@prefix cpm: . @prefix dc: . @prefix dcat: . @prefix dce: . @prefix dct: . @prefix grg: . @prefix iop: . @prefix ns0: . @prefix ns1: . @prefix owl: . @prefix pav: . @prefix prov: . @prefix puv: . @prefix qudt: . @prefix rdf: . @prefix rdfs: . @prefix reg: . @prefix semapv: . @prefix skos: . @prefix sssom: . @prefix void: . rdf:type skos:Concept ; dce:identifier "TOOL0084" ; dc:identifier "TOOL0084" ; dc:isVersionOf ; pav:authoredOn "30-NOV-09" ; pav:version "1" ; owl:versionInfo "1" ; skos:altLabel "Gill R3a anemometer" ; skos:definition "The Sonic Gill R3a Research Ultrasonic anemometer is designed to measure wind speed and direction. The sensor head of the anemometer consists of an array of three pairs of transducers orientated at different angles across the measurement region. Each pair of transducers act alternately as transmitters and receivers, sending pulses of ultrasound between them. By measuring the time of flight of the pulse in both directions, the velocity component of the air flow along the line of the transducer pair can be determined. This measurement is carried out for each of the three transducer pairs in turn. A mathematical transformation is then performed, to convert the resulting three wind vectors into U,V,W format." ; skos:notation "TOOL0084" ; skos:note "accepted" ; skos:prefLabel "Sonic Gill R3a Research Ultrasonic anemometer"@en .