Science Source
Thomas R. Knutson and Fanrong Zeng
AMS Journal of Climate
Published date March 12, 2018
AMS Journal of Climate
Published date March 12, 2018
Model Assessment of Observed Precipitation Trends Over Land Regions: Detectable Human Influences and Possible Low Bias in Model Trends
- Assesses precipitation trends for 1901–2010, 1951–2010, and 1981–2010 over relatively well-observed global land regions for detectable anthropogenic influences and for consistency with historical simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5)
- Finds that the CMIP5 historical all-forcing runs are broadly consistent with the observed trend pattern (1901–2010), but with an apparent low trend bias tendency in the simulations
- Finds, despite this bias, that observed and modeled trends are statistically consistent over 59% of the analyzed area.
- Finds that over 20% (9%) of the analyzed area, increased (decreased) precipitation is partly attributable to anthropogenic forcing, including:
- Increases over regions of the north-central United States, southern Canada, Europe, and southern South America and
- Decreases over parts of the Mediterranean region and northern tropical Africa
- Trends for the shorter periods (1951–2010 and 1981–2010) do not indicate a prominent low trend bias in the models, as found for the 1901–2010 trends
