Middle Atmospheric Water vapor Measurements from HALOE, EOS-MLS, and WVMS

From August 2004 until December 2005 middle atmospheric water vapor measurements from HALOE, EOS-MLS, and two ground-based WVMS systems at Network for the Detection of Atmospheric Composition Change (NDACC) sites at Mauna Loa, Hawaii (19.5°N, 204.4°E) and Lauder, New Zealand (45.0°S, 169.7°E) were available. Given the importance of HALOE measurements to the understanding of water vapor changes since 1991, this period of overlap is of particular importance if we are to maintain a consistent water vapor dataset with which to measure long-term trends. We will compare coincident measurements during this time period, with a special emphasis on the cases where measurements from three instruments are available. We will also present comparisons between WVMS and MLS measurements after December 2005, and investigate the consistency of both annual and interannual changes observed by these instruments. Particularly at Mauna Loa we find interannual changes which are well reproduced in the MLS and WVMS measurements; a consistency which will hopefully continue so as to provide good longer-term trend data. We will also show how the incorporation of MLS temperature measurements in the WVMS water vapor retrievals can be used to improve the quality of the MLS-WVMS agreement.