Publications des scientifiques de l'IRD

Fournier S., Vialard Jérôme, Lengaigne Matthieu, Lee T., Gierach M. M., Chaitanya A. V. S. (2017). Modulation of the Ganges-Brahmaputra River Plume by the Indian Ocean Dipole and Eddies Inferred from satellite observations. Journal of Geophysical Research : Oceans, 122 (12), p. 9591-9604. ISSN 2169-9275.

Titre du document
Modulation of the Ganges-Brahmaputra River Plume by the Indian Ocean Dipole and Eddies Inferred from satellite observations
Année de publication
2017
Type de document
Article référencé dans le Web of Science WOS:000422732100016
Auteurs
Fournier S., Vialard Jérôme, Lengaigne Matthieu, Lee T., Gierach M. M., Chaitanya A. V. S.
Source
Journal of Geophysical Research : Oceans, 2017, 122 (12), p. 9591-9604 ISSN 2169-9275
The Bay of Bengal receives large amounts of freshwater from the Ganga-Brahmaputra (GB) river during the summer monsoon. The resulting upper-ocean freshening influences seasonal rainfall, cyclones, and biological productivity. Sparse in situ observations and previous modeling studies suggest that the East India Coastal Current (EICC) transports these freshwaters southward after the monsoon as an approximately 200 km wide, 2,000 km long river in the sea along the East Indian coast. Sea surface salinity (SSS) from the Soil Moisture Active Passive (SMAP) satellite provides unprecedented views of this peculiar feature from intraseasonal to interannual timescales. SMAP SSS has a 0.83 correlation and 0.49 rms-difference to 0-5 m in situ measurements. SMAP and in stu data both indicate a SSS standard deviation of similar to 0.7 to 1 away from the coast, that rises to 2 pss within 100 km of the coast, providing a very favorable signal-to-noise ratio in coastal areas. SMAP also captures the strong northern BoB, postmonsoon cross-shore SSS contrasts (similar to 10 pss) measured along ship transects. SMAP data are also consistent with previous modeling results that suggested a modulation of the EICC/GB plume southward extent by the Indian Ocean Dipole (IOD). Remote forcing associated with the negative Indian Ocean Dipole in the fall of 2016 indeed caused a stronger EICC and river in the sea that extended by approximately 800 km further south than that in 2015 (positive IOD year). The combination of SMAP and altimeter data shows eddies stirring the freshwater plume away from the coast.
Plan de classement
Limnologie physique / Océanographie physique [032] ; Hydrologie [062] ; Télédétection [126]
Description Géographique
OCEAN INDIEN
Localisation
Fonds IRD [F B010072010]
Identifiant IRD
fdi:010072010
Contact