US D.O.C. / NOAA / OAR / ERL / PMEL / 1998 Science Review

The western equatorial Pacific is characterized by extremely warm sea surface temperatures (SST), strong atmospheric convection, and weak trade winds punctuated by westerly wind bursts.

Goal:   To determine what processes contribute to the sea surface temperature variability and how these processes couple the atmosphere and ocean in the western equatorial Pacific Warm Pool.
 

Accomplishments:

The TOGA Coupled Ocean Atmosphere Response Experiment  Enhanced Monitoring Array The EMA was the product of a multinational, multiagency effort. For approximately 2 years (August 1991 - April 1994) the TAO array was enhanced to monitor:

•  Hourly surface heat fluxes (shortwave radiation, bulk latent heat and sensible heat loss, bulk longwave radiation), moisture fluxes (bulk evaporation, ORG precipitation), and bulk wind stress at select sites including the central EMA site at 0,156E.
•  Hourly  surface and subsurface temperature and salinity along the equator and along the meridian 156E.
•  Hourly subsurface currents along the equator and the meridian 156E.

The bulk fluxes are computed using the COARE version 2.5b bulk algorithm.
 

Heat Balance Analyses
The atmosphere and ocean are coupled by surface heat fluxes which both affect and are affected by SST.  The upper ocean heat balance was evaluated to determine the processes responsible for SST variability.  To see the heat balance analyses, press here.
 

Salinity Balance Analyses
Salinity affects the stratification and buoyancy of the layer and thus can affect SST by inhibiting mixing, changing the effective heat capacity of the layer, and by increasing the amount of penetrative radiation. Because SST variability can affect the rainfall, we must understand the salinity variability and its affect on SST in order to understand the full hydrological cycle.  To see the salinity balance analyses, press  here.
 

Momentum Balance Analyses
Zonal advection is an important process in both the surface heat and salinity balances.  The large scale intraseasonal atmospheric convection are associated with westerly wind bursts which force the surface currents. To see the momentum balance analyses, press here.
 

Future Directions:
Enhance TAO array in the eastern tropical Pacific as a part of the NOAA Pan American Climate Study program. Likely enhancements include radiometers and rain gauges, current profilers, and subsurface temperature and salinity with increased horizontal and vertical resolution. With these data, processes which couple the atmosphere and ocean in the eastern tropical Pacific stratus deck region and ITCZ/cold tongue complex could be analyzed.
 

Meghan F. Cronin Pacific Marine Environmental Laboratory 7600 Sand Point Way NE Seattle, WA 98115 USA

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