<P> In addition, at certain Automated airport weather stations, additional instruments may be employed, including: </P> <Ul> <Li> Present Weather / Precipitation Identification Sensor for identifying falling precipitation </Li> <Li> Disdrometer for measuring drop size distribution </Li> <Li> Transmissometer for measuring visibility </Li> <Li> Ceilometer for measuring cloud ceiling </Li> </Ul> <Li> Present Weather / Precipitation Identification Sensor for identifying falling precipitation </Li> <Li> Disdrometer for measuring drop size distribution </Li>

5 different ways in which weather is measured