1. Development of an Indian Ocean Moored Buoy Array for Climate*
Mike McPhaden
NOAA/Pacific Marine Environmental Laboratory
Seattle, Washington
Outline: 1. Background; 2. Planning and Design; 3. Implementation and Initial Mooring Data; 4. Near-Term Plans; 5. Challenges to Developing Array
*October 2006 issue of CLIVAR Exchanges
NOAA Global Climate Coordination Team
25 October 2006

2. Tropical Moored Buoy Arrays for Climate Studies
Temperature 0°, 110°W ?

3. Indian Ocean Science Drivers
Improved description, understanding and prediction of:
Seasonal monsoon variability
Monsoon <=> ENSO interactions
Indian Ocean Dipole (ENSO-like phenomenon in the Indian Ocean)
Intraseasonal oscillations including both near and far field impacts (Asian monsoon active/break periods; west coast US rainfall, Atlantic hurricane formation, ENSO)
Decadal variability & SST warming trends since the 1970s
Indonesian Throughflow
General ocean circulation, ocean heat transport, and their variability
Indian Ocean Dipole

4. Integrated Multi-platform Ocean Observing System
Emphasis on ocean, but will provide surface met data as well
Argo floats 3°x 3° Drifters 5°x 5°
~20 real-time tide gauges for IOTWS
PLANNED OBSERVATIONS—IMPLEMENTATION IN 5 YEARS
STRONG SYNERGY WITH OCEAN STATE ESTIMATION
REGIONAL MOORING ARRAYS
INDONESIAN THROUGHFLOW: INSTANT, A MULTINATIONAL EXPERIMENT, THE INTENSIVE DATA SET COLLECTED DURING 3 YEARS WILL BE USED TO DEVELOP PROXY METHODS FOR LONG TERM MONITORING OF THE ITF TRANSPORTS OF MASS, HEAT AND SALT.
MADAGASCAR CHANNEL: LOCO, THE NETHERLANDS,
BAY OF BENGALL AND ARABIAN SEA: BOB & ASEA, INDIA, 25 OCEANOGRAPHIC AND METEOROLOGICAL BUOYS IN PLACE, 18 WORKING, PLAN TO ENHANCE TO 40 SITES BY 2007.
Enhanced XBT lines to monitor Indonesian Throughflow, inflow to western boundary, Java upwelling and 10°S thermocline ridge
Carbon/hydro cruise
High density XBT
Frequently repeated XBT
Regional mooring arrays

5. Typical Mooring (ATLAS or TRITON)
Standard
Meteorology: wind, rel. humidity, air temp, solar irradiance, rain
Oceanography: SST, SSS, T(10 depths), S(5 depths), velocity (10 m)
Flux Reference Sites: Standard plus--
Met: longwave radiation, atmos. press.
Ocean: additional T(z), S(z), v (z) in upper 100 m
All data (daily averages) transmitted to shore in real-time via Service Argos.
Internally recorded at 1-10 min intervals.
A typical ATLAS mooring deployed by PMEL. The JAMSTEC TRITON mooring provides essentially same data in real time and delayed mode. Mention advantages: samples hf variability so it is not aliased, ocean and atmos, multi-variate so powerful for diagnostic studies.

6. Strategy for Moored Buoy Array
Basin scale, tropical upper ocean (500 m) focus.
Arabian Sea, Bay of Bengal, Eq. Waveguide, Thermocline ridge (5°-10°S), subtropical subduction, Java upwelling.
Does not sample western boundary currents, ITF, coastal zones.
Design supported by numerical model observing system studies.
THE SCIENCE DRIVER FOR THE MOORING ARRAY IS THE NEED TO DESCRIBE, UNDERSTAND, MODEL AND PREDICT UPPER OCEAN CURRENTS, TEMPERATURE AND SALINITY, IN PARTICULAR IN THE MIXED LAYER.
PRESENT DAY COUPLED, NUMERICAL MODELS HAVE LOW SKILL IN PREDICTING TROPICAL INDIAN OCEAN SST, ALTHOUGH SIGNALS PERSIST FOR SEVERAL MONTHS DURING SOME YEARS. LOW SKILL COULD BE DUE TO INADEQUATE INITIALIZATION DATA AS WELL AS PROCESSES THAT ARE NOT PROPERLY MODELLED, SUCH AS THIN SALINITY LAYERS AND BARRIER LAYER DYNAMICS.
THE ARRAY ADDRESSES THE NEED FOR T(Z), S(Z) DATA THROUGHOUT THE TROPICS, VELOCITY ALONG THE EQUATOR AND SURFACE FLUXES FOR CALIBRATION OF SATELLITE ESTIMATES IN KEY CLIMATOLOGICAL REGIONS
Designed by the CLIVAR/GOOS Indian Ocean Panel

7. Rationale for Flux Sites
The flux sites have been chosen on the basis of their location in regions of strong ocean-atmosphere interactions. In addition, several of the sites are located in regions where currently available flux products are widely divergent in terms of their net mean values of air-sea heat exchange.
This figure shows the mean and standard deviation of record length means from an ensemble of six surface heat flux products in the tropical Indian Ocean. The six products are OFA+ISSCP (WHOI), NCEP/NCAR reanalysis (NCEP1), NCEP/DOE reanalysis (NCEP2), ECMWF operational analysis, ECMWF reanalysis (ERA-40), and Southampton Oceanography Centre (SOC) analysis.
The Indian Ocean flux reference sites will also constitute a contribution to the international OceanSITES program, which is establishing flux reference sites in all ocean basins as a way to improve surface flux estimates globally.
Lisan Yu, WHOI

8. Present Status JAMSTEC (since 2000) NIO (since 2002)
NIO/NCAOR/PMEL (since 2004)

9. Met Data 0°, 90°E (Oct 2004-May 2006) Zonal wind Meridional wind
Solar irradiance
Rain rate
Barometric Pressure
Note 1) Length of record; 2) mean seasonal cycle; 3) large amount of high frequency intraseasonal variability captured by the mooring time series.
Wind for example show NE and SW monsoon circulation but also lots of day to day and week to week fluctuations superimposed. Similar prevalence of HF fluctuations in the other variables (SWR, Rain, BP).

10. Indian Ocean Data Oct 2004 – Oct 2005 Oct 2005 – Sep 2006
These data are preliminary and relative to ADCP head, not at constant depth. ADCP ran for entire 22 month deployment.
22 month long ADCP raw data record reveals seasonal and intraseasonal near surface current variability

11. ORV Sagar Kanya 29 Aug – 5 Oct 2006

12. Indian Ocean Dipole September 2006
Zonal wind
20°C depth
SST

13. Indian Ocean Moored Buoy Data Assembly Center (DAC)
Modeled after TAO/ TRITON and PIRATA data processing and dissemination systems.
PMEL and JAMSTEC initial contributors.
Hosted at PMEL; potential for mirror sites outside the US.
PMEL will host a Indian Ocean Moored Buoy Data Assembly Center. Work in progress. Beta version GUI shown here. Pages will go public in May after JAMSTEC has successfully installed its new data processing system.

14. Near-Term Mooring Array Plans
RV Baruna Jaya Oct-Nov 2006 (BRKT/Indonesia)
RV Mirai Oct-Dec 2006 (JAMSTEC/Japan)
ORV Sagar Kanya Aug-Oct 2006 (India)
RV Suroit Jan-Feb 2007 (France)
State Oceanic Administration (China)?

15. Funding
$ NOAA Budget Initiative for Climate Observations and Services (2006):
“…[Funds] to expand the Tropical Atmosphere Ocean array… into the Indian Ocean. This expansion will enhance NOAA's capability to accurately document the state of ocean climactic conditions and improve seasonal forecasting capability.”
¥ JAMSTEC Budget Initiative for GEOSS (2006):
“Japan EOS (Earth Observation System) Promotion Program” (JEPP)--a new 5-year program to enable the development of new small size TRITON buoy and the continuation of the present TRITON sites in the Indian Ocean.

16. Challenges: Ship Time Requirements:
≥ 140 days per year to maintain full array
Must be available routinely and with regularity
Assumes 1-year mooring design lifetime and annual servicing cruises
*Actual sea days in 2006: involves more than just mooring work

17. Summary
The international CLIVAR and GOOS communities have developed plans for an integrated Indian Ocean Observing System (IndOOS).
The array design is based on observing, understanding, and predicting key ocean and climate phenomena that have significant socio-economics impacts on countries surrounding the basin and that affect global climate variability.
Implementation is underway with contributions from several nations.
The newest component of the observing system is a basin scale moored buoy array, with initial investments from the U.S., India, Japan, Indonesia, and France.
There are many challenges to full implementation (shiptime, fishing vandalism, funding, etc.) but success promises significant scientific and societal benefits.
There are opportunities for cooperative interdisciplinary studies leveraging investments from both physical and biogeochemical research communities; and opportunities to develop a multi-hazard warning system in cooperation with the tsunami community.

18. Why Now?
Scientific issues related to Indian Ocean’s role in climate have become more focused.
Potential societal benefits from development of skillful monsoon prediction models;
One of the most poorly sampled regions of the world ocean;
High precision satellite missions unsupported by regional in situ obs (TOPEX/Jason, QuikSCAT, TRMM, etc).
Modeling advances that require in situ data for validation, assimilation (state estimation), and intialization (forecasts)
Inauguration of plans for the Global Earth Observing System of Systems (GEOSS) in 2003;
One half of the world’s population is affected by the Asian Monsoons. Accurate prediction of seasonal monsoon rainfall would be of tremendous socio-economic value. Very limited predictive skill exists at present.