Recent Advances in Assimilation of
ATOVS & SSM/I Data in GDAFS
of India
V.S. Prasad,M. Das Gupta,D.Rajan, A.K.Mitra,S.C. Kar
& R.K. Paliwal
National Center for Medium Range Weather Forecasting
India.
• Description of Data Assimilation System
• Requirement for changes
• Design of Experiment
• Results
NCMRWF Global Data Assimilation System
6-hourly Intermittent Scheme
(00UTC, 06UTC, 12UTC and 18UTC)
(i) Data reception and quality Control
(ii) Data Analysis based on ‘Spectral Statistical
Interpolation’ (SSI); 3-D Variational
NCEP ( 1995 January Version)
(iii) Global NWP Model-provides the first guess
( background ) to the analysis scheme
Conventional Data
TEMP and TEMP-SHIP
PILOT and PILOT-SHIP
SYNOP, SYNOP-SHIP and BUOY
AMDAR, AIREP
Non-conventional Data
SATOB : INSAT,GMS, GOES and METEOSAT
High Resolution VIS, IR, WV from METEOSAT-5(63E)
SSM/I 75 Km resolution over ocean from DMSP Satellite series
(No.-13,14,15).
Aircraft
Radiosonde
Pilot
Balloon
Surface
observation
s
GTS
DATA
Satellite
data
input
RTH
NEW DELHI
D8
G
AT
U
TE
T
M
S
AC
Ships &
Buoys
FTP Satellite Data
MSMR, SSMI etc.
DATA RECEPTION
AT NCMRWF
PREVIOUS (6 HOURS)
ANALYSIS
DATA PROCESSING AND
QUALITY CONTROL
PREVIOUS (6HR.)
DATA PROCESSING
SSI
ANALYSIS
ANALYSIS
&
SURFACE
QUALITY CONTROL
BOUNDARY
CONDITION
SURFACE
S
BOUNDARY
T80 GLOBAL ANALYSIS
SPECTRAL
CONDITIONS
FORECAST MODEL
• IRS-P4 / MSMR Launched 1999
• Swath 1360 Km
6.6 , 10.6 , 18 and 21 G Hz (V, H)
• Indian Ocean Pass time ~ 06 & 18 UTC
Surface wind speed
Total Precipitable water content
Cloud Liquid Water Content
Sea Surface Temperature
(above parameters are received at 50,75, 150
km horizontal resolution )
Satellites - F 13 , F 14 , F15
18 , 22(v), 37, 85 Ghz
NASA’s Pathfinder Program : Earth science products
SSM/I daily products by ‘Remote Sensing Systems’
Unified physically based algorithm for simultaneous
retrieval of wind speed, total water vapor, rainfall,
Cloud liquid water ( Wentz 1998 )
RMS accuracies:
Wind speed (at 10 m ) - 1 m / s
Total Water vapor
- 1 mm
Cloud liquid water
- 0.03 mm
• Data NOAA 11/12 was received through
GTS in SATEM code at 500 km resolution
till April 2001.
• Temperature over ocean and TPWC (land &
ocean) from NOAA was being assimilated
till April 2001.
• Subsequently it was replaced with ATOVS
data in BUFR code at 120 km resolution
• Earlier studies of Basu et al (1999) suggested that
the NCMRWF analyses are found to be dryer than
the corresponding fields of JMA, Japan and
ECMWF,U.K
• Ocean surface wind speed is the new type of
observation and is being handled first time at
NCMRWF
• The details of the changes are given in Scientific
report by Rizvi et al. 2000.
•
•
•
•
EXP1
EXP2
EXP3
Exp4
:
:
:
:
Temp & TPWC (NOAA) L+O X
Temp and wind speed from SSM/I
Temp and TPWC NOAA ( Ocean only)
EXP3 + SSM/I Wind
• Exp5 : GTS data only
• These OSEs are conducted for the month of
Sep 2001.
S.H. MEAN BIAS(HT. FIELD)
NH MEAN BIAS HT. FIELD
16
14
14
12
10
EXP1
8
EXP2
6
EXP3
4
EXP4
10
EXP1
8
EXP2
6
EXP3
4
EXP4
BIAS
BIAS
12
2
2
0
-2
0
1000 925
850
700
500
400
350
300
350
200
1000 925
850
700
500
LEVEL
400
350
300
350
200
LEVEL
TROPICAL MEAN BIAS (UWIND)
TROPIC MEAN BAIS (HT. FIELD)
20
1.2
1
0.8
10
EXP1
0.6
EXP1
EXP2
0.4
EXP2
0.2
EXP3
EXP3
5
EXP4
BIAS
BIAS
15
0
-0.2 1000 925
0
1000 925
850
700
500
400
-5
350
300
350
200
EXP4
850 700
500
400
350 300
250
200
-0.4
-0.6
LEVEL
LEVEL
Mean Bias of analysis at various pressure levels averaged for 00UTC 1-30Sep 2001
.
• At NCMRWF an objective procedure was
evolved and implemented to study Indian
summer monsoon characteristics. In this
scheme
* Net Tropospheric moisture
* Mean Tropospheric Temp.
* 850 hPa Kinetic Energy
are monitored over Arabian Ocean(019.5Nn and 55.5-75E) and Bay of Bengal
etc.
ANA NTM over Arabian Ocean
D1 FCST NTM over Arabian Ocean
DAYS
Days
D2 FCST NTM over Arabian Ocean
35
34
33
32
31
30
29
28
27
26
25
D5 FCST NTM over Arabian Ocean
37
35
EXP-1
EXP-1
33
EXP-3
EXP-4
mm
EXP-2
EXP-2
31
EXP-3
EXP-4
29
EXP-5
EXP-5
Days
28
25
22
19
16
13
10
7
4
25
1
28
25
22
19
16
13
10
7
4
27
1
mm
31
1
31
28
25
22
19
16
13
10
7
4
1
25
EXP-5
28
27
EXP-4
25
EXP-5
22
29
EXP-3
19
EXP-4
EXP-2
16
EXP-3
13
31
mm
mm
EXP-2
EXP-1
10
EXP-1
33
7
35
35
34
33
32
31
30
29
28
27
26
25
4
37
Days
Daily variations of Net Tropospheric moisture over the Arabian Sea(1-30Sep 2001)
ANA NTM over BOB
D1 FCST NTM over BOB
Days
EXP3
EXP4
28
25
22
19
16
13
EXP5
10
28
25
22
19
16
13
10
7
EXP5
EXP2
7
EXP4
EXP1
4
EXP3
mm
EXP2
45
43
41
39
37
35
33
31
29
27
25
1
EXP1
4
28
D5 FCST NTM over BOB
45
43
41
39
37
35
33
31
29
27
25
1
mm
25
Days
D2 FCST NTM over BOB
Days
22
1
28
25
22
19
16
13
10
7
4
1
25
EXP5
19
EXP5
30
EXP4
16
EXP4
EXP3
13
EXP3
35
EXP2
10
EXP2
40
EXP1
7
EXP1
mm
mm
45
45
43
41
39
37
35
33
31
29
27
25
4
50
Days
Daily variations of Net Tropospheric moisture over the Bay of Bengal (1-30 Sep 200).
ANA Net 700 hPa K.E over Arabian Ocean
D1 FCST Net 850 hPa K.E over Arabian Ocean
70
60
60
50
EXP1
50
EXP1
40
EXP3
30
mm
EXP2
40
EXP4
20
EXP2
30
EXP3
EXP4
20
Days
28
25
Days
Daily variations of 700hPa K.E over the Arabian Sea (1-30 Sep 200).
29
27
25
23
21
19
17
15
29
27
25
23
21
19
17
15
13
11
9
7
5
0
EXP5
13
EXP5
10
EXP4
11
EXP4
20
EXP3
9
EXP3
7
30
EXP2
5
EXP2
EXP1
3
EXP1
40
50
45
40
35
30
25
20
15
10
5
0
1
50
3
22
D5 FCST Net 700 hPa K.E over Arabian Ocean
60
1
19
Days
D2 FCST Net 700 hPa K.E over Arabian Ocean
Days
16
13
10
1
29
27
25
23
21
19
17
15
13
11
9
7
5
3
0
1
0
7
EXP5
10
4
EXP5
10
D1 FCST Net 850 hPa K.E over Arabian Ocean
ANA Net 850 hPa KE over Arabian Ocean
60
80
70
50
Daily variations of 700hPa K.E over
EXP1 the Arabian Sea (1-30 Sep 200).
50
EXP2
40
EXP3
30
EXP4
20
EXP5
EXP1
40
mm
60
EXP2
30
EXP3
EXP4
20
EXP5
10
10
28
25
22
19
16
13
10
7
1
29
27
25
23
21
19
17
15
13
11
9
7
5
3
1
4
0
0
Days
Days
D2 FCST Net 850 hPa K.E. over Arabian Ocean
D5 FCST Net 850 hPa K.E. over Arabian Ocean
60
60
50
50
EXP1
40
EXP2
30
EXP3
EXP4
20
EXP1
40
EXP2
30
EXP3
EXP4
20
Days
29
27
25
23
21
19
17
15
13
11
9
7
5
29
27
25
23
21
19
17
15
13
11
9
7
5
3
0
1
0
3
EXP5
10
1
EXP5
10
Days
Daily variations of 850hPa K.E over the Arabian Sea (1-30 Sep 200).
D1 FCST 850 hPa K.E over BOB
ANA 850 hPa K.E over BOB
80
90
80
70
60
50
40
30
20
10
0
70
EXP1
60
EXP1
EXP2
50
EXP2
EXP3
40
EXP3
EXP4
30
EXP4
20
EXP5
EXP5
10
D2 FCST 850 hPa K.E over BOB
80
60
70
29
27
Days
Daily variations of 850hPa K.E over the Bay of Bengal (1-30 Sep 200).
29
27
29
27
25
23
21
19
17
15
13
0
11
0
9
25
EXP5
25
20
10
7
23
EXP5
23
EXP4
10
5
21
30
21
EXP4
19
EXP3
17
40
15
EXP3
13
EXP2
11
50
9
EXP2
7
20
EXP1
5
30
60
3
40
EXP1
1
50
3
19
D5 FCST 850 hPa KE over BOB
70
1
17
Days
Days
Days
15
13
11
9
7
5
3
29
27
25
23
21
19
17
15
13
11
9
7
5
3
1
1
0
D1 FCST 700 hPa K.E over BOB
ANA 700 hPa K.E over BOB
70
60
60
Daily variations of 850hPa K.E over
the Bay of Bengal (1-30 Sep 200).
EXP1 50
50
40
30
EXP2
40
EXP3
30
EXP4
20
EXP5
10
EXP1
EXP2
EXP3
EXP4
20
EXP5
10
D2 FCST Net 700hPa K.E over BOB
70
50
60
29
27
25
23
21
Days
Daily variations of 700 hPa K.E over the Bay of Bengal (1-30 Sep 200).
29
27
25
23
21
19
17
15
13
EXP5
11
29
27
25
23
21
19
17
15
13
11
9
7
0
5
0
3
10
1
10
Days
EXP4
20
9
EXP5
EXP3
30
7
EXP4
EXP2
40
5
EXP3
EXP1
50
3
EXP2
1
EXP1
20
19
D5 FCST 700hPa KE over BOB
60
30
17
Days
Days
40
15
13
11
9
7
5
1
29
27
25
23
21
19
17
15
13
11
9
7
5
3
1
3
0
0
D1 FCST NTT over Arabian Ocean
ANA NTT Over Arabian Ocean
265.5
264.5
265
°K
263.5
EXP1
264.5
EXP1
EXP2
264
EXP2
263.5
EXP3
EXP4
263
EXP4
EXP5
262.5
EXP5
EXP3
263
262.5
°K
264
262
28
25
22
19
16
13
10
Days
D3 FCST NTT over Arabian Ocean
D5 FCST NTT over Arabian Ocean
265
265
264.5
264.5
EXP1
28
25
22
19
16
13
10
EXP5
7
28
25
22
19
16
13
261.5
10
261.5
7
262
4
EXP4
262.5
262
Days
EXP3
263
4
EXP5
EXP2
263.5
1
EXP4
262.5
°K
EXP3
263
EXP1
264
EXP2
263.5
1
7
1
31
28
25
22
19
16
13
10
7
1
4
Days
264
mm
4
261.5
262
Days
Daily variations of Net Tropospheric Temperature over the Arabian Sea (1-30 Sep 200).
D1 FCST NTT over BOB
ANA NTT over BOB
EXP2
263.5
EXP3
EXP4
263
263.5
EXP2
EXP4
263
EXP5
EXP5
262.5
262.5
28
25
22
19
16
13
1
28
25
22
19
16
13
10
7
4
1
10
262
262
Days
Days
D5 FCST NTT over BOB
D2 FCST NTT over BOB
265
265
264.5
EXP2
263.5
28
25
22
19
EXP5
16
28
25
22
19
16
13
10
261.5
7
262
4
262
1
262.5
Days
EXP4
262.5
13
EXP5
EXP3
263
10
EXP4
263
EXP2
7
EXP3
EXP1
4
263.5
264
°K
264
EXP1
1
264.5
°K
EXP1
EXP3
7
°K
264
4
264.5
265
Daily variations of Net Tropospheric Temperature over the Arabian Sea
264.5
(1-30 Sep 200).
EXP1
264
°K
265
Days
Daily variations of Net Tropospheric Temperature over Bay of Bengal (1-30 Sep 200).
29th Sep Monsoon Depression
case
PLANS - 1
1)
Direct Raw Radiance Assimilation from ATOVS / GOES
/METEOSAT
•
3D-VAR allows us to make better use of observations
that are not directly related to the model variables
(e.g. radiances from IR, microwave,WV instruments)
•
This direct approach avoids the need to make the
assumptions that the retrieved parameters(t,q) are
independent of the model and that the errors at
different levels are uncorrelated
•
Large positive impact on analysis/forecast in both
hemispheres are reported. Large forecast impact
is reported in stratospheric events
PLANS -2
2) Wind speed and TPWC from Passive Microwave
sensors
•
In extremely moist conditions the accuracy to which
surface wind speed can be determined gets reduced
•
Large amounts of moisture also degrade the moisture
estimation
•
Presence of cloud and precipitation – accuracy of
retrievals
•
Use NCEP NN algorithm OMBNN3
Better products, more area coverage
weather
with
active