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STATUS:
04.19.2016
Instrument Status:
AIM continues to perform well with all subsystems operating nominally. The operations team successfully installed new sequences to help with battery maintenance as we approach the full sun period. In addition, they installed and started the CIPS Continuous Imaging sequence.
SOFIE:
The SOFIE instrument continues to operate normally. SOFIE V1.3 data for March 1 - August 31, 2015 were recently reprocessed. The update was to employ an improved algorithm for handling the attenuator balance sequence, which had crept into the CO2 channel calibration altitudes due to the changing AIM orbit. The primary change in these updated V1.3 data is that temperatures in the Northern Hemisphere are 5 to 15 K colder in the summer upper mesosphere. Additionally, 17 days of data that were previously unavailable were recovered by updating the ephemeris results. All of these new data are available on the SOFIE web and ftp sites.
Solar Backscatter Ultraviolet (SBUV) series of satellite instruments has observed PMCs since 1979, showing that the ice mass in PMCs has been increasing over the past 36 years. A rigorous interpretation of the SBUV results was recently published by Hervig et al. [2016] using SOFIE/AIM observations of PMCs, temperature, and water vapor since 2007. Analysis of SOFIE measurements allows the SBUV PMC results to be expressed in terms of the underlying changes in temperature and water vapor which have occurred near the mesopause. Interpreting the 36-year SBUV PMC record with the SOFIE analysis shows that temperatures are decreasing and that water vapor is increasing, at high latitudes near PMC altitudes (~83 km). The atmospheric change indicated by the SBUV/SOFIE results was compared to the Mesospheric Ice Microphysics and Transport (MIMAS) model from the Leibniz-Institute of Atmospheric Physics. The results, as shown in Hervig et al. [2016] and the Figure below, indicate that the model and satellites agree to within the error bars concerning trends in temperature and H2O, and the latitude dependence of these trends. These results confirm the long-standing assertion that PMCs are an indicator of changing conditions near the mesopause.
Hervig, M. E., U. Berger, and D. E. Siskind (2016), Decadal variability in PMCs and implications for changing temperature and water vapor in the upper mesosphere, J. Geophys. Res. Atmos., 121, doi:10.1002/2015JD024439.
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