New insight into deep ocean warming from tracer data and another decade of repeat hydrography
Previous comparisons of repeated hydrographic sections between the 1990s and 2000s revealed a global pattern of deep and abyssal ocean warming in regions of the ocean fed by dense waters of Southern Origin. However, the mechanisms driving the deep warming are still poorly understood. Here, we focus on deep ocean variability in the Pacific Ocean. First, we present updated deep ocean warming rates in the Pacific including five new repeated hydrographic sections. The abyssal Pacific, in contrast to a reversal in the trend seen in the South Atlantic, has shown a remarkably stable warming rate over the past 3 decades. Second, we use transient tracers to explore deep circulation and show there has been a detectible decrease in the tracer age of Antarctic Bottom Water (AABW) in the Pacific sector of the Southern Ocean.