The Tropical Ocean-Global Atmosphere (TOGA) was a major component of the World Climate Research Programme (WCRP) aimed specifically at the prediction of climate phenomena on time scales of months to years. The philosophy upon which TOGA was based purposefully emphasized the tropical oceans and their relationship to the global atmosphere. Underlying TOGA was the premise that the dynamic adjustment of the ocean in the tropics is far more rapid than at higher latitudes and, therefore, more closely in tune with the atmosphere. To gain a clear understanding of global climate change, the El NiƱo–Southern Oscillation (ENSO) phenomenon, and the intra-seasonal variability of the coupled atmosphere-ocean system, it was clear that a better specification of the coupling of the ocean and the atmosphere was required. An observational and modeling program, the TOGA Coupled Ocean Atmosphere Response Experiment (TOGA COARE), was designed to designed to address the objectives of TOGA above, and develop basic observational and modeling strategies to be employed.
The TOGA-COARE Intensive Observing Period (IOP) occurred from 1 November through 28 February 1993. During these 4 months, nearly 1,200 people from more than 20 nations conducted more than 700 days of ship operations, released nearly 12,000 rawinsondes, completed 125 aircraft flights, and maintained continuous operation of 30 moored instrument systems. In the months prior to and following the IOP, a few key atmospheric sounding systems and a few special oceanographic moorings were operated as part of the TOGA-COARE enhanced monitoring.
TOGA-COARE had four main science goals, aimed to describe and understand:
Collectively, the goals of TOGA-COARE were designed to provide an understanding of the role of the warm-pool regions of the tropics in the mean and transient state of the tropical ocean-atmosphere system. To carry out the goals of TOGA-COARE, three components of a major field experiment were defined:
TOGA-COARE took place in the western Pacific warm-pool region between 20°N and 20°S, bounded by Indonesia on the west and the International Date Line on the east. Within this broad region were three principal COARE domains:
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The experimental design called for a complex set of oceanographic and meteorological observations from a variety of platforms that carried out remote and in-situ measurements from these nested domains. The resulting high-quality dataset was required for the calculation of the interfacial fluxes of heat, momentum, and moisture, and providing ground truth for a wide range of remotely sensed variables for the calibration of satellite-derived algorithms. This satisfied the ultimate objective of the COARE dataset to improve air-sea interaction and boundary-layer parameterizations in models of the ocean and the atmosphere, and to validate coupled models.
The general observational strategy and data collection for TOGA-COARE varied by the 3 components of the Field Program:
Specific platforms, facilities, and data sources are listed below:
Aircraft | NCAR Electra; NASA ER-2; NASA DC-8; NOAA P-3 (2 aircraft); UK C-130; Australian Cessna 340 |
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Lightning | Lightning Direction Finding networks |
Model | ECMWF TOGA COARE Analysis and Forecasts |
Oceanographic | TOGA XBT Network (Data and Atlases); Ship observations (see below) |
Ocean Drifting Buoys | SVP Lagrangian; Marisonde GT; Bodega; ADCP; Japan drifters |
Ocean Moorings | ATLAS; ATLAS/TOPEX; PROTEUS; ADCP; Acoustic mooring; PCM; Surface Current Meter; IMET (WHOI); USF Mooring |
Profilers | NOAA 50 MHz Profiler (2 land sites); NCAR ISS; RASS and SODAR sites |
Radar | Ship C-band radars (3 ships) |
Satellite | GMS (Japan); NOAA POES (U.S.); DMSP (U.S.); ERS-1 (ESA); TOPEX/POSEIDON (U.S. and France) |
Ship | TOGA-COARE Research Vessel ADCP Data; Gridded (100 km) Freshwater Flux over Central IFA; Ships of Opportunity regional observations |
Ship | R/V Vickers (U.S.); R/V Xiangyanghong 5 (China PRC); R/V Keifu-Maru (Japan); R/V Moana Wave (U.S.); R/V Kexue 1 (China PRC); R/V Shiyan 3 (China); R/V Hakuho-Maru (Japan); R/V Natsushima (Japan); R/V Wecoma (U.S.); R/V Le Noroit (France); R/V Alis (France); R/V Franklin (Australia); R/V Kaiyo (Japan); S/V Malaita (New Zealand); R/V Onnuri (South Korea) |
Surface | WMO GTS regional surface observations; Various manual and automated surface station networks |
Surface | NCAR ISS System (4 land sites) |
Upper Air | TOGA-COARE Sounding Composite (5mb); WMO GTS regional soundings; |
Upper Air | Ship rawinsonde (4 ships); Ship rawinsonde (2 ship ISS systems); NCAR ISS System rawinsonde (4 land sites); |
Intensive operations occurred in the western equatorial Pacific Ocean region centered on the TOGA-COARE IFA. Coordination of intensive operations occurred from an Operations Center in Townsville, Australia. TOGA-COARE has made a commitment to communicate appropriate data in real time to the international operational meteorological and oceanographic centers. For example, surface data and atmospheric sounding data will be placed on the Global Telecommunications System (GTS) for dissemination immediately after the data are collected to be used in routine atmospheric forecast models and experimental ocean prediction models. An analysis and communications center in Honiara, Solomon Islands, supported turboprop aircraft operations from that site; aircraft also operated from Townsville and from Rabaul, Papua New Guinea. Ships called at ports in Australia, New Caledonia, Papua New Guinea, Solomon Islands, Federated States of Micronesia, and the Mariana Islands.
Australian Bureau of Meteorology forecasters located in the Townsville Operations Center provided forecast support for the entire region of operations. Their analyses, along with satellite images, daily reports from ships in the IFA, and upper air data transmitted via the GTS or via GOES satellite through NCAR, constituted the main information by which to view and monitor weather and direct operations.
During the course of intensive operations, TOGA-COARE participants endured long becalmed periods, severe squalls, fuel and water shortages, equipment failures, malaria, and the general stress of weeks and months of operations far from home.
Further information and specific details on TOGA-COARE can be found at: TOGA-COARE: The Coupled Ocean-Atmosphere Response Experiment (Webster et al.)
All photos copyright University Corporation for Atmospheric Research unless otherwise noted.