The considerable impact of earth observations from space on numerical weather prediction

Experiments were conducted to quantify the impact of satellite data (Earth Observations from Space-EOS) on the determination of current and future atmospheric state. These experiments have examined two different time periods using two different operational forecast models. The results show that, in the southern hemisphere, the accuracy of a no-satellite data 24-hour (one day) forecast is of the same accuracy, on average, as a 96 hour (four day) with-satellite data forecast when forecasts were verified against the control (all data used) analysis. Satellite data increases the forecast duration by a factor of four for the same accuracy forecast. In the northern hemisphere, the addition of satellite data results in the forecast duration increasing typically by a factor of around 1.6. This gain in forecast skill has resulted in significant societal benefits from improved forecasts, improved warnings and more apropriate time being available to prepare for extreme weather.