The Impact of Manually Derived Southern Hemisphere Sea Level Pressure Data upon Forecasts from a Global Model

Experiments have been conducted within the framework of the Australian Bureau of Meteorology's global data assimilation and prediction system to assess the forecast impact of Southern Hemisphere sea level pressure estimates [paid observations (PAOBs)] from manual analyses. Parallel assimilation cycles with and without PAOBs, for two periods each of about 4 weeks in different seasons, while inconclusive, suggest a small positive impact of PAOBs in Southern Hemisphere midlatitudes.