Dissolved inorganic carbon, alkalinity, pH, temperature, salinity, and other variables collected from profile observations using CTD, discrete bottles, and other instruments from October 7, 1977 to March 11, 2006, as synthesized in the CARbon dioxide IN the Atlantic Ocean (CARINA) Database (NCEI Accession 0113899)

The CARINA (CARbon dioxide IN the Atlantic Ocean) data synthesis project is an international collaborative effort of the EU IP CARBOOCEAN, and US partners. It has produced a merged internally consistent data set of open ocean subsurface measurements for biogeochemical investigations, in particular, studies involving the carbon system. The original focus area was the North Atlantic Ocean, but over time the geographic extent expanded and CARINA now includes data from the entire Atlantic, the Arctic Ocean, and the Southern Ocean.

Atlantic Ocean Data Synthesis

The Atlantic Ocean subset of the CARINA (CARINA-ATL) data set consists of 98 cruises/entries, of which one of is a time series including many cruises and two others are collections of multiple cruises within the framework of a common project. Additionally, six reference cruises were included in the secondary QC for CARINA-ATL to ensure consistency between CARINA and historical databases, in particular Global Ocean Data Analysis Project (GLODAP, Key et al., 2004). Five Atlantic cruises are in common with the Southern Ocean region, and five others are in common with the Arctic Mediterranean Seas region. These overlapping cruises ensure consistency between the three regions of the CARINA data set. The Atlantic Ocean region of CARINA is loosely defined as the area between of the Greenland-Scotland Ridge and 30 °S, but as mentioned, ten cruises overlap with the surrounding regions, thus extending the area covered. Most of the data are from the subpolar North Atlantic, and there are particularly large data gaps in the Tropical and South-Eastern Atlantic Ocean. The CARINA-ATL database covers the time period from 1978 to 2006, with the majority of the data from the mid 1990s to the mid 2000s. Overall, oxygen measurements show the highest incidence, followed by TCO2, Alkalinity and CFC data, although CFC data are particularly abundant for some specific regions.

Arctic Mediterranean Seas Data Synthesis

The Arctic Mediterranean Seas subset of CARINA (CARINA-AMS) includes data from 62 cruises/campaigns in the Arctic Ocean and Nordic Seas. One of these is a time series and one is a collection of data from multiple cruises to the same area conducted within a year. Five of the CARINA-AMS entries are in common with the CARINA-ATL subset ensuring consistency with the other CARINA subsets and thus GLODAP. While data coverage was quite dense in the Nordic Seas, it was sparse in the Arctic Ocean. This motivated the use of different methods for quality control in these two areas. The Arctic Ocean was defined as the region north of the Fram and Bering Straits, the Arctic Ocean shelf seas, and the Canadian Archipelago. The Nordic Seas was defined as the region enclosed by the Fram Strait to the North, Greenland to the west, the Greenland-Scotland Ridge to the South, and Norway, the Barents Sea Opening, and Spitsbergen to the east. The analyses of the Arctic Ocean data involved extended use of linear and multiple linear regressions and is described by Jutterström et al. (2009), while the analyses of the Nordic Seas data was mostly carried out using the crossover and inversion approach and is described per parameter in Falck and Olsen (2009), Olafsson and Olsen (2009), Olsen (2009), Olsen (2009) and Olsen et al. (2009). The analyses of the AMS CFC data are described by Jeansson et al. (2009).

Southern Ocean Carbon Synthesis

Compared to other regions within the CARINA data set, the Southern Ocean database consists of relatively few data - 37 cruises. Five cruises in the northern part of the Atlantic sector of the Southern Ocean are in common with the CARINA-ATL, thus additionally warranting high internal data quality. The northern boundary of the CARINA Southern Ocean region is roughly at 30°S latitude. Considering all stations in the Southern Ocean CARINA dataset there is a bias towards the north, indicating that data close to the Antarctic continent is still sparse. Besides the new CARINA cruises, 46 cruises from the GLODAP database were incorporated in the analysis as reference cruises. Nutrient and oxygen data have a clearly higher incidence than TCO2 and total alkalinity data. Chlorofluorocarbons (CFCs) are also included in the Southern Ocean dataset, but they have not been quality controlled. Not surprisingly, most of the CARINA Southern Ocean data originate from the post-GLODAP era, i.e., from 2000 or later. Region specific quality control is described in three papers, for the Pacific sector by Sabine et al. (2009), the Indian sector by Lo Monaco et al. (2009) and the Atlantic sector by Hoppema et al. (2009).