An observation at T-3 shows the background pressure to be too high. If the model background is used at the correct time, a modest negative increment results. The effect of time interpolation of the model background. Objective verification Table 1. Changes in the composite skill score and NWP index, as measured against observations.
Positive values indicate an improvement.
Table 1 shows the changes in skill score for the trials of the Spring 2000 package of changes compared against a control without those changes. The northern hemisphere impact is uniformly positive, irrespective of season or verification method. The tropical impact is near neutral. The southern hemisphere impact is near neutral compared against analyses, but significantly positive against observations. Table 2 shows these results partitioned by geographical area and verified against observations.