Decadal variability in PMCs and implications for changing temperature and water vapor in the upper mesosphere. Issue 5 (14th March 2016)

• Record Type: Journal Article
• Authors: Hervig, Mark E.; Berger, Uwe; Siskind, David E.
• Is Part Of: Journal of geophysical research. Volume 121:Issue 5(2016)
• Page Start: 2383
• Page End: 2392
• Publication Date: 2016-03-14
• Subjects: polar mesospheric cloud -- SBUV -- MIMAS -- PMC -- trends -- SOFIE; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2015JD024439
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Observations of polar mesospheric clouds (PMC) from the solar backscatter ultraviolet (SBUV) satellite instruments are used to characterize variability and trends from 1979 to 2014. The SBUV PMC record indicates decadal oscillations during the 1980s and 1990s, which are expected to result from the 11 year solar cycle. This oscillation is absent in the recent decade, however, and we speculate that solar cycle effects at PMC altitudes during the 1980s and 1990s may have been fortuitously amplified by stratospheric warming due to volcanic eruptions which occurred near solar maximum. SBUV trend results are compared with temperature, water vapor, and PMCs from the Mesospheric Ice Microphysics and Transport (MIMAS) model. Both SBUV and the model indicate positive trends in PMC vertically integrated water content (IWC), which increase toward higher latitudes. Using analysis of Solar Occultation for Ice Experiment (SOFIE) observations, the SBUV IWC trends are expressed in terms of the underlying changes in temperature and water vapor in the upper mesosphere. SBUV indicates cooling trends that increase toward higher latitudes (−0.5 ± 0.2 K decade −1 at 77°N), consistent with the MIMAS model and scant observations. SBUV indicates increasing water vapor in the Northern Hemisphere upper mesosphere (0.07 ± 0.03 ppmv decade −1 at 77°N, insignificant in the Southern Hemisphere), with values that are consistent with MIMAS but less than expected due to increasing methane. Key Points: Temperature and water vapor trends derived from PMCs are consistent with models and observations PMC trends and variability are consistent with solar and stratospheric forcing Decadal PMC oscillations in the 1980s and 1990s may have been amplified by volcanic forcing