Abstract

Trace gases are important in determining the dynamics, photochemistry, and radiation in the stratosphere. Water vapor^1,2) is one of them. Its mixing ratio decreases with height up to the tropopause due to the saturation. The source of stratospheric water vapor is supposed mainly through the tropopause in the tropics region. The extraordinary dryness is a characteristic feature of the stratosphere. Its increase affects the global warming phenomena, and it also has a role as a source of stratospheric HOx radicals. In spite of importance, the behavior of water vapor is not sufficiently known. Global aspect will be clarified by UARS and EOS missions in addition to the currently operating SAGE sensor. Here we investigated the possibility of a compact, high sensitive laser heterodyne sensor (LHS) using a room-temperature operating laser diode (LD) in the near infrared (1.4 μm) region as the local oscillator. As well known, the diffraction limits the throughput of the available incident light power, which is unfavorable to shorter wavelength. However, the compactness and easy handling of a room-temperature operating LD prevails over the disadvantage, and may realize a compact low power-consumption balloon-borne/satellite-borne sensor.

© 1991 Optical Society of America