Conference Agenda

Understanding the sensitivity of reference evapotranspiration(ET₀) to meteorological variables is critical for improving urban water management and climate adaptation strategies. This study analyzes the one-way and two-way sensitivity of ET₀ to maximum temperature(T_max), wind speed(u₂), solar radiation(Rs), and maximum relative humidity(RH_max) using the FAO-56 Penman-Monteith equation for multiple meteorological stations in Paris area. One-way sensitivity analysis revealed that T_max and Rs have the strongest influence on ET₀ in summer, while windspeed and RH_max show secondary notable effects, particularly in winter seasons. A two-way sensitivity analysis was conducted for T_max and RH_max, considering their joint influence on vapor pressure deficit(VPD). The results indicate a nonlinear relationship, where higher T_max and lower RHmax significantly increase VPD, amplifying ET₀, while increasing RHmax dampens this effect. Seasonal variations highlight stronger ET₀ sensitivity in summer and reduced impact of Rs in winter due to high humidity levels. Windspeed has its major role in shaping evapotranspiration in winter and in dense urban settings. These findings emphasize the need for climate-adaptive urban drainage models, integrating ET₀ variability to enhance stormwater retention, flood resilience, and green infrastructure efficiency under changing climate conditions. Future research should refine ET₀ modelling for urban microclimates, ensuring accurate water balance predictions in cities.