Introducing project ITHACA: Investigation of the Terrestrial HydrologicAl Cycle Acceleration

ITHACA is a 5-year project that aims to benchmark the terrestrial water cycle intensification. Our goal is to estimate the past range of the hydrological cycle variability, determine the present state of its acceleration, and understand its future impacts on the terrestrial water availability. To achieve this, we combine multi-source data products, stochastic analysis, and process-based hydrological modeling from regional to global scale. Here, we present the preliminary results after the completion of its first year, which come with multiple homogenized datasets of water cycle components, R software packages for data pre-processing and data-driven analyses, and methodological suggestions and insights for the cross-scale quantification of water cycle changes. We also discuss the current challenges and the future steps of the project, highlighting the numerous opportunities for active collaboration.