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Enhanced hydrological cycle increases ocean heat uptake and moderates transient climate change.

Maofeng LiuGabriel VecchiBrian SodenWenchang YangBosong Zhang
Published in: Nature climate change (2021)
The large-scale moistening of the atmosphere in response to increasing greenhouse gases amplifies the existing patterns of precipitation minus evaporation (P-E) which, in turn, amplifies the spatial contrast in sea surface salinity (SSS). Through a series of transient CO2 doubling experiments, we demonstrate that surface salinification driven by the amplified dry conditions (P-E < 0), primarily in the subtropical ocean, accelerates ocean heat uptake. The salinification also drives the sequestration of upper-level heat into the deeper ocean, reducing the thermal stratification and increasing the heat uptake through a positive feedback. The change in Atlantic Meridional Overturning Circulation due to salinification plays a secondary role in heat uptake. Consistent with the heat uptake changes, the transient climate response would increase by approximately 0.4 K without this process. Observed multi-decadal changes in subsurface temperature and salinity resembles those simulated, indicating that anthropogenically-forced changes in salinity are likely enhancing the ocean heat uptake.
Keyphrases
  • heat stress
  • climate change
  • microbial community
  • magnetic resonance imaging
  • magnetic resonance
  • contrast enhanced