Upper Ocean Stratification in the Bay of Bengal During Asiri
Abstract
In collaboration with Indian oceanographers, we seek to measure and understand the processes controlling the stratification of the upper 100m of the Bay of Bengal and to educate a new generation of young Indian oceanographers in the methods used. Upper ocean physics plays a key role in controlling the intensity and timing of the Northern Indian Ocean monsoons, with the ocean and atmosphere representing a strongly coupled air-sea interaction system, which in turn plays an important role in climate variability at both regional and global scales. The ASIRI program, a Departmental Research Initiative of ONR s code 32, seeks to understand these interactions through measurement and modeling focused on the Bay of Bengal. Existing coupled ocean-atmosphere models in this region show little skill in predicting the summer monsoon, particularly its IntraSeasonal Oscillations (ISO). One possible cause is a poor simulation of the air-sea interaction processes. The northern Bay of Bengal has strong ISO fluctuations in SST, which lead the monsoonal fluctuations by about a week, thereby suggesting a causal relationship between monsoon ISO variations and ocean dynamics. However, most existing models predict surface temperatures that are too cold and mixed layer depths that are too deep. The biases are large and likely reduce the intensity of air-sea interaction by overestimating the thermal inertia of the upper ocean and thus the time scale on which the ocean can respond to the atmosphere. A likely reason for this bias is an improper representation of the role of freshwater input, both from rain and from the enormous river inflow into the northern Bay of Bengal.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2013
- Accession Number
- ADA599036
Entities
People
- Eric A. D Asaro
Organizations
- University of Washington