STATUS:
05.08.11
Spacecraft Status
The LASP AIM operations team is happy to be celebrating AIM's 4th anniversary on April 25. The subsystems on the spacecraft continue to operate well ... and science operations continue nominally. [On May 8th we achieved the first bitlock since February 9th.]
Instrument Status
AIM has completed observing its eighth PMC season, with four seasons in the Northern Hemisphere (NH) and four in the Southern Hemisphere (SH). The figures below summarize the SOFIE observations, showing time series of ice occurrence frequency, ice water content (IWC), mesopause temperature, and water vapor (at 0.0055 hPa pressure, roughly the height of maximum PMC brightness). NH seasons are generally characterized by longer duration, greater ice frequency, and lower year-to-year variability, than in the SH (Figures a-b). A notable exception is the SH 2009-10 season when PMCs appeared earlier than all other NH and SH seasons. The other extreme example is the SH 2010-2011 SH season when PMC appeared more than 10 days later than in 2007-08 or 2008-09. The early onset of PMCs in the 2009-10 SH can be linked to colder temperatures and enhanced water vapor (Figures d and f), while the late appearance of PMCs in 2010-11 is associated with warm temperatures and low water
vapor.
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