Indian Forum for Water Adroit

Can we Constrain Uncertainty in Hydrologic Cycle Projections?

Pankaj Dey

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  • Institute : Indian Institute of Science
  • Programming language : MATLAB, R
How precipitation changes with warming is critically important for anticipating and responding to climate change, but climate models still disagree on many aspects of its change. A new study by Thackeray et al. (2018) reveals two intriguing aspects of precipitation change among the most recent generation of climate model projections: a compensation between precipitation change arising from the heaviest events and events that are not heavy events, and a dependence of this relationship on the climate model’s resolution. We argue that their findings point toward paths that could lead to further understanding and improvements in simulations of precipitation change.
Link to Thackeray et al.(2018): https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079698

The global water cycle is expected to intensify under climate change and can be generally characterized by greater rainfall and surface evaporation in the future. However, the rate at which the globally averaged precipitation increases is highly variable among different climate models. In this paper, we relate the intermodel variability in global water cycle intensification to differences in model projections of heavy precipitation in tropical and some extratropical regions. We also find that models consistently experience a trade‐off between increasing heavy and decreasing light‐moderate precipitation: Models with larger future increases in heavy precipitation exhibit greater compensating declines in light‐moderate rainfall. Differences in heavy precipitation changes are also tied to model resolution. Our study helps to provide new insight on the factors shaping projections of future precipitation extremes, which have strong implications for water resources, natural hazard risks associated with flooding, and ecosystem stability.


Link to the original paper: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL081529



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