vsnmurty-EIO mooring..

advertisement
OceanSITES meeting in SIO
30 Nov – 2 Dec. 2011
Status on Equatorial Indian Ocean – OceanSITES
Long-term measurements of currents in the equatorial
Indian Ocean using deep-sea moorings –
Project funded by INCOIS/ MoES
70
75
80
85
90
95
25
100
25
India
20
20
Latitude° N
by
Dr. VSN Murty
National Institute of Oceanography
Regional Centre
176 Lawsons Bay Colony,
Visakhapatnam
TS2 (17.5°N,89°E)
15
15
10
10
5
70
75
80
85
Longitude° E
90
95
5
100
Equatorial Indian Ocean Observational Array since 2000
EQCM3
EQCM1
EQCM2
The current meter moorings project is being executed
since February 2000. Servicing of the moorings is being
done regularly onboard ORV Sagar Kanya.
Update status of 4 deep-sea current meter moorings in equatorial Indian Ocean
Duration of the moorings at each location
Mooring
Location
D: Deployment
2000
EQCM 1
[Equator,
93°E]
EQCM 2
[Equator,
83°E]
2000-02
2002-03
2003-04
2004-06
2008-09
2009-10
D 13 Feb ‘00 D 23 Dec ‘00
D 01 Apr
2002
D 25 Sep 2003 D 07 Nov2004
D 15 Sep 2006
D 05 Jan 2009
To
To
to
To
To
to
To
R 21 Dec ‘02 R 30 Mar ‘02 R 23 Sep
2003
R 05 Nov 2004 R 13 Sep 2006
R 04 Jan 2009
R 03 Oct 2009
D 14 Dec ‘00
D 26 Dec
2002
D 19 Sep 2003 D 26 Oct 2004
D 21 Sep 2006
D 01 Jun 2008
To
To
To
To
To
R 24 Oct 2004 R 19 Sep 2006
R 30 May 2008
R 08 Oct 2009
D 10 Sep 2003 D 18 Oct 2004
D 27 Sep 2006
D 27 May 2008
To
To
To
R 25 May 2008
R 22 Oct 2009
R 24 Mar ‘02 R 17 Sep 2003
EQCM 3
[Equator,
77°E]
R: Recovery
To
To
R 17 Oct 2004 R 25 Sep 2006
Each mooring has one uplooking 75 kHz ADCPs at 400 m and
RCMs at 3 levels of nominal depths of 1000 m, 2000 m and 4000 m.
OOS program would continue till 2012.
Planning to extend the program for another 5 years [2012-2017]
Update status of 7 deep-sea current meter moorings in equatorial Indian Ocean
Duration of the moorings at each location
D: Deployment
R: Recovery
Mooring Location
2009-10
EQCM1 – [1N, 93E]
D 01 Oct 2009 R 11 Oct 2010
2010 – 2011
2011 - 2012
D 11 Oct 2010 R 2011
EQCM 1 – [Eq., 93E]
D 05 Oct 2010 R 9Oct 2010
D 10 Oct 2010 R 2011
EQCM1 – 1S, 93E]
D 02 Oct 2009 R 6 Oct 2010
D 08 Oct 2010 R 2011
EQCM 2
[Equator, 83°E]
D 10 Oct 2009 R 01 Oct 2010 D 03 Oct 2010 R 2011
EQCM3 – [1N, 77E]
D 21 Oct 2009 R 23 Sep 2010
EQCM 3 – [Eq., 77E]
D 24 Oct 2009 R 25 Sep 2010
EQCM3 – 1S, 77E]
D 20 Oct 2009 R 28 Sep 2010
NOT DONE due to
non-availability of the
vessels
NOT DONE due to
non-availability of the
vessels
D 24 Sep 2010 R 2011
D 27 Sep2010 R 2011
NOT DONE due to
non-availability of the
vessels
D 29 Sep 2010 R 2011
Each mooring has one uplooking 75 kHz ADCPs at 400 m and
RCMs at 3 levels of nominal depths of 1000 m, 2000 m and 4000 m.
OOS – Deep Sea Current meter moorings that are to be
Included in the OceanSITES list from the Indian Ocean
1)
2)
3)
4)
5)
6)
7)
1N, 93E
Eq., 93E
1S, 93E
Eq., 83E
1N, 77E
Eq., 77E
1S, 77E
Objectives
• To generate long-term currents data from the equatorial Indian
Ocean from 7 deep-sea mooring locations spread across and
along the equator from 77E to 93E.
• To describe the intraseasonal, interannual and long-term variability
of currents in the equatorial Indian Ocean.
• To decipher the ocean processes and dynamics those impact the
surface and subsurface variability by employing various model
simulations to understand climate variability of the region.
• To study the deep-sea circulation from observations and model
simulations in the equatorial Indian Ocean.
Achievements
 Generated a decade long time series current data at 93E location,
9 years long time series data at 83E and 7 years long time series at
77E in the eastern equatorial Indian. Additionally 4 moorings were
deployed in 2009 - at 1°N, 77°E; 1°S, 77°E, and 1°N, 93°E; 1°S, 93°E.
 Up-to-date data till 2010 were submitted to INCOIS and NIO, Goa.
 Identified and documented the intraseasonal variability in
meridional currents at biweekly (14 day) period in the upper 1000 m
from both observations and OGCM model simulations [Sengupta,
Retish, VSN Murty and V Fernando, JGR, 2004].
 Identified and documented the intraseasonal variability in
meridional currents at 10-20 day period in the deep-ocean waters
(2000 m and 4000m) and its linkage to the surface wind forcing,
from observations and OFES model simulations [Ogato, Masumoto,
VSN Murty and MSS Sarma, JGR, 2008].
Achievements
 Identified and documented the intraseasonal variability in
observed equatorial currents in relation to the Indian Ocean Dipole
mode events [David, D.T., S. Prasanna Kumar, P. Byju, M.SS. Sarma,
A. Suryanarayana and VSN Murty (JGR (Oceans), 2011].
Plan of Cruises from
2012 onwards
during XII plan –
i) Two separate
cruises to complete
servicing of 7
moorings
ii) To orient
optimum technical
staff in the
deep-sea mooring
operations
Thank You
Publications
David, D.T., S. Prasanna Kumar, P. Byju, M.S.S. Sarma, A. Suryanarayana and
V.S.N. Murty (2011) Observational evidence of lower frequency Yanai wave in the
central equatorial Indian Ocean. J. Geophys. Res., 116(6); 2011;
doi:10.1029/2010JC006603, 17 pp.
Ogata, T.; Sasaki, H.; Murty, V.S.N.; Sarma, M.S.S.; Masumoto, Y. (2008)
Intraseasonal meridional current variability in the eastern equatorial Indian Ocean.
J. Geophys. Res. (C: Oceans): 113(7); doi:10.1029/2007JC004331, 15 pp.
Cadden; D.D.H.; Subrahmanyam; B.; Chambers; D.P.; Murty; V.S.N. (2008)
Surface and subsurface geostrophic current variability in the Indian Ocean from
altimetry. Mar. Geod.: 32; 19-29.
Sengupta, D., Senan, Retish. Murty, V.S.N., Fernando, Vijayan. (2004). A
biweekly mode in the equatorial Indian Ocean. J. Geophys. Res., 109, C10003,
doi: 10.1029, 2004JC002329.
Conclusions
• The presentation highlights the recent studies in the EIO
using the OOS currents data.
• Current variability across-the equator at 93E location is
presented for the period from Sept 2006 - October 2010.
• Spring EUC occurred consistently in March-April at 93E.
Monsoon season intraseasonal jets are noticed in July-August.
• Observational evidence to the meandering of the EUC and
Jet. Meandering is more visible in Spring season.
Conclusions
• The presentation highlights the recent studies in the EIO
using the OOS currents data.
• Current variability across-the equator at 93E location is
presented for the period from Sept 2006 - October 2010.
• Spring EUC occurred consistently in March-April at 93E.
Monsoon season intraseasonal jets are noticed in July-August.
• Observational evidence to the meandering of the EUC and
Jet. Meandering is more visible in Spring season.
Conclusions
• The presentation highlights the recent studies in the EIO
using the OOS currents data.
• Current variability across-the equator at 93E location is
presented for the period from Sept 2006 - October 2010.
• Spring EUC occurred consistently in March-April at 93E.
Monsoon season intraseasonal jets are noticed in July-August.
• Observational evidence to the meandering of the EUC and
Jet. Meandering is more visible in Spring season.
Last servicing of 7 mooring was done during October –
November 2010
Servicing of these
Moorings could not
be done in 2011
due to non-availability
of the vessels.
Current variability at 93E location
during 2006 - 2010
Zonal current structure (96-464 m) at 0,93E during Sep 2006 – Dec 2008
2006 16-S 6-D 25-F 17-M
6-A 26-O 15-J 5-Ap 25-J 14-Sep 4-D 2008
Dominant eastward flows in the entire sub-surface layer
Zonal current structure (104-472 m) at Eq., 93E during Jan. 2009- Oct. 2009
2009 6-J 2-F
1-M 28-M 24-A 21-M 17-J 14-Jy 10-Au 6-Sep 3-O 2009
Winter & Spring EUC in 2009. Monsoon season EUC in 2009
Zonal current structure (48-368 m) at Eq., 93E during Oct 2009- Oct 2010
Zonal current(m/s) structure at 93E00 for 48 - 368 m layer
1.2
50
1
100
0.8
0.6
150
Depth(m)
0.4
200
0.2
0
250
-0.2
-0.4
300
-0.6
350
-0.8
06-Oct-200911-Nov-200918-Dec-200924-Jan-201002-Mar-201008-Apr-201015-May-201021-Jun-2010 28-Jul-2010 02-Sep-201009-Oct-2010
Time
2009 6-O 11-N 18-D 24-Jan 2-M 8-Apr 15-M 21-Ju 28-Jy 2-Sep 9-O 2010
Fall Jet in Nov 2009, Spring EUC & Jet ’10. Intraseasonal monsoon jets.
Zonal current structure (144-480 m) at 93E, 1N during 2009-2010
Zonal current(m/s) structure at location 93E1N for 144 - 480 m layer
0.6
150
200
0.4
250
Depth(m)
0.2
300
0
350
-0.2
400
-0.4
450
02-Oct-200908-Nov-200915-Dec-200922-Jan-201028-Feb-2010 07-Apr-201014-May-201021-Jun-2010 28-Jul-2010 04-Sep-201011-Oct-2010
Time
2-O 8-N 15-D 22-Jan 28-F 7-Apr 14-M 21-Ju 28-Jy 4-Sep 11-O 2010
EUC in March 2010 & Semi-annual variation is evident.
Zonal current structure (48-368 m) at Eq., 93E during 2009-10
Zonal current(m/s) structure at 93E00 for 48 - 368 m layer
1.2
50
1
100
0.8
0.6
150
Depth(m)
0.4
200
0.2
0
250
-0.2
-0.4
300
-0.6
350
-0.8
06-Oct-200911-Nov-200918-Dec-200924-Jan-201002-Mar-201008-Apr-201015-May-201021-Jun-2010 28-Jul-2010 02-Sep-201009-Oct-2010
Time
6-O 11-N 18-D 24-Jan 2-M 8-Apr 15-M 21-Ju 28-Jy 2-Sep 9-O 2010
Fall Jet in Nov 2009, Spring EUC & Jet ’10. Intraseasonal monsoon jets.
Zonal current structure (48-384 m) at 93E, 1S during Oct 2009-10
Zonal current(m/s) structure at location 93E1S for 48 - 384 m layer
1
50
0.8
100
0.6
150
Depth(m)
0.4
200
0.2
0
250
-0.2
300
-0.4
350
-0.6
03-Oct-200908-Nov-200915-Dec-200921-Jan-2010 27-Feb-2010 05-Apr-201012-May-201018-Jun-2010 25-Jul-201030-Aug-201006-Oct-2010
Time
3-O 8-N 15-D 21-Jan 27-F 5-Apr 12-M 18-Ju 25-Jy 30-Au 6-O 2010
Fall Jet ‘09 Spring EUC & Jet ‘10. Intraseasonal Monsoon Jets
Zonal current
structures in
upper 400 m
at 1N, Eq., 1S
at 93E show
similar
structures at
Eq. and 1S,
suggesting the
extent of
Jets and
EUC
across the
Equator
up to 1S.
1N,
93E
Eq,
93E
1S,
93E
6 Oct. 2009
08 Apr 2010
6 Oct. 2010
Meridional current structure across the Equator at 93E during 2009-10
Meridional current(m/s) structure at location 93E1N for 144 - 480 m layer
0.4
150
0.3
200
0.2
Depth(m)
250
0.1
0
300
1N,
93E
-0.1
350
-0.2
400
-0.3
-0.4
450
02-Oct-2009 08-Nov-200915-Dec-2009 22-Jan-201028-Feb-2010 07-Apr-201014-May-2010 21-Jun-2010 28-Jul-2010 04-Sep-201011-Oct-2010
Time
Meridional current(m/s) structure at location 93E00 for 48 - 368 m layer
0.8
50
0.6
100
0.4
0.2
150
Depth(m)
0
Eq,
93E
200
-0.2
250
-0.4
-0.6
300
-0.8
350
-1
06-Oct-200911-Nov-200918-Dec-2009 24-Jan-2010 02-Mar-2010 08-Apr-2010 15-May-201021-Jun-2010 28-Jul-2010 02-Sep-201009-Oct-2010
Time
Meridional current(m/s)
structure at location 93E1S for 48 - 384 m layer
50
0.4
100
0.2
150
Depth(m)
0
200
1S,
93E
-0.2
250
-0.4
300
-0.6
350
03-Oct-200908-Nov-200915-Dec-200921-Jan-2010 27-Feb-2010 05-Apr-201012-May-201018-Jun-2010 25-Jul-2010 30-Aug-201006-Oct-2010
Time
3-O 8-N 15-D 21-Jan 27-F 5-Apr 12-M 18-Ju 25-Jy 30-Aug 6-O2010
Thank You
EIO
experienced
IOD event
in 2002
Period in days
Intraseasonal variability at 30-50 d penetrates up to 4000 m depth and
the ISV period increases with depth: 75 d at 500-1000m and 85 d at 2 km.
EIO
experienced
IOD events
in 2005
and
in 2006
Period in days
Intraseasonal variability at 30-40 d penetrates up to 4000 m depth and
the ISV period increases with depth: 85 d at 500-1000m and 110 d at 2-4 km.
Impact of equatorial zonal currents on the
alongshore currents off east coast of India
1. Zonal current variability at Eq., 93E during May – Oct. 2010
2. Alongshore current variability off Visakhapatnam at the
same period
3. Comparison of the zonal currents and alongshore currents
at 48 m depth
4. Spectra in the alongshore currents at different depths.
Zonal current structure (48 – 96 m) at Eq., 93E from May-Oct. 2010
Alongshore current structure (48 – 96 m) at Visakhapatnam
With a lag of 21 days, the alongshore currents do relate to the
Zonal current at the Equator and the linkage is through Kelvin Waves
Spectra of alongshore currents off Visakhapatnam at 24, 56 & 92 m
The spectral peaks at 21 d and 24 d at 24 m, 56 m depth reveal the
Equatorial connection in the shelf currents at 100 m water depth
Plan of Cruises from
2012 onwards
during XII plan –
i) Two separate
cruises to complete
servicing of 7
moorings
ii) To orient
optimum technical
staff in the
deep-sea mooring
operations
Conclusions
• The presentation highlights the recent studies in the EIO
using the OOS currents data.
• Current variability across-the equator at 93E location is
presented for the period from Sept 2006 - October 2010.
• Spring EUC occurred consistently in March-April at 93E.
Monsoon season intraseasonal jets are noticed in July-August.
• Observational evidence to the meandering of the EUC and
Jet. Meandering is more visible in Spring season.
Conclusions contd…
• Meridional currents show the observational evidence of
the opposing currents at 1N and 1S at biweekly intervals
– more clear in winter months.
• During the IOD events the intraseasonal variability at
30-50 day period penetrates up to 4 km.
• The zonal currents at Eq, 93E during May-October 2010
are compared with the alongshore currents off
Visakhapatnam during the same period.
• A lag of 21 days in the alongshore currents relates the
alongshore currents with the equatorial zonal currents
through the propagation of downwelling and upwelling
Kelvin waves.
Zonal current
structures in the
upper 400 m
at 1N/1S, 77E &
Eq. , 83E
do suggest
large scale
extent of
Equatorial
Undercurrent
(EUC) across
Equator.
1N,
77E
Eq,
83E
1S,
77E
Fall jet – 3 d
Spring jet – 15 d
6 Oct. 2009
08 Apr 2010
6 Oct. 2010
Period in days
Intraseasonal variability at 50-60 day period is dominant.
OFES simulations showing large scale meander of spring and fall
jets in EIO
October 11, 2003
April 14, 2004
ADCP data analysis at 77E
Comparison of OFES
and ADCP currents
At 38 m
Semi-annual period of
180 day in U and
bi-weekly wave of 15
day period in V are
evident.
At 94 m
Download