Mar 4, 2019

Human Influence on Winter Precipitation Trends (1921–2015) over North America and Eurasia Revealed by Dynamical Adjustment

by
Ruixia Guo, Clara Deser, Laurent Terray, Flavio Lehner
,
Geophysical Research Letters
  • States that detecting and attributing a human influence on observed rainfall trends is a major challenge due to the presence of large amplitude internal variability on all time scales and by limited temporal and spatial data coverage
  • Applies a “dynamical adjustment” methodology to a gridded archive of monthly precipitation to estimate an anthropogenic influence on long‐term (1920–2015) trends over North America and Eurasia during winter (November–March)
  • This empirical approach aims to remove atmospheric circulation influences from precipitation variability and trends, thereby revealing the thermodynamically induced component as a residual
  • The geographical pattern and amplitude of this observed thermodynamic residual precipitation trend are in good agreement with anthropogenically forced trends obtained from ensembles of historical climate model simulations
  • Such consistency helps to reconcile observations and models and provides compelling evidence for a human influence on century‐scale precipitation trends over North America and Eurasia during the cold season
  • Concludes that we are able to identify a human influence on observed century‐scale precipitation trends over North America and Eurasia