precipitation Changes

Climatic variability is one of the fundamental aspects climate. Our scope knowledge this limited by unavailable long-term high-resolution spatial data. simulations indicate that warmer climate increases extreme precipitations but decreases high-frequency temperature variability. As an important climatologic variable, precipitation reported IPCC to increase in mid and high altitudes decrease subtropical areas. On a regional scale, such change needs spatio-parametric justification. In regard, regionalization approach relying on frequency characteristics parameters heavy may provide better insight into temporal changes, thus help us understand climatic extremes. This study introduces “index method”, which aims define hydrologic homogeneous regions throughout distribution monthly maximum hourly remains same and, therefore, investigate whether there are significant changes these regions. Homogenous defined based L-moment ratios distributions via cluster analysis considering contiguity gauging sites GIS. Regarding main precipitation, 12 indices order existence trends means t- Mann–Kendall tests for determined homogenous with similar behaviors. The case Japan, using data 150 gauges 1991–2010, shows statistically exist single-site observations should be regionally proved. Trends have region-specific properties across Japan. beneficially precipitation.