Program status reports

Pilot Research Moored Array in the Tropical Atlantic PIRATA (J. Servain, ORSTOM/Brest and M. Vianna, INPE)

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Summary

Opening of the meeting

Summary of current conditions in the Tropical Pacific

National reports

Program status reports

Science reports

Recommendations

Acknowledgments

The Pilot Research Moored Array in the Tropical Atlantic (PIRATA) is an extension of the TAO Array in the Atlantic. Twelve ATLAS moorings will be deployed during 1997-2000 as part of a multinational effort involving Brazil, France, and the United States. As for the TAO array, PIRATA will provide time series of surface heat fluxes and surface and subsurface temperatures, salinity, and currents in key regions of the tropical Atlantic. These key regions are chosen to get information about the two main modes of seasonal and interannual variability which occur in the tropical Atlantic, i.e., the El Niño-like equatorial mode and the meridional "dipole" mode. The PIRATA program proposed to install and maintain in the tropical Atlantic and array of 12 moored ATLAS along three lines (Figure 4).

• an equatorial line, with moorings at 35°W, 20°W (with an ADCP measuring currents from 30 to 200 m), 10°W, and 0°
• a meridional line along 38W with moorings at 4°N, 8°N, 12°N, and 15°N;
• a meridional line along 10°W, with moorings at 2°N, 0° , 2°S, 6°S, and 10°S.

Also as for the TAO Array, the PIRATA measurements are transmitted in near real-time, and are available to all research and operational communities via Internet and GTS.

PIRATA is being coordinated with other national and international programs scheduled for 1997 - 2000, which will also be taking observations in the tropical Atlantic.

The first two PIRATA moorings were successfully deployed in September 1997 by R/V Antea (ORSTOM, France) from Abidjan (Ivory Coast):

• Java site at 0°,10°W (5200 m)
• Gavotte site at 10°S,10°W (3840 m)

• Reggae site at 15°N,38°W
• Lambada site at 8°N,38°W
• Samba site at 0°,35°W

The PIRATA document is available via the Web (http://www.ifremer.fr/ird/pirata/pirataus.html) or directly via anonymous ftp (ftp.ifremer.fr/ifremer/orstom/pirata30.rtf.z). PIRATA information is available at http://www.ifremer.fr/ird/pirata/piratafr.html. PIRATA data are available at http://www.pmel.noaa.gov/pirata and http://www.ifremer.fr/ird/pirata/piratafr.html/. During 1998, Brazil and France will develop more complete mirror web sites with PMEL.

Joint Air-Sea Interaction Monsoon Experiment (JASMINE) (J. Godfrey, CSIRO/Hobart)

Material was presented relating to a newly-proposed initiative, the Joint Air-Sea Monsoon Investigation (JASMINE). Interannual variability of monsoon rainfall is dominated by intra-seasonal oscillations (ISO), in which rain events typically start on the equator, move northward and die over Asia. Bands of high/low precipitable water content associated with these ISO's extend from Africa to the dateline with weaker, but quite well-defined, bands in the southern hemisphere from Indonesia to Australia. These latter may affect Australia's winter rain. The long time series of the ISO's may be due to air-sea coupling.

It is hoped that the field phase of JASMINE will begin in May 1999, with the deployment of moorings along a line near 90°E, from 10N to 5S. R/V Ron Brown will be in the area, for buoy deployment and rain radar measurements. Ship time on the Australian vessel R/V Franklin has been allotted for about August 1999 to recover the moorings.

Solar Radiation Measurements from the TAO Array (R.M. Reynolds, Brookhaven National Laboratory)

Scientists in the Atmospheric Radiation Measurement (ARM) Program of the U.S. Department of Energy are concerned with decadal measurements of the global heat budget and seek better understanding of processes that control solar and infrared radiative transfer in the atmosphere (especially in clouds) and at the Earth's surface. In a collaborative effort, NOAA/PMEL and ARM are deploying special short-wave radiation sensors as part of the recent upgrade to the ATLAS system. A full description of this effort is presented as an attachment to this TAO Panel report. Four short-wave radiometers were deployed with next-generation ATLAS loggers in 1997 and will be recovered in January 1998. Two-minute continuous averages of solar radiation are stored in the ATLAS and are available after recovery. Daily insolation values, transmitted via Argos, agree qualitatively with satellite outgoing long-wave radiation (OLR) images and indicate that we might expect uncertainties of a few Wm between buoys. There are many sources of error in these optical measurements and careful field studies are required to gain confidence in the measurements.

Tropical Rainfall Measuring Mission (R. Murtugudde, U. Maryland)

The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan designed to monitor and study tropical rainfall and the associated release of energy that helps to power the global atmospheric circulation shaping both weather and climate around the globe. The TRMM Observatory carries five instruments. It will include the first spaceborne Precipitation Radar (PR), the TRMM Microwave Imager (TMI), a Visible and Infrared Scanner (VIRS), a Cloud and Earth Radiant Energy System (CERES), and a Lightning Imaging Sensor (LIS). The 17 ft tall and 12 ft diameter satellite weighing 3.2 tons was the largest spacecraft ever built at GSFC. The data rate is the highest of any NASA satellite to date.

The ground validation activities have been underway for several years with the primary validation sites are ready with radars, disdrometers, and rain gauges (Darwin, Kwajalein, Texas, and Florida; climatology sites: Israel, Thailand, Guam, Taiwan, Hawaii, and Brasil). The TOGA-COARE composite rainfall data is available from the TRMM office (http://trmm.gsfc.nasa.gov) . Several TRMM field campaigns are planned to verify individual algorithms, cloud models, etc., with high resolution rain estimates and vertical structure details. Where practical, field campaigns are coordinated other experiments (Texas-Florida Underflights (TEFLUN), South China Sea Monsoon Experiment (SCSMEX), the Large Scale Atmosphere-Biosphere in Amazonia (LBA), and TRMM Kwajalein Ocean Experiment (TKO).

TRMM was scheduled for launch in November 1997 from the Tanegashima Space Center on an H-II expendable launch vehicle, designed and built by Japan*. The circular orbit at an altitude of 350 km at an inclination of 35 degree to the equator with a total orbit period of approximately 96 minutes is designed specifically to capture the diurnal cycle of the tropical precipitation. The testing was completed and the satellite was shipped to Japan in August of 1997.

*Editor's note: TRMM was launched successfully on 27 November 1997. The latest TRMM images and other information is available at http://trmm.gsfc.nasa.gov.

Ocean Observations for Climate Panel (OOPC) (R. Weller, WHOI)

The work of the OOPC over the past year was briefly summarized, and two particular issues were brought to the attention of the TIP, a GOOS implementation meeting planned for March 1998 in Sydney, Australia and the Global Ocean Data Assimilation Experiment (GODAE).

OOPC met for the second time in Cape Town in February 1997. Since then, a Long Time Series Workshop was organized and held by OOPC in Baltimore, MD, in March. The workshop clarified the characteristics of long time series needed for understanding ocean climate. Such time series could be exploratory, taken at a location where little is known; laboratory, observing many different variables and processes; phenomenological, observing change or a processes that is key or central to long term variability; and reference, a baseline station. At present, relatively few long time series station exist that have demonstrated merit for ocean climate observing systems, though high latitude North Atlantic time series, such as Bravo and Mike were discussed as candidates. A report from this workshop is being prepared.

OOPC also participated in a NOAA Sea Level Workshop to help better define the observational system needed to measure sea level. A long-term system based on satellite altimetry and 30 in-situ sites was discussed; more detail is given in a workshop report and in a document, "Climate Sea Level Network Report," to be published by OOPC.

WMO, GOOS, and CMM have developed a plan for an implementation workshop to push toward improved mechanisms and lines of responsibility, consistency of approach, development of rationales, and clarification of the foci of the many groups working toward GOOS. This workshop will be in Sydney in March 1998. TIP will be one of the implementation groups asked to attend.

Over the past year, concerns for developing the justification for the continuation of existing global observations, especially remote sensing tools which have to date been flown as research instruments, has led OOPC to take a lead role in developing the idea of a Global Data Assimilation Experiment. A first GODAE Workshop was help in Martinique of July (and was reported on by Billy Kessler at this TIP meeting). It was noted that as GODAE got started, the tropical Pacific would likely serve as a testing ground for data assimilation and analysis methods. Thus, TIP may want to develop a liaison with GODAE.

CLIVAR Upper Ocean Panel/GODAE (W. Kessler, NOAA/PMEL)

The Global Ocean Data Assimilation Experiment (GODAE) held its first workshop in Martinique on 24 - 29 July 1997. GODAE is driven by the desire of the remote sensing community to make the best use of its products (altimetric sea surface height, scatterometer winds, and blended AVHRR/in situ SST) through assimilation. The aim of GODAE is to have a 3-year demonstration during 2003-2005 in which a global ocean fields (density and currents) would be constructed, based on the satellite data assimilated in models and constrained by in situ data. The fields would be used as integrated analyses for research, as initial conditions for climate models and boundary conditions for regional or coastal models, and for short timescale nowcasts and forecasts (for shipping and pollution monitoring). There will be several groups focusing at first on specific oceans, without a single operational center. French groups, particularly those associated with the satellite centers, are prominent supporters of GODAE.

The weakest link in the GODAE project appears to be the sparsity of in situ subsurface ocean observations, and it remains unclear to what degree the models will be sufficiently constrained by the existing data. The problem of how to distribute observed anomalies of sea surface height from altimeters through the water column is a difficult challenge. GODAE does not plan to seek support for any additional observations, but the results may provide clearer justification for in situ observations (or possibly show which are redundant).

The tropical Pacific is an important region for GODAE, since its relatively well-sampled in situ network makes it a good place to test assimilation strategies and the ability of observations to constrain models.

News from the CLIVAR International Project Office (CLIVAR IPO) (A. Villwock, International CLIVAR Office)

Since September 1997 the CLIVAR IPO has a new director. Dr. Michael Coughlan left the IPO to take over the director's position of the World Climate Programme in Geneva. His successor is Dr. Lydia Dmenil from the Max-Planck-Institut fur Meteorologie in Hamburg who will serve as acting director until the end of May 1998. In the meantime the director's position has been advertised widely seeking for a permanent director to take over on 1 May 1998.

CLIVAR is currently finishing its Initial Implementation Plan. An executive summary has already been published in the form of a brochure in time for the WCRP conference in August 1997. Until end of 1997 the Initial Implementation Plan will undergo a final revision, edited by Dr. George Needler. Dr. Needler, bringing in his experience from WOCE, kindly agreed to serve as an editor for the CLIVAR Implementation Plan. The CLIVAR IPO expects to publish the plan early 1998. The plan will serve as the main background document for the first CLIVAR conference scheduled for 1-3 December 1998 at UNESCO in Paris. This conference will be held as an intergovernmental meeting seeking for commitments for the initial phase of CLIVAR.

In the Initial Implementation Plan, the important role of the ocean observations provided by moored buoys, such as TAO, TRITON, or PIRATA is highlighted several times. These observations have been identified by a number of the CLIVAR core projects to be essential for the overall success of the programme. In particular recommendations to maintain and/or extend the moored buoy arrays are made within the following Principal Research Areas:

G1: Extending and Improving the Predictions
G2: Interannual Variability of the Asian-Australian Monsoon
G3: Variability of the American Monsoon System
G4: African Climate Variability
D2: Tropical Atlantic Variability
D4: Indo-Pacific Decadal Variability and in the integrating section on global ocean observations.

Global Ocean Observing System (GOOS) (J. Trotte, GOOS Project Office)

The Global Ocean Observing System (GOOS) is presently moving quite rapidly towards implementation, according to its five overlapping phases:

1. planning, including design and technical definition;
2. operational demonstrations and pilot experiments;
3. incorporation of suitable existing observing and related activities and new activities that can be immediately implemented within the GOOS framework;
4. gradual operational implementation of the "permanent" or ongoing Global Ocean Observing System; and
5. continued assessment and improvement in individual aspects and in the entire system.

A brief review of international GOOS activities has been made. On the development of the GOOS Panels, it was noted in particular the recent establishment of the Living Marine Resources and Coastal Panels, expected to have their first meetings in March 1998.

The implementation of GOOS will also be very largely dependent upon the commitments made by the participating nations to support the observational systems through their national observing agencies, and by providing elements such as data centres and distribution networks, scientific and technical research, development and installation. Much of the implementation will be accomplished using regional alliances, but a global approach is needed to address the ocean's role in the climate system.

In the U.S., NOAA has agreed that the TAO array of buoys in the Pacific forms a contribution to GOOS. Similarly, the SOOP Implementation Panel decided that the SOOP network formed a contribution to GOOS. In addition, several nations continued the development of GOOS within their own countries, forming national GOOS committees and considering which parts of their present systems might form contributions to GOOS. It is much hoped that the Indian Ocean nations will also consider starting a GOOS Pilot Project in the near future.

The mangers of GOOS and GCOS will meet with managers of existing systems to discuss an can plan planned GOOS Existing System Meeting, to be held in Sydney, Australia, March 1998 would urge continuation of TAO with international support, taking into account the fact that the U.S. has already provided support for considering TAO as a contribution to GOOS.

A guide on GOOS implementation is due to be published in June 1998, where the GOOS vision will be presented, as a global network to cope with critical marine-related issues including the ocean's effects on climate.

The TAO array remains a source of high priority observations for the climate module of GOOS (the ocean component of GCOS). The expansion of the tropical atmosphere ocean observing array to include the tropical Atlantic has already started, with the launching of PIRATA and its latest developments. Those two systems and eventually a similar one in the Indian Ocean are regarded by IOC as a milestone of GOOS and an excellent opportunity to the build up of technical and educational capacity in less-developed and smaller countries, enabling them to forecast their own possibilities to acquire, have access and use marine and oceanic data and products for their own particular needs.

Data Buoy Coordination Panel (E. Charpentier, DBCP)

• DBCP-13 session was held in La Reunion island, 13-17 October 1997. A scientific and technical workshop was associated with the DBCP session, stressing in applications of buoy data in both meteorology and oceanography. Workshop presentations will be published within the DBCP document series. The Panel decided to organize a similar workshop in association with the next DBCP session, Miami, 12 - 16 October 1998. The workshop will stress on scientific and operational applications of buoy data; moored buoy technology and data applications.
• Some of the requirements expressed by the users which had been presented and discussed at the previous DBCP session, and then included within the Argos development program (JTA-16) have been developed and implemented: Argos data bank extended from 4 to 10 days, remote and automatic technical file access for GTS platforms (via Email), and connection of Local User Terminals in Cape Town and La Reunion (to substantially decrease delays in the South Atlantic and Indian oceans respectively). The Panel decided that providing Argos users with data on CD ROM should be a top priority and urged Service Argos to propose and implement a solution as soon as possible.
• Data flow monitoring tools are being developed in the context of the DBCP server in co-operation with Meteo France, NWS and MEDS. Basically, users will be able to access GTS data of the preceding week via the web. Most recent data will be yesterday's data. Only GTS Bulletin header, WMO number, date of observation, delay, and presence of sensors will be indicated (for confidentiality reasons, we cannot provide location & sensor data on the web). These tools will make it easy for a user with no GTS access to rapidly check that a buoy is actually reporting on GTS and how many reports are being received.
• The panel is developing a comprehensive implementation strategy plan for itself and its action groups, in support of the requirements of both global programs and also national/regional projects. Such an implementation strategy would be essential input to the development of a comprehensive GOOS/GCOS implementation strategy. A draft implementation strategy plan was discussed at the Panel session and the following comments were proposed:

1. The strategy needed to stress importance of optimizing deployments in the light of limited available resources;
2. A climatology of drifter tracks would be very valuable as a tool for future reseeding of networks, and panel members should be encouraged to develop such a tool;
3. Better contacts were required among the action groups, to allow cross-fertilization of deployments;
4. GTS data flow monitoring should be included;
5. The strategy should be expanded to cover also moored buoy networks, stressing their importance, requirements and complementarity to drifters, with the title adjusted accordingly;
6. References to buoy hardware should be more comprehensive;
7. The value of meteorological/oceanographic coordination to optimize deployments should be emphasized, as well as the role of the DBCP as a link between observing network managers and data users;
8. Section 7 should be divided, to show separately summary and action items;
9. The action items should underline the direct participation of action group members in GOOS/GCOS; and the role of the DBCP in providing buoy data for GODAE; and the value of the action groups adopting mechanisms to identify primary applications of buoy data in their region and subsequently monitoring the use of the data in these applications; and
10. The strategy should clearly show its relationship to the panel's terms of reference.

• The Panel decided to submit the document reflecting DBCP views on encoding buoy data in BUFR to CBS in 1998 as a formal DBCP request. Copies of the document can be obtained from the Technical Co-ordinator of the DBCP.
• DBCP Technical Document No. 8 "Guide to moored buoys and other ocean data acquisition systems" (by Eric Meindl) is now available and can be obtained via the Technical Coordinator of the DBCP.

Status of NOAA Climate Observations in the U.S. (M. Johnson, NOAA/OGP)

In order to improve climate forecasts, NOAA's Office of Global Programs has set three strategic priorities for observations: 1) observe ENSO; 2) learn how to observe Atlantic modes of variability; and 3) learn how to observe Indo-Pacific modes of variability beyond ENSO. NOAA's first priority has been, and will remain, to support the successful observing system in the tropical Pacific that was developed during TOGA for monitoring ENSO. The TAO array is the cornerstone of this ENSO Observing System. Other components include the island tide gauge network, the VOS XBT network, and the surface drifter network. The President's FY 1998 budget presently before the U.S. Congress includes $4.9 million to "operationalize" the ENSO Observing System. This initiative will transfer responsibility for the TAO array (and the other existing networks) to NOAA's base budget and will free up climate research program funding for expansion of observations in pursuit of the other two priorities - Atlantic modes, and Indo-Pacific modes beyond ENSO. Although the U.S. Congress has not yet acted on this 1998 budget, we are optimistic that the initiative will be successful and are planning accordingly*.

Assuming congressional appropriation of the operational funding in 1998, NOAA's climate research program will support implementation of new pilot projects in the Atlantic to contribute to building a basin-scale composite observing system in support of improved weather/climate prediction. The PIRATA moorings will anchor the Atlantic observing system in the tropics; the other three complementary networks (tide gauges, drifters, VOS) plus a fourth network - autonomous profiling floats - will be used to extend observations into the higher latitudes. The hurricane genesis area of the Atlantic will also be targeted for observation to improve forecasts of intensity and landfall tracks of tropical cyclones. Simultaneously, NOAA will support expansion of the observing system in the Pacific with additional surface drifters, profiling floats, and high density VOS XBT lines (including automated surface meteorological observations from VOS). NOAA looks forward to the Indo Pacific expansions of the moored array by our international partners which, along with PIRATA, will advance the moored array toward becoming a truly global network.

The five complementary networks to which NOAA contributes - moorings, drifters, tide gauges, VOS, profilers - are all international efforts and global in scope. These five international networks provide a significant proportion of the elements of the ocean observing system called for by the draft CLIVAR Implementation Plan. NOAA considers the networks to be "building blocks" of a composite Global Ocean Observing System for climate. Each building block contributes its unique capabilities in concert with the others, and together they form a global observing system that serves both research and operational programs. In concept, each building block is made up of three elements - an international implementation panel, ocean platforms, and a global data center. The TAO Implementation Panel's coordination of the expanding moored array and its global data center provides an excellent model for this global observing network concept.

*Editor's note: The U.S. Congress passed the $4.9M budget initiative referred to in this presentation subsequent to the TAO Panel Meeting.

Pan American Climate Studies (PACS) (S. Piotrowicz, NOAA/OAR)

The Pan American Climate Studies Implementation Plan is in the process of being drafted and is expected to be completed in March. The overall plan, covering through 2005, will be available in hard copy. A more detailed version will be a "living document" continuously updated and available on the PACS web site at http://tao.atmos.washington.edu/PACS/. Presentations at TIP-4 and TIP-5 presented the pilot projects that were supported as part of the FY 1995 Program Announcement. Those projects are being implemented along, nominally, 125°W, from 3°S to 10°N. Though not complete at this time, it is expected that the region of emphasis for the field programs for PACS will be east of this area and extend both further north and further south.

Some areas of consideration are the stratus decks off the coast of South America, the ITCZ-cold tongue complex in the vicinity of 110°W, and the extreme convection region along the equator at and east of 95°W. Regardless exact location, studies of the ITCZ-cold tongue complex and the convection, i.e., studies along the equator, will be conducted in regions where southerly air flow exists for major portions of the year. Please refer to the Implementation Plan at the above URL for the most recent information regarding PACS.

Implementing Observations for Prediction and Assessment Purposes with an Emphasis on the ENSO Observing System (S. Piotrowicz, NOAA/OAR)

The requirements of NOAA to provide useful forecasts of weather and climate variability in the United States on seasonal to interannual time scales has justified the implementation and long-term maintenance of an observing system of the coupled ocean-atmosphere system in the equatorial Pacific for the ENSO (El Niño-Southern Oscillation) phenomenon. This ENSO Observing System consists of those components of the TOGA Observing System which have been shown to provide measurements essential for skillful forecasts of the ENSO phenomenon. As of today, those components are the TAO Array, a network of in situ sea level observing systems in and around the Pacific, the Volunteer Observing Ship (VOS) Program, and the Drifting Buoy Program. Fundamental to this observational program is the expectation that the observing system will evolve as required by the forecast products, and in response to analyses and scientific results.

The design and implementation of the ENSO Observing System is an example of a systematic approach to the development of an observing system to meet a particular objective - improving our ability to forecast ENSO events. The design of the system was based on the known space and time scales of tropical ocean and atmosphere variability, with the preliminary objective of improving our ability to produce, operationally, fields of the air-sea quantities of interest. The next step is to implement an on-going activity to assess the effectiveness of the observing system in meeting its goal of improved forecasting skill, and to guide the evolution of the observing system in order to optimize future forecast skill.

Our ENSO forecast skill is developing all the time because: new ideas about the mechanisms of ENSO are being uncovered; better ocean-atmosphere models are being implemented; and improved procedures for data assimilation are being adopted. The situation bears many similarities to operational weather forecasting - a never-ending process of model improvement, observing system re-evaluation and data assimilation system evolution is fundamental to our increasing weather forecasting skill. This means that assessment of the observing system will be an interactive process, that goes hand-in-hand with our developing ENSO forecast capability. At this time we cannot specify the forecast skill improvement that will result from a given improvement in our ability to observe and map any particular air-sea variable. Perhaps it is particular combinations of variables that must be observed in particular regions. Nor are we confident that we understand which aspects of the processes that cause ENSO must be observed to improve our forecasts.

ENSO forecasting development requires close interaction between the different elements of the ENSO community. Operational and experimental forecasters, ocean-atmosphere data assimilation technique developers, engineers and observational oceanographers, satellite remote sensing personnel and ENSO science researchers must all interact closely in the coming years to bring about the best development of our ENSO forecast skill. The ENSO observing system assessment activity, properly configured, will be an essential element that keeps all of these groups interacting productively with each other.

It is quite possible that new observations, new coupled models and new air-sea interaction process experiments will be needed to keep our forecast skill increasing. In a time of very tight governmental budget constraints, an integrated assessment activity - with forecast skill evaluation as its fundamental measure of success - offers the best hope of raising the resources required to support the needed observations and model development.

International Research Institute for Climate Prediction (R. Kleeman, IRI)

The philosophy and current status of the International Research Institute (IRI) was outlined. The organization is intended to be a so-called "end to end" prediction system. This involves the development of a seamless integration of climate model outputs (e.g., ENSO prediction) with societal applications. A pilot project demonstrating this involving Peruvian fisheries was outlined. The proposed international funding and management structure of the organization was outlined and the hiring strategy for the next three years was discussed. It is expected that there will be significant secondment of staff from interested international parties.

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