An update to the Surface Ocean CO<sub>2</sub> Atlas (SOCAT version 2)

Abstract

International audienceThe Surface Ocean CO₂ Atlas (SOCAT) is an effort by the international marine carbon research community. It aims to improve access to carbon dioxide measurements in the surface oceans by regular releases of quality controlled and fully documented synthesis and gridded <em>f</em>CO₂ (fugacity of carbon dioxide) products. SOCAT version 2 presented here extends the data set for the global oceans and coastal seas by four years and has 10.1 million surface water <em>f</em>CO₂ values from 2660 cruises between 1968 and 2011. The procedures for creating version 2 have been comparable to those for version 1. The SOCAT website (http://www.socat.info/) provides access to the individual cruise data files, as well as to the synthesis and gridded data products. Interactive online tools allow visitors to explore the richness of the data. Scientific users can also retrieve the data as downloadable files or via Ocean Data View. Version 2 enables carbon specialists to expand their studies until 2011. Applications of SOCAT include process studies, quantification of the ocean carbon sink and its spatial, seasonal, year-to-year and longer-term variation, as well as initialisation or validation of ocean carbon models and coupled-climate carbon models

Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean

“…Results in situ, however, demonstrate that this limitation may act only within a low range of CO 2 concentrations, up to a threshold of about 150 µatm, below which nutrient depletion would outweigh CO 2 limitation. Surface water in the European Arctic in the spring is depleted in CO 2 owing to strong net community production during the bloom 2,13 and freshening by sea-ice melting 10 , resulting in the lowest p CO 2 values reported anywhere in the ocean 11 , with values as low as 135 µatm found in our field survey, and 45 µatm reported in the literature 21 .…”

Measuring pH in the Arctic Ocean: Colorimetric method or SeaFET?

“…Generally, the Arctic Ocean remains one of the less documented oceans in terms of the regional dynamics of the carbonate system (e.g. GLODAP and SOCAT databases Sabine et al, 2005;Bakker et al, 2014). Available oceanographic data have been collected mostly in summer and across the shallow and large shelf (Bates and Mathis, 2009;Miller et al, 2014).…”

“…Available oceanographic data have been collected mostly in summer and across the shallow and large shelf (Bates and Mathis, 2009;Miller et al, 2014). Currently, the carbonate system parameter with the most abundant dataset is the partial pressure of CO 2 (pCO 2 ) as a result of the development of automated shipboard pCO 2 analysers running continuously on the underway water supply of scientific R/Vs, which are relatively easy to maintain (Bakker et al, 2014). The first surface oceanic pH values measured with an automated instrument along a cruise transect in the Arctic has recently been reported by Tynan et al (2016) for the Fram strait region.…”

Quantifying uncertainty sources in the gridded data of sea surface CO2 partial pressure

“…After Tan et al [1990], the first compilation of sea surface pCO 2 data measured since 1972, tremendous efforts have been devoted to acquiring surface ocean pCO 2 data, primarily through underway measurements around the world's oceans [e.g., Bakker et al, 2013;Pfeil et al, 2013;Sabine et al, 2013;Wanninkhof et al, 2013]. When estimating the air-sea CO 2 fluxes, observational CO 2 data are typically aggregated onto grid boxes to establish gridded data [e.g., Takahashi et al, 1997Takahashi et al, , 2002Takahashi et al, , 2009.…”