Pascal C. auteur aut IRD Ferrant Sylvain auteur aut IRD Rodriguez-Fernandez N. auteur aut IRD Kerr Y. auteur aut IRD Selles A. auteur aut IRD Merlin O. auteur aut IRD text journalArticle eng text/pdf born digital access Spaceborne L-band data have the potential to monitor flooded and irrigated areas. However, further studies are needed to assess in real cases the impact of flood-irrigated crops on soil moisture and ocean salinity (SMOS) and soil moisture active passive (SMAP) surface soil moisture (SSM) data. This letter demonstrates the ability of SMOS/SMAP SSM retrievals to quantify the fraction of flood-irrigated areas at the seasonal scale and at a 25-km resolution in the Telangana State in southern India. Over irrigated areas, both SMOS level 3 (L3) SSM and SMAP L3 enhanced SSM products present a bimodal annual cycle, with a peak of SSM during the monsoon (wet) season corresponding to rainfall and irrigation, and a peak during the dry season due to irrigation activities solely. The second peak is absent or has a very small amplitude in areas where rice represents a small fraction (typically below 5%-10%). More importantly, the amplitude of the second SSM peak is significantly correlated with the rice cover fraction within $25\times25$ km2 pixels ( $R = 0.81$ for SMOS and 0.77 for SMAP), showing its potential to assess crop fraction and hence the water used for irrigation. The SMOS/SMAP L3 SSM peak during the dry period occurs several months before the harvest, constituting an indicator for rice stocks at the end of the season. However, the irrigation signature is absent from the SMAP level 4 SSM product derived from the assimilation of SMAP brightness temperatures (Tbs) in a land surface model, which indicates that the data assimilation scheme is inefficient to restitute irrigation information. specialized Irrigation Microwave radiometry L-band Soil moisture Classification algorithms Land surface Crops regional scale rice cropping soil moisture soil moisture active passive (SMAP) soil moisture and ocean salinity (SMOS) water management INDE 072 126 20 4500205 [5 ] 2023 1545-598X https://www.documentation.ird.fr/hor/fdi:010088085 10.1109/lgrs.2023.3267825 1545-598X [F B010088085] https://www.documentation.ird.fr/hor/fdi:010088085 https://www.documentation.ird.fr/intranet/publi/2023-07/010088085.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2023-07-06 2026-06-12 fdi:010088085 fre