Paul Dirmeyer, Benjamin Kirtman, Eric Altshuler, Michael Fennessy

October 1999     www.iges.org/lba
 
 

• Preliminary comparisons of 3-month mean precipitation (Jan-Mar) during five different years are shown in each panel below from:
• Regional Spectral Model (RSM - Upper Left) at 80 km resolution
• Eta Regional Model (ETA - Upper Right) at 80 km resolution
• COLA Global GCM (GCM - Lower Left) at 1.8×2.8 resolution
• CMAP Observed Rainfall (Xie-Arkin - Lower Right) on a 2.5 grid
• The RSM appears to produce a geneally superior simulation over the other models, especially coverage and area of moderate-heavy precipitation over land and the ITCZ.
• Eta is too dry, especially on the northern and southern edges of the Amazon basin.
• Spectral models do have trouble over the Andes.
• Note how all models pick up the “double ITCZ” during 1989.