Evaluating Satellite Soil Moisture Datasets for Drought Monitoring in Australia and the South-West Pacific

Soil moisture (SM) is critical in monitoring the time-lagged impacts of agrometeorological drought. In Australia and several south-west Pacific Small Island Developing States (SIDS), there are a limited number situ SM stations that can adequately assess soil-water availability near-real-time context. Satellite datasets provide viable alternative for drought provision these regions. this study, we investigated performance Moisture Active Passive (SMAP), Ocean Salinity (SMOS), Operational Products System (SMOPS), from Advanced Microwave Scanning Radiometer 2 (AMSR-2) Scatterometer (ASCAT) over SIDS. were first evaluated Australia, given presence in-situ state-of-the-art hydrological model—the Australian Water Resources Assessment Landscape modelling system (AWRA-L). We further accuracy satellite through Triple Collocation analysis with two other reference datasets—ERA5 reanalysis data model Global Land Data Assimilation (GLDAS) dataset. All have differing observation periods ranging 1911-now, common period observations between 2015–2021. Results demonstrated ASCAT SMOS consistently superior their performance. Analysis six SIDS indicated reduced all products, still performing better than others most median R values 0.3–0.9. conducted case study 2015 El Niño Positive Indian Dipole-induced Papua New Guinea. It was shown valuable dataset indicative nation, highlighting value using products to early warning data-sparse regions Pacific.