1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Observing system experiments using the operational NWP system of JMA with T-PARC 2008 special observations targeted for Typhoon Jangmi Yoichiro Ohta*1, Koji Yamashita*1, Takuya Komori*1, Kiyotomi Sato*1 and Tetsuo Nakazawa*2 1 : Japan Meteorological Agency 2 : Meteorological Research Institute

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Outline Objectives Experimental Description Overall Results Case Study Summary and Conclusion

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) To investigate effectiveness of next generation forecast technology, "Interactive forecast system" Objectives Observation System Assimilation Numerical Prediction Sensitivity Analysis Forecast Targeted Observation Numerical Analysis and Prediction System Observational data Analysis and evaluated errors Presentation of Mr. Komori To evaluate targeted observational data for typhoon track forecasts using the operational NWP system at JMA

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Global Experiments Specification Model – Global Spectral Model ： TL959L60 (Reduced Gaussian Grid; top 0.1hPa) Assimilation –4D-Var method –Inner model resolution: T159L60 –Assimilation window: six hours (Init. ±3hour ; time res. ≒ 1 hour) –Six-hourly cycle Forecasts – 84-hour forecasts from 00,06,12 and 18 UTC –216-hour forecasts for the case studies Experiment period – From 00UTC 09/09/2008 to 18UTC 18/09/2008 for SINLAKU – From 00UTC 25/09/2008 to 18UTC 30/09/2008 for JANGMI Notice –Bogus data are used to generate realistic typhoon structures in the analysis fields of the operational system. –Bogus data are not used to evaluate only special observation. Presentation of Mr. Yamashita

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) General Results

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) OSEs for JANGMI – Experimental Description - Blue ： Before recurvature （ to 18UTC 28 th Sep. ） Green ： After recurvature （ from 00UTC 29 th Sep. ） ● ： Dropsonde ▲ ： Ship ★： Observatory （ Observation points) T0815 (JANGMI) Typhoon Track ( JMA Best Track ) Test Special Observations are assimilated ( With Drop ). Cntl No Special Observations are assimilated ( Without Drop ). TestCntl Dropsonde ○× Special upper sounding(3-hourly) ○×

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs (Special Observations) ～ Track Forecast Error for JANGMI ～ （ From 00 UTC 29/09/2008 to 18 UTC 30/09/2008 ） before-recurvature stageafter-recurvature stage （ From 00 UTC 25/09/2008 to 18 UTC 28/09/2008 ） significant improvement (95% conf. lev.) 24-42% Improvement for 18-h forecasts No significant difference

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs (TC Bogus) ～ Track Forecast Error for JANGMI ～ （ From 00 UTC 29/09/2008 to 18 UTC 30/09/2008 ） before-recurvature stageafter-recurvature stage (From 00 UTC 25/09/2008 to 18 UTC 28/09/2008 ） significant improvement (95% conf. lev.) 25% Improvement for 6-h forecast Slightly worse for 18- to 54-hour forecasts Worse for 42- to 78-hour forecasts Slightly better for other forecast times

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs (TC Bogus) ～ Track Forecast Error for JANGMI ～ Along Track Cross Track FT=48 FT=72 Forecast Bias Some “Outliers”

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs (TC Bogus) ～ Forecast Track Example for JANGMI ～ Initial: 06UTC 25Sep.Initial: 12UTC 25Sep. Best track Bogus No Bogus Best track No Bogus Bogus

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs (Special Observations) ～ Mean Central Pressure Error for JANGMI ～ （ From 00 UTC 29/09/2008 to 18 UTC 30/09/2008 ） before-recurvature stageafter-recurvature stage （ From 00 UTC 25/09/2008 to 18 UTC 28/09/2008 ） significant improvement (95% conf. lev.) Over 10hPa reduction of intensity bias for 54-hour forecasts No significant difference All samples are after ET

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs (TC Bogus) ～ Mean Central Pressure Error for JANGMI ～ （ From 00 UTC 29/09/2008 to 18 UTC 30/09/2008 ） before-recurvature stageafter-recurvature stage （ From 00 UTC 25/09/2008 to 18 UTC 28/09/2008 ） significant improvement (95% conf. lev.) Over 10hPa reduction of intensity bias for 54-hour forecasts Slightly stronger for ET stage All samples are after ET

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Results of OSEs ～ Central Pressure Forecasts for JANGMI ～ Initial: 12UTC 26 Sep. Initial: 18UTC 28 Sep. better intensity much better intensity too strong Black: Best track Blue: Cntl, Red: Test Green: With TC Bogus Both special observations and TC bogus help the intensification at the developing stage. TC bogus sometimes makes too strong TC at the ET stage.

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Summary for General results Special observations contributed to improve the track forecasts. JANGMI Track forecasts and intensity forecasts were improved during before-recurvature stage. Using TC bogus contributed to the initial relocation and reducing intensity forecast bias. But, they degraded the track and intensity forecasts in some cases.

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Case Study ~ Experiment A ~

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Typical Case for JANGMI – Case Study - Recurvature occurred Recurvature didn’t occur Better track forecast at the beginning 9/25 00UTC Initial (JANGMI) Better intensity forecast Red : With Drop ( Test ) Blue : Without Drop ( Cntl ) Black : JMA Besttrack

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Experiment A for JANGMI – 9/25 00UTC - Black Contour : Analysis field (sea-surface pressure) on 9/25 00UTC (Special observations are assimilated) Dropsonde Observations □ : 9/ UTC ● : 9/24 21UTC, 9/25 01UTC ● : 9/24 22UTC ● : 9/24 23UTC ● : 9/25 00UTC Additional Experiment (Assimilate) No Drop →Week TC and No Recurvature 2421/2501,2422 →Better Track and Recurvature 2423,2500 →Better Intensity Forecast

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Difference of Analysis and Forecast Fields (2421/2501 VS No Drop) 850hPa 500hPa (m) m/s Higher on Southeast side and Lower on West side Slightly Stronger Circulation 24h Slightly Stronger TC Slightly Higher on Southeast side

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Comparison with SV structures (3 rd SV) 24h Initial SV (03p, Ps) Final SV (03p, Ps) Initial SV (03p, 850) Final SV (03p, 850) Shaded: Perturbation Contour: Forecast(FT=0) Shaded: Perturbation Contour: Forecast(FT=24) Vector: Perturbation Contour: Forecast(FT=0) Vector: Perturbation Contour: Forecast(FT=24) Similar Structure

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Difference of Analysis and Forecast Fields (2423 VS No Drop) 850hPa 500hPa (m) m/s Typhoon Center is shifted Southwestward Stronger Circulation 24h Much Stronger TC Small Trough disappeared Typhoon Center is shifted Southwestward Slightly Stronger Ridge

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Comparison with SV structures (2 nd SV) 24h Initial SV (02p, Ps) Final SV (02p, Ps) Initial SV (02p, 850) Final SV (02p, 850) Shaded: Perturbation Contour: Forecast(FT=0) Shaded: Perturbation Contour: Forecast(FT=24) Vector: Perturbation Contour: Forecast(FT=0) Vector: Perturbation Contour: Forecast(FT=24) Similar Structure

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Summary for Experiment A Focused on the typical case (00UTC on 25 Sep.) Dropwindsonde observations of C-130 and P-3 –Assimilating observations on south-quadrant and east-quadrant of JANGMI, typhoon circulation became slightly stronger, geopotential height on southeast side slightly increased. → Then, track forecast was improved and, intensity forecast was slightly improved. –Assimilating observations around center and north-quadrant of JANGMI, typhoon circulation on lower troposphere became stronger, geopotential height on northeast side increased and southwest side decreased. → Then, intensity forecast was improved. But, track forecast at the beginning was shifted southwestward. –The structure of SV perturbation seems consistent with the OSE results. The growth of SV perturbation in the linear model was similar to the evolution of the impact of special observations in the short-range forecast.

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Case Study ~ Experiment B ~

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Assimilate each observation elements separately. –All Elements (Wind, Temperature, Humidity) –Without Humidity –Wind Only –No Special Observations Separate observations by the area –2421/2501,2422 : South and East side of JANGMI (SE) –2423,2500 : North side and Center of JANGMI (NC) Which element was effective? Experiment B for JANGMI – 9/25 00UTC - Black Contour : Analysis field (sea-surface pressure) on 9/25 00UTC (Special observations are assimilated) Dropsonde Observations □ : 9/ UTC ● : 9/24 21UTC, 9/25 01UTC ● : 9/24 22UTC ● : 9/24 23UTC ● : 9/25 00UTC ExperimentWindTemperatureHumidity All Elements○○○ Without Humidity○○× Wind Only○×× No Obs×××

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Experiment B for JANGMI -9/25 00UTC (SE)- Black: Best track Red: No Obs Blue: Wind Only Green: Without Humidity Aqua: All Elements Wind Only is similar to All Elements ~ South and East side ~

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Difference of Analysis and Forecast Field （ SE ） All Elements Wind Only 24h

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Initial 6h Forecast Precipitation （ SE ） No Obs Without Humidity Wind Only All Elements

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Experiment B for JANGMI -9/25 00UTC (NC)- ~ North side and Center ~ Black: Best track Red: No Obs Blue: Wind Only Green: Without Humidity Aqua: All Elements Wind Only is similar to All Elements but slightly stronger Slightly Stronger

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) 24h Difference of Analysis and Forecast Field （ NC ） All Elements Wind Only

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Initial 6h Forecast Precipitation （ NC ） No Obs Without Humidity Wind Only All Elements

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Character of Observations The analysis was fitted to the observations Large departure Most observations on the mandatory levels were assimilated Red: Use Gray: No Use

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Summary for Experiment B and Observations Assimilating each observation element separately –Largest impact was found with the wind observations, especially for the track forecasts and the short-range intensity forecasts. –Initial 6-hour precipitation was also largely affected by the wind observations. –Temperature and humidity observations had some impact on the intensity forecasts after 24 hour. Observation use on JMA operational system (near TC-core) –Most observations on the mandatory levels were assimilated. –No horizontal thinning was applied for the dropsonde observations. → Is it valid for horizontally dense observations ? –The analysis was fitted to the observations.

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Thank you for your attention !

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Supplemental Materials…

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Observations around SINLAKU （ EC ： 09UTC 11 Sep. ～ 21UTC 11 Sep. ）

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Observations around SINLAKU （ JMA ： 09UTC 11 Sep. ～ 21UTC 11 Sep. ）

1st December 2009, Tokyo ( 日本財団ビル ) 台風の進路予測技術の高度化に関する国際会議 (International Workshop on Advancement of Typhoon Track Forecast Technique) Improvements on TC Bogus Before March 2009March 2009 to October 2009After October 2009 Further improvements are now investigated under the JMA NPD. Blue: TC-Bogus with (I) Red: TC-Bogus with (II) TC on September 2008 in the Northwestern Pacific (I)(II)(III) Forecast track error