These bulletins describe the facilities, equipment, and services of the Research Aviation Facility, located at Jefferson County Airport in Broomfield, Colorado, and operated by the National Center for Atmospheric Research (NCAR) under the direction of the University Corporation for Atmospheric Re... Show moreThese bulletins describe the facilities, equipment, and services of the Research Aviation Facility, located at Jefferson County Airport in Broomfield, Colorado, and operated by the National Center for Atmospheric Research (NCAR) under the direction of the University Corporation for Atmospheric Research (UCAR). They are intended to guide scientists in making effective use of NCAR aircraft. The NCAR Research Aviation Facility (RAF) currently provides two types of instruments for the airborne measurement of atmospheric humidity. The standard humidity measurement, which is provided for all projects, is performed using the chilled mirror technique for measuring dew point temperature. This system combines good accuracy and a response adequate for mean humidity measurements with the ability to provide continuous readings over a wide range of environmental conditions. Projects requiring a fast response, high resolution flux measurements will need to add a second instrument which uses Lyman-alpha absorption to measure the moisture content directly. Both instruments have specific performance features that govern their use in different applications. This Bulletin provides a detailed description of each unit along with a discussion of their performance characteristics. Show less