Publication Date:
2013-09-17
Description:
[1] We show measurements of middle atmospheric water vapor as measured by two ground-based Water Vapor Millimeter-wave Spectrometer (WVMS) instruments, and three satellite-based instruments: the Aura Microwave Limb Sounder (MLS), the Atmospheric Chemistry Experiment (ACE), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We also show CH 4 measurements from the MIPAS and ACE instruments and use these to help interpret the H 2 O variations. We find that interannual changes in stratospheric H 2 O of ~0.5 ppmv, observed from Table Mountain, California at 26 km and 40 km from 2010–2012, are caused primarily by dynamically driven changes in CH 4 during this period. The interannual variations in H 2 O observed over Mauna Loa, Hawaii, are shown to be quite similar to the average variations observed over 50 o S-50 o N in the lower mesosphere, thus we conclude that a single ground-based microwave instrument can provide a useful estimate of interannual globally averaged lower mesospheric H 2 O variations, even when such changes are as small as ~0.2-0.3 ppmv. We find that the increase of ~0.2-0.3 ppmv in H 2 O in the lower mesosphere since 2006 is qualitatively consistent with an increase in tropical tropopause temperature since ~2001.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
