Abstract

The focus of this chapter is on the issues of monitoring water vapor in troposphere and stratosphere. The water vapor distribution in the upper troposphere (UT) and lower stratosphere (LS) is of central importance in several ways: it plays a major role in the balance of planetary radiation; it influences and responds to atmospheric motions; and it plays a key role in many aspects of UT/LS chemistry. Effects on the radiation balance are especially important because the water vapor molecule is strongly polar in shape giving it a strongly absorbing infrared spectrum. It was found that the increased stratospheric water vapor levels could also enhance ozone destruction. This means that the increase in the stratospheric concentration of water vapor presents a continuing threat to the global ozone layer.