SPARC logo (45 Ko)

Stratospheric Processes And their Role in Climate
A project of the World Climate Research Programme

Home Initiatives Organisation Publications Meetings Acronyms and Abbreviations Useful Links


Prepared by the SPARC Water Vapour Working Group under the auspices of the SPARC Scientific Streering Group

Edited by D. Kley, J.M. Russell III and C. Phillips

SPARC Assessment of
Upper Tropospheric and Stratospheric Water Vapour

December 2000





The World Climate Research Programme is jointly sponsored by the World Meteorological Organisation, the International Council for Science and the Intergovernmental Oceanographic Commission of UNESCO.



The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Meteorological Organisation concerning the legal status of any country, territory, city or areas, or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Table of Contents





1.1 Introduction

1.2 In situ hygrometers
1.2.1 Frost point hygrometers
1.2.2 Lyman-a hygrometers
1.2.3 Tuneable diode laser spectrometers
1.2.4 Radiosondes
1.2.5 MOZAIC sensors
1.2.6 Cryogenic samplers

1.3 Ground based, balloon-borne, and airborne remote sensing instruments
1.3.1 Microwave instruments
1.3.2 LIDAR
1.3.3 Infrared and far-infrared measurements

1.4 Satellite sensors
1.4.1 Operational satellite upper tropospheric humidity
1.4.2 Limb Infrared Monitor of the Stratosphere (LIMS)
1.4.3 Stratospheric Aerosol and Gas Experiment (SAGE) II
1.4.4 Atmospheric Trace MOlecule Spectroscopy (ATMOS)
1.4.5 Halogen Occultation Experiment (HALOE)
1.4.6 Microwave Limb Sounder (MLS) - lower stratosphere
1.4.7 Microwave Limb Sounder (MLS) - upper troposphere
1.4.8 Millimeter-wave atmospheric sounder (MAS)
1.4.9 Improved Limb Atmospheric Spectrometer (ILAS)
1.4.10 Polar Ozone and Aerosol Measurement (POAM) III

1.5 Summary and conclusions


2.1. Introduction

2.2 Comparisons between aircraft-borne, balloon-borne, and ground-based sensors
2.2.1 Stratospheric measurements
2.2.2 Laboratory intercomparison of the NOAA-CMDL, NOAA-AL, and Harvard
in situ instruments
2.2.3 Balloon infrared instrument comparisons
2.2.4 Tropospheric measurements

2.3 Comparisons made for the validation of satellite measurements
2.3.1 HALOE comparisons
2.3.2 MLS comparisons
2.3.3 SAGE II comparisons
2.3.4 ATMOS comparisons
2.3.5 ILAS comparisons
2.3.6 Upper stratosphere comparisons (WVMS and WASPAM)
2.3.7 Comparisons with TOVS/HIRS
2.3.8 MLS tropospheric comparisons

2.4 Comparisons between satellite systems
2.4.1 ATMOS Comparisons
2.4.2 MLS with HALOE
2.4.3 POAM III with HALOE
2.4.4 ILAS with HALOE
2.4.5 TOVS/HIRS upper tropospheric comparisons

2.5 Comparisons of derived quantities
2.5.1 SAGE II and HALOE annual averages
2.5.2 Satellite seasonal climatology comparisons
2.5.3 Lowermost stratosphere in situ and satellite climatologies
2.5.4 Entry level [H2O]e and 2 CH4+H2O
2.5.5 Comparison of water vapour long-term changes and seasonal oscillations

2.6 Summary of comparisons
2.6.1 Stratospheric comparisons
2.6.2 Upper tropospheric humidity comparisons
2.6.3 Conclusions and recommendations


3.1 Introduction
3.1.1 Radiation
3.1.2 Dynamics
3.1.3 Chemistry

3.2 Mean Distribution of LS/UT Water Vapour
3.2.1 Lower stratosphere
3.2.2 Upper troposphere

3.3 Seasonal Cycle
3.3.1 Lower stratosphere
3.3.2 Upper troposphere
3.3.3 The tropical tropopause region

3.4 Non-seasonal Variations
3.4.1 Interannual variations
3.4.2 Intraseasonal variations
3.4.3 Transient variability

3.5 Long-term variations
3.5.1 Stratospheric measurements
3.5.2 Tropospheric measurements
3.5.3 Causes of long-term variations
3.5.4 Consequences of long-term variations

3.6 Conclusions
3.6.1. Long-term variations
3.6.2. Recommendations


I. Co-chairs, Authors, Contributors and Reviewers
II. Acronyms and Abbreviations
III. WCRP Reports


Back to SPARC Publications Homepage