Correcting oceanic O-2/Ar-net community production estimates for vertical mixing using N2O observations

Citation:
Cassar, N, Nevison CD, Manizza M.  2014.  Correcting oceanic O-2/Ar-net community production estimates for vertical mixing using N2O observations. Geophysical Research Letters. 41:8961-8970.

Date Published:

2014/12

Keywords:

Ar, atmospheric n2o, bellingshausen sea, biological production, gas-exchange, inlet mass-spectrometry, n2o, net community production, nitrous-oxide production, north-atlantic ocean, o-2, oligotrophic ocean, oxygen, sea heat fluxes, southern-ocean

Abstract:

The O-2/Ar approach has become a key method to estimate oceanic net community production (NCP). However, in some seasons and regions of the ocean, strong vertical mixing of O-2-depleted deepwater introduces a large error into O-2/Ar-derived NCP estimates. In these cases, undersaturated-O-2/Ar observations have for all intents and purposes been ignored. We propose to combine underway O-2/Ar and N2O observations into a composite tracer that is conservative with respect to the influence of vertical mixing on the surface biological O-2 inventory. We test the proposed method with an ocean observing system simulation experiment (OSSE) in which we compare N2O-O-2/Ar and O-2/Ar-only gas flux estimates of NCP to the model-simulated true NCP in the Southern Ocean. Our proof-of-concept simulations show that the N2O-O-2/Ar tracer significantly improves NCP estimates when/where vertical mixing is important.

Notes:

n/a

Website

DOI:

10.1002/2014gl062040