COSMIC Retreat 2008 Impact of COSMIC on typhoon prediction Bill Kuo and Ted Iwabuchi
Historical Typhoon Tracks Inter-annual variations of typhoon path and activity It’s clear that we need observation over the ocean
Typhoon Paths in typhoons in 2008 (by Oct 9)
Typhoon Landfalls in Taiwan in 2008 Three typhoons have landfalled in Taiwan in 2008 How is relative importance of COSMIC data ?
Real-time Typhoon Forecast Design Cold 3DVAR: 6 hour DA time windows at 00 UTC Cycling 3DVAR: 3 hour DA time window every 3 hours from 00UTC for 24 hour time windows
Real-time Typhoon Forecast Design COSMIC + Conventional vs only Conventional (w/o COSMIC) Cold 3DVAR vs Cycling 3DVAR Conventional data (SYNOP, SHIP, BUOY, METAR, PILOT, SOUND, AMDAR, SATEM, SATOB, GPSPW, AIREP, PROFL)
COSMIC Profile Availability COSMIC data is available continuously –Not like radiosonde data available only at 00 and 12Z Cycling 3DVAR for long data assimilation time window is one of the optimal assimilation scheme for COSMIC DA (+1d) DAtime window: 09-25_00Z _00Z
Cold 3DVAR vs Cycling 3DVAR Significant improvement for track forecast in cycling 3DVAR Cold 3DVARCycling 3DVAR IC: _00Z
Track Forecast Errors Cycling 3DVAR forecast is much better than cold 3DVAR forecast Forecast with COSMIC profile is better than that without COSMIC profile Cold 3DVAR Cycling 3DVAR COSMIC IC: _00Z
Intensity Forecast Comparison Gaps between best track from JMA and WRF forecast Trend of intensity changes is more similar in cycling 3DVAR forecast than those in cold 3DVAR forecast
Typhoon Real-time Forecast with COSMIC Real-time and continuous ingestion of COSMIC profile helped to forecast typhoon Jangmi We need more test case studies for statistical discussions We need to mprove intensity forecasts
Landfall of Jangmi to Taiwan
Cold 3DVAR vs Cycling 3DVAR Significant improvement for track forecast in cycling 3DVAR and COSMIC IC: _00Z Cold 3DVARCycling 3DVAR
Track Forecast Errors Significant improvement for track forecast with COSMIC cycling DA IC: _00Z
Intensity Forecast Comparison
Cold 3DVAR vs Cycling 3DVAR Significant improvement for track forecast in cycling 3DVAR and COSMIC IC: _00Z Cold 3DVARCycling 3DVAR
Track Forecast Errors Significant improvement for track forecast with COSMIC cycling DA IC: _00Z
Intensity Forecast Comparison
Summary and Discussions Cycling 3DVAR DA can get maximum benefit of COSMIC data –Not like radiosonde only at 00 and 12Z Positive impact for track forecast continue more than 3 days –Improvement of environment around typhoon path ? More COSMIC profile should be helpful for forecast of tropical cyclone More intensity is needed for short-tern forecast –Longer DA time window? Which is important: number of data or number of cycling ?