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Published on: July 24, 2016
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Uncertainty reduction for precipitation prediction in North America
Dan Lou1, Wouter R Berghuijs2, Waheed Ullah3
1Nanjing Nriet Industrial Co., Ltd., Nanjing, China.
Plos One
|May 22, 2024
Summary
Future precipitation projections for North America are overestimated by climate models. An emergent constraint reveals that incorporating historical temperature trends narrows uncertainties and corrects precipitation and evaporation estimates.
Area of Science:
- Climate modeling and prediction
- Atmospheric science and land-atmosphere interactions
Background:
- Significant discrepancies exist in projected North American precipitation increases across 27 Coupled Model Intercomparison Project Phase 6 (CMIP6) models and four emission scenarios.
- These variations are partly attributed to inadequate representations of land-atmosphere interactions within current climate models.
Purpose of the Study:
- To establish an emergent constraint relationship linking future precipitation growth rates with historical temperature trends.
- To refine CMIP6 precipitation projections for North America by integrating observed warming data.
- To assess potential overestimations in temperature and evaporation rates predicted by existing models.
Main Methods:
- Developed an emergent constraint based on the relationship between annual precipitation growth rates and historical temperature growth rates.
- Applied observed warming trends to adjust original CMIP6 precipitation projections across four Shared Socioeconomic Pathways (SSPs).
- Quantified the reduction in uncertainty (standard deviation) of precipitation projections post-constraint.
Main Results:
- Constrained CMIP6 projections indicate lower future precipitation increases per decade: 0.40-0.48% (SSP126), 0.83-0.93% (SSP245), 1.29-1.45% (SSP370), and 1.70-1.87% (SSP585).
- The emergent constraint reduced projection uncertainties by 13.8-31.1%.
- Original CMIP6 models overestimated annual temperature increases (6.0-13.2%) and total evaporation (4.8-14.5%) compared to constrained results.
Conclusions:
- North American future precipitation projections from CMIP6 models are likely overestimated.
- Temperature plays a crucial role in accurate climate predictions, highlighting systematic errors in current model simulations.
- The study underscores the importance of refining land-atmosphere interactions and temperature representations in climate models.
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