Atmospheric water plays a key role in climate. Water vapour is the most abundant greenhouse gas and its condensed forms exert a profound influence on both incoming solar and outgoing infrared radiation. Unfortunately, accurate, height-resolved global-scale measurements of atmospheric humidity are difficult to obtain. The change in concentration of five orders of magnitude from the ground to the stratosphere means there is no standard instrument that will measure everywhere. This has led to different measuring techniques, all with strengths and weaknesses.

This book assesses all presently available techniques that are used in monitoring networks. Special weight is given to the different technical concepts, the accuracy of different sensor types, calibration issues and retrieval aspects.

Autorentext

Niklaus Kämpfer studied Physics and Astronomy at the University of Bern. He got his graduate degree in Physics in 1979 and Ph.D. in 1983 for the Analysis and Interpretation of Solar Flares. Thereafter he changed his field of interest and pursued research in microwave radiometry of the atmosphere where he was involved int he development of the Millimeter Wave Atmospheric Sounder, a space shuttle experiment.

Since 1994 he has been Professor for Applied Physics and Head of the Microwave Department at the University of Bern. His research interests include microwave remote sensing of the atmosphere and optics in the millimeter and submillimeter range.

Professor Kämpfer is member of several national and international organizations and steering committees, e.g. science committee of the International Space Science Institute, ISSI, or steering committee of the Network for the Detection of Atmospheric Composition Change, NDACC.

Zusammenfassung
Atmospheric water plays a key role in climate. Water vapour is the most important greenhouse gas and its condensed forms exert a profound influence on both incoming solar and outgoing infrared radiation. Unfortunately, accurate, height-resolved global-scale measurements of atmospheric humidity are difficult to obtain. The change in concentration of five orders of magnitude form the ground to the stratosphere means there is no standard instrument that will measure everywhere. This has led to different measuring techniques, all with strengths and weaknesses.

This book assesses all presently available techniques that are used in monitoring networks. Special weight is given to presenting the different technical concepts, the accuracy of different sensor types, addresses calibration issues and retrieval aspects.

Inhalt
In Situ Sensors.- Thin Film Capacitive Sensors.- Balloon-Borne Frostpoint-Hygrometry.- Application of Fluorescence Method.- Microwave Radiometry.- Fourier Transform Infrared Spectrometry.- Lidar.- Role of Networks and Long-Term.- Overview of Satellite Sensors.- Cominging Observation by Different Techniques.- Survey of Intercomparisons of Water Vapour Measurements.