Turbulence and Stratification on the TOGA-COARE Microstructure Pilot Cruise and Turbulence Produced by internal Waves in the Oceanic Thermocline at Mid and Low Latitudes.
Abstract
On the TOGA-COARE pilot cruise, at 147 deg E, in the western Pacific warm pool, we profiled for seventeen days at 0 deg N, and for five days at 2 deg N. Winds were generally light, and variable in direction, but rainfall was often quite intense. Contrary to what is seen in the central equatorial Pacific, we did not observe a deep diurnal cycle in dissipation extending below the mixed layer. Strong daytime restratification often prevented nightly convective deepening down to the seasonal thermocline, resulting in surface forcing remaining trapped in a shallow layer. The relaxation of horizontal density gradients into vertical appears to be an important process driving restratification. Turbulent fluxes in the bottom of the mixed layer were generally small. Following rainfall, we observed pools of fresh water, that typically disappeared within a few hours, leaving the mixed layer nearly homogeneous in salinity; thus we did not observe a permanent barrier layer. Modeling such events using the Price-Weller-Pinkle model suggests a fresh pool will be mixed away on time scales of a few days, primarily by nighttime convection. The observed vertical structure can be accounted for by local vertical mixing processes.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1996
- Accession Number
- ADA327235
Entities
People
- D. P. Winkel
- H. Peters
- K. E. Brainerd
- M. C. Gregg
- Thomas B. Sanford
Organizations
- University of Washington