CloudSat Epochs Information
Epochs reflect changes in the operating parameters of the mission, such as the CPR configuration.
Although CloudSat continues to only operate during the sunlit portion of the orbit, epoch 06 started when CloudSat returned to the A-Train formation on May 15th, 2012. Data products once again use MODIS and CALIPSO ancillary data although the overlap with CALIPSO is degraded because fewer formation flying maneuvers are performed.
Start: 15 May 2012 (day 136) 00:49:00
A battery anomaly on April 17th, 2011 caused the spacecraft to stop collecting data and lose formation with the A-Train. The radar was turned back on in November 2011 and now collects data only during the sunlit portion of the orbit. Epoch 05 represents this new operating paradigm. In addition, the spacecraft remained outside of the A-Train formation so all data products were processed in radar-only mode without MODIS or CALIPSO data. The impact of the missing MODIS data on the CloudSat products is still being assessed and the combined radar/lidar products (2B-GEOPROF-LIDAR, 2B-CLDCLASS-LIDAR, and 2B-FLXHR-LIDAR) are not available.
End: 15 May 2012 (day 136) 00:49:00
Start: 1 Nov 2011 (day 305) 10:28:27
Marks the beginning of a period where the CPR pulse rate will be periodically reduced, or increased, to manage the power draw on the battery (due to the reduced power margin as the battery ages). The increased or reduced pulsing with induce a slight change in sensitivity. The number of pulses can be found in the 1B-CPR field RayStatus_pulsesTx. The pulse rate will likely continue to be adjusted, seasonally, for the duration of the mission.
End: 17 Apr 2011 (day 107) 14:58:38
Start: 15 Feb 2011 (day 46) 18:06:30
Epoch 02 ended when a battery anomaly forced the CPR offline. It was brought back into operations with a slightly reduced pulse rate that decreases the radar sensitivity by approximately 0.25 dB. Epoch 03 tags the modified operating parameters.
End: 15 Feb 2011 (day 46) 18:06:30
Start: 15 Jan 2010 (day 15) 18:24:56
Increased specular reflection due to the nadir-pointing instrument caused an increase in ground clutter, so the spacecraft orientation was changed again so that the CPR pointed 0.16 degrees in the forward (along-track) direction.
End: 7 Dec 2009 (day 341) 11:43:22
Start: 15 Aug 2006 (day 188) 14:14:02
The pointing error was corrected and the spacecraft was oriented so that the CPR pointed to nadir.
End: 15 Aug 2006 (day 227) 20:56:31
Start: 7 Jul 2006 (day 188) 14:14:02
During the initial phase of the mission it was unknown that the CPR was pointing off-nadir 1.7021 degrees in the forward (along-track) direction and 0.1314 degress to the right (across-track).
End: 7 Jul 2006 (day 188) 14:14:02
Start: 2 Jun 2006 (day 153) 13:42:23