Accession Number : ADA195973

Title :   The Design and Operation of a Slowfall AXCP (Air-Deployed Expendable Current Profiler).

Descriptive Note : Technical rept.,

Corporate Author : WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s) : Osse, T J ; Drever, Robert G ; Sanford, Thomas B

PDF Url : ADA195973

Report Date : May 1988

Pagination or Media Count : 49

Abstract : Expendable current profilers (XCPs) were modified to fall slowly (1 m/s) through the upper ocean for the Ocean Storms research program. The modification was to improve launch and impact survival and to slow the unit so more cycles of surface wave oscillations could be observed in the upper 200 m of the ocean. The device was based on a standard air-deployable XCP. A drogue was installed on the sensor to slow its descent over a portion of the upper ocean while maintaining a sufficient spin, or rotation rate. At a preset depth, the drogue was jettisoned, and the profiler probe reverted to normal descent and spin rates. Forty slowfall AXCPs were deployed in late 1987. Three of these were dropped simultaneously with regular AXCPs. Nineteen units provided profile data. The success rates were 2/13, 7/13, and 10/14 for units operating on sonobuoy RF channels 12, 14, and 16, respectively. The combined success rate for the channel-14 and channel-16 units was 0.63. The probability of obtaining the channel-12 results, assuming a success probability of 0.63, is 0.1%. These results indicate that the poor performance of the channel-12 units was due to some factor not present in the units at other frequencies. Eleven of the thirteen channel-12 probes failed to produce RF emissions or lost the signals soon after deployment. This mode is unrelated to slowfall modification and suggests failure in the standard gas release and flotation bag system. (EDC)

Descriptors :   *OCEAN CURRENTS, *OCEANOGRAPHIC EQUIPMENT, AERIAL DELIVERY, BAGS, DEPLOYMENT, DEPTH, DESCENT, EMISSION, EXPENDABLE, FLOTATION, GASES, IMPACT, OCEANS, OSCILLATION, PROBES, PROFILES, RADIOFREQUENCY, RATES, RELEASE, ROTATION, SPINNING(MOTION), STORMS, SURFACE WAVES, SURVIVAL(GENERAL)

Subject Categories : Acoustic Detection and Detectors
      Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE