Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Developmental Testbed Center (DTC)

The Developmental Testbed Center plays a key role in objectively identifying improvements in forecast models. Betsy Weatherhead has played a key role in identifying statistical tests to determine whether a particular forecast model shows a significant improvement over other available models. The techniques included time series analysis of pairwise differences for wind, temperature and humidity.

The estimates for pair-wise mean differences between the RMSE values of forecasts with and without additional data are computed for each level in the atmosphere, using both 00Z and 12Z forecasts.  Each estimate has an associated uncertainty due, in part, to the small number of days we examined.  The estimate on the uncertainty on the mean is estimated as:

Standard Error on mean RMSE difference =   

Where n is the number of RMSE forecast values, x is the set of RMSE forecast values, and Missing Image

Is the lag one autocorrelation derived from the time series x.  This is empirically derived from the RMSE values with the approximation: