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Proceedings - TIP 9 | |
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| Proceedings
of the ninth session of the TAO Implementation Panel (TIP-9)
Perth, Australia, 16-17 November 2000 Edited
by Table of Contents
1.
Introduction
2. Current Conditions TAO/TRITON data indicate that La Nina conditions have waned since early 2000. At present, weak cool SST anomalies generally less than 1C are found in the eastern Pacific and weak warm anomalies generally less than 0.5C are found in the warm pool region of the western Pacific. Subsurface anomalies of 1-2C are found in the upper 200 m resulting from a stronger downward tilt to the equatorial thermocline. The structure of the subsurface anomalies (warm in the west, cool in the east) is similar to that which existed in December 1996 before the last El Nino. The latest NCEP coupled model project forecast (as of November 7) indicates a warming trend over the next three seasons, with development of 1C anomalies in the eastern equatorial Pacific. Other statistical and dynamical ENSO forecast models also show weak warming trends, though most do not indicate development of significant warm SST anomalies. Considering the range of forecasts over the next several seasons, the likelihood is that near neutral conditions will prevail in the tropical Pacific in the coming year. 3. Operational Analyses and Forecasting Ming Ji of NOAA/NCEP reported on the uses of TAO/TRITON data in operational analyses and forecasting. TAO/TRITON data are used at NCEP, ECMWF, and elsewhere for operational climate monitoring, and for initialization of coupled ocean-atmosphere forecast models used in operational ENSO and seasonal climate forecasting. Ji also noted that salinity variations on seasonal-to-interannual time scale are pronounced in the western equatorial Pacific. Although real-time salinity observations at present are very limited, NCEP has developed techniques to use TAO/TRITON subsurface temperature data and satellite altimetry data to derive pseudo-salinity data and assimilate both temperature and salinity data into the ocean model for improved ocean analyses. The new NCEP ocean data assimilation system is capable of assimilating both temperature and salinity from TAO/TRITON and from future ARGO floats. NCEP plans to produce operational global ocean analysis which assimilate both temperature and salinity based on real-time TAO/TRITON observations in the near future. 4. Status of TAO/TRITON Array 4.1 Designation of the array as TAO/TRITON As of 1 January 2000, the TAO array officially became known as the TAO/TRITON array in recognition of the fact that JAMSTEC has assumed responsibility for maintaining sites along 156E, 147E, and 138E in the western Pacific with TRITON moorings. Wind, SST, air temperature, relative humidity, and subsurface temperature from ATLAS and TRITON buoys are transmitted on the GTS and have been merged into a unified data set available on the World Wide Web at PMEL (/tao/) and a mirror site in Japan (http://www.jamstec.go.jp/jamstec/TRITON). Prior to withdrawal of ATLAS moorings from the western Pacific, several 6-8 month overlapping ATLAS and TRITON time series were collected from collocated moorings to ensure the comparability and consistency of data from the two mooring systems 4.2 Shiptime For calendar year 2000, 384 days at sea were required to support the TAO/TRITON array. NOAA ships (Ka'imimoana, Ron Brown) accounted for 275 days, JAMSTEC ships (Kaiyo, Mirai) accounted for 108 days. The French RV Alis contributed one day in April 2000 to recover the mooring from 2N, 165E which had broken free from its anchor. Shiptime use anticipated in 2001 is similar to that in 2000. 4.3 ATLAS
data return Efforts
to combat vandalism continue, though it is not clear they are making much
impact. These efforts included distribution of information brochures to
national fishing agencies, fishing boats in ports of call, and industry
representatives. Also, presentations on the effects of vandalism were
made in the past year in Martinique (International Fish Aggregation Device
Conference, September 1999), Lake Arrowhead, California (Inter-American
Tropical Tuna Commission, May 2000), and Monaco (International Hydrographic
Organization, June 2000). Engineering efforts to make moorings more robust
and vandal-resistant are under development as well. 4.5 TRITON deployment
schedule revisions Planned
deployments of TRITON buoys in November at 0, 90E and 5S, 95E in the Indian
Ocean were cancelled, though subsurface ADCP moorings were deployed by
the Mirai at these locations. Indian Ocean TRITON deployments have been
rescheduled for November 2001. Concerns about possible strong current
drag on the equatorial buoy were raised when a TRITON buoy deployed in
the Kuroshio Extension dragged its anchor dangerously close to a submarine
communications cable earlier this year. Engineering efforts to reduce
drag on TRITON moorings will be undertaken prior to Indian Ocean deployments
in 2001. 4.6 TRITON
salinity The
importance of surface and subsurface salinity data was emphasized by analysis
of TRITON data showing approximately 2.5-4.5 cm RMS errors in dynamic
height of the sea surface relative to 500 db when salinity is not taken
into account. 4.7 Eastern Pacific
Investigation of Climate (EPIC) Additional ATLAS moorings
were added to the 95W line at 3.5N, 10N, and 12N in the past year. All
moorings along this meridian are equipped with shortwave radiation, longwave
radiation, barometric pressure, and rainfall sensors in addition to the
usual suite of meteorological instrumentation. Also, these moorings include
salinity at 7 depths in the upper
120 m and current at 1 to 2 depths in the upper 40 m. These new measurements
will allow for accurate computation of surface heat, moisture, and momentum
fluxes, as well as the local oceanic response to those fluxes. The data
will also facilitate studies of atmospheric boundary layer dynamics .
All measurements (with the exception of salinity at three depths) are
now available in real-time as daily averages. Barometric pressure will
soon be added to the GTS data stream. Two ATLAS moorings in the ITCZ have
been instrumented with experimental acoustic raingauges as test of that
technology for long term moored buoy applications. A WHOI IMET mooring
deployed at 20ÚS, 85ÚW extends the ATLAS line southward
into the stratus deck region off the west coast of South America. As
noted in Section 4.4, problems with vandalism are affecting ATLAS data
and equipment return along 95W. 4.8 Woods
Hole Oceanographic Institute Intercomparison Study 5.
Pilot Research Moored Array in the
Tropical Atlantic (PIRATA) PIRATA, which is jointly sponsored by France, Brazil, and the US, will transition to a 5-year "consolidation" phase intended to run from 2001 to 2006. The consolidation phase will allow time for demonstrating the utility of PIRATA data in climate forecasting and applications. Success during the consolidation phase the array could lead to consideration of PIRATA as a permanent feature of the global ocean observing system and global climate observing system. Array design for the
consolidation phase has been modified to eliminate two ATLAS sites (2N
and 2S, 10W) where intense fishing vandalism has significantly limited
data and equipment return. These two sites are not critical for achieving
the basic objectives of the PIRATA field program, and their elimination
should improve overall data return which has been only 69% for the 3-year
period October 1997 to September 2000. This year, NOAA funded
an extension of PIRATA in the northwest basin with a Woods Hole flux mooring
to be deployed in April 2001 at 16N, 51W. Other possible extensions in
the next few years are under discussion for the northeast, southeast,
and southwest tropical Atlantic, with support from countries bordering
these regions. An
international conference tentatively scheduled for September 2001 in Paris
will consider implementation of an integrated satellite and in situ climate
observing system in the tropical Atlantic Ocean in support of CLIVAR,
GOOS, and GCOS. PIRATA figures to be a key element of that observing system. 6.
Ship-of-Opportunity Program (SOOP) Rick
Bailey, chair of SOOP Implementation Panel (SOOPIP), gave a presentation
on the status and future directions of the Ship-of-Opportunity Program
(SOOP). More details on SOOP are available at http://www.brest.ird.fr/soopip/.
Around 100 merchant vessels presently record upper ocean thermal data
(down to 800m) on selected, routinely repeated lines covering most of
the ocean basins. Several of the time series go back decades, and provide
in some areas such as the Indian Ocean some of the only sustained observations
of the upper ocean. These data in general complement other in situ and
remotely sensed data in support of operational (such as seasonal-to-interannual
climate forecasts) and research applications. In recent years there has
been a rapid expansion in the use of merchant vessels for the collection
of interdisciplinary observations, such as surface and subsurface salinity,
pCO2, surface fluxes, phytoplankton and zooplankton distributions, and
upper ocean currents. This suite of observations will coordinated with
other observational programs, such as TAO, under the CLIVAR Ocean Observations
Panel (COOP) and the Observations Program of JCOMM. During
1999, the OOPC, CLIVAR UOP and SOOPIP sponsored a review of the global
XBT network in light of the most recent scientific objectives of the network,
and taking into account the existence and advent of other in situ and
remote sensing observing systems such as TAO, profiling floats, and altimeters.
A background study was supported by NOAA's Office of Global Program (OGP),
Australian Bureau of Meteorology, and CSIRO Marine Research. From the
workshop and background a revised XBT network with unique contributions
to the globally integrated ocean observing system was proposed. The new
primary focus is on frequently repeated line sampling in the tropical
oceans, coupled with high-density eddy-resolving sections spanning the
major gyres and boundary currents to help resolve the ocean transport
of mass, heat and salt. The broadcast low-density XBT sampling, which
is presently used to mainly monitor heat content, is to be ceased once
and only if the Argo profiling float program is fully implemented and
proven successful. 7.
NOAA Climate Observing Program Sidney
Thurston, NOAA Office of Global Programs, presented an implementation
plan for NOAA's contribution to the ocean component of the global climate
observing system. The mission of the Climate Observing Program is to build
and maintain global observing networks needed to satisfy the long-term
requirements of the operational forecast centers, international research
programs, and the major climate assessments. National and international
partnerships are essential to success of this climate observing program.
The implementation strategy, therefore, is based on an extension of the
building blocks that are in place, and on the international plan drafted
by over 300 scientists from 26 nations that met in Saint Raphael, France
in October, 1999 (the OCEANOBS 99 Conference). A
global observing system by definition crosses international boundaries.
The way the observing systems projects are organized, implemented and
managed will reflect this. The Program will foster a "systems" approach
to effective international organization of complementary in-situ, satellite,
data and modeling components of climate observations. The systems approach
to development will start in 2000 with an "initial system" of 12 well-rationalized
networks. As knowledge increases, the Program will evolve over a phased
10-year implementation period by building each of these networks with
specific milestones and performance measures (deliverables). Implementation
will proceed while attempting to closely adhere to the "Ten Climate Monitoring
Principles" recently described in the 1999 Nation Research Council report
"Adequacy of Climate Observing Systems". The
SOCIO meeting earlier in the week provided a backdrop for TAO Panel discussions
of a sustained Indian Ocean observing system for climate. SOCIO reviewed
scientific issues relating to the Asian-Australian monsoons, intraseasonal
variations, the Indian Ocean diplole, ENSO interactions, and other climatically
relevant phenomena in the Indian Ocean. SOCIO also reviewed ongoing and
planned satellite and in situ observational activities in the Indian Ocean
to address these issues. The Indian Ocean is the least well observed of
the three tropical basins, and is one area where new ocean measurements
would have not only great scientific value, but potentially great societal
value as well. Views
at expressed at SOCIO with regard to ocean observations were consistent
with those put forward at OceanObs99 in San Raphael in October 1999, but
with some new and slightly different emphases, particularly with regard
to shorter time scales. These emphases included process studies of diurnal
to intraseasonal time scale variations (needed for seasonal prediction),
heightened emphasis on flux measurements, heightened emphasis on hydrological
cycle and a crucial need for salinity, and the need for both fixed-point
time series and broad scale basin coverage. Ocean state estimation emerged
as a crucial under-pinning strategy for societal and science issues. Some
augmentation of the GODAE strategy would be needed to address the shorter
time scales important for the Indian Ocean. Implementation of Argo in
the next few years will be a major step forward, but Argo will not provide
high temporal resolution data or surface fluxes in the near equatorial
region where rapid oceanic and atmospheric variations occur, and where
ocean-atmosphere coupling is strong. The emphasis on shorter time scales
and new fields (fluxes, salinity) lead specifically to a recommendation
for a mooring array. Moored buoys are ideally suited for providing critical data sets in this region, and therefore a valuable complement to other satellite and in situ measurement efforts. At present, there are 12 moored meteorological buoys deployed in the Arabian Sea, Bay of Bengal, and the EEZ of India under auspices of the Indian National Data Buoy Program. Three subsurface current meter moorings are presently deployed on or near the equator by JAMSTEC and the Indian National Institute for Oceanography. The number, instrument payloads, and distribution of these moorings however is inadequate for the purposes of providing basin scale coverage in support of climate forecasting and analyses. Recognizing that there
is great potential societal benefit to developing an integrated, sustained,
basin scale ocean observing system in the Indian Ocean for climate purposes,
and that a moored buoy program like that in the Atlantic and Pacific Oceans
would be a valuable component of such an observing system, the TAO Panel
recommends that priority be given to the design and implementation of
an Indian Ocean moored buoy array within the context of CLIVAR, GOOS,
and GCOS. The Panel further recommends that an ad hoc working group be
established to develop a science and implementation plan based on our
current understanding of climate variability and predictability in the
region. This group should be formed within the next year and should consist
of representatives from nations interested in contributing resources to
the development and maintenance of such an array. In addition, the panel
strongly endorses the Western Indian Marine Applications Project (WIMAP)
initiative lead by South Africa and Mauritius, and the JAMSTEC initiative
to deploy TRITON buoys at 0, 90E and 5S, 95E, as critical building blocks
for the successful development of a basin scale moored buoy array. 9.
Review of Tropical Moored Buoy Programs Tropical
moored buoy programs in support of climate research, forecasting, and
ocean state estimation will undergo review at an international workshop
to be held at the Pacific Marine Environmental Laboratory in Seattle,
Washington during the week of 10-14 September 2001. The purpose of the
review will be to document the utility of moored time series data for
climate studies, to identify strengths and weaknesses in existing programs,
and to provide advice on possible enhancements, extensions, or modifications
to those programs. It is anticipated that the meeting will be co-sponsored
by the WRCP, CLIVAR, GOOS, and GCOS. With
the dissolution of the existing TIP, a new Tropical Moored Buoy Implementation
Panel (also referred to as TIP) will be inaugurated under auspices of
CLIVAR, GOOS, and GCOS in the coming year. New terms of reference will
expand the scope of this panel to the global tropics, with emphasis on
technical and logistic issues related to implementing and sustaining buoy
programs in support of climate studies. The
Panel wishes to acknowledge the IOC Perth Regional Office and the West
Australian Department of Commerce and Trade for hosting TIP-9. Special
thanks to Bill Erb of IOC, and Gary Meyers and Bronwyn Marshall of CSIRO,
for their help with the many details involved in convening TIP in Perth.
The panel is also grateful for the financial support of IOC/GOOS, and
for the administrative assistance of Art Alexiou of IOC. The TAO Implementation
Panel is sponsored by IOC/GOOS, GCOS, and International CLIVAR. Rick Bailey, CSIRO, Australia Graeme Brough, Bureau of Meteorology, Australia Bill Erb, IOC/Perth, Australia Stuart Godfrey, CSIRO, Australia Peter Hacker, University of Hawaii, USA Ming Ji, NOAA/NCEP, USA Mark Jury, University of Zululand, South Africa Yoshifumi Kuroda, JAMSTEC, Japan Kunio Kutsuwada, Tokai University, Japan Mike Manton, Bureau of Meteorology, Australia Mike McPhaden, NOAA/PMEL, USA Gary Meyers, CSIRO, Australia Phil Parker, Bureau of Meteorology, Australia Steve Piotrowicz, NOAA/OAR, USA S. Ragoonaden, Meteorological Service, Mauritius Dwi Susanto, Lamont Doherty Earth Observatory, USA Sidney Thurston, NOAA/OGP, USA
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