92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Tuesday, 24 January 2012: 4:30 PM
Recent Improvements in the Specification of the Atmospheric Wind and Mass Field From Space for Weather Forecasting and Climate Monitoring
Room 257 (New Orleans Convention Center )
John F. Le Marshall, Bureau of Meteorology, Docklands, Vic., Australia; and R. G. Seecamp, Y. Xiao, P. Gregory, J. Lee, J. Jung, P. Steinle, and T. Skinner

The use of continuous wind observations from space, the use of GPS radio occultation observations and the use of ultraspectral radiances have greatly improved quality of analyses and forecasts over the Australian Region and Southern Hemisphere. In relation to the wind field, time continuous (hourly) high resolution atmospheric motion vectors (AMVs) have been generated at the Bureau of Meteorology (BoM) from Multi-functional Transport Satellite (MTSAT) calibrated and navigated radiance data (imagery) since 2005. The continuous AMVs have been error characterized and used with four dimensional variational assimilation (4DVAR) in near real time trials to quantify their impact on operational regional Numerical Weather Prediction (NWP). The beneficial impact of these data on the BoM's operational forecast system is described. After these trials, the high resolution time continuous AMVs were approved for introduction into NMOC's operational NWP suite for use by the operational Australian Community Climate Earth System Simulator (ACCESS) regional model ACCESS-R.

In relation to the mass field, radio occultation data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) mission and related missions have provided a new observation type for climate determination and operational meteorology. These data have been shown to provide significant improvements in the determination current and future atmospheric state. They have also enabled important activities such as examination of radiosonde performance and an examination of ionospheric composition. Three separate months of these radio occultation observations have been assimilated, using 4DVAR, into the global ACCESS system, ACCESS-G, which is being employed at the BoM to provide real-time operational forecasts. For the periods studied, the accuracy of these forecasts has been compared to forecasts generated without the use of the radio occultation data. The forecasts using radio occultation data have been found to be improved in the lower, middle and upper troposphere. In addition, because of the relatively unbiased nature of radio occultation observations, they have been used in a comparative study with radiosonde data to probe mean annual atmospheric temperature changes in the Australian region and the Southern Hemisphere. The results indicate their potential to improve operational analysis and forecasting in the Australian Region and also to make a very important and unique contribution to vital tasks such as climate monitoring and regional reanalysis. In addition to these studies ultraspectral observations have also been assimilated over the Southern Hemisphere and the beneficial impact of these data in the assimilation trials has been documented. Their utility for analysis and forecasting is well known and here we demonstrate their utility is expanded by extending the use of the information content in the ultraspectral data, particularly in cloudy situations.

Overall it is apparent, the use of high temporal density winds from space, the use of radio occultation data and the use of the ultraspectral sounding has improved analysis, forecasting and climate monitoring over the Australian Region and the Southern Hemisphere.

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