The WAVETRAX project is focused on enhancing our understanding and monitoring of climate change by studying the behavior of active microwave remote sensing observations in relation to surface processes and land-atmosphere interactions on a sub-daily timescale. It aims to bridge the observational gap in current satellite data, which miss rapid Earth system processes due to temporal limitations. For instance, plants' carbon capture through stomata and moisture redistribution, along with other quick-changing phenomena like dew formation and snow events, remain underobserved by satellites like Sentinel-1. To address these challenges, WAVETRAX is exploring novel satellite mission concepts such as Sub-daily Land Atmosphere INTEractions (SLAINTE), an initiative under preparation by the European Space Agency for Earth Explorer 12. This project's goal is to improve the physical understanding of these quick processes and their radar measurement impacts, thus refining the retrieval of Essential Climate Variables (ECVs) such as surface soil moisture, root-zone soil moisture, biomass, snow water equivalent, and land evaporation. Through detailed investigations at three instrumented sites equipped with advanced sensors, alongside in situ measurements and the development of physics-based and machine learning models, WAVETRAX seeks to enhance radar data's sensitivity to ECVs. The project's outcomes are expected to significantly advance Earth system monitoring capabilities, contributing to addressing pressing scientific and societal challenges outlined by ESA's Earth Observation Science strategy and the World Climate Research Program. SLAINTE's role in this effort highlights its potential to fill critical observational gaps and support improved global understanding of water, carbon cycles, and climate dynamics.