The Role of the Salinity Front in Preconditioning Air-Sea Interaction in the Arabian Sea Mini-Warm Pool
Abstract
Salinity-stratified barrier layers (BLs) act as a barrier to heat and momentum exchange between the surface and subsurface ocean and may have an important role in air-sea interaction. When barrier layers contain temperature inversions (TIs) of water warmer than the sea surface, they can be entrained into the overlying surface mixed layer and work to increase sea surface temperature (SST), hence having a significant impact in mediating air-sea exchanges. In the southeast Arabian Sea, intrusion of fresher and cooler water from the Bay of Bengal is a prime contributor to the formation of winter BLs and TIs, which is associated with a sharp salinity front. Although the salinity front has been recognized as a critical limitation zone of BL formation in the tropical ocean, the role of the salinity front in BL formation in the southeast Arabian Sea has never been investigated. The winter BLs and TIs can affect SST and precondition the upper ocean for the development of the mini-warm pool in the subsequent spring and potentially impact the development of the monsoon. The overarching scientific goal of the proposed work is to determine the role of salinity stratification in thecoupled air-sea exchanges within the vicinity of the southeast Arabian mini-warm pool. Two hypotheses about the nature of salinity variability and its consequences for air-sea interaction will be tested:-(1) First, it is hypothesized that the salinity front in the southeast Arabian Sea, associated with the intrusion of low salinity water from the Bay of Bengal, produces a critical zone for BLand TI formation. This hypothesis will be investigated to advance our knowledge of the dynamical mechanisms controlling the upper ocean stratification in the southeast Arabian Sea.(2) Second, it is hypothesized that the presence of BLs and TIs can significantly affect the development of the mini-warm pool and subsequent air-sea interaction through their influence on SST. Testing this hypothesis will help clarifythe role of salinity stratification on the heat transfer occurring at the air-sea interface and how that subsequently influences the coupled climate system.To test these hypotheses, we propose to conduct underway shipboard measurements across the salinity front to observe the synoptic features of upper ocean stratification in the southeast Arabian Sea. The proposed work will provide insights on the formation of BLs and TIs in the southeast Arabian Sea and their role in the development of the mini-warm pool and subsequent air-sea interactions. Our observations and proposed analysis will also provide a test bed for the evaluation, veracity, and refinement of the ability of numerical models to reproduce the ocean state and predict the strength and timing of the monsoon onset.Approved for Public Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2023
- Source ID
- N000142312091
Entities
People
- Shota Katsura
Organizations
- Office of Naval Research
- United States Navy
- University of California, San Diego