How Ocean Processes Imprint Variability on the Summer Monsoon
Abstract
Diurnal variability in sea surface temperature (SST) in the low latitude ocean influencesintraseasonal variability in the atmosphere. Intraseasonal atmospheric variability in turn feedsback to the diurnal cycle of SST. The accurate representation of this ocean-atmosphere feedback is a major challenge for coupled ocean-atmosphere models, but critical for effective forecasting of the southwest monsoon and its subseasonal, quasi-periodic variability (i.e. the Monsoon Intraseasonal Oscillation (MISO)). Diurnal cycling depends both on local surface forcing and the character of upper ocean variability, which is often influenced by non-local oceanographic dynamics across a range of spatiotemporal scales. Our understanding of diurnalcycling, and thus our ability to accurately parameterize SST variability and its influenceon MISOs, is limited by the availability of appropriate in situ observations.Here we propose to use a Wirewalker-based ~Diurnal Cycling Array~ ~ deployed overthe course of two cruises during the MISO-BOB DRI~to collect vertically, horizontally, andtemporally well-resolved observations of temperature, salinity, optical characteristics, turbulentmicrostructure, and velocity in the context of air/sea flux measurements. These data willbe used to diagnose the influence of internal waves (particularly near inertial internal waveshear), submesoscale lateral variability, and barrier layer-type stratification on the evolution ofdiurnal sea-surface temperature. The data will be useful in constraining a variety of 1-D mixedlayer models, 3-D process (e.g. LES) models, and to test the potential of various parameterizationsof the diurnal cycle in coupled ocean-atmosphere models (a known deficiency of such models). The proposed work aims to understand the impact of diurnal SST fluctuations on the difficult-to-model, but critical to accurately forecast, MISO phenomenon in the Bay of Bengal, and is therefore relevant to both societal and Naval concerns.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712390
Entities
People
- Amala Mahadevan
Organizations
- Office of Naval Research
- United States Navy
- Woods Hole Oceanographic Institution