Accession Number : ADA333479

Title :   Validation of Acoustic Measurements of Wind and Precipitation Using Expendable Ambient Noise Sensor (ANS) Drifters, AN/WSQ-6 (XAN-2).

Corporate Author : WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s) : Nystuen, Jeffrey A.

PDF Url : ADA333479

Report Date : OCT 1997

Pagination or Media Count : 49

Abstract : Air-deployable autonomous drifters have been developed to monitor upper ocean environmental conditions in remote or difficult regions. One version of these drifters (AN/WSO-6 series, model XAN-2) includes ambient noise measurements in 16 frequency bands from 5 Hz to 25 kHz. One application of this sensor is the passive identification and analysis of local weather conditions. This analysis is possible because breaking waves, related to wind speed or sea state, and precipitation produce loud and unique sound underwater. This report describes the performance of 15 of these ambient noise sensor (ANS) drifters deployed in a variety of water conditions at various locations around the world. Acoustically derived present weather conditions are compared with the Defense Meteorological Satellite Program (DMSP) passive microwave sensor (SSM/l) images. While regional variations in the high frequency (25 kHz) sound spectrum were observed, the acoustic measurement of wind speed using 8 kHz sound levels did not show regional or environmental variability. Overall, the correlation between the ANS and SSM/l wind speed measurements is 0.91. Acoustically detected precipitation is verified by the SSM/l sensors in 19 of 21 events (90.5%). The ANS drifters did not detect light rain/drizzle when the wind speed was greater than 10 m/s.

Descriptors :   *ACOUSTIC MEASUREMENT, *WIND VELOCITY, *ATMOSPHERIC PRECIPITATION, HIGH FREQUENCY, DEPARTMENT OF DEFENSE, DETECTORS, WEATHER, PASSIVE SYSTEMS, MICROWAVE EQUIPMENT, METEOROLOGICAL SATELLITES, RAIN, AMBIENT NOISE, SEA STATES, OCEAN ENVIRONMENTS, METROLOGY, UNDERWATER.

Subject Categories : Meteorology
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE