Moored observations of episodic abyssal flow and mixing at station ALOHA

Details Moored observations of episodic abyssal flow and mixing at station ALOHA Moored observations of episodic abyssal flow and mixing at station ALOHA

Aug 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011georl..3815606a&link_type=abstract

Geophysical Research Letters, Volume 38, Issue 15, CiteID L15606

Other

Oceanography: Physical: Deep Recirculations, Oceanography: Physical: Internal And Inertial Waves, Oceanography: Physical: Overflows, Oceanography: Physical: Turbulence, Diffusion, And Mixing Processes (4490)

Scientific paper

Moored measurements of abyssal velocity and temperature are presented with a focus on episodic cold overflow events first observed by Lukas et al. (2001) in the Hawaii Ocean Time-series (HOT), a 23-year-long time series of ≈ monthly CTD profiles at station ALOHA (22.75°N, 158°W). Three major cold events were observed in our 2.5-year record, of which we present one in detail. The event appeared in two pulses spaced by about two weeks, wherein potential temperature anomaly was <-0.015°C over the bottom 600 m. Flow was about 10 cms-1 to the southwest, confirming earlier interpretations of the events as overflows from the Maui deep to the east. Between the two pulses, flow veered to the northwest, possibly associated with seiching. Speed decreased rapidly below the sill depth (≈4625) m, suggesting sheltering by the basin walls. The associated shear, even smoothed over 200 m and not including internal waves, was nearly unstable to Kelvin-Helmholtz instability. During this period, a large mixed region was observed wherein the lower 240 m was homogenized, remaining so for 14 hours (1.2 buoyancy periods). From Thorpe scale analysis, the implied diffusivity of the event was (0.5-4.5) × 10-1m2s-1. No other overturning events greater than 50 m high were observed in the record, suggesting that abyssal mixing is strongly intermittent. We suggest that such intermittency in abyssal mixing and flow is likely the rule rather than the exception, calling for more highly temporally resolved observations.

Affiliated with

Also associated with

No associations

Rating

Moored observations of episodic abyssal flow and mixing at station ALOHA does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Moored observations of episodic abyssal flow and mixing at station ALOHA, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Moored observations of episodic abyssal flow and mixing at station ALOHA will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1675558