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A conceptual model for the temporal spectrum of oceanic oxygen variability
Author(s) -
Ito Taka,
Deutsch Curtis
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl041595
Subject(s) - spectrum (functional analysis) , geology , environmental science , climatology , atmospheric sciences , oceanography , geophysics , physics , quantum mechanics
Changes in dissolved O 2 observed across the world oceans in recent decades have been interpreted as a response of marine biogeochemistry to climate change. Little is known however about the spectrum of oceanic O 2 variability. Using an idealized model, we illustrate how fluctuations in ocean circulation and biological respiration lead to low‐frequency variability of thermocline oxygen. Because the ventilation of the thermocline naturally integrates the effects of anomalous respiration and advection over decadal timescales, short‐lived O 2 perturbations are strongly damped, producing a red spectrum, even in a randomly varying oceanic environment. This background red spectrum of O 2 suggests a new interpretation of the ubiquitous strength of decadal oxygen variability and provides a null hypothesis for the detection of climate change influence on oceanic oxygen. We find a statistically significant spectral peak at a 15–20 year timescale in the subpolar North Pacific, but the mechanisms connecting to climate variability remain uncertain.