slide 1 nargis 0600utc may 2nd progress in global tropical cyclone forecasting at ecmwf martin...
TRANSCRIPT
Slide 1
Slide 1Nargis 0600UTC May 2nd
Progress in global tropical Progress in global tropical cyclone forecasting at cyclone forecasting at
ECMWFECMWF
Martin Miller Martin Miller
Slide 2
Slide 2
Outline Introduction
General performance improvements
Objective scores
Systematic errors
TC forecast skill ECMWF: Tracks, intensity and genesis
Other Centres
Forecast system improvements Physical parametrizations
Observation quality control
Resolution
Extended-range forecasting Monthly
Seasonal
Conclusions
Slide 3
Slide 3
Historic Evolution of Skill
Slide 4
Slide 4
Global extra-tropics
Slide 5
Slide 5
Slide 6
Slide 6
Slide 7
Slide 7
Large-scale eg MJO
Slide 8
Slide 8
ECMWF Systematic Error: D+3 DJF
-10
-5
-5
-5
0
0
0
0
5
5
5
510
Mean FC Error: VPOT200 FC+3 (DJF 1986-1989)
-7-6-5-4-3-2-11234567
-120
-120-120
-60-60-60
00
0
606060
120120120
Mean FC Error: STRF200 FC+3 (DJF 1986-1989)
-10.5-9-7.5-6-4.5-3-1.5
1.534.567.5910.5
5200
5200
520
0
5400
5400
5400
5400
5400
5600
5600
5600
5600
560
0
5600
5800
5800
5800
5800
5800
5800
Mean Z500 FC Error: D+3 (DJF 1986-1989)
-35
-30
-25
-20
-15
-10
-55
10
15
20
25
30
35
-10
-5
-5
-5
0
0
0
0
5
5
5
5
Mean FC Error: VPOT200 FC+3 (DJF 1996-1999)
-7-6-5-4-3-2-11234567
-120
-120-120
-60-60-60
00
0
606060
120120120
Mean FC Error: STRF200 FC+3 (DJF 1996-1999)
-10.5-9-7.5-6-4.5-3-1.5
1.534.567.5910.5
5200
5200
5400
5400
5400
5400
5400
5600
5600
5600
5600
56 0
0
5600
5800
5800
5800
5800
5800
5800
Mean Z500 FC Error: D+3 (DJF 1996-1999)
-35
-30
-25
-20
-15
-10
-55
10
15
20
25
30
35
-12
-6
-6
-6
0
0
0
0
6
6
6
6
Mean FC Error: VPOT200 FC+3 (DJF 2006-2009)
-7-6-5-4-3-2-11234567
-120
-120-120
-60-60-600
0
0
606060
120120120
Mean FC Error: STRF200 FC+3 (DJF 2006-2009)
-10.5-9-7.5-6-4.5-3-1.5
1.534.567.5910.5
5200
5200
5400
5400
5400
5400
5400
5600
5600
5600
5600
56
00
5600
5800
5800
5800
5800
5800
5800
Mean Z500 FC Error: D+3 (DJF 2006-2009)
-35
-30
-25
-20
-15
-10
-55
10
15
20
25
30
35
Z500 Z500Z500
Stream Function 200hPa Stream Function 200hPa Stream Function 200hPa
Velocity Potential 200hPa Velocity Potential 200hPa Velocity Potential 200hPa
1986-1989 1996-1999 2006-2009
Slide 9
Slide 9
ECMWF Systematic Error: D+3 JJA
Z500 Z500Z500
Stream Function 200hPa Stream Function 200hPa Stream Function 200hPa
Velocity Potential 200hPa Velocity Potential 200hPa Velocity Potential 200hPa
1986-1989 1996-1999 2006-2009
5600
5600
5600
5800
5800
5800
5800
5800
Mean Z500 FC Error: D+3 (JJA 1986-1989)
-35
-30
-25
-20
-15
-10
-55
10
15
20
25
30
35
5600
5600
5600
5800
5800
58005800
5800
Mean Z500 FC Error: D+3 (JJA 1996-1999)
-35
-30
-25
-20
-15
-10
-55
10
15
20
25
30
35
5600
5600
5600
5800
5800
5800
5800
5800
Mean Z500 FC Error: D+3 (JJA 2006-2009)
-35
-30
-25
-20
-15
-10
-55
10
15
20
25
30
35
-50-50-50
000
0
5050
50
100100100
150150150
Mean FC Error: STRF200 FC+3 (JJA 1986-1989)
-10.5-9-7.5-6-4.5-3-1.5
1.534.567.5910.5
-50-50
-50
000
0
5050
50
100100100
150150150
Mean FC Error: STRF200 FC+3 (JJA 1996-1999)
-10.5-9-7.5-6-4.5-3-1.5
1.534.567.5910.5
-50-50
-50
000
0
5050
50
100100100
150150150
Mean FC Error: STRF200 FC+3 (JJA 2006-2009)
-10.5-9-7.5-6-4.5-3-1.5
1.534.567.5910.5
-12
-12
-6
-6
- 6
0
0
0
0
6
6
6
6
Mean FC Error: VPOT200 FC+3 (JJA 1986-1989)
-7-6-5-4-3-2-11234567
-12
-12-6
-6
-6
0
0
0
0
6
6
6
6
Mean FC Error: VPOT200 FC+3 (JJA 1996-1999)
-7-6-5-4-3-2-11234567
-18
-12
-12
-6-6
-6
0
0
0
0
6
6
6
6
12
Mean FC Error: VPOT200 FC+3 (JJA 2006-2009)
-7-6-5-4-3-2-11234567
Slide 16
Slide 16
Forecast system development
The current levels of success in TC forecasting at ECMWF are due to many important changes in the forecast system in the past, In particular some changes of note include:
implementation of 4D-Var;
increases in horizontal and vertical model resolution;
better model physics;
availability and assimilation of massive amounts of data from satellites, and also the drop-sondes released in and around TCs;
EPS stochastic physics and also targeted perturbations in the vicinity of the TCs.
A wide-range of improvements in seasonal forecasting systems involving both atmosphere and ocean
Slide 17
Slide 17
Tropical cyclones
Verification of TC predictions from the operational deterministic forecast for 12-month periods ending on 14 July. The latest period, 15 July 2008 to 14 July 2009, is shown in red.
Mean error in core pressure (left) and position (right).
Tropical cyclone position error(mean of 365 days ending 14 July)
0
100
200
300
400
500
600
0 12 24 36 48 60 72 84 96 108 120
forecast range (hours)
Err
or
(km
)
2003
2004
2005
2006
2007
2008
2009
Tropical cyclone mean intensity error(mean of 365 days ending 14 July)
0
5
10
15
20
25
30
0 12 24 36 48 60 72 84 96 108 120
forecast range (hours)
Err
or
(hP
a)
2003
2004
2005
2006
2007
2008
2009
Slide 19
Slide 19
Tropical cyclones
Verification of tropical cyclone predictions from the operational deterministic forecast for 12-month periods ending on 14 July.
Along track error: mean error in the direction of travel of the cyclone (negative values indicate slow bias)
Cross track error: mean error at right-angles to the direction of travel
Tropical cyclone mean along track error(mean of 365 days ending 14 July)
-250
-200
-150
-100
-50
0
50
100
0 12 24 36 48 60 72 84 96 108 120
forecast range (hours)
Err
or
(km
)
2003
2004
2005
2006
2007
2008
2009
Tropical cyclone mean cross track error(mean of 365 days ending 14 July)
-250
-200
-150
-100
-50
0
50
100
0 12 24 36 48 60 72 84 96 108 120
forecast range (hours)
Err
or
(km
)
2003
2004
2005
2006
2007
2008
2009
Slide 20
Slide 20
Slide 21
Slide 21
Nargis 0440UTC May 1st
Slide 22
Slide 22
D+5 from 23 april 00z T799 D+9 from 23 april 00z
EPS probabilities from 23 april 00z at D+5
Black dots are the first official reported positions of cyclone (~april 28th)
Slide 23
Slide 23
August-September 2008 Atlantic Basin
Tropical Storm Genesis
Increasingly ECMWF forecasts pick up tropical cyclones before they are
officially reported
Recent Atlantic hurricanes were predicted 5-7 days before they were observed
TS/Hurricane 1st Observed date Forecast detection
Fay 16-Aug D+6 (run: 10-Aug)
Gustav 25-Aug D+5 (run: 20-Aug)
Hanna 28-Aug D+5 (run: 23-Aug)
Ike 02-Sep D+7 (run: 26-Aug)
Josephine 03-Sep D+5 (run: 29-Aug)
Slide 24
Slide 24
Initial Tendencies: Mean u_vdgw 925, 20080603-20080831, Expver=33R1 f2nd, Analysis=yotc. Deep colours = 5% significance
Unit = m/s
-183 -15 -9 -3 3 9 15 141 -183 -15 -9 -3 3 9 15 141
Initial Tendencies: Mean u_dyn 925, 20080603-20080831, Expver=33R1 f2nd, Analysis=yotc. Deep colours = 5% significance
Unit = m/s
-183 -15 -9 -3 3 9 15 141 -183 -15 -9 -3 3 9 15 141
Precipitation GPCP (6-8 1963-2006)
1
3
5
7
9
11
13
15
Precipitation 32R3-GPCP (6-8 1963-2006)
-10
-4
-2
-0.5
0.5
2
4
10
Analysis Increments: Mean u925, 2008 JJA, Expver=oper 1, Analysis=dcda. Deep colours = 5% significance
0.8m/s0.8m/s
Unit = 0.1m/s
-29 -5 -3 -1 1 3 5 15 -29 -5 -3 -1 1 3 5 15
Initial Tendencies: Mean u_con 925, 20080603-20080831, Expver=33R1 f2nd, Analysis=yotc. Deep colours = 5% significance
Unit = m/s
-183 -15 -9 -3 3 9 15 141 -183 -15 -9 -3 3 9 15 141
Seamless Approach to Understanding Model Error
Precipitation Climatology JJA (GPCP)
Model Climate Error JJA (32R3)
Analysis Increments U925 (JJA 2008)
Process Tendencies U925 (JJA 2008)
DYN
CON
V.DIF
For the India monsoon, momentum tendency is a residual of the sum of large terms.
3 9 15-3-9-153 9 15-3-9-15 ms-1day-1
Unit = 0.1 ms-112hr-1
mmday-1
mmday-1
Slide 25
Slide 25
WGNE TC VerificationTC tracks on 2008 season
Northern-Hemisphere [2008/01/01 to 2008/12/31]
Southern-Hemisphere [2007/09/01 to 2008/08/31]Number of TCs , [best track data provider]
22 western North-Pacific [RSMC Tokyo]17 eastern North-Pacific (including Central-
Pacific) [RSMC Miami, Honolulu]
16 North Atlantic [RSMC Miami] 4 north Indian-Ocean [RSMC New-Delhi]12 south Indian-Ocean [RSMC La-Reunion] 4 around Australia [RSMC Nadi and 4
TCWCs ]
2217
16
12
4
4
Daisuke Hotta andTakuya Komori (NPD/JMA)
Slide 26
Slide 26
(a) Verification of western North-Pacific (WNP) domainPosition Error
22 TCs in 2008
Slide 27
Slide 27
(a) WNP domain Detection Rate
better
DetectionRate – PositionError map (FT +72)
Slide 28
Slide 28
JMAJMA ECMWFECMWF UKMOUKMO CMCCMC
DWDDWD NCEPNCEP NRLNRL Meteo FranceMeteo France
Scattering diagram of TC positions at 72 hour forecast.
Red : Before recurvature Green : During recurvature Blue : After
recurvature
Y-axis represents position errors in Along Track (AT) direction and X-
axis in the Cross Track (CT) direction. Unit: kms. ECMWF has a
small bias in all stages. CMC, DWD, NCEP,, NRL, Meteo France have
slow bias in “before recurvature” stage.
(a) WNP domain AT-CT bias map (FT +72)
Slide 29
Slide 29
JMAJMA ECMWFECMWF UKMOUKMO CMCCMC
DWDDWD NCEPNCEP NRLNRL Meteo FranceMeteo France
Scattering diagram of central pressure at 72 hour forecast.
Y-axis represents central pressure of forecast
and X-axis does that of analysis. Unit: hPa
Predicted central pressure of most models is higher than analysis
JMA and ECMWF has some relation ship between analysis and forecast.
Other center has very small.
(a) WNP domain Central Pressure scatter diagram (FT +72)
Slide 30
Slide 30
Time series of 2-day and 4-day forecast of JMA, ECM, UKM and 3 centres ensemble in WNP domain.
Slide 31
Slide 31
16 TCs in 2008
(b) Verification of North-Atlantic (NAT) domainPosition Error
Slide 32
Slide 32
(b) NAT domain Detection Rate
DetectionRate – PositionError map (FT +72)
better
Slide 33
Slide 33
A characteristic according to the domain of Northern Hemisphere.
Position error of each model will be compared in the next slide according to the domain.
Slide 35
Slide 35
(d) Verification of south Indian-Ocean (SIO) domainPosition Error
12 TCs in 2008
Slide 39
Slide 39
Tropical Forecast Biases Precipitation against GPCP for different cycles: from 15 year 5 months integrations for 1990-2005.
c 32r2 d 32r3
b 31r1a
Slide 40
Slide 40
2
2
/ 2
/ 2H x
pk x k
if |x| <= k,
if |x| > k,
Introduction of the Huber norm
Gaussian
Huber
Gaussian + flat
Slide 41
Slide 41
The Huber-norm and robust estimation
18 months of conventional dataFeb 2006 – Sep 2007
Normalised fit of PDF to data Best Gaussian fit
Best Huber norm fit
Slide 42
Slide 42
Comparing optimal observation weightsHuber-norm (red) vs. Gaussian+flat (blue)
More weight in the middle of the distribution
More weight on the edges of the distribution
More influence of data with large departures
Weights: 0 – 25%
25%
Slide 44
Slide 44
Implementation of the next resolution upgrade
Configuration: Deterministic model: T1279L91 (~16km) Outer loop of 4D-Var T1279L91 and inner
loops (T159/T255/T255) EPS resolution T639 (to 10 days) and T319
thereafter Wave model (25km and 36 directions)
Implementation planned for January 2010
Slide 45
Slide 45
OPS (35r2)
980hPa
(35r3) Use of improved QC (Huber norm)
961hPa
(36r1) High-res system (T1279 etc)
945hPa
Hurricane Bill, observed pressure~944hPa
Slide 47
Slide 47
ECMWF model simulations (T1279, ~15 km)compared with Satellite Observations (Met 9)
Slide 48
Slide 48
The MJO and tropical cyclones in the monthly forecast system
What is the state of play regarding the models MJO?What is the models TC climatology like?How does the MJO influence the model TC
15-member ensemble forecasts starting on the 15th of each month from 1989 to 2008.
46-day integrations
Cycle 32R3
T399 uncoupled till day 10 and T255 coupled after day 10
(Frederic Vitart – submitted to GRL)
Slide 49
Slide 49
MJO Propagation
1 2 3 4 5 6 7 8MJO Phase
0
2
4
6
Num
ber o
f Day
s
Time spent in each phase of the MJO
ERA-IModel
Slide 50
Slide 50
Amplitude of the MJO
Era Interim - VP200 Model - VP200
Era Interim - OLR Model - OLR
Slide 51
Slide 51
NDJFMAObservations Model
JASON
TS GENESIS
30°S30°S
20°S 20°S
10°S10°S
0° 0°
10°N10°N
20°N 20°N
30°N30°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 10 10.. 15 15.. 20 20.. 25 25.. 30 30.. 35 35.. 40 40.. 45 45.. 50 > 50
TS GENESIS
30°S30°S
20°S 20°S
10°S10°S
0° 0°
10°N10°N
20°N 20°N
30°N30°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 10 10.. 15 15.. 20 20.. 25 25.. 30 30.. 35 35.. 40 40.. 45 45.. 50 > 50
TS GENESIS
30°S30°S
20°S 20°S
10°S10°S
0° 0°
10°N10°N
20°N 20°N
30°N30°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 10 10.. 15 15.. 20 20.. 25 25.. 30 30.. 35 35.. 40 40.. 45 45.. 50 > 50
TS GENESIS
30°S30°S
20°S 20°S
10°S10°S
0° 0°
10°N10°N
20°N 20°N
30°N30°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 10 10.. 15 15.. 20 20.. 25 25.. 30 30.. 35 35.. 40 40.. 45 45.. 50 > 50
Tropical Cyclone Genesis climatology
1989-2008
Slide 52
Slide 52
NDJFMAObservations
JASON
Model
TS GENESIS
80°S80°S
70°S 70°S
60°S60°S
50°S 50°S
40°S40°S
30°S 30°S
20°S20°S
10°S 10°S
0°0°
10°N 10°N
20°N20°N
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
70°N 70°N
80°N80°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 2 2.. 4 4.. 8 8.. 12 12.. 16 16.. 20 20.. 24 24.. 28 28.. 32 > 32
TS GENESIS
80°S80°S
70°S 70°S
60°S60°S
50°S 50°S
40°S40°S
30°S 30°S
20°S20°S
10°S 10°S
0°0°
10°N 10°N
20°N20°N
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
70°N 70°N
80°N80°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 2 2.. 4 4.. 8 8.. 12 12.. 16 16.. 20 20.. 24 24.. 28 28.. 32 > 32
TS GENESIS
80°S80°S
70°S 70°S
60°S60°S
50°S 50°S
40°S40°S
30°S 30°S
20°S20°S
10°S 10°S
0°0°
10°N 10°N
20°N20°N
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
70°N 70°N
80°N80°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 2 2.. 4 4.. 8 8.. 12 12.. 16 16.. 20 20.. 24 24.. 28 28.. 32 > 32
TS GENESIS
80°S80°S
70°S 70°S
60°S60°S
50°S 50°S
40°S40°S
30°S 30°S
20°S20°S
10°S 10°S
0°0°
10°N 10°N
20°N20°N
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
70°N 70°N
80°N80°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< 2 2.. 4 4.. 8 8.. 12 12.. 16 16.. 20 20.. 24 24.. 28 28.. 32 > 32
Tropical Cyclone Density climatology
1989-2008
Slide 53
Slide 53
TS GENESIS
30°S30°S
20°S 20°S
10°S10°S
0° 0°
10°N10°N
20°N 20°N
30°N30°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
MJO Composite- ASO
Tropical storm density anomaly
Phases 2+3
Phases 4+5
Phases 6+7
Phases 8+1
ModelObservations
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-10 -10.. -5 -5.. -2 -2.. -1 -1.. 1 1.. 2 2.. 5 5.. 10 > 10
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< -7 -7.. -5 -5.. -2 -2.. -1 -1.. 1 1.. 2 2.. 5 5.. 7 > 7
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< -7 -7.. -5 -5.. -2 -2.. -1 -1.. 1 1.. 2 2.. 5 5.. 7 > 7
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< -7 -7.. -5 -5.. -2 -2.. -1 -1.. 1 1.. 2 2.. 5 5.. 7 > 7
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
< -7 -7.. -5 -5.. -2 -2.. -1 -1.. 1 1.. 2 2.. 5 5.. 7 > 7
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
Slide 54
Slide 54
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
TS GENESIS
10°N10°N
20°N 20°N
30°N30°N
40°N 40°N
160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
<-20 -20..-10 -10.. -5 -5.. -2 -2.. 2 2.. 5 5.. 10 10.. 20 > 20
Phases 6+7 – Phase 2+3
Observations
Model
MJO Composite- ASO
Tropical storm density anomaly
Slide 55
Slide 55
Example of Tropical Storm Seasonal Forecast
80°S80°S
70°S 70°S
60°S60°S
50°S 50°S
40°S40°S
30°S 30°S
20°S20°S
10°S 10°S
0°0°
10°N 10°N
20°N20°N
30°N 30°N
40°N40°N
50°N 50°N
60°N60°N
70°N 70°N
80°N80°N
20°E
20°E 40°E
40°E 60°E
60°E 80°E
80°E 100°E
100°E 120°E
120°E 140°E
140°E 160°E
160°E 180°
180° 160°W
160°W 140°W
140°W 120°W
120°W 100°W
100°W 80°W
80°W 60°W
60°W 40°W
40°W 20°W
20°W
8.1 12.18.5 12.323.2 21.82.62.53.8
Not Significant Significant at 5%
Ensemble size = 41,climate size =176Forecast start reference is 01/06/2009Tropical Storm FrequencyECMWF Seasonal Forecast
Climate = 1990-2005JASOND 2009
System 3
Forecast mean Standard deviation Climate mean
Slide 57
Slide 57
Interannual variability of Atlantic tropical storm ACE
Forecasts issued in June for the period July-December 1990-2009 Correlation: 0.72 RMS error: 0.40
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Year (start of verification period)
0.10.20.30.40.50.60.70.80.9
11.11.21.31.41.51.61.71.81.9
22.12.22.32.42.52.62.72.82.9
NO
RM
ALI
ZE
D A
CE
0.10.20.30.40.50.60.70.80.911.11.21.31.41.51.61.71.81.922.12.22.32.42.52.62.72.82.9
Ensemble size = 11 (real time = 41)Calibration period = 1990-2005Forecast start reference is 01/06/YYYYNorth Atlantic Accumulated Cyclone EnergyECMWF Seasonal Forecast
JASONDSystem 3
RMS Error= 0.40( 0.58)Correlation= 0.72( 1.00)
Forecast Observations +/- 1 Std. Deviation
Slide 58
Slide 58
Interannual variability of the frequency of Typhoons
Forecasts issued in April for the period May-October 1990-2009 Correlation: 0.66 RMS error: 3.29
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Year (start of verification period)
4
6
8
10
12
14
16
18
20
22
24
26
28
Typ
hoon
Num
ber
4
6
8
10
12
14
16
18
20
22
24
26
28
Ensemble size = 11 (real time = 41)Calibration period = 1990-2005Forecast start reference is 01/04/YYYYWestern North Pacific Typhoon FrequencyECMWF Seasonal Forecast
MJJASOSystem 3
RMS Error= 3.29( 3.49)Correlation= 0.66( 1.00)
Forecast Observations +/- 1 Std. Deviation
Slide 59
Slide 59
Closing remarks Steady improvements in skill in traditional measures such as 500hPa
geopotential (~1 day per decade for deterministic forecasts and ~1 day per 7
years for ensemble systems). Forecasts of weather parameters such as
precipitation, cloud etc. are ~ 1 day per 7 years.
Skill of tropical cyclone forecasting is improving at a similar rate with
emerging skill in intensity and genesis. ECMWF generally the best available
especially in the most recent years
Advanced assimilation methods enable better use of storm-related data
Progressive increases in resolution and improved physics are improving
realism of structures and intensity and hence improvements in tracking
Links to MJO activity provide some sub-seasonal skill in forecasting TC
statistics
Seasonal forecasting shows (surprisingly?) good skill in multi-basin statistics