The spacecraft continues to perform well and subsystems are functioning nominally. The bitlock situation continues to cause extended periods with no commands being sent, but the spacecraft autonomy on board completely mitigates this situation. During the latest bitlock opportunity we loaded the monthly CIPS Flat Field calibration.
SOFIE continues to operate nominally. All status flags remain GREEN, and all engineering parameters are well within tolerance. The last PMC observed by SOFIE for the 2010 Northern Hemisphere season was collected on August 30, 2010 Event number 36465.
The SOFIE PMC detection algorithm has been re-examined, in particular using the new V1.03 extinctions. Modifications have been made to allow for multiple cloud layers, and the results indicate that about 8% of the profiles during PMC season contain 2 layers, with less than 1% containing 3 layers. In addition, the new algorithm distinguishes between layers above 80 km, and lower layers which are known to exist in the near or far reaches of the line-of-sight. The new results are consistent with the old algorithm (which identified only the brightest layer), with the main differences that low clouds are generally absent, and the introduction of occasional second layers.
The data through August 25, 2010 has been validated and released to the public. The remainder of August has been processed and is awaiting validation before it is released. Concurrently we are processing with a new development software version and continuing to validate its results. This version contains several improvements to both the signal conditioning and to the forward model used in the retrieval. Most notably is the correction for Field of View effects and a more accurate forward model that accounts for CO2 Line Mixing and out of band signal contributions.
CIPS continues to operate nominally, with widespread clouds observed on a daily basis. The figure shows the clouds observed by CIPS from 29 July to 1 August. We obtained the fourth set of northern hemisphere 2010 season calibration observations at the end of July, so we are accumulating excellent calibration statistics. Operational data still use only the calibration data from the beginning of the season (March); all data will be reprocessed after the season with the full calibration data set.
Development of the next retrieval version, v4.20, is continuing. We are still on track to release this version in September. The primary remaining issue is to improve the cloud detection threshold, which depends on solar zenith angle and view angle. Work is also in progress to implement the calibration observations in autonomy; one of the next steps is to test the autonomous calibration RTS logic with the flatsat.