资源环境科技发展态势分析平台

The newly released simulations from the Sixth Phase of the Coupled Model Intercomparison Project (CMIP6) provide an opportunity to re‐examine long‐term soil moisture trends. In this study, we assessed the historical simulation (1850‐2014) of surface soil moisture from 18 General Circulation Models that are part of CMIP6 and compared them with model simulations from CMIP5 and NLDAS‐2, and in‐situ observations over CONUS. Our results show that for CONUS as a whole, there is no significant long‐term trend in soil moisture, but significant drying trends exist over medium‐term, short‐term and near‐present periods based on the CMIP6. Our comparison of CMIP6 to NLDAS‐2 (1980‐2014) and in‐situ observations (2004‐2014) demonstrates that it more accurately captures soil moisture trends in CONUS than CMIP5. CMIP6 shows a significant wetting trend in the Northwest, Midwest, Northeast and Southeast. There is greater agreement amongst the individual models in CMIP6 than CMIP5, but inter‐model variability still exists.