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gfdl's home page > gfdl on-line bibliography > 1994: Monthly Weather Review, 122(3), 507-516

Skill and return of skill in dynamic extended-range forecasts

Anderson, J. L., and H. M. van den Dool, 1994: Skill and return of skill in dynamic extended-range forecasts. Monthly Weather Review, 122(3), 507-516.
Abstract:The skill of a set of extended-range dynamical forecasts made with a modern numerical forecast model is examined. A forecast is said to be skillful if it produces a high quality forecast by correctly modeling some aspects of the dynamics of the real atmosphere; high quality forecasts may also occur by chance. The dangers of making a conclusion about model skill by verifying a single long-range forecast are pointed out by examples of apparently high "skill" verifications between extended-range forecasts and observed fields from entirely different years
To avoid these problems, the entire distribution of forecast quality for a large set of forecasts as a function of lead time is examined. A set of control forecasts that clearly have no skill is presented. The quality distribution for the extended-range forecasts is compared to the distributions of quality for the no-skill control forecast set
The extended-range forecast quality distributions are found to be essentially indistinguishable from those for the no-skill control at leads somewhat greater than 12 days. A search for individual forecasts with a "return of skill" at extended ranges is also made. Although it is possible to find individual forecasts that have a return of quality, a comparison to the no-skill controls demonstrates that these return of skill forecasts occur only as often as is expected by chance
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last modified: March 23 2004.