Can Smos Soil Moisture Dry-Downs Be Useful To Detect Flood Conditions Over The Argentinean Pampas Plains?

CAPPELLETTI LUCIA; SÖRENSSON, ANNA A.; RUSCICA, ROMINA C.; SALVIA, M.; JOBBAGY E; KUPPEL, SYLVAIN; FITA, LLUÍS

Santiago

Congreso; 2020 IEEE Latin American GRSS & ISPRS Remote Sensing Conference; 2020

Universidad de Chile

The process of soil drying following a single rainfall input offers an integrated perspective on soil-vegetation water dynamics in responses to atmospheric conditions during periods without rainfall. In this work, the soil moisture dry-down time scale events (τ) was calculated using surface soil moisture data from the SMOS mission, with the objective to explore if the spatio-temporal variability of τ could be used as a proxy for regional flooding and waterlogging characterization. Our working hypothesis is that soil moisture dries up more slowly under flooded conditions as a result of slower surface water elimination by infiltration and capillary rise of water from the saturated zone close to the surface. A clear difference precipitation-moisture coupling was detected between two regions with different flooding dynamics. In a region where flooding is triggered by precipitation excesses on weekly-to-monthly time scales and where the coupling between precipitation and evapotranspiration is strong, a positive correlation between dry-down and 6-month accumulated precipitation anomaly was found for all seasons except winter. By contrast, in the other region where flooding is largely de-coupled from precipitation and evapotranspiration, but rather coupled to groundwater table Dynamics n time scales from several months to years, no significant correlations were found. These preliminary results are based on a short period of data: March 2010 - November 2014, and the period of study will be completed with data from 2015-2019.