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Impacts on Global Forecasts: Conventional vs Satellite Data
From the March 2013 issue of the JCSDA Quarterly
Figure 1. Analysis through day 7 die off curves of anomaly correlations for geopotential heights during (a) August - September 2010 and (b) December 2010 - January 2011. The Control is in black, the no satellite data experiment is in red and the no conventional data experiment is in green. The lower panel curves are differences with respect to the control. Lines outside the same color box are statistically significant at the 95% level.
Observing System Experiments (OSEs) are used to quantify the contributions to the
forecast made by conventional in-situ and remotely sensed satellite data.
Figure 1 shows the global mid-latitude (20° - 80° Northern and Southern Hemisphere)
average 500 hPa geopotential height anomaly correlation (AC) scores for the control
(black curve) and two experiments (NOCONV-green curve and NOSAT-red curve)
through forecast day 7. The summer results are in Fig. 1a, the winter results
in Fig. 1b. Scores lower than the control values indicate a reduction in forecast
skill when the data are removed. Note the large degradation in the forecasts
when the satellite data are deleted. The bottom portions of Figure 1 illustrate
the application of statistical significance tests.