Evaluation of Temperature and Precipitation Trends and Long-Term Persistence in CMIP5 Twentieth-Century Climate Simulations
Kumar, Sanjiv, Venkatesh Merwade, James L. Kinter, Dev Niyogi, 2013: Evaluation of Temperature and Precipitation Trends and Long-Term Persistence in CMIP5 Twentieth-Century Climate Simulations. J. Climate, 26, 4168–4185.
The authors have analyzed twentieth-century temperature and precipitation trends and long-term persistence from 19 climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). This study is focused on continental areas (60°S–60°N) during 1930–2004 to ensure higher reliability in the observations. A nonparametric trend detection method is employed, and long-term persistence is quantified using the Hurst coefficient, taken from the hydrology literature.From CO2 Science: (link)
What was learned
Although some things were done well by the participating models, others were not. Kumar et al. report, for example, that "the models capture the long-term persistence in temperature reasonably well," but they say that "the models have limited capability to capture the long-term persistence in precipitation." They also state that "most climate models underestimate the spatial variability in temperature trends," and they say there were "large uncertainties in the simulation of regional-/local-scale temperature and precipitation trends." In addition, they report that "Sakaguchi et al. (2012a,b) have evaluated the simulation skill for temperature trends from selected CMIP3 and CMIP5 climate models," finding "limited skill in the simulation of temperature trends at regional scales in these climate models."
Finally, "from a regional natural resource planning perspective," the four scientists write that the multimodel-ensemble averages provide what they kindly call "conservative value for planning or design." As an example, they note that "the India and West Africa regions are drying much faster (-20 mm/decade) in the observations than simulations by the multimodel-ensemble average (-5 mm/decade)," while similarly noting that "north-central Asia is warming twice as fast as the global-average warming," which is something "not found in the multimodel-ensemble average."
What it means
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