A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP)

Abstract

During the 1990s, ocean sampling expeditions were carried out as part of the World Ocean Circulation Experiment (WOCE), the Joint Global Ocean Flux Study (JGOFS), and the Ocean Atmosphere Carbon Exchange Study (OACES). Subsequently, a group of U.S. scientists synthesized the data into easily usable and readily available products. This collaboration is known as the Global Ocean Data Analysis Project (GLODAP). Results were merged into a common format data set, segregated by ocean. For comparison purposes, each ocean data set includes a small number of high‐quality historical cruises. The data were subjected to rigorous quality control procedures to eliminate systematic data measurement biases. The calibrated 1990s data were used to estimate anthropogenic CO2, potential alkalinity, CFC watermass ages, CFC partial pressure, bomb‐produced radiocarbon, and natural radiocarbon. These quantities were merged into the measured data files. The data were used to produce objectively gridded property maps at a 1° resolution on 33 depth surfaces chosen to match existing climatologies for temperature, salinity, oxygen, and nutrients. The mapped fields are interpreted as an annual mean distribution in spite of the inaccuracy in that assumption. Both the calibrated data and the gridded products are available from the Carbon Dioxide Information Analysis Center. Here we describe the important details of the data treatment and the mapping procedure, and present summary quantities and integrals for the various parameters.

Developments in Radiocarbon Technologies: From the Libby Counter to Compound-Specific AMS Analyses

“…Δ 14 C (a measure of the offset from pre-bomb natural 14 C) is shown for the upper 1200 m of the water column in the Pacific, Southern, and Indian oceans, reflecting the penetration of 14 C generated in the 1960s by tropospheric nuclear bomb testing. The enormous task of compiling the data into formats usable in modeling and other types of interpretative assessments has been carried out by Princeton scientist Robert Key (Key 1996;Key et al 1996Key et al , 2002Key et al , 2004. The new data set vastly expands and refines the 14 C maps available from prior programs (e.g.…”

“…Matsumoto (2007) revisits the question how 14 C can help to determine the circulation age of the world oceans. He uses the gridded data by Key et al (2004) to establish a map of 14 C ages that takes proper account of surface reservoir ages. The measured 14 C levels at depths below 1500 m suggest maximum "ages" above 2000 yr for the Pacific, whereas the corrected values are less than 1200 yr.…”

Evaluation of a near-global eddy-resolving ocean model

“…initialised from GLODAP (Key et al, 2004). To generate the annual mean fields of DIC and ALK for the nominal year 1997, we started with the observed climatology of Takahashi et al (2009) from the year 2000, and then calculated ALK and DIC following Lenton et al (2012) using the annual mean sea surface and salinity from WOA2005 from Locarnini et al (2006) and Antonov et al (2006) respectively.…”

“…To correct the DIC to 1997, we used the observed global atmospheric growth rate from Mauna Loa (Earth System Research Laboratory, 2009) and the approximation of the Revelle factor (Sarmiento and Gruber, 2006). We then calculated the difference in the surface between our calculated DIC and ALK, and GLODAP DIC and ALK (Key et al, 2004), and corrected the entire water column based on this surface difference.…”

Variability of oceanic carbon cycle in the North Pacific from seasonal to decadal scales

“…The initial conditions for TALK and TCO 2 are prescribed from the GLODAP data set [Key et al, 2004]. The model has been forced with the climatological air-sea fluxes of momentum, heat, and fresh water as well as preindustrial atmospheric CO 2 for 100 years to reach a quasiequilibrium state.…”