Ensemble regional and global climate prediction for the 1997/1998 winter Journal Article uri icon



  • The ensemble global and regional forecasts for the 1997/1998 winter were made in October 1997. The forecasted sea surface temperature anomalies (SSTA) in the tropical Pacific are obtained from the National Centers for Environmental Prediction (NCEP) coupled atmosphere‐ocean model. Outside of the tropical Pacific the observed SSTs at the initial date are relaxed to the SST climatology with the e‐folding time of 1 month. The global forecasts with the resolution of T62 are then downscaled using the NCEP regional spectral model (RSM) to enhance precipitation and temperature anomalies over the United States. The horizontal resolution of the RSM is 50km. The global forecasts over this warm El Niño‐Southern Oscillation (ENSO) winter have high skill over the Pacific North American region. Overall, the RSM downscaling improves the surface temperature and precipitation forecasts over the United States. However, it is more difficult to predict precipitation over a small region with certainty, because the spread among the members in the ensemble increases with the increase of horizontal resolution. The 50‐km RSM model is unable to forecast anomalies over high mountains and many centers of precipitation maxima along the California coast. The sensitivity test shows that to forecast basin scale precipitation, a regional model with 20 km or less is needed. Although the 20‐km RSM forecasts tend to overestimate precipitation maxima, it provides a more realistic distribution of precipitation. It can distinguish rainfall belts over high mountains and the relative dryness over the valley.

publication date

  • December 27, 2000

has restriction

  • bronze

Date in CU Experts

  • June 16, 2021 8:58 AM

Full Author List

  • Mo K; Kanamitsu M; Juang HMH; Hong S

author count

  • 4

Other Profiles

International Standard Serial Number (ISSN)

  • 0148-0227

Additional Document Info

start page

  • 29609

end page

  • 29623


  • 105


  • D24