The meteorological observation service staff are responsible for the radiosonde releases and synoptic weather observations. Surface weather observations were taken hourly, and four radiosonde releases occurred daily. During the 1950s, Isachsen Station was primarily collecting radiosonde observations. It also has access to satellite, weather radar, weather buoy, radiosonde, and lightning data. One radiosonde from Clark Air Base, Philippines, reached an altitude of . He sent the first Finnish radiosonde aloft in December 1931. The NWS operates 92 radiosonde locations in North America and ten sites in the Caribbean. The base would also remain a weather radiosonde tracking station in the 1960s. The weight of a radiosonde is typically . The GPS Radiosonde of ISRO's VSSC is named after Pisharoty. Regular weather observations were maintained as Synopsies, Pibal and Radiosonde. It also supports the operation of 10 radiosonde sites in the Caribbean. As the Vaisala radiosonde became internationally renowned, the demand for them increased. Worldwide there are about 1,300 radiosonde launch sites. A typical radiosonde flight lasts 60 to 90 minutes.