OVERVIEW

11.28.07 - Aura Project given approval to move closer to other A-Train platforms

According to information from the ESMO project, A-Train Principals approved a plan to decrease the Aura satellite’s along track separation from Aqua and the other A-Train missions.  The move would  safely change Aura’s position from ~15 minutes behind Aqua (currently the lead satellite in the train) to ~8 minutes behind Aqua, thus enhancing cross instrument science.

Led by Mark Schoeberl (Afternoon Constellation and Aura Project Scientist), Angie Kelly (ESMO Constellation Team Manager), and Bill Guit (Aqua and Aura Mission DIrector), supported by the Mission Operations Working Group, the maneuver to move the Aura platform ahead by ~7 minutes to follow closer behind the other A-Train platforms, was approved by all Instrument Teams, Mission Operations personnel, and the NASA Headquarters Program Executive for Operations.  The move will:

• Improve science from OMI and MLS
• Enable Cloudsat/CALIPSO/MLS cross-instrument science to be performed.  (Prior to this move, Cloudsat/CALIPSO and MLS followed different tracks that did not overlap until they came close to the poles.)
• Allow ATDD cross-instrument data users to retrieve one set of MODIS and/or OMI subsets along one track instead of two sets of subsetted data along each of two tracks

As can be seen in the following diagram (Presented at the NASA HQ Review), the Aura instrument (bluebox) will fly closer to the other instruments in the lower (approved "proposed") illustration.

The next two diagrams (also presented at the NASA HQ Review) illustrate how the MLS field of view overlaps Aqua MODIS nadir prior to the maneuver (upper illustration).  After the maneuver (lower illustration) MLS field of view will be collocated with the Cloudsat/CALIPSO track, and still falls within the MODIS field of view.

11.28.07 -The CALIPSO pitch angle change (from 0.3 degrees to 3.0 degrees)  is expected to eliminate  ice crystal effects in cloud property retrievals

According to information from CALIPSO and CloudSat projects, the CALIPSO platform changed its pitch angle to 3.0  degrees to "nearly" eliminate ice crystal presence which currently renders the cloud property retrievals (extinction, etc.) unreliable.  This move has no adverse effect on CALIPSO standard data products.  However, as a result of CALIOP field of view looking more forward, the CloudSat satellite is moved 5 seconds forward on the track, so that the CloudSat field of view again coincides with that of CALIOP.  In addition, Aura will also be moved an additional 5 seconds forward on the track (see other news item on this day), so that MLS field of view will be collocated within seconds with the new Cloudsat/CALIPSO position.

Also note that the Cloudsat/CALIPSO merged product will be reprocessed with modified algorithms by the CloudSat team to accommodate the pitch angle change.  This product will be publicly available in approximately 6 months.  Information about the status of this radar-lidar product will be announced on the CloudSat and CIRA web pages.

CloudSat and CALIPSO implementation began November 27 and was completed November 29.