A proposition on Seasonal Prediction of TC Activity over western North Pacific H. Joe Kwon Kongju National University, KOREA

K ongju N ational U niversity

TC activity Prediction for 2005 PredictionClimatologyObservation May - Dec 19 – 32 (22.7) Sep - Nov 9 – 11 (9.7) KMA’s seasonal forecast (2/3)

K ongju N ational U niversity TC activity Prediction for Sep-Nov 2004 PredictionClimatologyObservation WNP (Sep-Nov) (10.1) Korea (Sep-Nov) (1.4) 0.91 KMA’s seasonal forecast (3/3)

K ongju N ational U niversity KMA/CPD issues seasonal(JJA, SON) outlook for temp/precip and TC activity.  Number of TCs over western North Pacific, affecting Korea. Joint Meeting for seasonal forecast (CN-JP-KR) University contribution - Hongkong (Prof. Chan): Statistical model - Kongju (Prof. Kwon): Statistical model & Dynamic model ensemble APCC(APEC Climate Center)  Seasonal prediction of TC may be one of the important components. IRI  Seasonal forecast for WNP and ATL ECMWF  TC genesis over the whole basin (coupled global model) Activities over western North Pacific for Seasonal forecast of TC

K ongju N ational U niversity Hurricane outlook of NHC, USA Probability forecast Number of TC genesis & ACE Category forecast

K ongju N ational U niversity ACE (Accumulated Cyclone Energy) = ACE

K ongju N ational U niversity Definition of hurricane season of NHC

K ongju N ational U niversity Typhoon genesis over the western N. Pacific 16 39

K ongju N ational U niversity Accumulated distribution of AN,NN,BN based on tropical cyclone activities Classification by annual total of tropical cyclones(1/2)

K ongju N ational U niversity Below Normal Near Normal Above Normal Classification of AN, NN, BN based on tropical cyclone activities Classification by annual total of tropical cyclones(2/2)

K ongju N ational U niversity Example of 2 different tropical cyclones

K ongju N ational U niversity NTA (Normalized Typhoon Activity) Index = = 6-hourly maximum sustained wind speed V TY = 64 kt NTA = 1 means that a tropical cyclone of TY strength exists for 1 day ▶ ▶ Classification by NTA, annual total of tropical cyclones and TY genesis number Comprehensive Typhoon Activity Index based upon frequency, duration and intensity frequency, duration and intensity

K ongju N ational U niversity NTA = 0.3 NTA = 17,4

K ongju N ational U niversity AN NN BN Classification by NTA, annual total of tropical cyclones and TY genesis number NTA 128.1

K ongju N ational U niversity ClassificationNTA Annual Total of Tropical Cyclone TY AN152 or higher30 or higher17 or higher NN118 ~ ~ 2914 ~ 16 BN118 or lower24 or lower13 or lower Classification by NTA, annual total of tropical cyclones and TY genesis number

K ongju N ational U niversity Classification by NTA, annual total of tropical cyclones and TY genesis number NTA nTC nTY AN NN BN NTA nTC nTY NTA nTC nTY nTC means annual total number of tropical cyclone nTC means annual total number of tropical cyclone nTY means number above TY grade nTY means number above TY grade

K ongju N ational U niversity YEARNTATS(12)TY(15)SUMClassification AN AN AN AN AN AN AN AN AN AN AN AN AN AN AN AN AN NN AN NN NN NN NN NN NN NN NN NN NN NN AN NN NN BN NN NN NN BN BN BN BN BN NN BN BN BN BN BN BN BN BN BN BN BN Classification by NTA, annual total of tropical cyclones and TY genesis number Y=1968, NTA=222, TC=27, TY=23 Y=2004, NTA=194, TC=29, TY=19 Y=1964, NTA=112, TC=34, TY=14 Y=1987, NTA=174, TC=23, TY=17

K ongju N ational U niversity NN ⇒ AN A Few Example NN ⇒ AN

K ongju N ational U niversity A Few Example AN ⇒ NN BN ⇒ AN

K ongju N ational U niversity Summary Definition for Normal, Above Normal, Below Normal range of tropical cyclone activity over the western North Pacific Proposition # 1 Proposition # 2 Things to be predicted - NTA index, No of Total TC, No of Typhoon

K ongju N ational U niversity ? - June SST, MSLP, Z500,... ? - June SST, MSLP, Z500,... Selection of Predictors ? - June SST, MSLP, Z500,... ? - June SST, MSLP, Z500,... ? - June SST, MSLP, Z500,... ? - June SST, MSLP, Z500, Lag Correlation?

K ongju N ational U niversity MSLP E 22.5N SST W 16N Example of lag correlation between SON TCs and synoptic variables A priori assumption: (1) stronger correlation between NTA and synoptic variables (2) better prediction of NTA

K ongju N ational U niversity International/Inter-organizational collaborations are highly recommended. - Joint meeting for seasonal forecast (CN-JP-KR) - APCC - IRI - Kongju University, Hongkong University Proposition # 3 Any Contributions Welcome!

Thank you!