John P. George

Data Assimilation : NCMRWF
Experience & Challenges
John P. George
National Centre for medium Range Weather Forecasting
A-50, Sector-62, Noida (U.P),India-201309
Outline
• Data Assimilation system at NCMRWF
– Current Status
• Deficiencies of the current system (UM-DA)
• Focus areas
Present Status: Global NWP Models at NCMRWF
Model
Version
Horizontal
Resolution
Forecast
Length
GFS T574L64
GFS version
9.0.1
~25 km
240 Hrs
UKMO-UM
N512L70
UM 7.9
~25 km
168 Hrs
Global
Global
Data Assimilation System (Global) - NCMRWF
Year
(Real time)
NWP Model
Model
Horizontal
Resolution
DA Scheme
1994 - 2007
T80L18 (NCEP),
150 km
T80L18 (with Improved
Physics),
T170L28
3DVAR (SSI)
2007
T254L64
50 km
3DVAR (SSI)
2009
T254L64
50 km
3DVAR (GSI)
2010
T382L64
35 km
3DVAR (GSI)
2010 -
T574L64
25 km
3DVAR (GSI)
2012 -
UM-N512L70
25 km
4DVAR
All are six hourly intermittent schemes,
4 times a day - 0000, 0600, 1200,1800 UTC with
± 3 hours observation window
7 Day
Fcst
Obs
(Obstore)
Software
Version (NCMRWFtill Nov-2012)
Version (NCMRWFSince Dec, 2013)
UM Model
UM 7.7
UM 7.9
Resolution
(NCMRWF)
N512L70
(1024x769)
(Height ~80km)
Variational Analysis
(4d-Var)
VAR 27.1.0
Observation Processing
System (OPS)
OPS 27.1.0
VAR 27.2.0
N216L70 (432x325)
(Height ~80 km)
OPS 27.2.0
UM Data Assimilation System at NCMRWF
No. of Iteration
49
52
55
58
61
52
55
58
61
37
34
31
28
49
4.5
46
4.7
46
4.9
43
5.1
43
5.3
40
No. of Iteration
40
37
34
31
28
25
22
19
16
13
7
10
4
1
Log10 (Jo)
5.5
25
5.5
22
19
16
13
7
10
4
1
Log10 (J)
61
58
55
52
49
46
43
40
37
34
31
28
25
22
19
16
13
7
10
4
1
Log10 (Jb)
Cost function
(4DVAR at NCMRWF)
5
4
3
2
1
0
No. of Iteration
5.3
5.1
4.9
4.7
4.5
Observation Preparation for UM DA system at
NCMRWF
# NCMRWF (GFS-based) bufr-tank
# Conventional observations are
packed in UM-obstore format
# Satellite observations in BUFR format
Observations Assimilated at NCMRWF (UM)
Percentage of Satellite Obs Assimilated (UM-August 2013)
Satellite Observations (UM System - August 2013)
ATOVS
ATOVS
Total Observation
GPSRO
GPSRO
Assimilated
AIRS
AIRS
Scatwd
Scatwd
00 UTC (17.19)
06 UTC (17.11)
12 UTC (18.08)
IASI
IASI
18 UTC (17.02)
AVE (17.34)
Satwind
Satwind
0
1
2
3
4
Log10 (Observations)
5
6
7
8
0
10
20
30
40
50 60 70
Percentage (%)
80
90 100
Verification of NCUM Analysis against Observation (RS/RW)
Verification of NCUM Analysis against Observation (RS/RW)
Verification of NCUM Analysis against Observation (RS/RW)
Surface Observations
Observation – Background
Bias of Surface Observations (P & RH) over India against UM background
Figure shows the bias for each day from January to June 2013 at different hour (00 UTC, 06 UTC
12 UTC and 18 UTC). The top panel is for Pressure (mb) and the bottom panel for relative
humidity (%).
Bias of Surface Observations (Wind & T ) over India against UM background
Figure shows the bias for each day from January to June 2013 at different hour (00 UTC, 06 UTC
12 UTC and 18 UTC). The top panel is for wind speed (m/s) and the bottom panel for surface
temperature (Deg C).
RMSE of Surface Observations (Wind & T) over India against UM background
Analysis of Root Mean Square Error (RMSE) for each day from January to June 2013 at different
hour (00 UTC, 06 UTC 12 UTC and 18 UTC). The top panel is for Wind Speed (m/s) and the
bottom panel for temperature (Deg C). The numbers in each panel represents the average RMSE
for all the six months.
Bias of Surface Observations (Wind) - against UM background (Global)
Systematic Error (850 hPa) – August, 2013
Unified Model at NCMRWF (NCUM)
Systematic Error (850 hPa) – August, 2013
UK Met Office Unified Model
Regional Assimilation (NCMRWF):
South Asia Model – 12 km
Regional 3DVAR & 4DVAR tested with an older version of the
UM Assimilation system (OPS/VAR 26.1)
- Regional Assimilation system is being upgraded
- Plans to use Indian DWR Wind observations
Kedarnath
13:00 UTC -16th June 2013
U wind comparisons between Delhi C band radar with Delhi S band radar &
V wind comparisons between Delhi C band radar with Delhi S band radar
U wind comparisons between Delhi C band radar with Jaipur C band radar & V
wind comparisons between Delhi C band radar with Jaipur C band radar.
UM DA system (NCMRWF) –
Current Focus Areas.....
- Static (Climatological) Background Error to Flow dependent BE
Maximise the use of observations in the DA system
- Use of Indian DWR data in NCUM-DA system
- New Indian Satellite observations (MT, INSAT-3D) in the
NCUM- DA system
- Use of DWR Observations
Challenges.......
- Global, Regional & Convective Scale DA system –
Observations (relative importance) & DA technique
- Innovative data assimilation techniques in order to
extract maximum information from different types of
(non-conventional) observations
- Operational NWP depends on “TimeLines” - Observation
availability “in time” & Speed of NWP System are
important – Faster DA system
Thank You
Computing Power Availability at NCMRWF
Year
HPC
Performance
1988-1993
Cray-XMP
4 MFLOPS
1993-1998
Cray-YMP
16 MFLOPS
1999-2011
Dec-Alpha
9.6 GFLOPS
2001-2006
Cray SV1
28.8 GFLOPS
2006-2011
PARAM (C-DAC)
500 GFLOPS
2006-2011
Cray-X1E
1.1 TFLOPS
2010-
IBM (P6 system)
24 TFLOPS
End of 2013 -
IBM (The New System
is being installed)
Reception of Global observations at NCMRWF
Indian DWR GPSRO
Euro. Wind Profiler …..
700
600
- GTS via RTH New Delhi,
dedicated link
~ 90MB/day (2008)
~ 250MB/day (2010)
~ 600MB/day(2011 & 12)
Volume/day(MB)
500
MFI
Aircraft Ship
Buoy AMVs …
400
300
200
100
0
1997
2001
2003
2006
2008
2009
2010
2011
2012
Year
Volume of data reception through GTS (MB/day)
10000
NESDIS Lvl 1B Radiance NOAA, METOP
9000
Volume/day(MB)
8000
7000
6000
ASCAT, Polar AMVs ,IASI ….
5000
OSCAT, AIRS
GPSRO ….
4000
3000
2000
1000
0
1997
2001
2003
2006
2008
Year
2009
2010
2011
Volume of data reception through FTP (MB/day)
2012
Download through ftp Satellite observations
~ 550 MB/day (2008)
~ 3.5 GB/day (2010)
~ 5 GB/day (2011)
~ 9 GB/day (2012)
RMSE of Surface Temperature - Indian Surface Observations