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Evaluation of Potential Impacts of Doppler Lidar Wind

Evaluation of Potential Impacts of Doppler Lidar Wind Measurements on High-impact Weather Forecasting: A Regional OSSE Study. Zhaoxia Pu and Lei Zhang University of Utah Collaborate with Bruce Gentry NASA GSFC Belay Demoz Howard University. Acknowledgements:

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Evaluation of Potential Impacts of Doppler Lidar Wind

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  1. Evaluation of Potential Impacts of Doppler Lidar Wind Measurements on High-impact Weather Forecasting: A Regional OSSE Study Zhaoxia Pu and Lei Zhang University of Utah Collaborate with Bruce Gentry NASA GSFC Belay Demoz Howard University Acknowledgements: Michiko Masutani, EMC/NCEP, Joint OSSEs Las Peter Riishojgaard, JCSDA Robert Atlas, NOAA/AMOL NASA/HQ 13th IOAS-AOLS 89th AMS Annual Meeting, Phoenix, AZ January 15, 2009

  2. About this talk • Observing system simulation experiments (OSSEs) with Doppler Wind Lidar (DWL) measurements • Problems and challenges in regional OSSEs

  3. Backgorund • “Tropospheric winds are the number one unmet measurement for improving weather forecasts.” • -- National Research Council • NASA has supported a “Lidar wind science” program to help develop next generation space-based Doppler Wind Lidar (DWL) measurements. • It is expected that the future DWL will provide much denser (high horizontal and vertical resolution) wind profile observations than the currently available rawinsonde networks • It has also been well recognized that thefuture DWL should be operated in adaptive observation mode in order to save power resources.

  4. General concept of OSSEs (Courtesy of R. Atlas 2008)

  5. The objective of OSSEs • Access the impact of the data from future instruments • Define minimum requirements for future instruments in order • to meet a certain goals in weather/climate prediction. • Previous OSSEs with Doppler Lidar Wind (DLW) • Liu and Kalnay (2007), adaptive targeting strategies (simple global model) • R. Atlats et al. (2008), Impact of DLW on hurricane track forecast (NASA global model) • M. Masutani (2008), Evaluation of the impact of DLW with NCEP GFS • D. Emmitt (2008), Various experiments with DLW • Most of previous OSSEs have been done with global models • Impact of DLW data on high-impact weather system (e.g. hurricane) has been examined ( Atlas et al. 2008; Emmitt et al. 2008). • Positive impact has been shown on hurricane track forecast.

  6. Issues and Research Objectives • For these high-impact weather systems, we not only care about their • track, but are also concerned about their intensity and structures • For instance • Hurricane intensity forecast remains a challenging problem (Roger et al. 2006) • Then: • To what extent can next generation DLW observing system improve the • hurricane intensity forecast?

  7. Do ECMWF global natural runs represent hurricane structure? Track Case: 00UTC October 1 2005 – 00UTC October 4, 2005 3-h rainfall (T511) SLP Tropical cyclones were found to be reasonably well represented in the Natural Run for a model of intermediate resolution.

  8. Are ECMWF natural runs adequate for verification purposes? WRF 9-km 3-h rainfall T511 WRF 3-km Due to the relatively low resolution of the Natural Run in comparison with the scale of the storm inner core structure, the data may only be useful for the OSSEs that focus on tropical cyclone track forecasting rather than intensity forecasting.

  9. Regional OSSEs Regional Natural Run: Regional numerical simulation with Advanced Research Version of Weather Research and Forecasting (WRF) model Nested inside of ECMWF T799 natural run Resolution: 27km, 9km and 3km Physics option: BMJ cumulus, LIN microphysics, MYJ PBL Simulation of the data (25-km resolution) CTRL run: WRF simulation nested inside of T511 Resolution: 27km, 9km and 3km Physics option: KF cumulus, WSM6 microphysics, YSU PBL Data Assimilation : WRF 3DVAR Verification

  10. Regional OSSE results Data Impact

  11. Regional OSSE results 3-h precipitation at 48 h fcst CTRL Exp Truth

  12. Regional OSSE results Minimum central SLP Maximum surface wind

  13. Some issues with regional OSSEs Forecast is very sensitive to physics Parameterization options Can be good or bad

  14. Some issues with regional OSSEs

  15. Some issues with regional OSSEs Forecast is very sensitive to the boundary conditions Exp.1 T799 IC and T799 BC Exp.2 T799IC and FNL BC

  16. Concluding remarks • Future DLW measurements could be a very useful data source for • improving the forecast of high-impact weather systems (e.g., hurricane) • More work needs to be done to explore the instrument strategies • In order to improve the intensity forecast • There are some issues (such as the impact of model physics, boundary • conditions, and resolution) that need to be studied carefully with regional • OSSEs in order to make a realistic assessment of the impact. • The study is ongoing…

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