Transcript TTISS DAOS-B: 10:00-10:15, Wednesday, 16 September 2009 Propagation of the Impact Signal of the Additionally-Assimilated Observations over the Indian Ocean through tropical waves Qoosaku MOTEKI RIGC/JAMSTEC K. T. T. S. Yoneyama・

TTISS DAOS-B: 10:00-10:15, Wednesday, 16 September 2009
Propagation of the Impact Signal of
the Additionally-Assimilated Observations
over the Indian Ocean
through tropical waves
Qoosaku MOTEKI
RIGC/JAMSTEC
K.
T.
T.
S.
Yoneyama・ R. Shirooka・ M. Katsumata・M. Yoshizaki：
JAMSTEC/RIGC
Enomoto：
JAMSTEC/ESC
Miyoshi：
Univ. of Maryland
Yamane：
Doshisya Univ.
A field experiment of MISMO
“ALERA” (AFES-LETKF Experimental ReAnalysis)
Free download from “http://www.jamstec.go.jp/esc/afes/dods/alera”
produced by JMA, JAMSTEC/ESC, and CIS
using an ensemble Kalman filter
Impact signal of the observations
impactsignal  variablewithMISMO  variablewithoutMISMO
According to Hodyss and Majumdar
(2007, QJRMS), ‘data impact’ fields may
become contaminated by unmeaning noises
due to the model’s schemes!
Impact signal of the observations
(significant difference between the datasets with t-test at the 95% confidence level)
impactsignal  variablewithMISMO  variablewithoutMISMO ,
variablewithMISMO  variablewithoutMISMO ,
((spreadwithMISMO )2  (spreadwithoutMISMO )2 ) /(40  1)
Difference total energy norm
DTE   u   v 
2
2
Cp
Tr
T
index of dynamical relation
2
 2.02
Objective
To describe the propagation of
impact of the MISMO sondes.
the
Are there any impacts on the typhoons?
cf. Frank and Roundy [2006, MWR]
Signal propagation with Rossby waves
color: OLR
contour : ER filtered OLR
color: DTE
contour: ER filtered DTE
Adopting the wavenumber-frequency filter based on Straub and Kiladis (2002).
Signal propagation with Kelvin waves
color: OLR
contour : Kelvin filtered OLR
color: DTE
contour: Kelvin filtered DTE
Adopting the wavenumber-frequency filter based on Straub and Kiladis (2002).
Kelvin waves affect the TCs?
×: DB
○: TD
○: TS
○: TY
Sensitivity experiment
for the data before November 1
×: DB
○: TD
○: TS
○: TY
Sensitivity experiment
for the data November 5
×: DB
○: TD
○: TS
○: TY
Error reduction rate (%)
(significant difference between the datasets with F-test at the 95% confidence level)
spreadwithoutMISMO  spreadwithMISMO
error reductionrate  100
,
spreadwithoutMISMO
(spreadwithoutMISMO )2
(spreadwithoutMISMO )2
 1.875,
 1 / 1.875
2
2
(spreadwithMISMO )
(spreadwithMISMO )
positive
improve (reduce error)
index of accumulated dynamical relation
negative
degrade (enlarge error)
Error reduction rate (%)
around the typhoons
improve
degrade
date
date
The region improved by MISMO
error reduction rate (%)
Conclusions
The MISMO sondes have a significant impact on
the analysis accuracy of the typhoons through
the Kelvin waves.
degrade
improve
error reduction rate (%)
Conclusions
The MISMO sondes have a significant impact on
the analysis accuracy of the typhoons through
the Kelvin waves.
degrade
improve
error reduction rate (%)
Tropical waves are
good TRANSPORTERS
of the observation information.
error reduction rate (%)
Signal around Durian
at the passage of the Kelvin wave
passage of
Kelvin wave
average
Signal propagation with MRG waves
color: OLR
contour : MRG filtered OLR
color: DTE
contour: MRG filtered DTE
Adopting the wavenumber-frequency filter based on Straub and Kiladis (2002).
Signal propagation with MJO (ISO-E)
color: OLR
contour : MJO filtered OLR
color: DTE
contour: MJO filtered DTE
Adopting the wavenumber-frequency filter based on Straub and Kiladis (2002).
Sensitivity experiments
for the assimilated period
×: DB
○: TD
○: TS
○: TY
Time-averaged error reduction rate (%)
TY0619 Cimaron
(00Z25Oct.-12Z07Nov.)
TY0620 Chebi
(06Z07Nov.-00Z15Nov.)
TY0621 Durian
(12Z24Nov.-18Z09Dec.)
EX2
(Assim. : 22Oct.-2Dec.)
0.50 (Ave. : 1Nov.-7Nov.)
0.57 (Ave. : 7Nov.-15Nov.)
3.18(Ave. : 24Nov.-02Dec.)
EX3
(Assim. : 1Nov.-5Nov.)
0.33 (Ave. : 1Nov.-7Nov.)
0.04 (Ave. : 7Nov.-15Nov.)
0.09(Ave. : 24Nov.-2Dec.)
0.26 (Ave. : 7Nov.-15Nov.)
0.08(Ave. : 24Nov.-02Dec.)
EX4
(Assim. : 6Nov.-15Nov.)
EX5
(Assim. : 16Nov.-2Dec.)
0.53(Ave. : 24Nov.-2Dec.)