Penetrative radiative flux in the Bay of Bengal

TitlePenetrative radiative flux in the Bay of Bengal
Publication TypeJournal Article
Year of Publication2016
AuthorsLotliker A.A, Omand M.M, Lucas A.J, Laney S.R, Mahadevan A., Ravichandran M.
JournalOceanography
Volume29
Pagination214-221
Date Published2016/06
Type of ArticleArticle
ISBN Number1042-8275
Accession NumberWOS:000380572500024
Keywordscirculation; diffuse attenuation coefficient; downwelling irradiance; models; upper ocean
Abstract

The Bay of Bengal (BoB), a semi-enclosed basin in the northern Indian Ocean, is a complex region with large freshwater inputs and strong vertical stratification that result in a shallow, spatially variable mixed layer. With the exception of shortwave insolation, the air-sea heat exchange occurs at the sea surface and is vertically redistributed by mixing and advection. Strongly stratified, shallow mixed layers inhibit vertical mixing, and the penetration of solar radiation through the base of the mixed layer can lead to redistribution of upper-ocean heat. This paper compiles observations of hyperspectral downwelling irradiance (E-d) from 67 profiles collected during six research cruises in the BoB that span a broad range of regions and seasons between 2009 and 2014. We report attenuation length scales computed using double and single exponential models and quantify the penetration of radiative flux below the mixed layer depth (Q(pen)). We then evaluate estimates of Qpen obtained from published chlorophyll-based models and compare them to our observations. We find that the largest penetrative heat flux (up to 40% of the incident E-d) occurs near 16 degrees N where the mixed layers are shallow and the water is optically clear.

DOI10.5670/oceanog.2016.53
Short TitleOceanography
Student Publication: 
No