Sparse observations induce large biases in estimates of the global ocean CO2 sink: an ocean model subsampling experiment
Type | Article | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Date | 2023-06 | ||||||||||||
Language | English | ||||||||||||
Author(s) | Hauck Judith1, Nissen Cara1, 2, 3, Landschuetzer Peter4, Roedenbeck Christian5, Bushinsky Seth6, Olsen Are7, 8 | ||||||||||||
Affiliation(s) | 1 : Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany 2 : Department of Atmospheric and Oceanic Sciences, Boulder, CO, USA 3 : Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA 4 : Flanders Marine Institute (VLIZ), Ostend, Belgium 5 : Max Planck Institut für Biogeochemie, Jena, Germany 6 : School of Ocean and Earth Science and Technology, University of Hawai’i at M¯anoa, Department of Oceanography, Honolulu, HI, USA 7 : Geophysical Institute, University of Bergen, Bergen, Norway 8 : Bjerknes Centre for Climate Research, Bergen, Norway |
||||||||||||
Source | Philosophical Transactions Of The Royal Society A-mathematical Physical And Engineering Sciences (1364-503X) (Royal Soc), 2023-06 , Vol. 381 , N. 2249 , P. 20220063 (24p.) | ||||||||||||
DOI | 10.1098/rsta.2022.0063 | ||||||||||||
WOS© Times Cited | 15 | ||||||||||||
Keyword(s) | carbon dioxide, ocean carbon sink, pCO(2) observations, observation system design | ||||||||||||
Abstract | Estimates of ocean CO2 uptake from global ocean biogeochemistry models and pCO(2)-based data products differ substantially, especially in high latitudes and in the trend of the CO2 uptake since 2000. Here, we assess the effect of data sparsity on two pCO(2)-based estimates by subsampling output from a global ocean biogeochemistry model. The estimates of the ocean CO2 uptake are improved from a sampling scheme that mimics present-day sampling to an ideal sampling scheme with 1000 evenly distributed sites. In particular, insufficient sampling has given rise to strong biases in the trend of the ocean carbon sink in the pCO(2) products. The overestimation of the CO2 flux trend by 20-35% globally and 50-130% in the Southern Ocean with the present-day sampling is reduced to less than 15% with the ideal sampling scheme. A substantial overestimation of the decadal variability of the Southern Ocean carbon sink occurs in one product and appears related to a skewed data distribution in pCO(2) space. With the ideal sampling, the bias in the mean CO2 flux is reduced from 9-12% to 2-9% globally and from 14-26% to 5-17% in the Southern Ocean. On top of that, discrepancies of about 0.4 PgC yr(-1) (15%) persist due to uncertainties in the gas-exchange calculation.This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'. |
||||||||||||
Full Text |
|