Temporal evolution of mooring-based observations of double diffusive staircases in the southeast Canada Basin

Qu Ling; Song Xuelong; Zhou Shengqi

doi:10.3969/j.issn.0253-4193.2015.01.003

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Qu Ling, Song Xuelong, Zhou Shengqi. Temporal evolution of mooring-based observations of double diffusive staircases in the southeast Canada Basin[J]. Haiyang Xuebao, 2015, 37(1): 21-29. doi: 10.3969/j.issn.0253-4193.2015.01.003

Citation:

Qu Ling, Song Xuelong, Zhou Shengqi. Temporal evolution of mooring-based observations of double diffusive staircases in the southeast Canada Basin[J]. Haiyang Xuebao, 2015, 37(1): 21-29. doi: 10.3969/j.issn.0253-4193.2015.01.003

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Temporal evolution of mooring-based observations of double diffusive staircases in the southeast Canada Basin

doi: 10.3969/j.issn.0253-4193.2015.01.003

1.
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;University of Chinese Academy of Sciences, Beijing 100049, China
2.
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China

Received Date: 2014-03-26
Rev Recd Date: 2014-05-11

Abstract

Abstract

In the upper Canada Basin,double-diffusive staircases are located between the Atlantic Water (AW) and the Lower Halocline Water (LHW). The McLane Moored Profiler (MMP) data measured from August 2005 to August 2011 at subsurface mooring stations are analyzed to explore the relationship between double-diffusive staircases and these two water masses. In the fixed salinity interval between 34.45 and 34.83,eighteen staircases are identified. It is found that the potential temperature of staircases is affected by their adjacent water masses and also the formation and decay of their adjacent staircases. There is heart transfer from the AW to the overlying staircases and the LHW,and the depth variations of the staircases and the AW are determined by the depth of the LHW. The adjacent staircases show almost the same variation trend between its potential temperature and depth. Based on the empirical formula,the heat flux across the staircase is estimated to be 0.05 to 0.6 W/m². The vertical heat flux is found to gradually increase as the salinity decreases upward. In addition,the effective vertical diffusivity,which is caused by double-diffusive convection,is estimated to be about 3×10^-6 to 3.3×10^-5 m²/s,and it gradually decreases as the salinity decreases.
- Canada Basin,
- double-diffusive staircase,
- water mass

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