Autonomous seawater partial pressure of carbon dioxide (pCO2) and pH time series from 40 surface buoys between 2004 and 2017 (NCEI Accession 0173932)

This dataset consists of the data synthesis product files that include autonomous seawater pCO2, pH, sea surface temperature and salinity time series measurements from 40 surface buoys between 2004 and 2017. Ship-based time series, some now approaching over three decades long, are critical climate records that have dramatically improved our ability to characterize natural and anthropogenic drivers of ocean carbon dioxide (CO2) uptake and biogeochemical processes. Advancements in autonomous ocean carbon observing technology over the last two decades have led to the expansion of fixed time series stations with the added capability of characterizing sub-seasonal variability. Here we present a data product of 40 autonomous moored surface ocean pCO2 and pH time series established between 2004 and 2013. These time series characterize a wide range of seawater pCO2 and pH conditions in different oceanic (17 sites) and coastal (13 sites) regimes including coral reefs (10 sites). With well-constrained daily to interannual variability and an estimate of decadal variability, these data suggest the length of time series necessary to detect an anthropogenic trend in seawater pCO2 and pH varies from 8 to 15 years at the open ocean sites, 16 to 41 years at the coastal sites, and 9 to 22 years at the coral reef sites. Only two open ocean pCO2 time series, WHOTS in the subtropical North Pacific and Stratus in the South Pacific gyre, are longer than the estimated time of emergence, and deseasoned monthly means show anthropogenic trends of 1.9+/-0.3 µatm yr-1 and 1.6+/-0.3 µatm yr-1, respectively. In the future, it is possible that updates to this product will allow for estimating anthropogenic trends at more sites; however, the product currently provides a valuable tool in an accessible format for evaluating climatology and natural variability of surface ocean carbonate chemistry in a variety of regions.