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A proposition on Seasonal Prediction of TC Activity over western North Pacific. H. Joe Kwon Kongju National University, KOREA. KMA’s seasonal forecast (2/3). TC activity Prediction for 2005. KMA’s seasonal forecast (3/3). TC activity Prediction for Sep-Nov 2004.
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A proposition on Seasonal Prediction of TC Activity over western North Pacific H. Joe Kwon Kongju National University, KOREA
KMA’s seasonal forecast (2/3) TC activity Prediction for 2005
KMA’s seasonal forecast (3/3) TC activity Prediction for Sep-Nov 2004
Activities over western North Pacific for Seasonal forecast of TC 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)
Probability forecast Category forecast Number of TC genesis & ACE Hurricane outlook of NHC, USA
ACE ACE (Accumulated Cyclone Energy) =
Classification by annual total of tropical cyclones(1/2) Accumulated distribution of AN,NN,BN based on 1951-2004 tropical cyclone activities 28.7 23.7
Classification by annual total of tropical cyclones(2/2) Classification of AN, NN, BN based on 1951-2004 tropical cyclone activities 28.7 23.7 Near Normal Above Normal Below Normal
Classification by NTA, annual total of tropical cyclones and TY genesis number Comprehensive Typhoon Activity Index based upon frequency, duration and intensity • NTA (Normalized Typhoon Activity) Index = = 6-hourly maximum sustained wind speed ▶ VTY = 64 kt NTA = 1 means that a tropical cyclone of TY strength exists for 1 day ▶
NTA = 17,4 NTA = 0.3
128.1 Classification by NTA, annual total of tropical cyclones and TY genesis number NTA AN NN BN
Classification by NTA, annual total of tropical cyclones and TY genesis number
Classification by NTA, annual total of tropical cyclones and TY genesis number AN NTA 118 118 152 152 118 152 nTC 24 24 29 29 24 29 nTY 13 13 17 17 13 17 NN NTA 118 152 118 118 152 152 118 152 nTC 24 29 24 24 29 29 24 29 nTY 13 17 13 13 17 17 17 13 BN NTA 118 118 152 152 nTC 24 24 29 29 • nTC means annual total number of tropical cyclone • nTY means number above TY grade nTY 13 13 17 17
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=1987, NTA=174, TC=23, TY=17 Y=1964, NTA=112, TC=34, TY=14
NN ⇒ AN NN ⇒ AN A Few Example
AN ⇒ NN BN ⇒ AN A Few Example
Summary Proposition # 1 Definition for Normal, Above Normal, Below Normal range of tropical cyclone activity over the western North Pacific Proposition # 2 Things to be predicted - NTA index, No of Total TC, No of Typhoon
Selection of Predictors 1952 1952 ? - June SST, MSLP, Z500, . . . Lag Correlation? 2002 2002 ? - June SST, MSLP, Z500, . . . 2003 2003 ? - June SST, MSLP, Z500, . . .
Example of lag correlation between SON TCs and synoptic variables MSLP-12 0.421 160E 22.5N SST+4 0.393 166W 16N A priori assumption: (1) stronger correlation between NTA and synoptic variables (2) better prediction of NTA
Proposition # 3 International/Inter-organizational collaborations are highly recommended. - Joint meeting for seasonal forecast (CN-JP-KR) - APCC - IRI - Kongju University, Hongkong University Any Contributions Welcome!