Skip Top Navigation
JCSDA Logo and banner

JCSDA News and Newsletters


Impacts on Global Forecasts: Conventional vs Satellite Data

From the March 2013 issue of the JCSDA Quarterly

Impacts on Global Forecasts: Conventional vs Satellite Data

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.

The results are a dramatic demonstration of the importance of satellite data in NWP. Eliminating all conventional observations results in a decrease of 6 hours in forecast skill at day 7, but eliminating all satellite data results in an almost 3 day decrease in skill. In other words, the addition of the satellite data makes the 7 day forecast about as skillful as the 4 day forecast without satellite data.

(Jim Jung, CIMSS/JCSDA)

See the full article in the March 2013 Quarterly Newsletter)

Newsletters supplied as PDFs


 
 
Modified April 24, 2013 4:04 PM
NOAA | NWS | NASA
Navy Weather | Air Force Weather
Level A conformance icon, W3C-WAI Web Content Accessibility Guidelines 1.0Valid HTML 4.01