1. Heavy rainfall caused by tropical cyclones in 2015 and related forecasts/warnings from JMA Isao Takano Director, Typhoon Research Department Meteorological Research Institute Japan Meteorological Agency Tsukuba, Ibaraki, Japan 1 2015 APEC Typhoon Symposium, 24-25 November 2015

2. 2 Outline ○ Overview of the tropical cyclones that have affected Japan in 2015 ○ Heavy rainfall caused by tropical cyclone Etau ○ Flooding of the northern Kanto area ○ Forecasts and warnings issued by JMA ○ Numerical forecasts by JMA models

3. OVERVIEW OF TROPICAL CYCLONES THAT HAVE AFFECTED JAPAN IN 2015

4. Tropical cyclones affected Japan in 2015 (as of 5 Oct.)  13 TCs approached (normal: 11.4 TCs / year)  7 TCs affected (1506, 1509, 1511, 1512, 1515, 1518, 1521)  4 TCs made landfall (1511, 1512, 1515, 1518) Halola (1512) Goni (1515) Etau (1518) Dujuan (1521) VIS image at 0644 UTC on 28 Sep. 2015 Goni (1515) Radar at 0354 UTC on 25 Aug. 2015 A 24-hour precipitation amount of 535 mm was recorded at Owase City. A peak gust of 81.1 m/s was recorded at Yonagunijima Island. Nangka (1511)

5. HEAVY RAIN CAUSED BY SEVERE TROPICAL CYCLONE ETAU IN JAPAN

6. Summary of the Event  Tropical cyclone Etau with influences of tropical cyclone Kilo caused heavy rain over Honshu island to produce record breaking precipitation in Kanto and Tohoku areas.  The total rainfall amounts from 7 to 11 September were more than twice as much as monthly normal of September 500 mm to 600 mm in part of Kanto and Tohoku areas  Numerical guidance provided good estimation of quantitative rainfall amount over 24 hours  Advisories and warnings by JMA were prepared in advance of the disaster Emergency Warnings were issued to the most affected areas  Eight deaths were reported as of Oct 14, and more than 16 thousand of houses were damaged.  A dyke of the Kinu River (Class A river) collapsed and resulted in flooding over wide area of City of Joso.  Accurate rainfall prediction with uncertainty estimation is desirable for timely warnings appropriate to DRR operation.

7. Tropical Cyclone Tracks of Etau and Kilo in 2015 7 Around 01UTC, OCT 9 Landfalling over Aichi 00UTC, OCT 9 00UTC, Oct 7 Etau 00UTC, Oct 8 12UTC, Oct 9 Extratropical cyclone 00UTC, Oct 9 Kilo 00UTC, Oct 10 00UTC, Oct 11 12UTC, Oct 11 Extratropical cyclone Surface weather chart at 00 UTC, 9 Sep 2015

8. 00UTC 08 SEP 201500UTC 09 SEP 2015 12UTC 09 SEP 201500UTC 10 SEP 2015 IR imagery of Himawari-8

9. Composite radar from 12UTC to 18UTC, September 9 Total rainfall amount (7 to 11 September 2015) Composite Radar on September 9 Composite radar image of every 5 minutes shows convective systems passed northward in the area of instability over Kanto area, which corresponds with the Kinu River basin.

10. Sequence of Meteorological Information for Tochigi Sep 9Sep 10 Sediment Disaster Warnings and Advisories for Heavy Rain WarningAdvisory 22 ： 31 2 Meteorological Information 07 ： 41 43 5 6 7 Imaichi, Tochigi 14 ： 25 Emergency Warning 00 ： 20 1 Local Met Info for Etau Local Met Info for Heavy Rain, Thunderstorm, and Gust Canceled at 05:15, Oct 11 Downgraded to Advisory at 06:15, Oct 11, canceled, at 03:58 Oct 12 3 Direct call from Met Office to the City 21 ： 50 “Emergency Warning issued for Heavy rain. Having rainfall with an intensity unexperienced by local people. Be alert at the highest level” Direct call from Met Office to the city on Emergency Warning 0 ： 07 4 Monthly Normal of September 280.0 mm Hourly Rainfall Amount Accumulated Rainfall Amount Hourly rainfall (mm) Accumulated Rainfall (mm) 000306091215182100030609121518

11. Intensity level (Precipitation etc.) Advisory level AdvisoryAdvisory Time WarningWarning Emergency Warning * Once in 50 years level DisasterSerious Disaster Serious disasters may happen Serious Disasters (Higher possibility) Warning level Serious disasters will most probably happen Disasters may happen * The issuance of an Emergency Warning indicates a level of exceptional risk of magnitude that could be observed only once every few decades. Residents should pay attention to their surroundings and relevant information such as municipal evacuation advisories and orders, and should take all steps necessary to protect life. Meteorological Warning System by JMA

12. 3 茨城県常総市の警報等発表状況 9/9 9/10 WarningAdvisory （８日 13 ： 29 に発 表） 1 3 4 16 ： 36 dd 日 hh 時 mm 分 解除 dd 日 hh 時 mm 分 解除 42 56 自治体向け台風説明会 にて解説 7 Shimotsuma, Joso, Ibaraki hh ： mm ○○ 市長へ ○○ 地方気象 台長から電話連絡 d 日 hh ： mm 04 ： 15 hh ： mm Emergency Warning 5 日 7 時 00 分 現在継続中 07 ： 45 23 4 4 ： 25 Accumulated Rainfall Amount Hourly Rainfall Amount Sequence of Meteorological Information for Ibaraki Warnings and Advisories for Heavy Rain Sediment Disaster Meteorological Information Monthly Normal of September 176.0 mm Direct call from Met Office to the city on Emergency Warning Direct call from Met Office to the city Hourly rainfall Accum. rainfall “Emergency Warning issued for Heavy rain. Having rainfall with an intensity unexperienced by local people. Be alert at the highest level” 7 ： 14

13. the Kinu River basin Total rainfall amount (7 to 11 September 2015) Heavy rainfall was concentrated over the upper reaches of the Kinu River basin

14. The altitude map around the lower reaches of the Kinu River Flood area of Joso City at 18:00 10 Sep. Flood area of Joso City at 10:00 11 Sep. From the products of the Geospatial Information Authority of Japan dyke collapse

15. Photos: Kanto Regional Development Bureau Sky view of flooding over Joso City

16. 16 QPE FT=45 FT=51FT=57FT=39 FT=27FT=33 The heavy rain event was predicted by the global model (GSM) of all initials from 18 UTC 7 September. Rainfall Prediction by Global Model of JMA

17. Meso-Scale Model provides better information than the global model with respect to the intensity of the rainfall. 17 QPE FT=33 FT=36FT=39FT=30 FT=24FT=27 Rainfall Prediction by Meso-Scale Model of JMA

18. 18 Emergency Warning with Reference to a Hydrological Index Intensity level ( Precipitation etc.) Advisory level AdvisoryAdvisory Time WarningWarning Emergency Warning Once-in-50-year level Disaster Serious Disaster Serious disasters may occur Serious Disasters (High probability) Warning level Serious disasters will most probably occur Disasters may occur Soil Water Index of once-in-50-year frequency Parameters of criteria for Heavy Rain Emergency Warnings against sediment disasters: - 3-hour rainfall amount - 48-hour rainfall amount - Soil water index