Abyssal Circulation andVentilation of Deep Ocean Basins

Roger LukasKlaus Wyrtki SymposiumKlaus Wyrtki Symposium

April 9, 2013

Upper 1000 m of the Pacific Ocean

Cold water sphere and Warm Water sphere

Sections from J. Reid along ~160W

My Discovery of the DeepMy Discovery of the Deep

• Like Klaus I found the slow abyssalLike Klaus, I found the slow abyssal circulations to be less interesting than the monsoons and El Niñomonsoons and El Niño

• Serendipity and the HOT project changed thatthat

• Klaus and the Conveyor Belt

Indonesian Seas

Solomon and Coral Seas ‐ 1961Solomon and Coral Seas  1961

2TKTw

2z

Kz

w T

The Red Sea ‐ 1974The Red Sea  1974

see also Patzert (1974, Ph.D.)

Wyrtki (1994, unpublished)Wyrtki (1994, unpublished)

annotations/updates by RL

Kauai Deep and Station ALOHAKauai Deep and Station ALOHA

Cold overflow eventsCold overflow events

Cold overflow eventsCold overflow events

Advection ‐ DiffusionAdvection  Diffusion

• Classic assumption of steady stateC ass c assu pt o o steady state• Estimates of w given assumptions• Assumptions about constant eddy diffusivityAssumptions about constant eddy diffusivity

zTK

zzTw

tT

T

• No time‐series to do better• HOT provided the opportunity to do better

HOT provided the opportunity to do better• With a simple time‐dependent model, estimates of KT(z,t) were possibleof KT(z,t) were possible

Klaus’ workKlaus  work

Enhanced vertical mixingEnhanced vertical mixing

ALOHA CabledALOHA Cabled Observatory

The ALOHA Cabled Observatory

The ALOHA Cabled Observatory

A deep basin internal seiche!

but, I beg to disagreebut, I beg to disagree

Equatorial Theoretical Panel, 1983? @Nova U.@ Nova U.

SummarySummary

• Klaus delighted in discovery –g y• “If you look closer, you will always find something.”

• So, I was wrong – the abyss is interesting:highly episodic– highly episodic

– turbulent kinetic energy greatly enhanced during overflows

– very dynamic• ACO – monitoring the abyss!

Penang, Malaysia/IOC/WESTPAC 1991

photo by W. Patzert