In the first trial of its kind for more than a decade, the Met Office global model was rerun for a period of a month during August and September 2006 with tropical cyclone initialisation switched off. The results show that the initialisation technique still produces a mean decrease in track forecast error of 12.2%. In addition, the detection rate of tropical cyclones at day 5 in the forecast dropped from 96% to 75% and the mean forecast intensity of tropical cyclones dropped by 20.6% when the initialisation technique was not used.
Having established the value of the current initialisation technique, a trial was undertaken of a change to the technique to reduce the areal coverage of the bogus' data produced for small tropical cyclones. This change was proposed in order to address a perceived weakness in the original formulation of the initialisation technique. The revised formulation produced a further reduction in track forecast errors of 4.6% for the August/September 2006 trial period. As a consequence of these good results, the revised formulation became operational in the Met Office global model in November 2007.