资源环境科技发展态势分析平台

Changes in Southern Ocean ventilation imprint on dissolved gases, nutrients, radiocarbon, temperature, and salinity. We deconvolve tracer measurements for the distribution, G, of times and locations of last ventilation using a maximum-entropy approach. Decadal changes of G are quantified by deconvolving hydrographies measured during the early 1990s and again some 15years later. Our analysis reveals coherent changes across the five meridional sections analyzed: The fraction of water younger than 30years decreased by approximate to 20% per decade south of 40 degrees S in circumpolar deep water (CDW) and increased by approximate to 10% per decade north of approximate to 40 degrees S in subantarctic mode water (SAMW). Ventilation locations shifted, with more water south of 40 degrees S being ventilated north of the subantarctic front. These ventilation changes impacted CFC uptake, with concentrations south of 40 degrees S less than (and north of 40 degrees S higher than) expected for steady flow. The inferred changes imply increased SAMW formation and CDW upwelling consistent with strengthened westerly winds.