Indian Equatorial Moorings

A Programme Funded by the Department of Ocean DevelopmentGovernment of India

Principal Investigator: Dr. V.S.N. MurtyNational Institute of OceanographyDona Paula, Goa, India

The 6th CLIVAR Asian-Australian Monsoon Panel and the 1st CLIVAR/IOC Indian Ocean Panel Joint Meeting

18-20 February 2004Indian Institute of Tropical Meteorology, Pune

93E, 83E and 76E.

 Station No.

Deployment/Recovery of moorings

D: date of deployment R: date of recovery

EQCM 193°E

D 13 Feb. 2000

R 21 Dec. 2000

D 23 Dec. 2000

R 30 Mar. 2002

D 01 Apr. 2002

R 23 Sep. 2003

D 25 Sep. 2003

R ……

EQCM 283°E

  D 14 Dec. 2000

R 24 Mar. 2002

D 26 Dec. 2002

R 17 Sep. 2003

D 19 Sep. 2003

R …….

EQCM 3 76°E

    D 20 Mar. 2002

R 08 Sep. 2003

D 10 Sep. 2003

R …….

Status of Deep-sea Current meter moorings

 Station No. Mean depths of RCMs (m)

I II III IV

EQCM193°E

135, 280, 487, 983, 1996, 3995 

106, 264, 462, 966, 1969, 3968

106, 344, 529, 1032, 2004, 4015

EQCM283°E

  385, 590, 1072, 2081, 4095

140, 343, 545, 1047, 2049, 4052

EQCM 376°E

    418, 621, 823, 1326, 2330, 4134 MicroCat

Depths of RCMs in each mooring

Added during the last deployment

One up-looking ADCP was added to the mooring at 77°E to profile the top 100m of the water column.

One Microcat CTD was attached to the mooring at 83°E at 4000

m depth. With this there are now two MicroCAT CTDs attached to two moorings.

Proposed during the next deployment

Add 2 uplooking ADCPs on the top of 83°E and 93°E moorings and one Microcat CTD at 93°E mooring.

93 E : 2002-03

Annual variation of Pressure, temperature and currents at Equator, 93E during 2002-03.

50

100

150

200

Temperature

Pressure

12

16

20

24

28

32Temperature

-50

-25

0

25

50

( °C

)cm

/s

U V

Depth-wise variation of SD of zonal (red) and meridional (blue) velocities (cm/s)

4000

3000

2000

1000

0

0 5 10 15 20

0 5 10 15 20

(a)

D

epth

(m)

0 5 10 15 20

0 5 10 15 20

(b)

0 5 10 15 20

0 5 10 15 20

(c)

76°E 83°E 93°E

Spectra of zonal (red) and meridional (blue) currents at Eq., 93°E at 100 m during 2002-03

0

500

1000

1500

2000

2500

3000

Sp

ectr

al

En

ergy

(cm

/sec)

2 /cp

d)) S

pectr

al

En

ergy

(cm

/sec)

2 /cp

d

U, VEqu,93°E, 2000-01Depth 135 m

0.02 0.04 0.06 0.08 0.100

500

1000

1500

2000

2500

3000 Frequency(cpd)

Period(days)Period(days)1010 12.512.516.6 16.650 252550

Frequency(cpd)

U, VEqu, 93°E, 2001-02Depth 106 m

0.02 0.04 0.06 0.08 0.100

500

1000

1500

2000

2500

3000

U, VEqu, 93°E, 2002-03Depth 105 m

1.02

1.04

1.06

1.08

Tem

peratu

re (

°C

)

34.732

34.734

34.736

34.738

34.740

Salin

ity (

psu

)

-12

-9

-6

-3

0

3

6

9

12 U V

Speed (

cm

/s)

Prepared scientific papers for publication: 11 nos1. Masumoto, Y., V.S.N. Murty, M. Jury, M.J. McPhaden, P. Hacker, Jerome Vialard, Robert Molcard and Gary Meyers. Tropical

Indian Ocean mooring array: Present status and future plans. Proceedings of Indian Ocean GOOS Conference held at Mauritius during 6-9 November, 2002, 2002.

2. Murty, V.S.N., A. Suryanarayana, Y.K. Somayajulu, Varsha Raikar and V. Tilvi. VM-ADCP measured upper ocean currents in the southeastern Arabian Sea and Equatorial Indian Ocean during December, 2002. Proceedings of Pan Ocean Remote Sensing Conference (PORSEC) held at Bali, Indonesia during 3-6 December, 2002, Vol. I, 29-33, 2002.

3.  Murty, V.S.N., A. Suryanarayana, M.S.S. Sarma, V. Tilvi, Vijayan Fernando, G. Nampoothiri, Areef Sardar, D. Gracias and Shadashiv Khalap. First results of Indian Current meter moorings along the equator: Vertical current structure variability at equator, 93°E during February – December, 2000. Proceedings of Pan Ocean Remote Sensing Conference (PORSEC) held at Bali, Indonesia during 3-6 December, 2002, Vol. I, 25-28, 2002.

4.  Murty, V.S.N., V. Ramesh Babu, Krishna Kumari, Sugandha Sardessai, Lina P. Mergulhao, Soniya Sukumaran, J. Cathrine Sumathi, Nisha S. Pires, M.K. Antony, Y.K. Somayajulu, R.J.K. Charyulu and MV.S. Guptha. Fall equatorial jet and its influence on the biogeochemical parameters in the Indian Ocean. Proceedings of IUGG 2003 IAPSO symposium on “Physical Oceanography of the Indian Ocean”, during 29 June – 11 July 2003 at Sapporo, Japan

5. Retish Senan, D. Sengupta, V. S. N. Murty, B. N. Goswami and M. S. S. Sarma. Variability of equatorial indian ocean zonal currents during 1999-2002. Proceedings of IUGG 2003 IAPSO symposium on “Physical Oceanography of the Indian Ocean”, during 29 June – 11 July 2003 at Sapporo, Japan.

6. Sengupta, D., Retish Senan, V.S. N. Murty and Vijayan Fernando. Biweekly variability of meridional currents at the equator in the eastern Indian Ocean. Proceedings of IUGG 2003 IAPSO symposium on “Physical Oceanography of the Indian Ocean”, during 29 June – 11 July, 2003 at Sapporo, Japan.

7. V.S.N. Murty, A. Suryanarayana, M.S.S. Sarma, M.K. Antony, D. Sengupta, Vijayan Fernando, G. Nampoothiri and Areef Sardar (2003). Long-term measurements of currents in the equatorial Indian Ocean through current meter moorings. (A Hindi abstract). In: Proceedings of ‘Ocean Observations System and Weather Forecasting’, 24 November, 2003, New Delhi.

8. Sengupta, D., Retish Senan, V.S. N. Murty and Vijayan Fernando (2004). A biweekly mode in the eastern Indian Ocean. To be submitted to J. Geophys. Res.

9. Murty, V.S.N., M.S.S. Sarma, M.K. Antony, D. Sengupta, A. Suryanarayana, Retish Senan, V. Tilvi, Vijayan Fernando, G. Nampoothiri, Areef Sardar and D. Gracias. Intra-seasonal variability of currents in the eastern equatorial Indian Ocean. Paper under preparation.

10. V.S.N. Murty, M.S.S. Sarma, M.K. Antony, A. Suryanarayana, Vijayan Fernando, Areef Sardar and G. Nampoothiri (2004). Variability of observed currents in the eastern equatorial Indian Ocean during 2000-2003. Abstract submitted to the International workshop on INDOCLIM to be held at IITM, Pune during 23-27 February, 2004

11. Vialard, J., D. Sengupta, V.S.N. Murty, R. Senan and M.S.S. Sarma (2004)Mixed Rossby-Gravity wave variability at monthly timescale in the equatorial Indian Ocean. Abstract. Submitted to the INDOCLIM under the Theme 2 (Describing and Understanding Indian Ocean Variability, sub-theme Intraseasonal variability in the Indian Ocean