Two-Dimensional Measurements of Ocean Microstructure: The Role of Double Diffusion

Abstract

Johns Hopkins Univ., Appl. Phys. Lab., Laurel, MD 20707, USA ISSN 0022-3670 J (Journal-Article) M (Marine) Two-dimensional measurements of ocean microstructure are reported from four cruises to the Atlantic and Pacific. A Neil Brown Instrument Systems CTD has been modified to enhance its capability in the microstructure regime by replacing the standard thermistor with a Thermometrics FP07 "7-ms" thermistor, by separately digitizing the temperature channels at 50 Hz, and by using a unique passive-motion compensation device to obtain a uniform descent rate. The resulting instrumentation system measures the centimeter-scale temperature and conductivity signature of microstructure and the salinity structure over scales of a few tens of centimeters. Numerous observations of flat patches of microstructure of order several meters in the vertical and hundreds of meters in the horizontal are reported at sites of temperature-stabilized salinit...