1 st mahasri issc meeting, 19-20 oct 2006, bangkok, thailand issues related to winter monsoon in...
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1ST MAHASRI ISSC Meeting, 19-20 Oct 2006, Bangkok, Thailand
ISSUES RELATED TO WINTER MONSOON IN MALAYSIA
Subramaniam MotenMalaysian Meteorological Department
OUTLINE
Rainfall characteristics
Synoptic features
Characteristics of SST over the SC sea
MEAN ANNUAL RAINFALL (mm) FOR MALAYSIA
Mean Monthly Rainfall (cm)
NOVEMBER
JANUARY
DECEMBER
FEBRUARY
STEAMLINE ANALYSIS AT 850 hPa LEVEL
1951/12 to 2002/02 all vortex centers
C.P. Chang et al, 2002
0
1
2
3
4
5
6
7
8
9
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour of Observation
Per
cen
t
BAYAN LEPASBAYAN LEPAS
MELAKA
0
1
2
3
4
5
6
7
8
9
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour of Observation
Per
cen
t
MELAKA
KOTA BHARU
0
2
4
6
8
10
12
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour of Observation
Per
cen
t
>0.1 >5 >10>20 >30 >50
KOTA BHARU
RAINFALL FREQUENCY RAINFALL FREQ FOR DIFF INTENSITIES
0
50
100
150
200
250
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Rai
nfa
ll (m
m)
November 1973 December 1973 January 1974
0
50
100
150
200
250
300
350
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Rai
nfal
l (m
m)
November 1984 December 1984 January 1985
0
50
100
150
200
250
300
350
400
450
500
550
600
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Rai
nfa
ll (m
m)
November 1975 December 1975 January 1976
0
50
100
150
200
250
300
350
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Rai
nfal
l (m
m)
November 1999 December 1999 January 2000
0
50
100
150
200
250
300
350
400
450
500
550
600
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Rai
nfal
l (m
m)
November 1986 December 1986 January 1987
0
50
100
150
200
250
300
350
400
450
500
550
600
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Rai
nfa
ll (m
m)
November 1981 December 1981 January 1982
KOTA BHARU
KOTA BHARU
KOTA BHARU
KUANTAN
MERSING
KUCHING
DAILY RAINFALL
60 30 20 15 12 10 8.6 7.5 6.7 6.0 5.5 5.0 4.6 4.3PERIOD (DAYS)
Spectra of Monsoon Rainfall (Nov – Feb)
0
0.01
0.02
0.03
0.04
0.05
0.06
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55
Frequency (per day)
Powe
r Spe
ctra
All Years
El Nino Years
La Nina Years
Spectra of Monsoon Rainfall (Nov – Feb)
Peak Oscillation centered around 30 days
Intraseasonal Oscillation in Monsoon Rainfall
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04
Year
An
nu
al R
ain
fall
An
om
aly
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04
Year
An
nu
al R
ain
fall
An
om
aly
Normal El Nino La Nina
PENINSULAR MALAYSIA
SABAH & SARAWAK
STANDARDIZED ANNUAL RAINFALL ANOMALY
Mean Monthly SST Gradient over South China Sea (1951-2000)
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Tem
pera
ture
Gra
dien
t
Montly Mean SST Gradient over South China Sea
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02
Year
Anom
aly
Summer Winter Annual
Time Series of Seasonal and Annual SST anomaly over the South China Sea
0
0.02
0.04
0.06
0.08
0.1
0.12
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55
Frequency (per year)
Pow
er-S
pect
ral D
ensi
ty
Pow er-Spectral Density Red Noise Spectrum 95%CL
Power Spectrum of Annual SST Over The South China Sea
7 years
17 years
Time-Longitude Section of SST Correlation between South China Sea and Equatorial Pacific at Lag –2
1000 HPA WIND VECTOR ANOMALY DURING POSITIVE SST ANOMALY FOR JANUARY
1000 HPA WIND VECTOR ANOMALY DURING NEGETIVE SST ANOMALY FOR JANUARY
Composite OLR during El Nino (January)
Composite SST during El Nino (January)
Composite OLR during La Nina (January)
Composite SST during La Nina (January)
Composite OLR during El Nino (February)
Composite SST during El Nino (February)
Composite OLR during La Nina (February)
Composite SST during La Nina (February)
Issues relevant to winter monsoon
Monsoon Vortex (Borneo Low)
Cold Surges and Heavy rain episodes
Intraseasonal Oscillation
Interannual Variability
SST over the South China Sea
THANK YOU