A proposition on Seasonal Prediction of A proposition on Seasonal Prediction of
TC Activity over western North PacificTC Activity over western North Pacific
H. Joe KwonKongju National University, KOREAKongju National University, KOREA
KKongju ongju NNational ational UUniversityniversity
KKongju ongju NNational ational UUniversityniversity
TC activity Prediction for 2005
Prediction Climatology Observation
May - Dec19 – 32(22.7) 25.1 20
Sep - Nov9 – 11(9.7) 11.5 9
KMA’s seasonal forecast (2/3)KMA’s seasonal forecast (2/3)
KKongju ongju NNational ational UUniversityniversity
TC activity Prediction for Sep-Nov 2004
Prediction Climatology Observation
WNP (Sep-Nov)9 - 12(10.1) 11.5 9
Korea (Sep-Nov)1 - 2(1.4) 0.9 1
KMA’s seasonal forecast (3/3)KMA’s seasonal forecast (3/3)
KKongju ongju NNational ational UUniversityniversity
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 TCActivities over western North Pacific for Seasonal forecast of TC
KKongju ongju NNational ational UUniversityniversity
Hurricane outlook of NHC, USAHurricane outlook of NHC, USA
Probability forecastProbability forecast
Number of Number of TC genesis &TC genesis &ACEACE
Category forecastCategory forecast
KKongju ongju NNational ational UUniversityniversity
N
n
nV1
2max )(ACE (Accumulated Cyclone Energy)
=
ACEACE
KKongju ongju NNational ational UUniversityniversity
Definition of hurricane season of NHC Definition of hurricane season of NHC
KKongju ongju NNational ational UUniversityniversity
Typhoon genesis over the western N. PacificTyphoon genesis over the western N. Pacific
16163939
KKongju ongju NNational ational UUniversityniversity
23.7 28.7
Accumulated distribution of AN,NN,BN Accumulated distribution of AN,NN,BN based on 1951-2004 tropical cyclone activitiesbased on 1951-2004 tropical cyclone activities
Classification by annual total of tropical cyclones(1/2)Classification by annual total of tropical cyclones(1/2)
KKongju ongju NNational ational UUniversityniversity
0
1
2
3
4
5
6
7
8
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39Annual Total of Tropical Cyclones
Num
ber
of
Year
Below Normal Near Normal
Above Normal
23.7 28.7
Classification of AN, NN, BN Classification of AN, NN, BN based on 1951-2004 tropical cyclone activitiesbased on 1951-2004 tropical cyclone activities
Classification by annual total of tropical cyclones(2/2)Classification by annual total of tropical cyclones(2/2)
KKongju ongju NNational ational UUniversityniversity
Example of 2 different tropical cyclonesExample of 2 different tropical cyclones
KKongju ongju NNational ational UUniversityniversity
2
1max )/)((
4
1TY
N
n
VnV
)(max nV
• 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
▶▶
▶▶
Classification by NTA, annual total of tropical cyclones and TY genesis numberClassification by NTA, annual total of tropical cyclones and TY genesis number
Comprehensive Typhoon Activity Index based uponComprehensive Typhoon Activity Index based upon frequency, duration and intensityfrequency, duration and intensity
KKongju ongju NNational ational UUniversityniversity
NTA = 0.3NTA = 0.3 NTA = 17,4NTA = 17,4
KKongju ongju NNational ational UUniversityniversity
AN
NN
BN
Classification by NTA, annual total of tropical cyclones and TY genesis numberClassification by NTA, annual total of tropical cyclones and TY genesis number
NTANTA
128.1128.1
KKongju ongju NNational ational UUniversityniversity
ClassificationClassification NTANTAAnnual Total of Annual Total of Tropical CycloneTropical Cyclone
TYTY
AN 152 or higher 30 or higher 17 or higher
NN 118 ~ 152 25 ~ 29 14 ~ 16
BN 118 or lower 24 or lower 13 or lower
Classification by NTA, annual total of tropical cyclones and TY genesis numberClassification by NTA, annual total of tropical cyclones and TY genesis number
KKongju ongju NNational ational UUniversityniversity
Classification by NTA, annual total of tropical cyclones and TY genesis numberClassification by NTA, annual total of tropical cyclones and TY genesis number
NTANTA
nTCnTC
nTYnTY
2424 2929
ANAN
NNNN
BNBN
118118 152152
1313 1717
NTANTA
nTCnTC
nTYnTY
2424 2929
118118 152152
1313 1717
NTANTA
nTCnTC
nTYnTY
2424 2929
118118 152152
1313 1717
2424 2929
118118 152152
1313 1717
2424 2929
118118 152152
1313 1717
2424 2929
118118 152152
1313 1717
2424 2929
118118 152152
1313 1717
2424 2929
118118 152152
1313 1717
2424 2929
118118 152152
1313 1717
• nTC means annual total number of tropical cyclonenTC means annual total number of tropical cyclone• nTY means number above TY gradenTY means number above TY grade
KKongju ongju NNational ational UUniversityniversity
YEARYEAR NTANTA TS(12)TS(12) TY(15)TY(15) SUMSUM ClassificationClassification
1968 222 4 23 27 AN
1997 198 11 17 28 AN
2004 194 10 19 29 AN
1967 192 21 18 39 AN
1994 191 17 19 36 AN
1991 190 12 17 29 AN
1992 188 15 16 31 AN
1972 185 12 19 31 AN
1971 181 16 20 36 AN
1982 181 7 18 25 AN
1987 174 6 17 23 AN
1986 171 11 18 29 AN
1958 168 15 16 31 AN
1962 166 12 18 30 AN
1976 162 11 14 25 AN
1990 162 10 19 29 AN
2002 156 11 15 26 AN
1957 153 7 15 22 NN
1989 150 12 20 32 AN
1953 144 9 14 23 NN
1963 143 10 14 24 NN
1979 142 11 13 24 NN
1965 140 18 14 32 NN
1978 137 15 15 30 NN
1954 135 7 14 21 NN
1959 134 7 16 23 NN
1996 133 11 15 26 NN
1970 133 13 13 26 NN
1960 129 13 14 27 NN
1984 129 11 16 27 NN
1966 128 18 17 35 AN
1980 125 9 15 24 NN
2003 125 7 14 21 NN
1951 120 11 10 21 BN
1981 119 16 13 29 NN
1952 118 13 14 27 NN
1961 118 16 13 29 NN
1969 117 5 14 19 BN
2001 116 10 16 26 BN
1985 115 11 16 27 BN
1993 115 13 15 28 BN
1974 113 17 15 32 BN
1964 112 20 14 34 NN
1983 106 13 10 23 BN
1988 104 20 11 31 BN
2000 99 10 13 23 BN
1956 97 11 12 23 BN
1955 96 17 11 28 BN
1977 95 10 11 21 BN
1975 86 8 13 21 BN
1995 81 14 9 23 BN
1973 72 10 11 21 BN
1998 55 8 8 16 BN
1999 45 17 5 22 BN
Classification by NTA, annual total of tropical cyclones and TY genesis numberClassification by NTA, annual total of tropical cyclones and TY genesis number
Y=1968, NTA=222, TC=27, Y=1968, NTA=222, TC=27, TY=23TY=23
Y=2004, NTA=194, TC=29, Y=2004, NTA=194, TC=29, TY=19TY=19
Y=1964, NTA=112, TC=34, Y=1964, NTA=112, TC=34, TY=14TY=14
Y=1987, NTA=174, TC=23, Y=1987, NTA=174, TC=23, TY=17TY=17
KKongju ongju NNational ational UUniversityniversity
NN AN⇒
A Few ExampleA Few Example
NN AN⇒
KKongju ongju NNational ational UUniversityniversity
A Few ExampleA Few Example
AN NN⇒
BN AN⇒
KKongju ongju NNational ational UUniversityniversity
SummarySummary
Definition for Normal, Above Normal, Below Normal range of tropical cyclone activity over the western North Pacific
Proposition # 1Proposition # 1
Proposition # 2Proposition # 2
Things to be predicted - NTA index, No of Total TC, No of Typhoon
KKongju ongju NNational ational UUniversityniversity
? - June
SST, MSLP, Z500, . . .
? - June
SST, MSLP, Z500, . . .
Selection of Predictors
1952
2002
2003
? - June
SST, MSLP, Z500, . . .
? - June
SST, MSLP, Z500, . . .
? - June
SST, MSLP, Z500, . . .
? - June
SST, MSLP, Z500, . . .
1952
2002
2003
Lag Correlation?
KKongju ongju NNational ational UUniversityniversity
MSLP-120.421
160E 22.5N
SST+40.393
166W 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
KKongju ongju NNational ational UUniversityniversity
International/Inter-organizational collaborations are highly recommended. - Joint meeting for seasonal forecast (CN-JP-KR) - APCC - IRI - Kongju University, Hongkong University
Proposition # 3Proposition # 3
Any Contributions Welcome!Any Contributions Welcome!
Thank you!Thank you!