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STATUS:
04.01.2017
Instrument Status:
AIM transitioned into a full sun orbit on March 5th. To prepare for this event, battery charge control settings on AIM have been modified to prevent overcharging the battery. Also, AIM was commanded into Contingency mode and the OOMP (the autonomous maneuver planner) disabled as the autonomy doesn’t work when there are no eclipses. Since entering Full Sun, the power system has been stabilized and CIPS has started taking images in the Continuous Imaging mode. The SOFIE instrument remains on in science mode, however without the spacecraft autonomy SOFIE is unable to view the sun.
Shortly after entering full sun, the AIM spacecraft had bitlock on 2 sequential Tracking and Data Relay Satellite System (TDRSS) contacts. This was the first bitlock event in 1,685 days. Unfortunately this appears to have been a single event due to the warming of the receiver after entering full sun, as no bitlock events have occurred since.
The AIM Flight Operations Team is currently working on updating the safehold charge control so the battery will not get overcharged in the event of a future anomaly. Once that is completed, sequences to test and install Roll Control to aid in CIPS nadir pointing will be uploaded.
CIPS
The CIPS team has recently developed a near-global, nadir-imaging data set that can be used to infer GWs near an altitude of 50-55 km. New Level 2 data and images for these "Rayleigh Albedo Anomaly" (RAA) retrievals have been posted to the CIPS website. At the current time, data are available for the time period of Continuous Imaging mode operations, from 20 March 2016 through 23 February 2017. Data from the standard operating mode prior to 2016 will be processed in the near future. The RAA is defined as the residual difference, expressed in percent, between the observed Rayleigh scattering albedo and a "baseline" albedo that would be observed in the absence of any small-scale atmospheric variations. Since the Rayleigh scattering signal observed by CIPS is controlled by the atmospheric neutral density and is modulated strongly by ozone absorption, small-scale perturbations to the observed Rayleigh scattering signal are often indicative of GW-induced variations in the neutral density and/or ozone near 50-55 km.
Two examples of the rich information included in the RAA images are given in the figure here. The left panel shows the signature of concentric gravity waves observed on 30 October 2016 (orbit 52021), over the South China Sea near Hainan island. The origin of these waves is still unclear, but the concentric nature of the waves suggests a point source. The right panel shows signatures of gravity waves over the Southern Ocean on 30 May 2016 (orbit 49713), which were likely generated by turbulence along the edge of the stratospheric polar vortex.
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