Background
The authors write that "the Asian monsoon influences almost half of the world's population with their agriculture, life and society depending on monsoon climate," and, therefore, they say that "understanding the physical processes that determine the character of the monsoon systems and also providing accurate extended range predictions on a seasonal timescale is crucial [italics added] for the economy and policy planning in the monsoon regions."

What was done
Kim et al. assessed the seasonal prediction skill of the Asian summer monsoon via the use of "retrospective predictions (1982-2009) from the ECMWF System 4 (SYS4) and NCEP CFS version 2 (CFSv2) seasonal prediction systems."

What was learned
In the words of the four researchers, "in both SYS4 and CFSv2, a cold bias of sea-surface temperature (SST) is found over the Equatorial Pacific, North Atlantic [and] Indian Oceans," as well as "over a broad region in the Southern Hemisphere relative to observations," while "a warm bias is found over the northern part of the North Pacific and North Atlantic." In addition, they state that "excessive precipitation is found along the Intertropical Convergence Zone, equatorial Atlantic, equatorial Indian Ocean and the maritime continent." And, last of all, they indicate that "the southwest monsoon flow and the Somali Jet are stronger in SYS4, while the south-easterly trade winds over the tropical Indian Ocean, the Somali Jet and the Subtropical northwestern Pacific high are weaker in CFSv2 relative to the reanalysis."

What it means
With both of the world's most advanced climate modeling systems "performing poorly," in the estimation of Kim et al., in simulating monsoon precipitation that affects almost half of the world's population, it would appear that the climate modeling enterprise still has a long ways to go before anyone should get too excited about what the fruits of that endeavor are suggesting.