Freely Drifting Swallow Float Array: September 1987 Trip Report
Abstract
Representative data collected during the 17-18 September, 1987 deployment of the Swallow floats are presented in this report. This report presents the instrument deployment locations and times, the positions and characteristics of known signal sources, environmental data such as expendable bathythermograph (XBT), conductivity-temperature-depth (CTD), and anemometer measurements as well as basic weather observations, and representative Swallow float, OBS, and VLA data. The Swallow float data include battery voltage, compass heading, and automatic gain control (AGC) measurements, the 8 kHz acoustic localization ping arrivals, and the infrasonic water particle velocity data. All 12 Swallow floats operated flawlessly, except for float 1's 8 kHz hydrophone which was destroyed during deployment, resulting in a 99.5% full data set. The OBS geophone and hydrophone data and the VLA hydrophone channel data have first been resampled to 50 Hz, the Swallow float sampling frequency, so that quantitative comparisons can be made between the data sets. The Swallow floats were able to hear the 11, 16, 21, and 22 Hz tones generated by the HLF 3 source deployed at long range from the sensors. The vertical line array also appeared to hear the 16 Hz and 22 Hz tones, although a 22 Hz line occurred in many of the spectra during times when the HLF 3 was transmitting 16 Hz, and a 16 Hz line occurred when the source was transmitting 22 Hz. The origin of these contaminating lines, including an additional line at 20 Hz, is unknown. The array apparently did not detect the 11 Hz tone. The ocean bottom seismometer could hear neither the 11 Hz or the 22 Hz tones.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1989
- Accession Number
- ADA220173
Entities
People
- G. L. D'spain
- G. L. Edmonds
- William Hodgkiss
Organizations
- Scripps Institution of Oceanography