12. Seasonal winds might drive current variability in the northern Indian Ocean
Oceanographers and meteorologists need to understand the forces driving upper ocean currents and sea level variability. To study the dynamics of the response of the northern Indian Ocean to intraseasonal winds, Vialard et al. analyze satellite observations of sea level and wind stress as well as a new data set of currents recorded at 15 degrees North on the west coast of India. They find that while sea level shows a seasonal variability, the alongshore current shows no clear seasonal cycle but is dominated by intraseasonal (55-110 day) fluctuations. These current variations, the authors find, arise as a response of the northern Indian Ocean to intraseasonal winds associated with the Madden-Julian Oscillation. The authors use linear wave theory to explain these observations. Although the study focuses on the Indian Ocean, the authors believe that similar dynamics could drive coastal current variability in the Atlantic and Pacific oceans. The results could also have implications for coastal current monitoring, the authors suggest.
Title: Intraseasonal response of the northern Indian Ocean coastal waveguide to the Madden-Julian Oscillation
Authors: J. Vialard: Laboratoire d'Ocanographie Exprimentation et Approches Numriques, IRD, Universit Pierre et Marie Curie, Paris, France;
S. S. C. Shenoi: Indian National Centre for Ocean Information Services, Hyderabad, India;
J. P. McCreary: International Pacific Research Centre, University of Hawaii, Honolulu, Hawaii, USA;
D. Shankar, V. Fernando, and S. R. Shetye: Physical Oceanography Division, National Institute of Oceanography, CSIR, Goa, India;
F. Durand: Laboratoire d'Etudes en Gophysique et Oceanographie Spatiales, IRD, Toulouse, France.
|Contact: Maria-Jose Vinas|
American Geophysical Union